welding design procedures and inspection

8/10/2019 Welding Design Procedures and Inspection

1/98

TM 5-805-7

TECHNICAL MANUAL

WELDING

DESIGN, PROCEDURES AND INSPECTION

H EA DQ UA RT ER S , D EPAR T ME N T O F T HE A RM Y

20 MAY 1985


2/98

M 5 - 8 0 5 - 7

REPRODUCTION AUTHORIZATION/RESTRICTIONS

This manual has been prepared by or or !he "o#ernmen! and is publi$ prop%

er!y and no! sub&e$! !o $opyri'h!(

Reprin!s or republi$a!ions o !his manual should in$lude a $redi! subs!an!ially

as ollo)s* +Depar!men! o !he Army Te$hni$al ,anual T, -%.-%01 2eldin'*

Desi'n1 Pro$edures and Inspe$!ion( 3


3/98

T M 5 -8 05 -7

WELDING: DESIGN, PROCEDURES AND INSPECTION

Para grap h Page

Chapter 1. INTRODUCTION

Purpose and scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . Welding applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . .

Chapter 2.. DESIN !ND INSPECTION RESPONSI"I#ITIES

Designer responsi$ilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .

. . . . . . . . . Contractor responsi$ilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . Inspection re%uire&ents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter '. WE#DIN PROCESSES

4%4

4%5

5%45%55%6

4%4

4%4

5%45%6

5%-

eneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . .6..%.4. Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 6..%.5

6%46%4

Shielded &etal(arc )S*!W+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . as &etal(arc )*!W+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . ,lu-(cored arc elding ),C!W+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . as tungsten(arc )T!W+ . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Su$&erged arc )S!W+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-other&ic elding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . !rc(stud elding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Process selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter /. WE#DIN O, ST!IN#ESS STEE#

6%66%76%-

6%86%0

6%.6%96%4

6%56%45

6%54

6%556%56

6%586%5.

6%6

eneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .7..%.4. Welda$ilit0 o stainless steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . 7..%5oint design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . .7..%.6..

7%4

7%47%-

*ethods o elding stainless steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . Shielded &etal(arc )S*!W+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . as &etal(arc )*!W+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . ,lu-(cored arc elding ),C!W+ . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7%7

7%-7%87%0

7%-

7%-7%87%8

Su$&erged arc )S!W+. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . .. . . .7..%..Special considerations in elding stainless steels . .....................................................

.

.

.

.

.

.

.

.

.

.

.

..

.

.

.

.

.

7%9

7%07%0

Chapter 3. WE#DIN C!R"ON STEE# !ND #OW(!##O4 STEE#S

eneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .-..%.4

-%4

Welda$ilit0 o car$on and lo(allo0 steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ..................

-%5 -%4

oint design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . .-..%.6.

-%6

*ethods o elding car$on steels and lo(allo0 steels . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . ..

-%7 -%6

Shielded &etal(arc )S*!W+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . .. . -.. %.-

-%6

5&etal(arc )*!W+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . .

,lu-(cored arc elding ),C!W+. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . .

-%8

-%0

-%7

-%7


4/98

Su$&erged arc )S!W+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . .. . . . .-..%.... .

-%-


5/98

T M 5 - 8 0 5 - 7

.Chapter 6. WE#DIN !#U*INU*

!##O4S

Paragraph Page

eneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .8%4

789 : 8%4

Welda$ilit0 o alu&inu& allo0s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .

. . . . . . . . .

oint design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .

. . . . . . . . . *ethods o elding alu&inu& allo0s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . as &etal(arc )*!W+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . as tungsten(arc )T!W+ . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8%58%6

8%78%-8:8

8%48%6

8%68%68%7

Chapter ;. WE#DIN ,OR SPECI!# !PP#IC!TIONS

eneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .....0....%4 78

0%4

Chapter ?0%7

0%-0%8

0%40%50%50%60%6

eneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . ..%4

789 : .%4

@ualiication o personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . .

.%5 .%4

Inspectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . .. %6Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . ...%7

7897

.%4

.%4

Aisual inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .

. . . . . . . . . *agnetic particle inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . .

Penetrant inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .

. . . . . . . . . . Radiographic inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . Ultrasonic inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DestructiBe testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . #ea testing . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

.%-

.%8

.%0.%.

.%9

.:4

.%44

.%5

.%6

.%8.%.

.%45

.%49

.%57

Chapter . S!,ET4

eneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .9%4

789 : 9%4

!ppendi- !.

!ppendi-

".

"i$liograph

0

:aards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .9%5 789 :

RE,ERENCES

@U!#I,IC!TION

TESTIN

9%4

A%4

;%4

;I;


6/98

48( TraBel speed li&its or current leBels used or lF


7/98

T M 5 - 8 0 5 - 7

Page

6%40(

6%4.(

6%49(

3-20.

6%54(

6%55(

6%56(6%57(6%5-(

6%58(

6%50(

7%4(.%4(.%5(

.%6(

.%7(

.%-(

.%8(

.%0(

.%.(

.%9(

.%4(

.%44(

.%45(

.%46(

.%47(

.%4-(

.%48(

.%40(

Aoltage Bersus current or E;GS(6 1F16(inch(dia&eter electrode and car$on dio-ide shield gas.

Aoltage Bersus current or E11GS 1F16(inch(dia&eter electrode and shield gas o argon ith 2 percent o-0gen

addition.

The output current aBe or& o the pulsed(current poer suppl0.

Steps in short(circuiting &etal trans1er.

Cross sections o lu-(cored ires.

The CT!W process.

The S!W process.

!uto&atic S!W e%uip&ent and controls or auto&atic elding in the lat position.

Ther&it elding cruci$le and &old.

Steps in stud elding

operation. Stud elding

e%uip&ent.

SchaelerHs diagra& or the &icrostructure o1 stainless steel

elds. ages or &easuring 1illet eld contour.

Weld no&enclature.

Disruption o &agnetic ield $0 eld(&etal de1ect.

*agnetic ield created around a eld as current is passed $eteen to test prods.

*aor steps o luorescent penetrant inspection.

Radiographic setup.

Details o1 penetra&eters.

! scan presentation on cathode ra0 tu$e.

Straight $ea& inspection techni%ues used in scanning a tee eld.Scanning procedure using angle $ea& and straight $ea& on a corner eld.

SeBeral uses o the IIW $loc.

Scanning procedures or elds not ground 1lush.

Scanning procedures or elds ground

lush. Tensile test speci&ens.

uided $end test ig.

,ree $end test.

TransBerse illet(eld shear speci&en.

6%4.6%49

6%56%54

6%556%576%5-6%586%506%5.6%59

7%6.%6.%7.%-.%0.%.

.%4

.%44

.%47

.%4-

.%48

.%40

.%4.

.%4.

.%5

.%54

.%55

.%56

Table

6%4( Esta$lished Boltage li&its.

LIST OFTABLES Page

6%456%5(

7%4(.%4(.%5#

.%6(

.%7(

Su&&ar0 o elding processes and application.

!ustenitic stainless steels &ost co&&onl0 used or cr0ogenic and Bacuu& enBiron&ente%uip&ent. Uses o Barious inspection techni%ues.

Characteristics o radioisotope sources.

Co&parison o ultrasonics ith other techni%ues.

,re%uenc0(application chart.

6%64

7%..%5.%9

.%46

.%47


8/98

T M 5 -8 05 -7

CHAPTER 1

INTRODUCTION

1-1. Pu!"#$ %&' #("!$This manual $on!ains $ri!eria and basi$ da!a or

)elded $ons!ru$!ion desi'n1 $ons!ru$!ion me!hods1

and inspe$!ion pro$edures or Army $ons!ru$!ion(

This manual $o#ers only !he ollo)in' )eldin' pro%

$esses and ma!erials $ommonly used or ield $on%

s!ru$!ion pro&e$!s* shielded me!al%ar$1 'as me!al%ar$1

'as !un's!en%ar$1 lu=%$ored ar$1 submer'ed ar$1

e=o!hermi$1 and ar$ s!ud )eldin' pro$esses( Dis$us%

sions o physi$s1 $hemis!ry1 and me!allur'y are lim%

i!ed !o areas helpul in sele$!in' )eldin' pro$esses1

ma!erials1 and inspe$!ion pro$edures or !he appli$a%

!ions lis!ed in para'raph 4%6( >or supplemen!al

inorma!ion1 see !he Ameri$an 2eldin' So$ie!y?A2S@ Welding Handbook ?a#ailable in i#e se$!ions@

and T, 9%560( Appendi= A lis!s o!her )ors1 $odes1

and spe$ii$a!ions )hi$h are reeren$ed in !his man%

ualB desi'ners should no!e !ha! !here are dieren$es

amon' !h e do$um en!s reuiremen!s( Thereore1

)hen !his ma!erial is used1 !he edi!ions )hi$h apply

!o a 'i#en desi'n mus! be spe$iied(

1-). W$*'i&+ %!!*i(%i"

This manual dis$usses !he ollo)in' ma!erials(

a( S!eel(

?4@ S!ru$!ural $arbon s!eel )elded !o

s!ru$!ural $arbon s!eel(

?5@ S!ru$!ural $arbon s!eel )elded !o hi'h%s!ren'!h1 lo)%alloy s!eel(

?6@ Hi'h%s!ren'!h1 lo)%alloy s!eel )elded !o

hi'h%s!ren'!h1 lo)%alloy s!eel(

?7@ Carbon or hi'h%s!ren'!h1 lo)%alloy s!eels or

all !ypes o pipin' sys!ems(

?-@ Con$re!e reinor$in' s!eel(

?8@ Rails(

?0@ S!eel $as!in's1 ei!her $arbon or hi'h%

s!ren'!h1 lo)%alloy(

b( S!ainless s!eels(

?4@ Cryo'eni$ #essels and pipin' ma!erials used

or s!ora'e and !ranspor! o e=!remely lo)%!empera%

!ure liuids(?5@ a$uum $hambers(

?6@ All o!her uses(

$( Ni$el s!eels and ni$el alloys or $ryo'eni$

#essels and pipin' sys!ems(

d( Aluminum alloys or $ryo'eni$ #essels1 pipin'

sys!ems1 and o!her uses(

e( Carbon and hi'h%s!ren'!h1 lo)%alloy s!eels

)elded !o s!ainless s!eels( An e=ample o !his use

is )hen s!eel suppor !s or s!ien ers are a!!a$hed

!o s!ainless s!eel #essels(

1-1


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T M 5-805 -7

CHAPTER )

DESIGN AND INSPECTION RESPONSIBILITIES

)-1. D$#i+&$ $#!"ii*ii$#

a( The desi'ner mus! spe$iy !he base me!al o r

!he s!ru$!ure1 a$$ordin' !o desi'n and ser#i$e

reuiremen!s and pro#ide essen!ial me!allur'i$al

and desi'n inorma!ion in !he spe$ii$a!ions( 2eld%

in' pro$ess and iller me!als are sele$!ed by !he

abri$a!or or1 in some $ases1 spe$iied by !he desi'n

oi$e !o i! !he ma!erial reuiremen!sB !hese i!ems

should be in$luded in !he spe$ii$a!ions and indi%

$a!ed on !he dra)in's( The &oin! desi'ns mus! be

sho)n on !he dra)in's by a s!andard )eldin' sym%

bol or by de!ailed dra)in's o !he )eld &oin!s(

b ( The desi'ner mus! de!ermi n e !he )eldin'

reuiremen!s1 and mus! de#elop or sele$! !he appro%pria!e )eldin' se$!ions o !he $on!ra$! or ea$h pro&%

e$!( These de$isions are based on ins!ru$!ions rom

!he usin' a'en$y( The desi'ner mus! de#elop $on%

!ra$! spe$ii$a!ions !ha! ensure !he $on!ra$!or no)s

!he )eldin' uali!y !ha! mus! be main!ained( The

desi'ner uses !he ollo)in' $ri!eria !o de!ermine !he

reuired de'ree o $on!rol o#er )eldin' uali!y(

?4@ S!ri$! $on!rol o#er )eldin' pro$edures and

opera!ions is reuired in i#e $ases ?lis!ed in order

o in$reasin' impor!an$e@*

?a@ Dis!ress in one member $ould $ause a!

leas! par!ial $ollapse or ailure )i!h some haFard !o

lie and proper!yB appli$a!ion o !he desi'n load mayapproa$h 41 $y$les o#er many years(

?b@ Some o !he )elds reuired or s!ru$!ural

in!e'ri!y are hi'hly s!ressedB appli$a!ion o !he

desi'n load may e=$eed 41 $y$les o#er many

years(

?$@ Empiri$al desi'n reuiremen!s $ompen%

sa!e or o#erloads1 abuse1 mishandlin'1 +a$!s o

"od13 and similar haFardsB appli$a!ion o !he desi'n

load may be on !he order o 41 $y$les(

?d@ >ailure o )elds or $omponen!s $ould be

$a!as!rophi$1 as in s!ru$!ures su$h as brid'es or hi'h%

%pressure 'as pipin' sys!emsB a!i'ue o ma!erials

mus! be $areully $onsidered or appl i$a! ion odesi'n load is on !he order o 5 million $y$les(

?e@ Appli$a!ions reuire !he hi'hes! uali!y o

ma!erial and )ormanship !hrou'hou!1 su$h as o r

nu$lear1 spa$e1 and ballis!i$ appli$a!ions and or sys%

!ems sub&e$!ed !o haFardous $hemi$als1 or e=!reme

pressures or !empera!ures(

?5@ ollo) desi'n $ri!eria and $odes !ha! spe$iy

!he e=!en! o inspe$!ion and !es!in' reuired rela!i#e

!o )orin' s!resses1 &oin! ei$ien$ies1 or $ondi!ions

o use(

?6@ Inspe$! #isually in non$ri!i$al appli$a!ions or

$ondi! ionsB #ery l i ! ! le o!her !es! in' should be

reuired(

?7@ Iden!iy !he $ri!i$al &oin!s and )elds and

$hoose !hose !o be !es!ed( The $ri!i$ali!y o ea$h

)eld should de!ermine !he e=!en! o nondes!ru$!i#eand des!ru$!i#e !es!sB !hese !es!s supplemen! !he

uali!y $on!rol pro#ided by ualiied pro$edures1

ualiied )elders and opera!ors1 and #isual inspe$%

!ion( The )eld $an be $ri!i$al be$ause o hi'h

s!resses1 impa$!1 #ibra!ion1 !empera!ure1 sae!y1

insuran$e a'ains! opera!ional ailure1 hard%!o%)eld

ma!erial1 or a $ombina!ion o !hese a$!ors( In a

mul% !is!ory oi$e or )arehouse buildin' )i!h

s!ru$!ural

)- 1


10/98

T M 5 -8 05 -7

s!eel ramin'1 or e=ample1 !es!in' )ould be done al!erin' !he &oin! desi'n ?in$reasin' !he roo! a$e or

mainly a! !he hi'hly s!ressed &oin!s( In a $ri!i$al pip%

in' sys!em1 ho)e#er1 ei!her all &o in!s )ould be

nondes!ru$!i#ely !es!ed or a uniormly applied ran%

de$reasin' !he roo! openin'@ or by

ble inser! rin's(

?7@ I !he &oin! is )elded rom

usin' $onsuma%

bo !h sides1 !he

dom !es! pro$edure )ould be used(

?-@ De!ermine !he e=!en! o random !es!in' in

pipin'1 !ans1 and o!her elemen!s !ha! ha#e uniorm

&o in !s and desi'n le#els ( This number $an bee=pressed as a per$en!a'e o all )elds in !he

sys!em1 $oupled )i!h a ini!e !es! in$remen!(

Ho)e#er1 !he e=!en! o random !es!in' in lar'e

s!ee l s! ru$ !ure s )i!h a #arie!y o )elds and )idely

#aryin' desi'n s!re sse s should no! be e=pressed

!his )ay( The desi'ner is responsible or

spe$iyin' !he appropri% a!e !es!s or $ri!i$al and

non$ri!i$al )elds( To insure $lar i!y in bidd in' and

inspe$!ion do$umen!s1 !he lo$a!ion1 numbers 1 and

minimum in$remen! len'!hs o !he random !es!s

should be $learly ou!lined(

( The desi'ner mus! indi$a!e in !he spe$ii$a!ion

)ha! !o do )hen )elds ail !o mee! a$$ep!an$ereuiremen!s(

'( The desi'ner mus! desi'n !he )eld so !ha! !he

opera!or $an rea$h !he )eld &oin! easily( I !he &oin!

is lo$a!ed so !ha! !he )elder $anno! obser#e !he

)eldin' opera!ion easily or posi!ion !he )eldin' 'un

or ele$!rode properly1 a poor )eld may resul!( In

su$h $ases1 i! may be hard or impossible !o repair

any )eld dee$!s(

?4@ The dimensions and shape o !he &oin! sur%

a$es should allo) !he )eld me!al !o pene!ra!e !he

&oin! ully( I pie$es o dieren! !hi$nesses are !o

be &oined1 !he ed'e o !he !hi$er pie$e should

be !apered !o !he !hi$ness o !he !hinner pie$e(The !apered !ransi!ions mus! $onorm !o !he

reuire% men!s o !he ollo)in' publi$a!ions1 as

appli$able* A2S D4(4B !he Ameri$an So$ie!y o

,e$han i$a l En'ineers ?AS,E@ ;oiler and Pressure

essel Code1 Se$!ion III or Se$!ion IIIB or !he

Ameri$an Na!ional S!andards Ins!i!u!e ?ANSI@ S!andard

; 64(4(

?5@ "ood &oin! desi'n pra$!i$es or #essels are

sho)n in se$!ion III o !he AS,E ;oiler and Pres%

sure essel CodeB or pipin' in appendi= D o ANSI

;64(4B and or s!ru$!ural )or in !he Ameri$an Ins!i%

!u!e o S!ee Cons!ru$!ions ?AISC@ Manual of Steel

Construction and A2S Dl(4(

?6@ In some )eldin' opera!ions1 some !ype o

)eld &oin! ba$in' is used !o suppor! !he mol!en

)eld me!al and pre#en! e=$essi#e pene!ra!ion( ;a$%

in' s!rips1 )hen used1 mus! be o ma!erial similar !o

!he base me!als )hi$h are pene!ra!ed by !he )eld

me!al( Non$onsumable3 ba$in' rin's in pipin' sys%

!ems should no! be permi!!ed unless absolu!ely ne$%

re#erse side o !he roo! pass ?!he side opposi!e !ha!

on )hi$h !he )eld )as deposi !ed@ should be

$hipped1 'round1 or 'ou'ed ou! !o sound me!al

beore any )eldin' is done rom !he se$ond side(This opera!ion )ill pre#en! la$ o usion a! !he

roo! o !he &oin!( The re#erse side o sin'le +3

)eld &oin!s may also be 'round ou! and

re)elded !o impro#e !he $on!our( Comple!e

pene !ra! io n 'roo#e )elds mus! be )elded rom

bo!h sides un less a proper ba$up pla!e is used(

h( The desi'ner mus! de$ide )hi$h )elds are !o

be peened and )hi$h are no! and indi$a!e !hem on

!he dra)in's( Peenin' is !he me$hani$al )orin' o

me!als by hammer blo)s( This !e$hniue is useul

or redu$in' dis!or!ion and residual s!resses $aused

by shrina'e o !he )eld me!al as i! $ools( Ho)e#er1

!he !e$hniue $an be harmul i e=!reme $are is no!used( Sin$e i! $an $ause $ra$in'1 o#erlappin'1 or

o!her dee$!s1 peenin' is no! permi!!ed on sura$e

passes o !he )eld &oin!s( In!ermedia!e passes

may be peened only )i!h !he $on!ra$!in' oi$er s

per% mission( Peenin' o s!ainless s!eel )elds is no!

per% mi!!ed be$ause i! $auses hardenin' o !he

)eld

me!al ( Care should be !aen !o p re#en! peenin'

)hen sla' is remo#ed rom !he sura$e pass )i!h

$hippin' hammers(

i( The desi'ner mus! de!ermine i !he shape o !he

)eld sura$e and i!s hei'h! abo#e !he base me!al

?reinor$emen!@ are impor!an! and indi$a!e !he

shape on !he dra)in's( An abrup! $han'e in $on!our

be !)een !he )eld sur a$e and !he base me!al may

resul! in s!ress $on$en!ra!ions hi'h enou'h !o $ause

ailure under ser#i$e loadin's( Thereore1 !he )eld

sura$e should blend smoo!hly in!o !he sura$e o

!he base me!al( I ne$essary1 !he ed'es o !he )eld

should be 'round !o a$hie#e a smoo!h blend o

sura$es(

?4@ Under$u! a! !he ed'e o !he )eld $an be

repaired by 'rindin' i !he dep!h o under$u! does

no! e=$eed 4/4 8 in$h( I under$u! is deeper !han

4/48 in$h1 i! should be repaired by addin' )eld

me!al !o !his area and !hen 'rindin' !he sura$e !o

a smoo!h1 e#en $on!our(

?5@ "rindin' also should be used !o remo#e

o#erlap a! !he )eld ed'es and any abrup! rid'es or

#alleys in !he )eld sura$e(

?6@ The ma=imum amoun! o )eld reinor$e%

men! should be be!)een 4/65 and 4/. in$h(

essary( Ins!ead1 pene !ra! io n $an be $on! ro lled by

5%5


11/98

T* 3(


12/98

T M 5 -8 05 -7

prehea !ed !o 0o

> or hi'her or )eldin' and ep!

a! ! hi s ! empera !ure ! hrou'hou! ! he )eldin'

opera!ion( prehea!in' o s!ru$!ural s!eel mus! $onorm

!o A2S D4(4(

e( The $on!ra$!or mus! insure proper repair )eld%

in'( Dee$!i#e )elds mus! be repaired by remo#in'

!he dee$!s rom !he )eld &oin! and re)eldin' !he

&o in!s ( Dee$! s may be remo#ed me$hani$ally by

'rindin'1 $hippin'1 or ma$hinin'1 or by ar$ or lame

' o u ' i n ' ( A $ombina! ion o me!hods is o !en

reuired( >or e=ample1 i !he dee$!s are remo#ed

by lame or ar$ 'ou'in'1 !he $u! sura$e may need !o

be $leaned me$hani$ally and smoo!hed beore !he

repair )eld is made(

?4@ >lame% or ar$%$u! sura$es o s!ainless s!eel

and ni$el s!eel ha#e a hea#y s$ale or o=ide $oa!in'

!ha! mus! be remo#ed beore )eldin' !o eep i!

rom ae$!in' !he uali!y o !he repair )eld( Also1

hea! rom !he 'ou'in' opera!ion $an ae$! s!ren'!h

by $ausin' me!allur'i$al $han'es in !he )eld me!al

ad&a$en! !o !he $u! sura$es( Thereore1 an addi%

!ional 4/. in$h o me!al should be me$hani$ally

remo#ed rom !hese $u! sura$es(

?5@ Dee$!s in aluminum alloys mus! be remo#ed

only by me$hani$al means(

?6@ E=!ra $are mus! be used )hen remo#in'

$ra$s rom )elds( Nondes !ru$ !i#e inspe$!ion may

no! indi$a!e !he !rue len'!h o !he $ra$1 )hi$h may

be !oo narro) !o be de!e$!ed )i!h !he !es! me!hod

bein' used( So1 one should remo#e no! only !he )eld

me!al in !he $ra$1 bu ! also some sound me!al a!

ea$h end o !he $ra$( The amoun! remo#ed should

be !)i$e !he base me!al !hi$ness or 5 in$hes1)hi$he#er is less a! ea$h end o !he $ra$( A!er !he

me!al is !aen ou! and beore repairs1 )elds should

be inspe$!ed a'ain !o insure !ha! !he ull len'!h o

!he $ra$ has been remo#ed(

?7@ Repair )eldin' mus! be done by a ualiied

)elder usin' only ualiied )eldin' pro$edures(

The repair )or mi'h! be easier )i!h a smaller

diame!er ele$!rode or iller )ire !han )as used !o

mae !he ori'inal )eld(

( On $ri!i$al )elds or )hen reues!ed by inspe$%

!ors or !he $on!ra$!in' oi$er1 !he $on!ra$!or mus!

ha#e a )elder or )eldin' opera!or apply a prede!er%

mined iden!ii$a!ion mar !o !he $omple!ed )eld&oin!( This mar is normally made on !he base me!al

ne=! !o !he )eld me!al( ,a!erials may be mared by

any me!hod a$$ep!able !o !he inspe$!or as lon' as i!

does no! $ause no!$hes or sharp dis$on!inui!ies !ha!

$ould ail under ser#i$e loadin'( The iden!iyin'

mar mus! remain le'ible un!il a$$ep!an$e o !he

)eld me!als or !he s!ru$!ure in )hi$h !he )eld is

$on!ained( 2hen reues!ed1 !he )elder should

apply a mar !ha! )ill remain le'ible or !he lie o

!he s!ru$!ure(

'( The $on!ra$!or mus! se! up pro$edures or

prehea!in'1 pos!hea! in'1 and s! re ss relie#in'( The

$ondi!ions !o )hi$h a )eldmen! )ill be e=posed dur%

in' ser#i$e opera!ions de!ermine !he !hermal !rea!%

men! ne$essary( >or a broad $o#era'e o !hermal

!rea!men!1 see !he A2S Welding Handbook, olume

41 +>undamen!als o 2eldin'(3 Sin$e prehea!in'

and pos!%)eld hea! !rea!men! ae$! !he physi$al

proper!ies o !he )eld1 !he pro$edures mus! be se!

up in de!ail by !he $on!ra$!or or abri$a!or and

in$luded in !he )eldin' pro$edure ualii$a!ion(

?4@ Prehea!in' is !he appli$a!ion o hea! !o a

base me!a l beo re )eldin' or $u!!in'( Prehea!in'

may be used durin' )eldin' !o help $omple!e !he

)elded &oin! ( The need or and ! empera!ure o

pr ehea!in' depend on se#eral a$!ors1 su$h as !he

$hemi$al analysis o !he ma!erial1 de'ree o res!rain!

o !he par!s bein' &oined1 physi$al proper!ies a! ele%#a!ed !empera!ures1 ma!erial !hi$ness1 and ambien!

!empera!ure(

?a@ Prehea!in' may be reuired or re$om%

mended or )eldin' perormed under $odes or spe$%

ii$a!ions su$h as !hose o A2S1 AS,E1 or !he

Ameri$an Pe!roleum Ins! i !u!e ?API@( Ho)e#er1

pr ehea !in' does no ! ne$essarily assure sa!isa$!ory

$omple!ion o !he )elded &oin !1 and reuiremen!s

mus! be sui!ed !o !he indi#idual ma!erials and

appli$a!ions(

?b@ Prehea!in' may #ary rom a !empera!ure

)hi$h is )arm !o !he !ou$h o !he hand )hen )eld%

in' ou!doors in )in!er1 !o as hi'h as 8 > )hen)eldin' hi'hly hardenable s!eels( 2hen !he ambien!

!empera!ure is less !han 65 +>1 lo$al prehea! o !he

)eld &oin! area !o 0 > is re$ommended(

?5@ Pos!%)eld hea! !rea!men! ?or pos!hea!in'@ is

a 'eneral !erm $o#erin' !rea!men!s done a!er )eld%

in' !o res!ore !he proper!ies o !he base me!al and !o

produ$ e !he de si re d mi$ros !ru$ !ure in !he base and

iller me!als( Pos!%)eld hea! !rea!men! may reuire

normaliFin'1 ull annealin'1 uen$hin' and !emper%

in'1 or solu!ion and pre$ipi!a!ion !rea!men!s(

?6@ S!ress relie hea! !rea!men! is !he uniorm

hea!in' o a s!ru$!ure ?or par! o i!@ !o a !empera!ure

belo) !he $ri!i$al ran'e1 bu! hi'h enou'h !o relie#emos! o !he residual s!ressesB !his is ollo)ed by uni%

orm $oolin'( S!ress relie#in' should no! be $on%

u se d ) i ! h o ! h e r p o s ! % ) e l d h e a ! ! r e a ! m e n !

pro$esses1 )hi$h may or may no! pre#en! !he need

or s!ress relie#in'1 dependin' on !he ma=imum

!empera!ure a!!ained in !he pos!%)eld hea! !rea!%

men! and !he ra!e o $oolin' rom !his !empera!ure(

5%7


13/98

T M 5 - 8 0 5 - 7

)-. I!$(i"& $/ui$$

Inspe$!ion is done !o mee! $on!ra$! uali!y spe$ii%

$a!ions and !o main!ain uali!y $on!rol on !he )eld%

er s and )eldin' opera!ors( Ee$!i#e inspe$!ion

reuires $oopera!ion be!)een !he )elder or )eldin'

opera!or and !he inspe$!or( Inspe$!ors should al)ays

en$oura'e !he )elders and )eldin' opera!or !o$he$ !heir o)n )or and !o repor! ues!ionable

)elds or )eldin' pro$edures( There mus! also be a

mu!ual unders!andin' be!)een $on!ra$!or and 'o#%

ernmen!super#isory personnel( Inspe$!ion $os!s

money1 bu! 'ood inspe$!ion o!en sa#es more !han i!

$os!s by redu$in' e=pensi#e1 ! ime:$onsumin'

re&e$!s or repairs1 and by de!e$!in' promp!ly unsa!%

isa$!ory )eldin' pro$edures or poor )ormanship(

,os! inspe$!ions are !o be done by !he $on!ra$!ors

?abri$a!ors@ sin$e !hey )ill 'ain or lose rom !he

uali!y o !he produ$!( They $an also !ae immedia!e

$orre$!i#e a$!ion )hen dee$!i#e )eldmen!s are

ound( 2hen $on!ra$!ors do !heir o)n inspe$!ions1!he inspe$!ion personnel should be or'aniFa!ionally

separa!e rom !he produ$ !ion personnelB inspe$!ion

personnel should ans)er no! !o !he pro&e$! superin%

!enden! bu! !o a uali!y $on!rol elemen! o !he or'a%

niFa!ion( Con!ra$!ors may employ independen!

$ommer$ial inspe$!ion and !es!in' labora!ories !o

perorm !hese ser#i$es1 espe$ially )hen !he $on!ra$%

! or s p ro du $!io n o r ual i !y reui remen!s #ary

)idely( I !he $on!ra$!or has pro#ided rel iable

inspe$!ors1 !he 'o#ernmen! $an simply spo! $he$ !o

mae sure !he inspe$!ion me!hods )ere adeua!e(

"o#ernmen! inspe$!ion $an be done ei!her by 'o#%

ernmen! personnel or by an independen! $ommer%$ial inspe$!ion or !es!in' labora!ory( The $hoi$e )ill

depend on a number o a$!ors1 su$h as a#ailabili!y

o ualiied personnel and euipmen!1 len'!h o !he

pro& e$ !1 $os! o inspe$ !ion 1 lo$a!ion o !he pro&e$!1

and $ri!i$ali!y o inspe$!ion or !es!in' reuiremen!s(

2hen ualiied 'o#ernmen! personnel are a#ailable1

!hey should do !he inspe$!ion and !es!in'( This is

desirable rom !he s!andpoin!s o adminis!ra!i#e $on%

!rol1 main!enan$e o ualiied 'o#ernmen! inspe$%

!ion personnel1 and personal in!eres! in !he uali!y

o !he produ$!( 2hen $ir$ums!an$es reuire )or

by a $ommer$ial labora!ory1 !hese inspe$!ors a$! as

a'en!s or !he 'o#ernmen!(a( Con!ra$!ual rela!ions(

?4@ Desi'ners1 $on!ra$!ors1 inspe$!ors1 )elders1

and )eldin' opera!ors should $oopera!e( The ual%

i!y o !he )eldin' depends lar'ely on !he sill o

!he $on!ra$!ors personnel1 !he proper $hoi$e o

ma!eri% als1 and !he adeua$y o !he )eldin'

pro$edure( The $o n! ra $!or depe nds on !he inspe$!ors

or de$ision s abou! )he!her !he $omple!ed )elds

are a$$ep!able(

?5@ Inspe$!ors should de#elop a $lear under%

s!andin' o !he spe$iied reuiremen!s1 in!erpre!

$on!ra$! pro#isions $onsis!en!ly1 and a#oid ei!her

a#orin' !he $on!ra$!or or main' unreasonable

demands( In shor!1 !hey should be absolu!ely air !o

bo!h !he 'o#ernmen! and !he $on!ra$!or(

?6@ Al!hou'h inspe$!ors usually mae !he inal

de$ision abou! !he uali!y o a )eld1 !hey should no!!ae o#er !he role o super#isors or !he $on!ra$!or(

A$$ep!abili!y o )elds should no! be le! !o dis$re%

!ion1 bu! be based on mee!in' !he spe$iied reuire%

men!s( Compe!en! $on!ra$!or super#ision should be

pro#ided !o see !ha! !he )eldin' pro$edures are

be in' o llo)ed and !ha! !he reues!s made by !he

inspe$!ors are $arried ou!( As mu$h as possible1 !he

inspe$!or should as !he $on!ra$!ors super#isory

personne l !o re'ula!e opera!ions1 and should no!

'i#e orders dire$!ly !o )ormen(

?7@ A !horou'h no)led'e o !he )or is !he

bes! assuran$e o a sa!isa$!ory &ob and a 'ood )or%

in' rela!ionship be!)een !he 'o#ernmen! and !he$on!ra$!or( The ine=perien$ed inspe$!or may un)i!%

!in'ly penaliFe bo!h $on!ra$!in' par! ies by undu ly

emphasiFin' insi'nii$an! bu ! $os!ly de!ails o !he

)or1 !hus imposin' a needless hardship on !he $on%

!ra$!or )i!h li!!le benei! !o !he 'o#ernmen!( A! !he

same !ime1 !he inspe$!or mi'h! o#erloo o!her oper%

a!ions !ha! may be #i!ally impor!an! !o !he &ob G or

e=ample1 o#eremphasis on !he s!ren'!h o !he )eld

)hen appearan$e is mos! impor!an!1 and #i$e #ersa(

b( Inspe$!ion or$e( On a lar'e pro&e$ !1 'o#ern%

men! inspe$!ion o )eldin' opera!ions is assi'ned !o

an inspe$!ion se$!ion headed by an e=perien$ed

super#isor( This diers rom an isola!ed &ob o )eld%in' )here inspe$!ion may be !he responsibili!y o

one or !)o indi#iduals( On a lar'e pro&e$! )here !he

inspe$!ion o al l )eldin' is 'i#en !o a spe$ialiFed

!eam1 assi'nmen!s in !he early s!a'es o $ons!ru$!ion

may be arran'ed so !ha! ine=perien$ed inspe$!ors

$an )a!$h !he a$!ions and de$isions o e=perien$ed

personnel( This pro$edure )i ll help !rain a $ompe%

!en! !eam !ha! )ill opera!e ei$ien!ly a! a la!er s!a'e

o )or( This approa$h is no! possible1 ho)e#er1 on

small pro&e$!s )i!h only one inspe$!or( Only e=per%

ien$ed $ons!ru$!ion personnel should be assi'ned in

su$h $ases(

$( Inspe$!ors du!ies( The inspe$!or mus!

