2 (b) No, this process is not expected to be as effective for welding Al and Cu alloys because the low electrical resistance of these filler wires means ineffective resistance heating.
3 (c) High deposition rates can be obtained without using high arc powers, which can melt too much base metal to excessively dilute the deposit.
References
1 1 Kearns, W.H. (ed.) (1980). Welding Handbook, 7e, vol. 3, 170–238. Miami, FL: American Welding Society.
2 2 Mendez, P.F. and Eagar, T.W. (2001). Welding processes for aeronautics. Advanced Materials and Processes 159 (5): 39–43.
3 3 American Welding Society (1976). Welding Handbook, 7e, vol. 1, 2–32. Miami, FL: American Welding Society.
4 4 (1998). Welding workbook, data sheet 212a. Welding Journal 77: 65.
5 5 American Welding Society (1978). Welding Handbook, 7e, vol. 2, 78–112, 296–330. Miami, FL: American Welding Society.
6 6 Lyttle, K. (1993). Shielding gases. In: Welding, Brazing and Soldering, ASM Handbook, vol. 6, 64–69. Materials Park, OH: ASM International.
7 7 Schwartz, M.M. (1979). Metals Joining Manual, 2–1 to 3–40. New York: McGraw‐Hill.
8 8 Lesnewich, A. (1978). The welding processes in relation to weldability. In: Weldability of Steels, 3e (eds. R.D. Stout and W.D. Doty), 5. New York, NY: Welding Research Council.
9 9 Gibbs, F.E. (1980). Ceramic backing for all‐position GMA welding 5083 aluminum‐alloy. Welding Journal 59 (12): 23s–30s.
10 10 (2000). Fact sheet—choosing shielding for GMA welding. Welding Journal 79: 18.
11 11 Jones, L.A., Eagar, T.W., and Lang, J.H. (1998). Images of a steel electrode in Ar‐2% O~ 2 shielding during constant current gas metal arc welding. Welding Journal 77 (4): 135s–141s.
12 12 Blackman, S.A. and Dorling, D.V. (2000). Technology advancements push pipeline welding productivity. Welding Journal 79 (8): 39s–44s.
13 13 Eichhorn, F., Remmel, J., and Wubbels, B. (1984). High‐speed electroslag welding. Welding Journal 63 (1): 37s–41s.
14 14 Cary, H.B. (1979). Modern Welding Technology. Englewood Cliffs, NJ: Prentice‐Hall.
15 15 Arata, Y., Development of ultra high energy density heat source and its application to heat processing, Okada Memorial Japan Society, New York, NY. 1985.
16 16 Farrell, W.J. (1962‐1963). ASTME Paper SP 63–208. The Use of Electron Beam to Fabricate Structural Members. Creative Manufacturing Seminars.
17 17 Blakeley, P.J. and Sanderson, A. (1984). The origin and effects of magnetic fields in electron beam welding. Welding Journal 63 (1): 42s–49s.
18 18 Metzbower, E.A., Private communication. Naval Research Laboratory: Washington, DC.
19 19 Bliedtner, J., Heyse, T., Jahn, D. et al. (2001). Advances in diode lasers increase weld penetration. Welding Journal 80 (6): 47s–51s.
20 20 Quintino, L., Costa, A., