abstract of presentation this paper presents … · abstract of presentation title: welding...

ABSTRACT OF PRESENTATION

TITLE: Welding Development at Marshall Space Flight Center

This paper presents the basic understanding of the friction stir welding process. It covers processdescription, pin tool operation and materials, metal flow theory, mechanical properties, andmaterials welded using the process. It also discusses the thermal stir welding process and thedifferences between thermal stir and friction stir welding. MSFC weld tools used for developmentare also presented.

https://ntrs.nasa.gov/search.jsp?R=20080015864 2018-08-19T11:30:22+00:00Z

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National Aeronautics and Space AdministrationGeorge C. Marshall Space Flight Center

Materials, Processes and Manufacturing Department

WELDING DEVELOPMENT

MARSHALL SPACE FLIGHTCENTER

Jeff Ding

Metallic Materials & Processing

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NASAGeorge C. Marshall Space Flight CenterJune 27. 2007

R. Jeffrey Ding

Robert.!. [email protected]

National Aeronautics and Space AdministrationGeorge C. Marshall Space Flight Center

Materials, Processes and Manufacturing Department

AGENDA• Introduction

• Conventional FSW Process:

• Description

• Microstructure

• Hardness

• Mechanical Properties

• Self Reactin9 FSW

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NASAGeorge C. Marshall Space Flight CenterJune 27, 2007

R. Jeffrey Ding

[email protected]

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Friction Stir Welding and ProcessingEd. R.S. Mishra and M.W. Mahoney

2007, ASM International

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1. Introduction (R. Mishra-UMR & M. Mahoney-Rockwell Scientific Co.)2. FSW Tooling (C. Fuller- Rockwell Scientific Co.)3. Metal Flow and Temperature Distribution (J. Schneider-MSU)4. Microstructural Evolution in AI Alloys (A. Reynolds-USC)5. Mechanical Properties of FSWed AI. Alloys (M. Mahoney-Rockwell Scientific Co.)6. FSWing of Ferrous and Nickel Alloys (C. Sorensen & T. Nelson-BYU)7. Microstructure & Mechanical Prop. of FSW Ti Alloys (T. Lienert-LANL)8. Microstructures & Mechanical Prop. of Cu Alloys (T. McNelley-NPS)9. Corrosion Properties of FSW AI. Alloys (J. Lumsden - Rockwell Scientific Co.)

10. Process Modeling (A.Askari & S. Silling-Cambridge)11. Robots & Machines for FSW/FSP (C. Smith-Friction Stir Link, Inc.)12. Friction Stir Spot Welding (H. Badarinarayan, F. Hunt, K. Okamoto - Hitachi)13. Application of FSW & Related Applications (W. Arbegast-SDSMM)14. Friction Stir Processing (R. Mishra-UMR & M. Mahoney-Rockwell Scientific Co.)15. Future Outlook for FSW/FSP (R. Mishra-UMR & M. Mahoney-Rockwell Scientific Co.)


R. Jeffrey Ding

[email protected]

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BackgroundFriction Stir Welding

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• Jeff Ding brought FSW to the NASA agency in 1995.

• Patented by The Weld Institute (TWI) Cambridge, U.K in 1991.

• Solid state (non-melting) joining process using frictional heat

to raise temperature into the metals plastic state.

• Recognized as significant advancements in welding technology.

ASAGeorge C. Marshall Space Flight CenterJune 27, 2007

R. Jeffrey Ding

[email protected]

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". ".: .' - ..FSW Metallography

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Macro transverse section of FSW

NASAGeorge C. Marshall Space Flighl CenterJune 27, 2007

Macro transverse section of VPPA

R. Jeffrey Ding

[email protected]

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Conventional FSW Process

,Downward force

Tool rotation /

_-~:'---:7' Leading edge of shoulder

Friction stir welded region

Retreating slde'+-----\Advancing side

Chapter 1: Introduction

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• Tool serves 3 primary functions:• Heat: Heating of workpiece• Stir: Movement of material to product the joint• Forge: Contaiment of material


R. Jeffrey Ding

[email protected]

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Conventional FSW

Process Parameters

300-400 rpm

Chapter 2: FSW Tooling: Tool Materials & Design

Shoulderheat input

NASAGeorge C. Marshall Space Flighl CenterJune 27. 2007

Pin stirringaction

Direction of Travel

Transverse View

.4-5 ipm

2195 Base Plate

Backing Bar

Longitudinal View

R. Jeffrey Ding

[email protected]

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FSW of 1" thick panels

NASAGeorge C. Marshall Space Flight CenterJune 27. 2007 r. ff.

R. Jeffrey Ding

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Temperature Distributionin FSW

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1000

900

EoTop Surface Temperature are in °c

E 415800

.257 .315 • 330 • HZ • 379 • 402 • -155 • 475 U<1l 1 til 700 Tmp-AI-0 .,

{g2

·322 .335 .388 .400 e435 e4111 ~:J ., 600(/) ...