e=amine in de!ail ea$h phase o !he )eldin'

opera!ion !o mae sure !he )or is bein' done

ri'h!( The inspe$% !or mus! obser#e su$h

reuir emen!s as pro$edu re and )elder ualii$a!ions1

&oin! desi'n and prepara% !ion 1 al i'nmen!1 ele$ !rod e

siFe and !ype1 )eldin' euipmen!1 and !e$hniue(

2hen an assi'nmen! is ro!a!ed1 a ne) inspe$!or

mus! learn abou! !he pro$e% dures bein' ollo)ed and

!he s!a!us o )eldin' and

5%-


14/98

T M 5 - 8 0 5 - 7

inspe$!ion beore assumin' inspe$!ion

responsibili!y(

d( Super#ision( "ood super#ision o inspe$!ors is

impor!an! !o sa!isa$!ory )eldin' opera!ions on a

lar'e pro&e$!( E#en !he mos! e=perien$ed inspe$!or

$an do li!!le unless properly ins!ru$!ed in !he )or

and 'i#en !he ulles! suppor! in dealin's )i!h )eld%

in' personnel ( The super#isor mus! $lariy !heresponsibili!ies o ea$h par! o !he or'aniFa!ion and

ou!line !he limi!s o ea$h inspe$!ors au!hori!y( The

super#isor should !ell !he inspe$!or abou! all de$i%

sions on a$$ep!an$e reuiremen!s and o!her issues(

I! is 'ood super#isory pra$!i$e !o $ir$ula!e memo%

randa ou!linin' all pro&e$! de$isions made by !hose

in au!hori!y and summariFin' ma!!ers )hi$h inspe$%

!ors $an s!ill de$ide )i!h some le=ibili!y( ;eore

de$isions are made abou! $ons!ru$!ion me!hods1 !he

opinions o !he inspe$!ors assi'ned !o !he )or

should be $onsidered( O$$asional mee!in's be!)een

inspe$!ors and super#isors !o dis$uss any &obprob lems1 pra$ !i$es1 and re uiremen!s ar e helpul

and o!en ne$essary(


15/98

T M 5 - 8 0 5 - 7

CHAPTER

WELDING PROCESSES

-1. G$&$%*This $hap!er $on!ains 'eneral reuiremen!s or

)eldin' pro$esses !ha! may be used or !he appli$a%

!ions $o#ered in para'raph 4%5(

-). P"($##$#

$urren! rom !he ele$!rode !o !he )or p ie$e!hrou'h a 'ap( The $urren! mel!s !he base me!al and

!he ele$!rode i i! is a $onsumable !ype1 $rea!in' a

mol!en pool( On solidiyin'1 !he )eld is ormed( An

al!erna!e me!hod employs a non$onsumable ele$%

!rode su$h as a !un's!en rod( In !his $ase1 !he )eld is

a( The

)eldin'.

pro$esses $o#ered by !his desi'n ormed by mel!in' and solidiyin' !he base me!al a!

manual are as ollo)s*

?4@ Shielded me!al%ar$ ?S,A2@?5@ "as me!al%ar$ ?",A2@

?a@ >ree%li'h! !ranser

?b@ Pulsed%$urren! ou!%o%posi!ion )eldin'

?$@ Shor! $ir$ui!in'

?6@ >lu=%$ored ar$ )eldin' ?>CA2@

?7@ "as !un's!en%ar$ ?"TA2@

?-@ Submer'ed%ar$ ?SA2@

?8@ E=o!hermi$ ?Thermi!@

?0@ Ar$ s!ud ?STUD@

b( ;asi$ally1 in !he ele$!ri$ )eldin' pro$esses1 an

ar$ is produ$ed be!)een an ele$!rode and !he )or

% pie$e ?base me!al@( The ar$ is ormed by passin' a

!he &oin!( In some ins!an$es1 addi!ional me!al is

reuired and is added !o !he mol!en pool rom a

iller rod(

$( Ele$!rodes )hi$h be$ome !he deposi!ed )eld

me!al are a#ailable in #arious diame!ers and len'!hs(

In )eldin'1 !he mol!en pool mus! be pro!e$!ed rom

!he ambien! a!mosphere !o pre#en ! $on!amina!ion(

There are !hree )ays !o do !his( T)o in#ol#e a lu=B

in one1 !he lu= is par! o !he ele$!rode1 ei!her as

a $oa!in' on !he )ire or as !he $ore o a hollo)

)ire( The se$ond me!hod uses a 'ranula!ed lu=

!ha! is app lie d separa!ely beore )eldin'( The

!hi rdme!hod in#ol#es a 'as su$h as helium1 ar'on1

or $ar% bon dio=ide( In addi!ion !o shieldin'1 !he

lu= may

. -1


16/98

TM 5-805-7

un$!ion as a deo=idiFer !o puriy !he deposi!ed

me!al or !o orm sla' !o pro!e$! !he )eld me!al rom

o=ida!ion( The lu= may $on!ain ioniFin' elemen!s !o

pro# ide smoo!her opera!ion1 alloyin' elemen!s !o

pro#ide h i'her s! ren'!h1 and iron po)der !o

in$rease produ$!ion ra!es( The sele$!ion o ele$%

!rodes or a spe$ii$ &ob $an be based on !he ollo)%

in' ei'h! a$!ors*?4@ ;ase me!al s!ren'!h proper!ies

?5@ ;ase me!al $omposi!ion

?6@ 2eldin' posi!ion

?7@ 2eldin' $urren!

?-@ Koin! desi'n and i!%up

?8@ Thi$ness and shape o base me!al

?0@ Ser#i$e $ondi!ions and/or spe$ii$a!ions

?.@ Produ$!ion ei$ien$y and &ob $ondi!ions

The A2S publishes a 'roup o spe$ii$a!ions or il%

ler me!als ?ele$!rodes@ and re$ommends !he )eldin'

pro$ess or )hi$h !hey are !o be used( In addi!ion1

A2S D4(4 des$ribes !he )eldin' pro$edures !o be

used )i!h !he #arious )eldin' pro$esses(d( 2eldin' ma!erial G ele$!rodes1 )eldin' )ire1

and lu=es G mus! produ$e sa!isa$!ory )elds )hen

used by a ualiied )elder or )eldin' opera!or usin'

ualiied )eldin' pro$edures ( 2eldin' ma!erials

mus! $omply )i!h !he appli$able reuiremen!s o

A2S D4(41 AS,E ;oiler and Pressure essel Code1

Se$!ion II1 or o!her reuiremen!s in !he $on!ra$!

spe$ii$a!ions(

-. Si$*'$' $%*-%( 2SMAW3

This is !he mos! )idely used me!hod or 'enera l:

)eldin' appli$a!ionB i! may also be reerred !o as

me!alli$%ar$1 manual me!al%ar$1 or s!i$%ele$!rode

)eldin'(

a( Ad#an!a'es( The S,A2 pro$ess $an be used

or )eldin' mos! s!ru$!ural and alloy s!eels(These in$lude lo )%$arb on o r mild s!eelsB lo)%alloy1

hea!% !rea!able s!eelsB and hi'h%alloy s!eels su$h as

s!ain% less s!eels( S,A2 is used or &oinin' $ommon

ni$el alloys and $an be used or $opper and

aluminum alloys( This )eldin' pro$ess $an be used

in all posi% !ions G la!1 #er!i$al1 horiFon!al1 or

o#erhead G and reuires only !he simples!

euipmen!( Thus1 S,A2 lends i!sel #ery )ell !o ield

)or ?i' 6%l@(

b( Disad#an!a'es( S,A2 is $learly inerior !o

",A2 i one $ompares !he $os! o !he !ime and

ma!erials needed !o deposi! !he )eld me!al( S,A2

deposi!s !he )eld more slo)ly !han does ",A2( In

addi!ion1 sla' remo#al1 unused ele$!rode s!ubs1 and

spa!!er add a lo! !o !he $os! o S,A2B !he la!!er !)o

i!ems a$$oun! or abou! 77 per$en! o !he $onsumed

ele$!rodes( Ano!her po!en!ial $os! is !he en!rapmen!

o sla' in !he orm o in$lusions )hi$h may ha#e !o

be remo#ed(

$( Pro$ess prin$iples( The S,A2 pro$ess pro%

du$es an ar$ be!)een !he base me!al and !he ele$%

!rode( The ele$!rode1 pu! in a hand%held $lamp1 is

-)


17/98

T M 5 - 8 0 5 - 7

-


18/98

6%7


19/98

T M 5 - 8 0 5 - 7

6 % -


20/98

T M 5 - 8 0 5 - 7

)4

6%8


21/98

T, -%--%0

)8

-)5

)4

))

)0

8

5

4

)

6%0


22/98

T M 5 - 8 0 5 - 7

6% .


23/98

TM 5 - 8 0 5 - 7

s!ru$ a'ains! !he base me!al and )i!hdra)n !o $re%

a!e a 'ap( The mol!en por!ion o !he ele$!rode uses

in!o !he mol!en pool o !he base me!al1 produ$in'

!he )eld ?i' 6%5@( Sin$e S,A2 is a manual pro$ess1

!he opera!or is pr imar ily responsible or uali!y o

!he )eld( ,os! o !he mel!ed ele$!rode me!al is

!ranserred !o !he )or pie$eB !he res! is !hro)n ree

o !he )eld as spa!!er or is #aporiFed( O !ha!

#aporiFed1 some es$apes in!o !he surroundin' air1

be$omes o=idiFed1 and appears as smoe or umes(

The ele$!rode used or S,A2 has a spe$ial $o#erin'

)hi$h ser#es se#eral purposes( Par! o !he $o#erin'

$on!ains 'as%produ$in' $ompounds !ha! 1 )hen

hea!ed1 produ$e a 'aseous en#elope around !he ar$

!ha! displa$es air and s!abiliFes !he ar$( The $o#erin'

also pro!e$!s !he mol!en )eld me!al rom $on!amina%

!ion by air( 2i!hou! !his s!abiliFa!ion1 !he ar$ )ould

be er ra !i$1 )ould o!en shor! ou!1 and 'enerally

)ould be hard !o $on!rol( Dieren! 'as%produ$in'

$ompounds are used in !he $oa!in'1 dependin' on

!he !ype o $urren! G al!erna!in' ?AC@ or dire$!

?DC@( The $o#erin' also $on!ains sla'%ormin' ma!e%

rials !ha! mi= )i!h !he mol!en )eld me!al and pi$

up impuri!ies rom !he )eld me!al( This $leanin'

a$!ion impro#es !he uali!y o !he )eld( ,os! o !he

ele$!rode $oa!in' does no! be$ome #aporiFed bu!

ins!ead is mel!ed by !he ar$ hea! and orms a mol!en

sla' $o#er o#er !he !op o !he )eld bead( This mol%

!en sla' $o#er helps !o $on!rol !he shape o !he )eld

bead( I! also helps !o hold !he mol!en )eld me!al

in pla$e durin' ou!%o%posi!ion )eldin' ?i(e(1 )eldin'

in !he o#erhead1 #er!i$al1 or horiFon!alposi !ions@ ( Chap!ers 7 and - dis$uss !he

numberin' sys!em1 $olor $odin'1 lu= $omposi!ion1

and o!her da!a $on% $ernin ' )eldin' ele$!rod es( In

shielded me!a l%a r$ )eldin'1 i#e dis!in$! or$es are

responsible or !he !ranser o mol!en iller me!al and

mol!en sla' !o !he base me!al(

?4@ "ra#i!y(( "ra#i!y is !he prin$ipal or$e

)hi$h a$$oun!s or !he !ranser o iller me!al in la!posi%!ion )eldin'( In o!her posi!ions1 !he sura$e !ension

is unable !o re!ain mu$h mol!en me!al and sla' in !he

6%9


24/98

$ra!er( Thereore1 smaller ele$!rodes mus! be used

!o a#oid e=$essi#e loss o )eld me!al and sla'(

?5@ "as e=pansion( "ases are produ$ed by !he

burn in' and #o la!i liFa !ion o !he ele$!rode $oa!in'

and are e=panded by !he hea! o !he boilin' ele$%

!rode !ip( The $oa!in' e=!endin' beyond !he me!al

!ip o !he ele$!rode $on!rols !he dire$!ion o !he

rapid 'as e=pansion and dire$!s !he mol!en me!al'lobule in!o !he )eld me!al pool ormed in !he base

me!al(

?6@ Ele$!roma'ne!i$ or$es( The ele$!rode !ip is

an ele$!ri$al $ondu$!or1 as is !he mol!en me!al 'lob%

ule a! !he !ip( Thereore1 !he 'lobule is ae$!ed by

ma'ne!i$ or$es a$!in' a! 9 de'rees !o !he dire$!ion

o !he $urren! lo)( These or$es produ$e a pin$hin'

ee$! on !he me!al 'lobules and speed up !he sepa%

ra!ion o !he mol!en me!al rom !he end o !he ele$%

!rode( This is par!i$ularly helpul in !ranserrin'

me!al in horiFon!al1 #er!i$al1 and o#erhead posi!ion

)eldin'(

?7@ Ele$!ri$al or$es( The or$e produ$ed by !he#ol!a'e a$ross !he ar$ pulls !he small1 pin$hed%o

'lobule o me!al1 re'ardless o !he posi!ion o )eld%

in'( This or$e is espe$ially helpul )hen one uses

dire$!%$urren!1 s!rai'h!%polari!y1 mineral%$oa!ed

ele$!rodes1 )hi$h do no! produ$e lar'e #olumes o

'as(

?-@ Sura$e !ension( The or$e )hi$h eeps !he

iller me!al and sla' 'lobules in $on!a$! )i!h mol!en

base or )eld me!al in !he $ra!er is no)n as

sura$e !ension( I! helps !o re!ain !he mol!en me!al

in hori% Fon!al1 #er!i$al1 and o#erhead )eldin'1 and!o de!er% mine !he shape o )eld $on!ours(

d( Euipmen! 1 T he e ui pm en ! n e e d e d o r

shielded me!al%ar$ )eldin' is mu$h less $omple=

!han !ha! needed or o!her ar$ )eldin' pro$esses(

,anual )eldin' euipmen! in$ludes a po)er sour$e

?!ransormer1 DC 'enera!or1 AC 'enera!or1 or DC

re$!iier@1 ele$!rodeholder1 $ables1 $onne$!ors1

$hippin' hammer1 )ire brush1 and ele$!rodes(

e( 2eldin' parame!ers( 2eldin' #ol!a'e1 $urren!1

and !ra#el speed are #ery impor!an! !o !he uali!y

o !he deposi!ed S,A2 bead( Table 6%4 sho)s

#ol!a'e limi!s or some S,A2 ele$!rodes( The $urren!

limi!s are sho)n in !he appendi= !o A2S A-(4(

>i'ures 6%6 !hrou'h 6%9 sho) !he !ra#el speed

limi! s or !he ele$!rodes lis!ed in !able 6%4(

. - 1 0


25/98

T M 5 - 8 0 5 - 7

WIRE DRI!E MAY "E

LOCATED IN WELDING GUN

HANDLE

OR AT WIRE REEL

3-11


26/98

T M 5 -8 05 -7

JNote all electrodes 1F


27/98

T M 5 - 8 0 5 - 7

. - 1 .


28/98

T M 5 - 8 0 5 - 7

3-1#


29/98

TM 5-805-7

. - 1 5


30/98

1$


31/98

T M 5 - 8 0 5 - 7

3-1%


32/98

3-18


33/98

manual and au!oma!i$ )eldin' 'uns are a#ailable(

The manual )eldin' 'uns ha#e many desi'ns( All !he

manual 'uns ha#e a noFFle or dire$!in' !he shield%

in' 'as around !he ar$ and o#er !he )eld puddle(

The iller )ire passes !hrou'h a $opper $on!a$! !ube

in !he 'un1 )here i! pi$s up !he )eldin' $urren!(

Some manual )eldin' 'uns $on!ain !he )ire%dri#in'

me$hanism )i!hin !he 'un i!sel( o!her 'uns reuire

!ha! !h e )ire%eedin' me$hanism be lo$a!ed a! !he

spool o )ire1 )hi$h is some dis!an$e rom !he 'un(

In !his $ase1 !he )ire is dri#en !hrou'h a le=ible

$ondui! !o !he )eldin' 'un( Ano!her manual 'un

desi'n $ombines eed me$hanisms )i!hin !he 'un

and a! !he )ire supply i!sel( Ar'on is !he

shieldin' 'as used mos! o!en( Small amoun!s o o=y'en

?5 !o - per$en!@ reuen!l y are added !o !he

shieldin ' 'as )hen s !eel is ) elded( This s!abiliFes

!he ar$ and promo!es a be!!er )e!!in' a$!ion1

produ$in' a more uniorm )eld bead and redu$in'

under$u!( Carbo n dio=ide is also used as a shieldin'

'as be$ause i! is $he ape r !han ar'on and ar'on%

o=y'en mi=!ures(

Ele$!rodes desi'ned !o be used )i!h $arbon dio=ide

shieldin' 'as reuire e=!ra deo=idiFers in !heir or%

mula!ion be$ause in !he hea! o !he ar$1 !he $arbon

dio=ide disso$ia!es !o $arbon mono=ide and o=y'en1

)hi$h $an $ause o=ida!ion o !he )eld me!al(

?-@ 2eldin' parame!ers( >i'ures 6%45 !hrou'h

6%4. sho) !he rela!ionship be!)een !he #ol!a'e and

$urren! le#els1 and !he !ype o !ranser a$ross !he

ar$s(

b( Pulsed%$urren! ",A2 pro$ess(

?4@ Ad#an!a'es( This pro$ess is useul )hen lo)

hea! inpu! is reuired G )hen one is )orin' )i!h

!hin ma!erials or doin' ou!%o%posi!ion )eldin'1 or

e=ample( In !he lo)er hea!%inpu! ran'e1 pulsed $ur%

ren! has !h e ad#an!a'e o !he $on!inous pro&e$!ed

spray%!ranser pro$ess( Hi'h%uali!y )elds $an be

produ$ed in mild and lo)%alloy s!eels( In !he )eld%

in' o aluminum1 lar'er diame!er )ires $an be usedB

)elds )i!h less porosi!y are produ$ed be$ause !here

is less hydro'en and o=y'en pi$up on !he )ire

sura$e(

6%49


34/98

TM 5 - 8 0 5 - 7

?5@ Disad#an!a'es( The ma&or disad#an!a'e o

!his pro$ess is !he $omple= po)er supply reuired in

addi!ion !o !he ",A2 )ire eeder and )eldin'

!or$h(

?6@ Pro$ess prin$iples( Pulsed%$urren! ",A2 is

a modii$a!ion o !he pro$ess used !o ob!ain spray%

!ype !ranser )i!h a#era'e $urren! le#els in !he 'lob%

ular%!ranser ran'e( This pro$ess pro# ides a hi'herra!io o hea! inpu! !o me!al deposi!ion ra!e !han !he

shor! %$i r$ui ! in' p ro$ess ( Pulsed%$urren! ",A2

opera!es a! hea! inpu!s be!)een !hose used or spray

!ranser and shor!%$ir$ui!in' !ranser1 )i!h some

o#erlap in !he ran'es( In !his pro$ess1 !he $urren! is

pu lsed ba$ and or! h be !)een pro& e$ !ed% !ranser

and 'ra#i!a!ional%!ranser ran'es by ele$!roni$ally

s)i!$hin' !he $urren! le#el ba$ and or!h be!)een

!hem( >i'ure 6%49 sho)s !he $urren! ou!pu!%)a#e

orm and me!al%!ranser seuen$e( Pulsed%$urren!

)eldin' is also no)n by !he !rade name +pulsed%

ar$( 3

?7@ Euipmen!( The po)er sour$es or pulsed

$urren! $ombine a !hree%phase1 ull%)a#e !rans%

ormer%re$!iier po)er supply1 and a sin'le%phase1

hal%)a#e pulse uni!( These uni!s are $onne$!ed in

parallel1 bu! are ele$!roni$ally s)i!$hed in opera!ion

!o 'i#e !he ou!pu! )a#eorm sho)n in i'ure 6%49(

I ) .4

S!andard ",A2 )ire eeder and !or$hes are used

in !his pro$ess(

$( Shor!%$ir$ui!in' !ranser ",A2 )eldin'(

?4@ Ad#an!a'es( The shor!%$ir$ui!in' pro$ess is

)idely used or ui$ly )eldin' !hin ma!erials ?up

!o

4/7 in$h@ in all posi!ionsB i! $auses li!!le dis!or!ion

and e) me!allur'i$al dee$!s( This pro$ess is used

on $arbon and lo)%alloy s!eels1 and less o!en on

s!ainless s!eel and aluminumB i! is also used or ou!%

o%posi!ion )eldin' o !hi$er ma!erials(

?5@ Disad#an!a'es( "enerally1 )elds made )i!h

!he shor!%$ir$ui!in' pro$ess are o sli'h!ly poorer

uali!y !han !hose produ$ed by !he spray%!ranser

me!hod( This may no! $ause !rouble i hi'h%uali!y

)elds are no! reuired(

?6@ Pro$ess prin$iples( The shor! %$ ir $u i! in'

!ranser #aria!ion o !he ",A2 pro$ess is 'enerally

similar !o spray%!ranser )eldin'( The main dier%

en$e is !he )ay !he mol!en me!al is !ranserred rom

!he end o !he ele$!rode )ire !o !he )eld puddle( In

spray%!ranser )eldin'1 drople!s are ! ranser red

!hrou'h !he ar$( 2i!h !he shor!%$ir$ui!in' pro$ess1

me!al !ranser o$$urs durin' repe!i!i#e shor! $ir$ui!s

$aused )hen !he mol!en me!al rom !he ele$!rode

$on!a$!s !he )eld puddle ( The )eldin' $u rren ! is

)ell be lo) !he !ransi!ion le#el reuired or spray

5


35/98

T M 5 - 8 0 5 - 7

!ranser( As !he end o !he iller )ire mel!s1 i! orms

a ball ?i' 6%5@( This be$omes lar'er un!il i! !ou$hes

!he )eld puddle1 e=!in'uishin' !he ar$ and $rea!in'

a shor! $ir$ui!( The ar$ len'!h is delibera!ely ep!

shor! so !ha! !he me!al ba ll !ou$hes !he puddle

beore i! separa!es rom !he end o !he iller )ire(

2hen !he shor! $ir$ui! o$$urs1 !he )eldin' $urren!

in$reases rapidly1 $ausin' !he drop o mol!en me!al!o be +pin$hed3 rom !he end o !he iller )ire(

The ar$ is reini!ia!ed and !he pro$ess repea!ed(

The shor!%$ir$ui!in' a$!ion is #ery rapidB as many as

5 shor! $ir$ui!s per se$ond may o$$ur( This

pro$ess is also no)n as +shor! ar$1 3 dip%!ranser1 or

ine )ire )eldin'1

?7@ Euipmen!( Shor!%$ir$ui!in' !ranser )eld%

in' uses !he same $ons!an! #ol!a'e euipmen! as

does spray !ranser( The po)er sour$e mus! ha#e a

de#i$e !ha! inser!s a #ariable bu! $on!rolled amoun!

o indu$!an$e in!o !he ele$!ri$al $ir$ui!( This indu$%

!an$e $on!rols !he ra!e o $urren! in$rease )hen !he

shor! $ir$ui! o$$urs and permi!s !he ar$ !o res!ar!

