welding symbols weld preparations
DESCRIPTION
Welding SymbolsTRANSCRIPT
-
7/18/2019 Welding Symbols Weld Preparations
1/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
TWICSWIP 3.1
WIS 5WELDING INSPECTION
WELDING SYMBOLS ANDWELD PREPARATION
-
7/18/2019 Welding Symbols Weld Preparations
2/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Joints may be indicated:- by detailed sketches, showing every dimension
- by symbolic representation
Weld symbols on drawings
-
7/18/2019 Welding Symbols Weld Preparations
3/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
A method of transferring information from thedesign office to the workshop is:
The above information does not tell us much aboutthe wishes of the designer. We obviously need somesort of code which would be understood by everyone.
Most countries have their own standards for symbols.
Some of them are BS 499 Part 2, AWS A2.4 &
BS EN 22553 (ISO 2553)
Please weld here
Weld symbols on drawings
-
7/18/2019 Welding Symbols Weld Preparations
4/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Advantages of symbolic representation:
Weld symbols on drawings
Disadvantages of symbolic representation:
simple and quick plotting on the drawing
does not over-burden the drawing
no need for additional view
gives all necessary indications regardingthe specific joint to be obtained
used only for usual joints
requires training for properlyunderstanding of symbols
-
7/18/2019 Welding Symbols Weld Preparations
5/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Usually, the symbolic representationincludes:
Weld symbols on drawings
The elementary symbol may be completed by:
an arrow line
a reference line
an elementary symbol
a supplementary symbol
a means of showing dimensions
some complementary indications
-
7/18/2019 Welding Symbols Weld Preparations
6/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld elementary symbols
Various categories of joints are characterised byan elementary symbol.
This symbol is similar to the shape of the weld tobe made.
Square butt weld
Weld type Sketch Symbol
Single V butt weld
-
7/18/2019 Welding Symbols Weld Preparations
7/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld elementary symbols
Single-V buttweld with broadroot face
Weld type Sketch Symbol
Single bevelbutt weld
Single bevel butt
weld with broadroot face
Backing run
-
7/18/2019 Welding Symbols Weld Preparations
8/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld elementary symbols
Single-U
butt weld
Weld type Sketch Symbol
Single-Jbutt weld
Fillet weld
Surfacing
-
7/18/2019 Welding Symbols Weld Preparations
9/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Convention of the arrow line (BS EN & AWS):
Arrow line
a) Shall touch the joint intersection
b) Shall not be parallel to the drawingc) Shall point towards a single plate preparation(when only one plate has preparation)
-
7/18/2019 Welding Symbols Weld Preparations
10/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Convention of the reference line AWS A 2.4
Reference linea) Shall touch the arrow line
b) Shall be parallel to the bottom of the drawing
-
7/18/2019 Welding Symbols Weld Preparations
11/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Convention of the reference line(BS EN ISO 22553):
or
Reference linea) Shall touch the arrow line
b) Shall be parallel to the bottom of the drawing
c) There shall be a further broken line above orbeneath the reference line (Not necessary wherethe weld is symmetrical!)
-
7/18/2019 Welding Symbols Weld Preparations
12/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Welds on arrow sideof joint go underneath thereference line while welds the other sideof the joint,go on top of the reference line
Symbols with a vertical line component must be drawnwith the vertical line to the left side of the symbol
All CSA dimensions are shown to the left of the symbol
All linear dimensions are shown on the right of thesymbol i.e. number of welds, length of welds, length of
any spaces
Included angle and root opening are shown on top ofthe symbol
AWS A 2.4 rules
-
7/18/2019 Welding Symbols Weld Preparations
13/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
10 3 x 50 (70)
AWS A 2.4 rules-example
10
50
70
-
7/18/2019 Welding Symbols Weld Preparations
14/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Welds this side of joint, go on the unbroken reference
line while welds the other side of the joint, go on thebroken reference line
Symbols with a vertical line component must bedrawn with the vertical line to the left side of the
symbol
All CSA dimensions are shown to the left of thesymbol
All linear dimensions are shown on the right of thesymbol i.e. number of welds, length of welds, lengthof any spaces
Included angle and root opening are shown on top of
the symbol
BS EN 22553 rules
-
7/18/2019 Welding Symbols Weld Preparations
15/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
z 10 3 x 50 (50)
BS EN 22553 rules - example
10
50
50
All leg lengths shall be preceded by z and throat by a
or s (in case of deep penetration welds)
-
7/18/2019 Welding Symbols Weld Preparations
16/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
8
8
5
5 x 8
8
Fillet weld dimensions according AWS A 2.4Fillet welds
5 leg on
vertical
member
-
7/18/2019 Welding Symbols Weld Preparations
17/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
5
a 5 (z 8)
8
Fillet weld dimensions according BS EN 22553
or
8
z 8or
z 8
a 5 (z 8)
Fillet welds
-
7/18/2019 Welding Symbols Weld Preparations
18/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Intermittent fillet welds
Chain intermittent fillet weld
length (l)pitch (e) a
z
a nl(e)a nl(e)
z nl(e)z nl(e)
or
Symbol to BS EN 22553
-
7/18/2019 Welding Symbols Weld Preparations
