1. Resistance and Solid-State Welding Processes
Chapter 32

2. 32.1 Introduction

3. 32.2 Theory of Resistance Welding

4. Basic Resistive Welding
FIGURE 32-1 The basic resistance welding circuit.

5. Resistive Welding Temperature Distribution
FIGURE 32-2 The desired
temperature distribution across
the electrodes and workpieces
during resistance welding.

6. Current and Pressure for Resistive Welding
FIGURE 32-3 A typical current and pressure cycle for resistance welding. This cycle includes forging and postheating operations.

7. Schematic of Resistive Welding
FIGURE 32-4 The
arrangement of the electrodes
and workpieces in resistance
spot welding.

8. 32.3 Resistance Welding Processes

9. Microstructure of a Resistance Weld
FIGURE 32-5 A spot-weld nugget between two sheets of 1.3-mm (0.05-in.) aluminum alloy. The nugget is not symmetrical because the radius of the upper electrode is greater than that of the lower electrode. (Courtesy Lockheed Martin Corporation, Bethesda, MD.)

10. Tear Test FIGURE 32-6 Tear test of a satisfactory spot
weld, showing how failure occurs outside of
the weld.

11. Resistive Welder FIGURE 32-7 Single-phase, air-operated, press-type
resistance welder with
microprocessor control.
(Courtesy Sciaky Inc., Chicago, IL.)

12. Spot Welding Application

13. Spot Welding Seams FIGURE 32-8 Seam welds made with overlapping spots
of varied spacing. (Courtesy
Taylor-Winfield Corporation,
Brookfield, OH.)

14. Schematic of Seam Welding
FIGURE 32-9 Schematic
representation of the
seam-welding process.
those

15. Tube Welding FIGURE 32-10 Using high- Squeeze roll
frequency AC current to produce
a resistance seam weld in buttwelded
tubing. Arrows from the
contacts indicate the path of the
high-frequency current

16. Projection Welding FIGURE 32-11 Principle of
projection welding (a) prior to
application of current and
pressure and (b) after formation
of the welds.

17. 32.4 Advantages and Limitations of Resistance Welding

18. 32.5 Solid-State Welding Processes

19. Process Summary for RW

20. Cold Welding
FIGURE Small parts joined by cold welding. (Courtesy of Koldweld Corporation, Willoughby, OH.)

21. Roll Welding FIGURE 32-13 Examples of roll-bonded refrigerator freezer
evaporators. Note the raised
channels that have been
formed between the roll-bonded
sheets. (Courtesy Olin Brass,
East Alton, IL.)

22. Friction Welding
FIGURE Sequence for making a friction weld. (a) Components with square surfaces are inserted into a machine where one part is rotated and the other is held stationary. (b) The components are pushed together with a low axial pressure to clean and prepare the surfaces. (c) The pressure is increased, causing an increase in temperature, softening, and possibly some melting. (d) Rotation is stopped and the pressure is increased rapidly, creating a forged joint with external flash.

23. Schematic for Friction Welding
FIGURE Schematic diagram of the equipment used for friction welding. (Courtesy of Materials Engineering.)

24. Inertia Welding FIGURE 32-16 Schematic representation of the various
steps in inertia welding. The
rotating part is now attached
to a large flywheel.

25. Examples of Friction Welding
FIGURE Some typical
friction-welded parts. (Top)
Impeller made by joining a
chrome–moly steel shaft to a
nickel–steel casting. (Center)
Stud plate with two mild steel
studs joined to a square plate.
(Bottom) Tube component
where a turned segment is
joined to medium-carbon steel
tubing. (Courtesy of Newcor Bay
City, Division of Newcor, Inc.,
Royal Oak, MI.)

26. Stir Welding
FIGURE Schematic of the friction-stir welding process. The rotating probe generates frictional heat,
while the shoulder provides additional friction heating and prevents expulsion
of the softened material from the joint. (Note: To provide additional forging
action and confine the softened material, the tool may be tilted so the
trailing edge is lower than the leading segment.)

27. Example of Stir Welding
FIGURE (a) Top surface
of a friction-stir weld joining 1.5-
mm- and 1.65-mm-thick
aluminum sheets with 1500-rpm
pin rotation. The welding tool
has traversed left-to-right and
has retracted at the right of the
photo. (b) Metallurgical cross
section through an alloy 356
aluminum casting that has been
modified by friction-stir
processing.

28. Features of Stir Welding

29. Schematic of Ultrasonic Welding
FIGURE Diagram of the
equipment used in ultrasonic
welding

30. Application of Ultrasonic Welding

31. Explosive Welding
FIGURE (Left) Schematic of the explosive welding process. (Right) Explosive weld between mild steel and stainless steel, showing the characteristic wavy interface.