)i!hou! )eld%me!al spa!!er(

?a@ Shor!%$ir$ui!in' )eldin' reuires a smaller

diame!er iller )ire ?(6%in$h diame!er1 or e=am%

pl e@ !han i s 'en era l ly use d or sp ray% ! ranser

)eldin'(

?b@ The shieldin' 'as used or shor!%$ir$ui!in'

)eldin' depends on !he me!al bein' )elded( Ar'on1

helium1 or mi=!ures o !hese ar e used or )eldin'

aluminum( Carbon dio=ide1 a mi=!ure o $arbon

dio=ide and ar'on1 or ar'on )i!h a small o=y'en

addi!ion is used )hen )eldin' mild or lo)%alloy

s!eel( >or s!ainless s!eel1 ar'on )i!h o=y'en or $ar%

bon dio=ide addi!ions is used(

-5. F*u6-("$' %( $*'i&+ 2FCAW3

>lu=%$ored1 !ubular%ele$!rode )eldin' has e#ol#ed

rom !he ",A2 pro$ess !o impro#e ar$ a$!ion1

me!al !ranser1 )eld%me!al proper !ies 1 and )eld

appearan$e(

a( Ad#an!a'es( The ma&or ad#an!a'es o lu=%$ored

)eldin' are redu$ed $os! and hi'her deposi!ionra!es !han ei!her S,A2 or solid )ire ",A2( The

$os! is less or lu=%$ored ele$!rodes be$ause !he

alloyin' a'en!s are in !he lu=1 no! in !he s!eel iller

)ire as !hey are )i!h solid ele$!rodes( >le=%$ored

)eldin' is ideal )here bead appearan$e is impor!an!

and no ma$hinin' o !he )eld is reuired( >le=%

$ored )eldin' )i!hou! $arbon dio=ide shieldin' $an

be used or mos! mild s!ee l $ons !ru$ !ion appli$a%

!ions1 The resul!in' )elds ha#e hi'her s!ren'!h bu!

less du$!ili!y !han !hose or )hi$h $arbon dio=ide

shieldin' is used( There is less porosi!y and 'rea!er

pene!ra!ion o !he )eld )i!h $arbon dio=ide shield%

in'1 The lu=%$ored pro$ess has in$reased !oleran$esor s$ale and dir!B !here is less )eld spa!!er !han )i!h

solid%)ire ",A2(

b( Disad#an!a'es( ,o s! lo)%al loy or mild%s!eel

ele$!rodes o !he lu=%$ored !ype are more sensi!i#e

!o $han'es in )eldin' $ondi!ions !han are S,A2

ele$!rodes( This sensi!i#i!y1 $alled #ol!a'e !oleran$e1

$an be de$reased i a shieldin' 'as is used1 or i !he

sla'%ormin' $omponen!s o !he $ore ma!erial are

in$reased( A $ons!an!%po!en!ial po)er sour$e and

$ons!an!%speed ele$!rode eeder are needed !o main%

!ain a $ons!an! ar$ #ol!a'e(

$( Pro$ess prin$iples( The lu=%$ore )eldin' )ire1

or ele$!rode1 is a hollo) !ube illed )i!h a mi=!ure odeo=idiFers1 lu=in' a'en!s1 me!al po)ders1 and

erro alloys1 as sho)n in i'ure 6%54( The $losure

seam1 )hi$h appears as a ine line1 is !he only #isible

I 5 6 7 - 8

3-21


36/98

TM 5-805-%

dieren$e be!)een lu=%$ored )ires and solid $old%

dra)n )ire( >lu=%$ored ele$!rode )eldin' $an be

done in !)o )ays* $arbon dio=ide 'as $an be used

)i!h !he lu= !o pro#ide addi!ional shieldin'1 or !he

lu= $ore alone $an pro#ide all !he shieldin' 'as and

sla''in' ma!erials( The $arbon dio=ide 'as shield

produ$es a deeply pene!ra!in' ar$ and usually pro%

#ides be!!er )eld !han is possible )i!hou! an e=!er%

nal 'as shield(

d( Euipmen!( The euipmen! and $on!rols or !he

lu=%$ore pro$ess are similar !o1 and some!imes !he

same as1 !hose used in !he s!ray%!ranser me!hod(

The uni! $onsis!s o a $ons!an!%speed )ire%dri#e sys%

!em1 )a!er% or air%$ooled )eldin' !or$h1 and a $on%

s!an!%po!en!ial DC uni! )i!h a 4%per$en! du!y

$y$le(

-. G%# u&+#$&-%( 2GTAW3

The "TA2 pro$ess uses a non$onsumable ele$!rode

and an iner! shieldin' 'as( This pro$ess is also no)n

as TI" ?!un's!en iner! 'as@ and by !he !rade name

+Heliar$(3 "TA2 is similar !o o!her ar$%)eldin'

pro$esse s in !ha! !he hea! is 'enera!ed by an ar$

be!)een a non$onsumable ele$!rode and !he )or

pie$e1 bu ! !he euipmen! and !he ele$!rode !ype

dis! in'uish "TA2 rom !he o!her ar$ )eldin'

pro$es ses(

&. Ad#an!a'es( The "TA2 pro$ess is !he mos!

popular me!hod or )eld in' aluminum1 s!ain less L

s!eel1 and ni$el base alloys( I! produ$es !op uali!y

)elds in almos! all me!als and alloys used in indus%

!ry( The pro$ess pro#ides more pre$ ise $on!rol o

!he )eld !han any o!her ar$ )eldin' me!hod

be$ause !he ar $ hea! and iller me!al are indepen%

den!ly $on!rolled1 isibili!y is e=$ellen! be$ause no

smoe or umes are produ$ed durin' )eldin'B !here

is no sla' or spla!!er !ha! mus! be $leaned be!)een

passes or on a $omple!ed )eld1 "TA2 is usually

$onsidered one o !he mos! #ersa!ile pro$es se s

be$ause i! produ$es !he hi'hes! uali!y )elds in any

posi!ion or $oni'ura!ion1 The inal ma&or ad#an!a'e

is redu$ed dis!or!ion in !he )eld &oin! be$ause o !he

$on$en!ra!ed hea! sour$e( This is one o !he bes!

pre$au!ions !ha! $an be !aen !o pre#en! )eld $ra$%

in' or lo$ed%up s!resses(

b( Disad#an!a'es( The "TA2 pro$ess is e=pensi#e

be$ause !he ar$ !ra#el speed and )eld me!al deposi%!ion ra!es are lo)er !han )i!h some o!her me!hods(

In addi!ion1 i! is less ad#an!a'eous !o use "TA2 on

hea#y1 !hi$ ma!erials(

$( Pro$ess prin$iples( In !he "TA2 pro$ess1 !he

!un's!en alloy ele$!rode is moun!ed in a spe$ial

ele$!rode holder desi'ned !o urnish a lo) o iner!

'as around !he ele$!rode and !he ar$( The ar$ is

CROSS-SECTIONS

OF FLU'-CORED WIRES

3-22


37/98

TM 5 - 8 0 5 -7

s!ru$ be!)een !he base me!al and !he ele$!rode by

one o !)o me!hods( In !he irs!1 $alled a s$ra!$h

s!ar!1 !he opera!or a$!ually !ou$hes !he )or pie$e

)i!h !he !un's!en and )i!hdra)s sli'h!ly( The se$%

ond me!hod uses hi'h%reuen$y dis$har'e rom !he

ele$!rode !o !he )or pie$e !o es!ablish !he ar$( This

is be!!er or )elds !ha! ha#e !o be #ery $leanB a

s$ra!$h s!ar! $ould lea#e par!i$les o !un's!en in !he)eld1 $ausin' bri!!le spo!s( A!er !he ar$ is s!ar!ed1

!he iller me!al1 i reuired1 is ed in!o !he )eld pool

near !he ar$1 as sho)n in i'ure 6%55( The mol!en

)eld me!al1 !he ad&a$en! base me!al1 and !he ele$%

!rodes are pro!e$!ed by a lo)in' 'aseous en#elope

o iner! 'as* 'enerally ar'on1 helium1 or a mi=!ure

o !he !)o( ,os! "TA2 is done manually1 bu! or

pro% du$! ion or assembly !ype )elds su$h as lon'

bu!! )elds1 !he sys!em $an be en!irely au!oma!ed(

AC is used 'enerally or aluminum and ma'nesium1

)hile DC s!rai'h! polari!y is used or all o!her me!als(

d( Euipmen!( The euipmen! in$ludes an ele$!ri%

$al po)er sour$e1 ele$!rode holder ?!or$h@1 !un's!en

or !un's!en alloy ele$!rodes1 'as lo) re'ula!in'

euipmen!1 and usually a remo!e rheos!a! or o%on

s)i!$hin' and $urren! $on!rol ?i' 6%55@(

?4@ There are AC and DC po)er uni!s )i!h

buil!%in hi'h reuen$y 'enera!ors desi'ned spe$ii%

$ally or "TA2( These au!oma!i$ally $on!rol 'as

and )a!er lo) )hen )eldin' be'ins and ends( Ho)%

e#er1 po)er supplies )i!hou! !hese $on!rols $an also

be used(

?5@ I !he ele$!rode holder ?!or$h@ is )a!er%

$ooled1 a supply o $oolin' )a!er is needed( Ele$%

!rode holders are made so !ha! ele$!rodes and 'as

noFFles $an be readily $han'ed1 ei!her or dieren!

siFes or or repla$emen!(

?6@ ,e$haniFed "TA2 euipmen! may in$lude

ele$!roni$ de#i$es or $he$in' and ad&us!in' !he

)eldin' !or$h le#el1 euipmen! or )or handlin'1

pro#isions or ini!ia!in' !he ar$ and $on!rollin' 'as

and )a!er lo)1 and iller me!al eed me$hanisms(

-7. Su$+$' %( 2SAW3

In !he SA2 pro$ess1 !he ar$ is no! #isible1 bu! is

submer'ed under a layer o 'ranula!ed lu= ?i' 6%

56@( This pro$ess $an be used )i!h ei!her a sin'le

ele$!rode )ire or many( A2S D4(4 des$ribes !he

pro$edure1 euipmen! 1 ele$!rodes1 and lu= used

)i!h SA2(a( Ad#an!a'es( SA2 is an ei$ien! pro$ess !ha!

