No Slide Title

The Metallurgy of Welding; Welding Design and Process SelectionCHAPTER 7-3Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Fusion Weld Zone

Figure 29.1 Characteristics of a typical fusion weld zone in oxyfuel gas and arc welding. See also Figs. 27.16 and 28.14.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Grain Structure in Shallow and Deep Welds

(a)(b)Figure 29.2 Grain structure in (a) a deep weld (b) a shallow weld. Note that the grains in the solidified weld metal are perpendicular to the surface of the base metal. In a good weld, the solidification line at the center in the deep weld shown in (a) has grain migration, which develops uniform strength in the weld bead.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Weld BeadsFigure 29.3 (a) Weld bead (on a cold-rolled nickel strip) produced by a laser beam. (b) Microhardness profile across the weld bead. Note the lower hardness of the weld bead compared to the base metal. Source: IIT Research Institute.

(a)(b)Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Regions in a Fusion Weld Zone

Figure 29.4 Schematic illustration of various regions in a fusion weld zone (and the corresponding phase diagram) for 0.30% carbon steel. Source: American Welding Society.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Corrosion

Figure 29.5 Intergranular corrosion of a 310-stainless-steel welded tube after exposure to a caustic solution. The weld line is at the center of the photograph. Scanning electron micrograph at 20 X. Source: Courtesy of B. R. Jack, Allegheny Ludlum Steel Corp.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Incomplete Fusion

Figure 29.6 Low-quality weld beads, the result of incomplete fusion. Source: American Welding Society.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Discontinuities in Fusion Welds

Figure 29.7 Schematic illustration of various discontinuities in fusion welds. Source: American Welding Society.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Cracks in Welded Joints

Figure 29.8 Types of cracks (in welded joints) caused by thermal stresses that develop during solidification and contraction of the weld bead and the surrounding structure. (a) Crater cracks. (b) Various types of cracks in butt and T joints.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Crack in a Weld Bead

Figure 29.9 Crack in a weld bead, due to the fact that the two components were not allowed to contract after the weld was completed. Source: S. L. Meiley, Packer Engineering Associates, Inc.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Distortion After Welding

Figure 29.10 Distortion of parts after welding: (a) butt joints; (b) fillet welds. Distortion is caused by differential thermal expansion and contraction of different parts of the welded assembly.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Residual Stresses Developed During Welding

Figure 29.11 Residual stresses developed during welding of a butt joint. Source: American Welding Society.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Overview of Commercial Joining Processes

Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Overview of Commercial Joining Processes (cont.)

Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Overview of Commercial Joining Processes (cont.)

Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Destructive Techniques

Figure 29.12 Two types of specimens for tension-shear testing of welded joints.Figure 29.13 (a) Wrap-around bend test method. (b) Three-point bending of welded specimens--see also Fig. 2.11.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Testing of Spot Welds

Figure 29.14 (a) Tension-shear test for spot welds. (b) Cross-tension test. (c) Twist test. (d) Peel test; see also Fig. 30.8.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Welding Design Guidelines

Figure 29.15 Design guidelines for welding. Source: J. G. Bralla (ed.), Handbook of Product Design for Manufacturing. Copyright 1986, McGraw-Hill Publishing Company. Used with permission.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Standard Identification and Symbols for Welds

Figure 29.16Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#Weld Design Selection

Figure 29.17Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 29-#TABLE 29.1 Overview of Commercial Joining Processes*

Joining Process

MaterialThick-nessS

M

A

WS

A

WG

M

A

WF

C

A

WG

T

A

WP

A

WE

S

WE

G

WR

WF

WO

F

WD

F

WF

R

WE

B

WL

B

WBrazing

T

BF

BI

BR

BD

BI

R

BD

F

B

Carbon steelS

I

M

Tx

x

x

xx

x

x

xx

x

x

xx

x

xx

x

xxx

x

xx

x

x

xx

x

x

x

x

x

xx

x

x

xx

x

xx

x

xx

x

x

xx

x

xx

x

x

x

x

x

x

x

x

Low-alloy steelS

I

M

Tx

x

x

xx

x

x

xx

x

x

xx

x

xx

x

x

x

x

xx

x

x

xxx

x

x

xx

x

xx

x

x

xx

x

xx

x

x

xx

x

xx

x

xxxxx

x

x

Stainless steelS

I

M

Tx

x

x

xx

x

x

xx

x

x

xx

x

xx

x

xx

x

xx

x

xx

x

x

xx

x

x

x

xx

x

xx

x

x

xx

x

xx

x

xx

x

x

xx

x

xxxxx

x

x

x

Cast ironI

M

Tx

x

xx

xx

xx

x

x

x

x

x

xx

x

xx

x

x

x

x

Nickel and alloysS

I

M

Tx

x

x

xx

xx

x

x

x

x

x

x

x

xx

x

x

x

x

x

xx

x

x

xx

x

x

xx

x

xx

x

xx

x

x

xx

x

xxxx

x

x

x

TABLE 29.1 (continued)

Joining Process

MaterialThick-nessS

M

A

WS

A

WG

M

A

WF

C

A

WG

T

A

WP

A

WE

S

WE

G

WR

WF

WO

F

WD

F

WF

R

WE

B

WL

B

WBrazing

T

BF

BI

BR

BD

BI

R

BD

F

BS

Aliminum and alloysS

I

M

Tx

x

x

x

x

x

x

x

x

x

xxxxx

xx

x

x

xxx

xx

x

xx

x

x

xx

x

x

x

xx

x

x

xxxx

x

xxx

x

x

xx

x

Titanium and alloysS

I

M

T

x

x

x

x

x

x

xx

x

x

xx

x

x

x

x

x

x

xx

xx

x

x

xx

x

xxx

x

x

xx

xx

x

x

x

Copper and alloysS

I

M

T

x

x

x

x

xx

x

x

x

x

x

x

xx

x

x

x

x

x

xx

x

x

xxx

x

x

x

x

xx

x

Magnesium and alloysS

I

M

T

x

x

x

x

x

x

x

xx

x

x

x

xx

x

x

xx

x

xx

xx

x

x

x

x

x

x

x

Refractory alloysS

I

M

T

x

x

xx

x

x

xx

x

x

x

x

x

xx

xxx

xx

x

*This table is presented as a general survey only. In selecting processes to be used with specific alloys, the reader should refer to other

appropriate sources of information.

Source: Courtesy of the American Welding Society.

TABLE 29.1 (continued)

Legend

Process codeThickness

SMAWShielded Metal-Arc Welding

SAWSubmerged Arc Welding

GMAWGas Metal-Arc Welding

FCAWFlux-Cored Arc Welding

GTAWGas Tungsten-Arc Welding

PAWPlasma Arc Welding

ESWElectroslag Welding

EGWElectrogas Welding

RWResistance Welding

FWFlash Welding

OFWOxyfuel Gas Welding

DFWDiffusion WeldingFRWFriction Welding

EBWElectron Beam Welding

LBWLaser Beam Welding

TBTorch Brazing

FBFurnace Brazing

IBInduction Brazing

RBResistance Brazing

DBDip Brazing

IRBInfrared Brazing

DFBDiffusion Brazing

SSoldering

SSheet: up to 3 mm in.B

IIntermediate: 3 to 6 mm A in.B

MMedium: 6 to 19 mm A in.B

TThick: 19 mm A in. B and up