19/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Intermittent fillet welds
Chain intermittent fillet weld
length (l)pitch (e)
z
z l - ez l - e
Symbol to AWS A2.4
-
7/18/2019 Welding Symbols Weld Preparations
20/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Intermittent fillet welds
Staggered intermittent fillet weld
length (l)pitch (e) a
z
a nl (e)a nl (e)
z nl (e)
z nl (e)
or
Symbol to BS EN 22553
-
7/18/2019 Welding Symbols Weld Preparations
21/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Intermittent fillet welds
Staggered intermittent fillet weldlength (l)pitch (e)
z
z l - ez l - e
Symbol to AWS A2.4
e/2
-
7/18/2019 Welding Symbols Weld Preparations
22/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Concave or Convex
Supplementary weld symbols
Toes to be groundsmoothly (BS EN only)Site Weld
Weld all round
Supplementary symbols
-
7/18/2019 Welding Symbols Weld Preparations
23/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Supplementary weld symbols
Ground flush
111
Further supplementary information, such as WPSnumber, or NDT may be placed in the fish tail
Supplementary symbols
Welding processnumerical BS EN
MR
Removable
backing strip Permanent
backing strip
M
-
7/18/2019 Welding Symbols Weld Preparations
24/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Fillet weld
Double V
Double bevel
Double U
Double J
Representation of welds done from both sidesofthe joint intersection, touched by the arrow head
Double side weld symbols
-
7/18/2019 Welding Symbols Weld Preparations
25/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Example:
Produce a drawing giving symbols for the weld givenas shown below to the specification AWS A2.4
Weld Drawing
Symbol Drawing
MMA
Weld symbols on drawings
-
7/18/2019 Welding Symbols Weld Preparations
26/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Example:
Draw the symbols for the weld given as shownbelow to the specification BS EN 22553
Weld drawing
Symbol Drawing 111
Weld symbols on drawings
MMA
-
7/18/2019 Welding Symbols Weld Preparations
27/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
1020
30
35
15
7
Student symbols exerciseComplete a symbols drawing for the welded jointgiven below to AWS A2.4 & BS EN 22553
All fillet weld leg lengths are 10 mm
Weld symbols on drawings
-
7/18/2019 Welding Symbols Weld Preparations
28/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Solution AWS A2.4 10302010
10351510
Weld symbols on drawings
-
7/18/2019 Welding Symbols Weld Preparations
29/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Solution BS EN 22553 z 10s 30s 20z 10
a 7 z 10s 35s 15z 10
Weld symbols on drawings
-
7/18/2019 Welding Symbols Weld Preparations
30/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
This has major effects on economics and distortioncontrol!
The basic rule is this:
The more you take out, then the more you must putback in!
The purposes of a weld preparation is to allowaccess for the welding process, penetration andfusion through the area of the joint and its faces
Weld preparations
-
7/18/2019 Welding Symbols Weld Preparations
31/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparation
Weld preparation depend on:welding process
preparation method available
access
type of joint
type of parent material
thickness
welding position
in-service type of loadingWeld preparation for arc welding - see BS EN 29692!
-
7/18/2019 Welding Symbols Weld Preparations
32/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparation
Welding process impacts upon weld preparation
Arc welding EBW
-
7/18/2019 Welding Symbols Weld Preparations
33/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparation
Welding process impacts upon weld preparation
MMA MAGhigh heat input process allow a larger root face, less weldmetal required, less distortions, higher productivity
if gap is too big risk of possible burn-through
if gap is too small risk of lack of penetration
-
7/18/2019 Welding Symbols Weld Preparations
34/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparation
Preparation method impacts upon weld
preparation
Requires machining slow andexpensive
Tight tolerance easier set-upCan be flame/plasma cut fastand cheap
Large tolerance set-up can bedifficult
-
7/18/2019 Welding Symbols Weld Preparations
35/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparation
Preparation method impacts upon weld preparation
Variations incutting line
Root face too large lack ofpenetration
Root face too small burn-through
Variations incutting angle
Included angle too largeheavy distortions, increase
amount of filler metalrequired
Included angle too smalllack of penetration, lack ofside wall fusion
-
7/18/2019 Welding Symbols Weld Preparations
36/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparation
Preparation method impacts upon weld
preparation - corrective measures
Backing strip (6 mm ormore, same material)
No root face
Root face too large Recut groove preparationIncrease root gap anduse backing strip
-
7/18/2019 Welding Symbols Weld Preparations
37/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparation
Preparation method impacts upon weldpreparation - corrective measures
Too big/too smallincluded angle Recut groove preparation
Increase root gap anduse backing strip
Warning! Backing strips give a built-in crevice
susceptible to corrosion
give a lower fatigue life
-
7/18/2019 Welding Symbols Weld Preparations
38/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Access impacts upon weld preparation
-
7/18/2019 Welding Symbols Weld Preparations
39/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Access impacts upon weld preparation
-
7/18/2019 Welding Symbols Weld Preparations
40/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Access impacts upon weld preparationPipe weld preparation - one side access only!
for wall thickness up to 3 mm
for wall thickness 3 to 20 mmfor wall thickness over 20 mm
-
7/18/2019 Welding Symbols Weld Preparations
41/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Access impacts upon weld preparationPipe weld preparation - one side access only!
self-adjusting items
no danger of burn-through
susceptible to corrosion
lower fatigue lifeTo ensure minimum rootmismatch, the internalbore is sometimesmachined with a lowangled bevel
-
7/18/2019 Welding Symbols Weld Preparations
42/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Type of joint impacts upon weld preparation
danger of burn-through
difficult to set-upeasy set-up
no burn-through
corner joints require offset
offset
ld i
-
7/18/2019 Welding Symbols Weld Preparations
43/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Type of joint impacts upon weld preparation
Bevel angle = 30
Included angle = 60Included angle = Bevel
angle = 50
lap and square edge butt joints do not requirepreparation
ld i
-
7/18/2019 Welding Symbols Weld Preparations
44/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Type of parent material impacts upon weld
preparation
Steel Aluminium
to reduce distortions on stainless steels welds,reduce included angle and increase root face
to avoid lack of side wall fusion problems aluminiumrequire larger included angles than steel
6030
70-90
35-45
W ld i
-
7/18/2019 Welding Symbols Weld Preparations
45/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Thickness of parent material impacts upon weld
preparationa single bevel groove requires a volume of weldmetal proportional to the square of plate thickness
its lack of symmetry lead to distortions
Reduce shrinkage by:
reduce weld volume
use single pass welding
W ld i
-
7/18/2019 Welding Symbols Weld Preparations
46/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Reduce weld volume by:
reduce included angle
Thickness of parent material impacts upon weld
preparation
reduce root gap
W ld ti
-
7/18/2019 Welding Symbols Weld Preparations
47/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Reduce weld volume by:
increase root face
Thickness of parent material impacts upon weld
preparation
use double bevel weld prep
W ld ti
-
7/18/2019 Welding Symbols Weld Preparations
48/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Reduce weld volume by:
use U prep instead V prep
Thickness of parent material impacts upon weld
preparation
U prep better than V prepV prep better than U prep
W ld ti
-
7/18/2019 Welding Symbols Weld Preparations
49/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparations
Reduce distortions by using an asymmetric V prepinstead of a symmetric V prep
Thickness of parent material impacts upon weld
preparation
t/3t
weld first into deeper side
after welding half of depth, root back gouging
weld completely on backside
complete welding on first side
W ld ti
-
7/18/2019 Welding Symbols Weld Preparations
50/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparation
PF symmetric
preparation
Welding position impacts upon weld preparation
PC asymmetricpreparation
If symmetric preparation is used in the PC position theweld may spill out of the groove
6030 60
15
W ld ti
-
7/18/2019 Welding Symbols Weld Preparations
51/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparation
Type of loading impacts upon weld preparationStatic loads - prohibited application of one sidedfillet weld
W ld ti
-
7/18/2019 Welding Symbols Weld Preparations
52/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparation
Type of loading impacts upon weld preparationStatic loads - equal throat T joints
13 mm
weld area = 160 mm2 weld area = 90 mm2
13 mm
no preparation required
danger of lamellar tearingpreparation required
reduced distortions
60
W ld ti
-
7/18/2019 Welding Symbols Weld Preparations
53/54
Copyright 2004, TWI Ltd World Centre for Materials Joining Technology
Weld preparation
Type of loading impacts upon weld preparationStatic loads - equal throat T beams in bending
neutralaxis
deep penetrationfillet weldsnormal filletwelds
neutral
axis
Lower neutral axis is more advantageous (alsohelps to reduce residual distortions!)
W ld ti
-
7/18/2019 Welding Symbols Weld Preparations
54/54
Weld preparation
Type of loading impacts upon weld preparationDynamic loads - full vs. partial penetration welds
double bevel weldfillet weldsLack of penetration promotes cracking!
cyclic load