$an be used on nearly all errous me!als( 2elds o

#ery 'ood uali!y are produ$ed in a )ide ran'e o

me!als !hi$er !han 4/4 8 in$h( Carbon1 alloy1 or

s!ainless s!eels up !o l/5%in$h !hi$ are )elded in

one pass1 )hile !hi$er ma!erials reuire more

passes( 2eld me!al deposi!ion ra!es1 ar$ !ra#el

speeds1 and )eld $omple!ion ra!es are be !!er !han

!hose or o!her pro$esses( There is no #isible ar$ and

no )eld spa!!er1 and !he deep pene!ra!in' ee$! o

$on$en!ra!ed hea! allo)s narro) )eldin' 'roo#es(

Thus1 i! !aes less iller me!al !o mae a &oin! )i!h

SA2 !han )i!h o!her )eldin' pro$esses1 The

unused lu= $an be re$o#ered and re$y$led )hen

!he )eldin' is inished(b( Disad#an!a'es( The basi$ limi!a!ion o SA2 is

!ha! i! $an only be used in !he la! posi!ion and or

horiFon!al ille! )elds( 2elds $an be made in !he

horiFon!al posi!ion1 bu! sin$e !he 'ranular lu=

needed !o shield !he )eld me!al mus! be in pla$e in

ron! o !he ele$!rode1 $ompli$a!ed dams and sup%

por! s may be reuired !o $on!ain !he lu=( The

euipmen! used in !his pro$ess $an be hand%held1

bu! is usually me$haniFed1 main' i! hea#y and

$um% bersome and !hereby limi!in' i!s use !o

abri$a!ion shops( The used lu= mus! be remo#ed

by $hippin' and )ire brushin'(

$( Pro$ess prin$iples( SA2 !aes pla$e benea!h!he lu= $o#erin' )i!hou! spars1 spa!!er1 smoe1 or

lash( The ele$!rode and )eld pool are $omple!ely

$o#ered a! all !imes durin' )eldin'( The lu= maes

poss ib le !hese spe$ia l opera!in' $ondi!ions1 )hi$h

dis!in'uish SA2 rom o!her pro$esses( 2hen $old1

!he lu= does no! $ondu$! ele$!ri$i!yB !hereore1 !he

)elder mus! es!ablish a $ondu$!i#e pa!h or s!ar!in'

!he ar$( This $an be done by s$ra!$h s!ar!in' )here

!he ele$!rode !ou$hes !he base pla!e or by buryin'

some s!eel )ool in !he lu= a! !he s!ar!in' poin!( In

!he mol!en s!a!e1 !he lu= be$omes hi'hly $ondu$%

!i#e( On$e !he ar$ is s!ar!ed1 !he hea! produ$ed by

!he $urren! $auses !he surroundin' lu= !o be$ome

mol!en( This orms a $ondu$!i#e pa!h1 )hi$h is ep!

mol!en by !he $on!inued lo) o )eldin' $urren!(

The buried par! o !he lu= is mel!edB !he #isible par!

remains un$han'ed in bo!h appearan$e and proper%

!ies1 and $an be reused( All $urren!s and polari!ies

are used1 dependin' on !he desired pene!ra!ion and

bead shape1 Re#erse polari!y pro#ides !he bes! bead

shape and pene!ra!ion1 )hile s!rai'h! polari!y 'i#es

hi'her deposi!ion ra!es bu! less pene!ra!ion( Al!er%

na!in' $urren! pro#ides pe ne !ra! ion some)here

be!)een !he !)o and is preerre d or mul!i%)ire

)eldin'( The used lu= is $hipped o !he )eld and

dis$arded(

?4@ The )eldin' ele$!rodes mus! be posi!ioned

properly( >lu= is ed in ron! o and around !he ele$%

!rode by a hopper( The ar$ is s!ru$ and !he ele$%

!rodes mo#ed alon' !he )eld( The opera!or )a!$hes

!he amme!er and #ol!me!er readin's !o $on!rol $ur%

ren! and #ol!a'e ad&us!men!s( A #ariable%speed

mo!or $on!rols !he ele$!rode eedB a po)er%opera!ed

3-23


38/98

TM 5-805-7

-)4


39/98

$arria'e $on!rols !he !ra#el ra!e( Unused lu= is ed

ba$ in!o !he hopper(

?5@ ,odera!ely !hi$ se$!ions o ma!erial ?up !o

4 in$h@ )i!h a $arbon $on!en! up !o (6- per$en! $an

be )elded )i !hou ! pre$au !ion s su $h as prehea!in'

and pos!)eld hea! !rea!men!( Prehea!in' is 'ener%

ally needed )hen !he $arbon $on!en! is o#er (6-

per$en!(

rapidly so !ha! desirable mi$ros!ru$!ure orm( An

!hin' !ha! delays $oolin'1 su$h as prehea!in' or h

)eldin' hea! inpu!s1 should be a#oided(

d( Euipmen!( ;o!h semi%au!oma!i$ and au!oma

SA2 euipmen! is a#ailableB !he !ype used 'enera

depends on !he )or !o be done1 and on e$onom

a$!ors( Semi%au!oma!i$ euipmen! is be!!er

repair )eldin' and or )eldin' !ha! $anno! be do

?6@ i'ure 6%57 sho)s !he euipmen! needed or au!

ma!i$ SA2B in$luded are a po)er sour$e1 )ire ee

in' sys!em1 lu= eedin' sys!em1 and a )eldin' !or

?4@ The po)er supply may be DC $ons!an! $

ren!1 DC $ons!an! #ol!a'e1 or AC( The po)er sup

and )ire%dri#e me$hanism mus! be desi'ned

opera!e !o'e!her so !ha! !he ar$ len'!h $an be $

!rolled ee$!i#ely( SA2 'enerally is done a! hi'

$urren!s ?- !o 4 amperes@ !han o!her !ypes

ar$ )eldin'1 so !he po)er supply mus! ha#e a h

$urren! ra!in' a! hi'h du!y $y$les(

6%5


40/98

T M 5 - 8 0 5 - 7

?5@ The ele$!rodes used )i!h SA2 are 'enerally

bare rods or )ire in $oils( The $hoi$e o ele$!rode

depends on !he )ay !he alloyin' elemen!s are in!ro%

du$ed in!o !he )eld( One me!hod is !o use mild%s!eel ele$!rodes )i!h lu=es $on!ainin' !he alloy(

Ano!her me!hod o!en used reuires spe$ial alloy

s!eel ele$!rodes and neu!ral lu=1 and in$ludes lo)%

$arbon s!eel1 lo)%$arbon alloy s!eel1 spe$ial alloy

s!eels1 hi'h%$arbon s!eels1 s!ainless s!eels1 and non%

errous alloys(

?6@ The lu=es are 'ranula!ed1 usible mineral

ma!erials o #arious $omposi!ions and par!i$le siFes(

The $hoi$e o lu= depends on !he )eldin' pro$e%

dure1 &oin! $oni'ura!ion1 and $omposi!ion o !he

base me!a l !o be )elded( The lu= may in$lude

alloyin' elemen!s(

-8. E6"$i( $*'i&+

In e=o!hermi$ )eldin'1 hea! is 'enera!ed by !he

$hemi$al rea$!ion be!)een a $ombina!ion o alumi%

num and iron o=ide( This mi=!ure is pla$ed in a hop%

per abo#e a mold )hi$h surrounds !he &oin!1 and is

!hen i'ni!ed( A $hemi$al rea$!ion o$$urs1 and !he

mol!en me!al and sla' drop !hrou'h !he hopper(

Sin$e !he mol!en me!al is hea#ier !han !he sla'1 i!

se!!les !o !he bo!!om o !he mold and !ou$hes !he

6%58

s!eel &oin!( The mol!en me!al mel!s !he sura$e o !he

me!al and uses )i!h i!1 ormin' !he )eld( This

pro% $ess1 $ommonly reerred !o as +!hermi! )eldin'1

3 is used or &oinin' reinor$in' rods1 rails1 lar'e$as!in's or or'in's1 and or repairin' lar'e s!ru$!ural

shapes( His!ori$ally1 !hermi! )eldin' )as lar'ely

$onined !o s!ru$!ures made o iron and s!eel( ;u!

re$en!ly1 !he subs!i!u!ion o a $opper o=ide or iron

o=ide has led !o many appli$a!ions )i!hin !he

ele$!ri$ al indus!ry su$h as &oinin' or repairin'

ele$!ri$al $onne$!ors1 $ables1 bus bars1 and bus !ubes(

Thermi! )eldin' is also used or )eldin' pipe( In

!his appli$a!ion !he !hermi! does no! mi= )i!h

!he pipe me!al1 bu ! merely urnishes !he hea! !o

mel! !he pipe ends1

)hi$h are !hen bu!!ed !o'e!her as !hey mel!(

a( Ad#an!a'es(?4@ The )elder needs #ery li!!le ins!ru$!ion or

e=perien$e !o produ$e 'ood )elds rapidly(

?5@


41/98

TM 5 - 8 0 5 - 7

b( Disad#an!a'es( ,olds are needed () hold !he

mol!en me!al around !he )eld &oin!( >or one%o%a%

ind &obs1 su$h &* repairs1 !he molds mus! be $on%

s!ru$!ed indi#idually1 and a sui!able )a= or plas!i$

orm iller ma!erials +*(be inser!ed in !he 'ap !o

insure proper $learan$e be !) een !he par!s(

Preormed permanen! molds are used or repe!i!i#e

&o bs G )eldin' rails or reinor$in' rods1 ore=ample(

$( Pro$ess prin$iples( Thermi! )eldin' is based on

!he undamen!al prin$iple !ha! aluminum is more

$hemi$ally a$!i#e !han iron( The )eldin' pro$ess

-).*/*(* o mi=in' !he iron o=ide and aluminum1 bo!h

in po)der orm1 and pla$ in' !hem in a hopper or

$ru$ible abo#e a mold )hi$h surrounds !he &oin!

area( ?The &oin! !o be )elded mus! be $leaned1 prop%

erly spa$ed1 and prehea!ed( @ An i'ni!ion po)der1

su$h as a mi=!ure o barium pero=ide and aluminum

po)der1 is pla$ed on !op o !he !hermi!1 and a use is

inser!ed in!o !he po)der( The rea$!ion s!ar!s a!er

!he use i'ni!es !he mi=!ureB !his happens a! abou!

5 +>( The rea$!ion is none=plosi#e and !aes

abou! 6 se$ondsB on$e !he mi=!ure s!ar!s !o burn1 i!

is sel%propa'a!in'( 2hen !he rea$!ion is $omple!e1

!he mol!en me!al has rea$hed a !empera!ure o

a p p ro = i m a ! e l y 7 - o

>1 )hi$h is nearly 4 8 o >

hi'her !han !he !empera!ure o ordinary mol!en

s!eel( The me!al is poured in!o !he mold !o orm !he

)eld ?i' 6%5-@( The mold is allo)ed !o remain in

posi !ion or se#eral hours !o permi! solidii$a!ion

and !o anneal !he )eld( The deposi!ed me!al $ools

uniormly and is $ompara!i#ely ree rom s!resses(

The mold is !hen remo#ed and !he 'a!es and risers

are $u! a)ay1 E=$ess )eld $an be 'round or

ma$hined( Al!hou'h !he pr in$ipa l appli$a!ion o

!hermi! )eldin' has been )i!h !he aluminum and

iron o=ide mi=!ure on s!eel s!ru$!ures1 o!her me!als

or !heir o=ides may be in$luded in !he !hermi! mi=%

!ure( Chromium1 ni$el1 man'anese1 !un's!en1 !i!a%

nium1 molybdenum1 and $obal! $an be used( These

3-2%


42/98

T M 5 - 8 0 5 - 7

elemen!s alloy )i!h iron and are used )hen hi'her

s!ren'!h1 du$!ili!y1 or hardness is reuired( They

also permi! $on!rol o !he !empera!ure and !ime o

!he rea$!ion( Cas! iron $an be )elded )i!h a spe$ial

!hermi! mi=!ure(

d( Euipmen!( Thermi! )eldin' i!s are a#ailable(

They $onsis! o a permanen! mold1 prepa$a'ed

!hermi! $har'es1 $onsumable !appin' dis$s1 $har'eso i'ni!ion po)der1 and uses( An indi#idually $on%

s!ru$!ed mold reuires )a= or oam iller1 sand mold

?a spe$ial mi=!ure o sili$a sand and plas!i$ $lay@1 and

'a!es1 risers1 pourin' 'a!es1 and a sla' basin ?i' 6%

5-@(

-. A(-#u' $*'i&+

Ar$%s!ud )eldin' is an ar$ )eldin' pro$ess in )hi$h

an ele$!ri$ ar$ is s!ru$ be!)een a me!al s!ud and

ano!her pie$e o me!al( 2hen !he sura$es !o be

3-28

&o in !e d are p roperly hea!ed 1 !hey are b rou'h!