463 ::l0. • )01 310. -397 e415 e440. 58 " -0 3 oll E 500I- oll .,

445 ::l Q.:;;

4 • 255 ·305 .327 .342 • 405 • 420 .443 • 460 Z E 4000<1l ::: .,

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m 432 VJ

5 _284 • 310 -)42 _353 -JgZ -368 e392 • 433 u. .>< 300<1l '"0

.,C 'lIS a.

'" 6 -308 • 328 • 372 • 378 .400 • 4 200(jj

0 10 8 6 4 2 0 100

Distance from Edge of FSW Nugget, mm 02195·T8 6061·T6 7075-T651

NASAGeorge C. Marshall Space Flighl CenterJune 27, 2007

Chapter 3: Temperature Distribution and Resulting Metal FlowR. Jeffrey Ding


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Mechanical Properties ,.., •.. '.:':" .

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HRS hardness traverse across weld

2219 AI FSW HCF specimen 6

Hardness AA2219

200 r-~--~-~-----""""'"

-0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8

Distance, in.

PMAWAge

100

90

80:::-III-'" 70-.c::- 60Clc:Ql 50...-lIJ~ 40

IIIc: 30QlI-

20

10

0

Parent Parent

·-\HAZ Weld- HAZj\center

\ I-_Stir __Ifzone

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80

75

70<D

~ 65

50

45

,;~ 60c-e~ 55r

-e-GTAW180 Weld --0- F$W

~ 160 L.rn 20

TI24 melal 2024 o..!

a> ~ cf'1:j<l qpR:P <Yij 140 <9 ~o 0 cY;- 120 0 "00

~ 100 ..,.I~.""'."'''''NotI : I~.:~ IL-=__-;,;:---.::S:::tir:::rj~ng!..!p::a::rt---;,:--_---;o,-

40 -20 -10 0 10 20

Distance from center of weld, mm

TIG vs FSW Hardness

NASAGeorge C. Marshall Space Flight CenterJune 27. 2007 Chapter 5: Mechanical Properties of FSW AI Alloys

R. Jeffrey Ding

Robert.!. [email protected]

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~FSW properties independent

of material thickness

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NASAGeorge C. Marshall Space Flight CenterJune 27, 2007 Chapter 5: Mechanical Properties of FSW AI Alloys

R. Jeffrey Ding

RobertJ. [email protected]

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FSW Benefits

Chapter 1: Introduction R. Jeffrey Ding

[email protected]

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FSW Limitations. ..

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• Exit hole left after withdrawing tool.• Significant down force and traversing forces required.

• Lacks the flexibility of manual and arc processes.

NASAGeorge C. Marshall Space Flight CenterJune 27,2007

R. Jeffrey Ding

[email protected]

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Production BenefitsObtained with FSW

• The formation of low distortion, solid-phase, welds of repeatable high qualityand mechanical properties, which could improve existing products and lead toasubstantial number of new product design opportunities, hitherto notpossible, in many different industries.

• Low welding operation costs due to the low welding power requirement andthe elimination of filler wires, weld pool shielding gases and the special jointedge preparations required by fusion welding techniques.

• The machine tool operation, once correctly set, does not require operator skilland the machine settings can be easily monitored to provide in-process weldquality assurance.

• The process is clean and does not produce any major safety hazards, such aswelding fume or radiation.


R. Jeffrey Ding

RobertJ [email protected]

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Two basic componentsof we/dtoo/

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Shoulder

Pin/Nib

Generally the shoulder is twice as wide as the pin.NASAGeorge C. Marshall Space Flight CenterJune 27, 2007

R. Jeffrey Ding

[email protected]

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Basic shoulder geometriesCross sections of pin tool

Concave smooth shoulder

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View showing scrolls on shoulder

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Flat shoulder with scrolls

Scrolls

Shoulder

Pin

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~ Weld Tool Pin Configurations .Z"@., .

-2mm

-2mm -2mm


Threaded features on eithercylindrical or tapered pin

Chapter 2: FSW Tooling: Tool Materials & Design R. Jeffrey Ding

[email protected]

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Weld Tool Shoulder Features.' ..

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Shoulderfestures

Probe

NASAGeorge C. Marshall Space Flight CenlerJune 27. 2007 Chapter 2: FSW Tooling: Tool Materials & Design

R. Jeffrey Ding

[email protected]

Theorized Metal Flow Paths in FSWWorkpiece/Pin Tool Interaction


R. Jeffrey Ding

[email protected]

Kinematic mathematical model approach defines thetheoretical flow fields and resultant currents

in the neighborhood of the conventional FSW tool

RetreatingSide

MaelstromCurrent

AdvancingSide

StraightThroughCurrentRing

Vortex

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UniformTranslation

RigidBodyRotation

Chapter 3: Temperature Distribution and Resulting Metal Flow

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Shear texture bands are observedin the weld nugget

Similar texture has been reported in weld nuggets,independent of the initial PM texture

(6063) DP Field, et. al., 2001.(1100) K. V., Jata, S.L. Semiatin, 2000.

i

1000 mm-

NASA , ,George C. Marshall Space Flight CenterJune 27, 2007 Schneider, J.A., Nunes, Jr., A.C., Met. Trans. B, 2004.