!o'e!her under pressure( A $erami$ errule sur%

roundin' !he s!ud $an pro#ide par!ial shieldin'( The

pro$ess is 'enerally reerred !o as +s!ud )eldin'( 3

A2S D4(4 des$ribes s!ud )eldin' pro$edures1

euipmen!1 )ormanship1 ual i !y $on!rol 1 and

inspe$!ion reuiremen!s(

a( Ad#an!a'es( Ar$%s!ud )eldin' has many ad#an%!a'es and uses( 2i!h !his pro$ess1 !here is no need !o

drill or pun$h holes1 nor !o as!en an ob&e$! me$han%

i$ally !o a main s!ru$!ure )i!h bol!s1 ri#e!s1 or

s$re)s( Ar$%s!ud )eldin' is )idely a$$ep!ed by all

!he me!al%)orin' indus!ries( Sin$e #ir!ually e#ery

phase o !he opera!ion is au!oma!i$1 no pre#ious

)eldin' e=perien$e i s ne$essary ( Ine=per ien$ed

opera!ors $an be !rained ui$ly1 and on$e !he

euipmen! is se! or a par! i$ular &ob1 hi'h%uali!y

)elds are ui$ly and easily made( The )eldin' 'un

b. Trigger is depressed


43/98

CONTROL

TM 5-805-%

3-29


44/98


45/98

T M 5 - 8 0 5 - 7

Table 3-2. Summary of welding processes and application

Conditions

*aterials

co&&onl0

elded

.-.1


46/98

T M 5 -8 05 -7

CHAPTER 4

WELDING OF STAINLESS STEEL

4-1. G$&$%*

S!ainless s!eels )ere ori'inally de#eloped be$ause o

!heir ou!s!andin' resis!an$e !o $orrosion( They also

e=hibi! 'ood me$hani$al proper!ies1 )hi$h $an be as

impor!an! !o !he lie o !he s!ru$!ure as !he $orrosion

resis!an$e( There are our !ypes o s!ainless s!eel*

mar!ensi!i$1 erri!i$1 aus!eni!i$1 and pre$ipi!a!ion

hardened( These s!eels e=hibi! a )ide ran'e o

me$hani$al proper!ies bo!h a! room !empera!ures

and a! $ryo'eni$ !empera!ure s ?belo) : 4 -

de'rees >@( The s!ainless s!eels $ommonly used are

$o#ered in spe$ii$a!ions o AST,1 !he Ameri$an

Iron and S!eel Ins!i!u!e ?AISI@1 !he So$ie!y o Au!o%mo!i#e En'ineers ?SAE@1 AS,E1 API1 and !he mili%

!ary or o!her >ederal a'en$ies( Commonly used

s!ainless s!eels are !he aus!eni!i$ $lass !ha! mee!

spe$ii$a!ions or AISI 'rades in !he 5 and 6

series( ,ar!ensi!i$ s!ainless s!eels in !he AISI 7

series are also used( 2hen desi'nin' or 7 series

s!ainless s!eels1 one mus! use e=!ra $are be$ause o

!heir sensi!i#i!y in hea! !rea!in'( S!ainless s!eels !ha!

$onorm !o o!her spe$ii$a!ions $an be used )here

par!i$ular reuiremen!s mus! be me!( S!ainless s!eel

)eldin' ele$!rodes are spe$iied by A2S or mili!ary

do$umen!s( Commonly used )eldin' ele$!rodes o r

abri$a!ion mee! spe$ii$a!ions A2S A-(71 A-(91

A-(441 A-(471 and A-(55(

4-). W$*'%i*i9 ": #%i&*$## #$$*#

The aus!eni!i$ $hromium%ni$el s!eels ar e o!en

used or $ryo'eni$ and #a$uum sys!ems( These s!eels

are $hara$!eriFed by !heir $orrosion resis!an$e1 lo)%

ma'ne!i$ permeabi li !y 1 'ood hi'h%!empera!ure

s!ren'!h1 and e=$ellen! lo)%!empera!ure du$!ili!y

and no!$h !ou'hness( Some o !he aus!eni!i$ s!eels1

ho)e#er1 do ha#e $hara$!eris!i$s !ha! res!ri$! !heir

use in $ryo'eni$ appli$a!ions ?!able 7%4@( ;u! !heaus!eni!i$ s!eels are $onsidered !he mos! )eldable o

!he hi'h alloy s!eels( Three basi$ a$!ors ae$! !he

)eldabili!y o s!ainless s!eels* ?4@ !he $hemi$al $om%

posi!ion o !he base me!al and !he )eld me!al1 ?5@

!he mi$ros!ru$!ure o !he base me!al and !he )eld

me!al1 and ?6@ !he use o !he $orre$! )eldin' pro$e%

dures and !e$hniues

a( Chemi$al $omposi!ion( The ma&or $ons!i!uen!s

in s!ainless s!eels are iron1 $arbon1 man'anese1

sili$on1 $hromium1 and ni$el( The $hromium is pri%

marily responsible or !he s!ain and $orrosion resis%

!an$e o !hese s!eels( I! has an aini!y or o=y'en and

orms a !hin1 imper#ious1 pro!e$ !i#e 1 o=ide layer(

Chromium also has an aini!y or $arbon and orms

$hromium%$arbides rapidly be!)een . a n d

48J>(

?4@ 2hen $hromium%$arbides are ormed1 !hey

!ie up mu$h o !he $hromium and se#erely redu$e

!he $orrosion resis!an$e o !he s!eel( Typi$ally1 !his

$an happen in a Fone ne=! !o and on ei!her side o

!he )eld &oin!( This phenomenon1 no)n as sensi!i%

Fa!ion1 o$$urs be$ause a re'ion ne=! !o !he )eld is

hea!ed !o be!)een . and 48 +> by !he )eldin'

ar$( I !he )eld &oin! is sub&e$!ed !o a $orrosi#e

en#ironmen!1 nie%line a!!a$ resul!s( Three !e$h%

niues are used !o mi!i'a!e sensi!iFa!ion( These

me!hods $an be e=pensi#e and should be used only

)hen sensi!iFa!ion is a problem(

?a@ E=!ra%lo) $arbon ?less !han (6 per$en!

$arbon@ 'rades o s!eel $an be used( This $arbon

$on!en! is !he ma=imum amoun! !ha! is soluble in

s!ainless s!eels and does no! easily $ome ou! o

solu!ion(

?b@ S!abiliFin' elemen!s su$h as $olumbium

and !an!alum $an be used( These orm $arbides pre%

eren!ially o#er $hromium1 !hereby !yin' up !he

$arbon(

?$@ A pos!%)eld hea! !rea!men! $an be used(

The mos! $ommon hea! !rea!men! !e$hniue is !o

solu!ion anneal a! 49J>1 !hen )a!er uen$h( This

!e$hniue pu!s all !he $arbon in solu!ion and eeps

i! !here by rapidly $oolin' !hrou'h !he 48 !o .o

> ran'e(

?5@ In a ully aus!eni!i$ s!ainless s!eel )eld ?su$h

as a !ype 64@1 !he du$!ili!y and soundness o !he

)eld depend on !he $arbon !o sili$on ra!io( Ideally1

!his ra!io should be abou! 4*5( An in$rease in

sili$on abo#e !his ra!io $auses issurin'?mi$ro$ra$in'@ in !he )eld me!a l an d a rapid loss

o du$!ili!y( An

in$rease in !he $arbon ra!io $auses a less se#ere

de$rease in du$!ili!y )i!hou! ae$!in' )eld sound%

ness( 2i!h ully aus!eni!i$ s!ainless s!eels1 !he $ar%

bon !o sili$on ra!io mus! be $losely $on!rolled( This

!ends !o limi! !he use o su$h s!eels )hen )eld &oin!s

)i!h !he bes! uali!y and du$!ili!y are reuired(

b( ,i$ros !ru$ !ura l ee$!s( T)o mi$ros!ru$!ural

a$!ors ae$! !he uali!y o aus!eni!i$ s!ainless s!eel

7%4


47/98

TM 5 - 8 0 5 - 7

)eld &oin!s* erri!e $on!en! in )eld me!al and base

me!al1 and 'rain 'ro)!h in )eld me!al and !he hea!%

ae$!ed Fone( The ollo)in' dis$ussion des$ribes

me!hods o $on!rollin' !hese a$!ors( Desi'ners $an

use !his inorma!ion !o spe$iy !he proper base ma!e%

rials1 and )eldin' pro$edures and ma!erials(

?4@ >erri!e $on!en!(

?a@ >ully aus!eni!i$ )eld &oin!s o!en !end !ode#elop mi$ro$ra$s and issures durin' )eldin'( To

pre#en! !his1 desi'ners should sele$! iller me!als or

ele$!rodes !ha! )ill orm an aus!eni!i$ )eld deposi!

$on!ainin' a small per$en!a'e o erri!e( Su$h )elds

are hi'hly resis!an! !o $ra$in'( Ho)e#er1 i !he er%

ri!e $on!en! be$omes !oo hi'h in $ryo'eni$ appli$a%

!ions1 !he )eld me!als impa$! s!ren'!h a! ser#i$e

!empera!ures $an be seriously redu$ed( >or !hese

appli$a!ions( !he erri!e $on!en! o !he )eld me!al

should be )i!hin !he ran'e o 7 !o 4 per$en!(

?b@ The a$!ual erri!e $on!en! depends on !he

$omposi!ions o !he base me!al and iller me!al or

ele$!rode1 and !he e=!en! !o )hi$h !he )eld me!aldeposi! is dilu!ed by !he )elded paren! me!al( A

S$haeler dia'ram ?i' 7%4@ $an help desi'ners es!i%

ma!e bo!h !he per$en!a'e o erri!e in !he )eld

deposi! and !he iller me!al $omposi!ion ne$essary !o

orm !he reuired erri!e in !he )eld me!al( This

dia'ram is used !o predi$! !he amoun! o erri!e in

s!ainless s!eel )eld me!al on !he basis o )eld me!al

$omposi!ion( The dia'ram sho)s ho) !he mi$ro%

s!ru$!ure o !he )eld deposi! is ae$!ed by !he alloy

elemen!s in s!ainless s!eel !ha! a$! lie ni$el1 and

!hose !ha! a$! lie $hromium( The ni$el eui#alen!

!he )eld me!al be$ause o base me!al dilu!ion( >or

e=ample1 i !ype 65 s!ainless s!eel is )elded usin'

!ype 6. ele$!rode1 !hen !he ni$el eui#alen! or

!he 65 s!ainless is 451 and !he $hromium eui#alen!

is 4.(5-( 2hen !his poin! is plo!!ed1 i! is !o!ally in

!he aus!eni!i$ re'ion1 so !here )ill be no erri!e( The

!ype 6. ele$!rode )ill ha#e a ni$el eui#alen! o

451 and a $hromium eui#alen! o 541 !hus pu!!in'i! $lose !o !he 4 per$en! erri!e line(

?d@ The S$haeler dia'ram $an predi$ ! no!

only !he amoun! o erri!e in !he mi$ros!ru$!ure1 bu!

also !he ele$!rode $omposi!ion !ha! )ill pre#en!

e=$essi#e erri!e or mar!ensi!e $on!en! in s!ainless

s!eel )eld me!al( In addi!ion1 !he dia'ram is helpul

in es!ima!in' !he !rend o !he mi$ros!ru$!ure de#el%

oped )hen dissimilar s!eels are )elded( I pie$es o

$arbon s!eel and s!ainless s!eel are !o be )elded

!o'e!her1 !he $omposi!ions o !he !)o $an be mared

on !he dia'ramB !he !ie line dra)n be!)een !hem

indi$a!es ! h e mi$ ro s! ru $! ur e !ha! may be

en$oun!ered(?5@ "rain 'ro)!h( The !ou'hness and du$!ili!y o

!he hea!%ae$!ed Fone and !he )eld me!al may be

redu$ed some)ha! be$ause o 'rain 'ro)!h $aused

by !he )eldin' hea! ( Ho)e#er1 unless e=!remely

hi'h )eldin' hea!s are used or #ery hea#y )eld

passes ar e deposi !ed1 !he problem o de$reased

!ou'hness and du$!ili!y resul!in' rom 'rain 'ro)!h

is no! serious( I impa$! !es!

welding design procedures and inspection

Documents