'A' fiber texture{111} <hkl>

2195-T8

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FSW Microstructure

Retreating side Advancing side.

NASAGeorge C. Marshall Space Flight CenterJune 27, 2007 Chapter 5: Mechanical Properties of FSW AI Alloys

R. Jeffrey Ding

[email protected]

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Sharp boundary exists betweenparent grains and recrystallized

_______n_ugget 9...ra_i_n_s _

RS

OIM

2195-T8

Optical lightMicrograph

of weld nugget

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Studies were conducted totrace variations in the metal flow paths

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Study produced:117 each 6.5 " welds

-Tungsten wire: 0.001" dia-AI 2219 plates: 0.25" thick

Based on position andprocess parameter

Force Travel Rotation(lbf) (ipm) (rpm)

6500 3 150

7000 4.5 200

8000 6 300

Colligan, Welding Journal, 1999.

Seidel & Reynolds, Met. & Mat. Trans. A, 2001.

NASA Chapter 3: Temperature Distribution and Resulting Metal FlowGeorge C. Marshall Space Flight Center R. Jeffrey DingJune 27, 2007 Roben.J.Ding@nasa,gov

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~.Strain experienced by the metal

can be determined from awire marker spacing

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~~ tooltravel

\ .tracer wire

radial velocityprofile

0.026" length

shear zonethickness

Optical imageInitial dia. =0.0025"Final dia. =0.0024"

A T (Jtungsten wiretiL ';:::j r -

(Jweld metal

rotating metal plugthickness

R. Jeffrey Ding

[email protected]

Chapter 3: Temperature Distribution and Resulting Metal FlowNASAGeorge C. Marshall Space Flight CenterJune 27.2007

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The rotating plug of metalcontains the

Maelstrom current

Rotating Metal Plug

-Shear Surface

Tooltravel

tracerwire

NASAGeorge C. Marshall Spaee Flight CenterJune 27, 2007

Nunes, Automotive Alloys and Joining Aluminum, TMS, 2001.

R. Jeffrey Ding

[email protected]

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Summary of metal flow variationwith entrance into weld zone

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C227000 Ibf /300 RPM /4.5 ipm

C207000 Ibf /300 RPM /4.5 ipm

RSAS

8000 Ibf /200 RPM /4.5 ipmI cos

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NASAGeorge C. Marshall Space Flight Center R. Jeffrey DingJune 27, 2007 Chapter 3: Temperature Distribution and Resulting Metal Flow [email protected]

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Self Reacting Friction Stir Welding(SR-FSW)

NASAGeorge C. Marshall Space Flighl CenterJune 27. 2007

R. Jeffrey Ding

Robert.J [email protected]

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Similar Macro Transverse Sectionsin SR-FSW and C-FSW

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Macro transverse section of SR-FSW


Macro transverse section of FSW

R.. Jeffrey Ding

[email protected]


FSW Weld Tools

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R. Jeffrey Ding

[email protected]

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Thermal Stir Welding(TSW)

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• A new solid state welding process similar to frictionstir welding (FSW) but with independent stirring,heating and forging function controls.

• Joins similar and dissimilar metals.

.• More degrees of freedom for greater process controland optimization.

• Provides mechanical means to produce localizedsuperplastic material in high melting alloys, i.e.,titanium.

NASAGeorge C. Marshall Spaee flighl CenlerJune 27, 2007

R. Jeffrey Ding


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Thermal Stir Welding

Process Description

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300-400 rpm

Rolle

Roller?


[J~rrod

ContainmentPlate

Heat Source

Plate motion 4 ipm, 12 ipm? 30 ipm?4

Base Material

Heat Source

R. Jeffrey Ding

[email protected]

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Thermal Stir Welding

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• Key-hole close out

• Joining of dissimilar metals

• Elimination of backside anvil

• Optional inert processingenvironment

• Complex joint designs

RIGHT-ANGLE WELDJOINTS


R. Jeffrey Ding

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~ Thermal Stir Welding

Prototype System


R. Jeffrey Ding

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Comparison Between FSW

and TSW Microstructure

Macro transverse section of TSW

NASAGeorge C. Marshall Space Flighl CenlerJune 27. 2007

Macro transverse section ofconventional FSW

R. Jeffrey Ding

[email protected]

abstract of presentation this paper presents … · abstract of presentation title: welding...

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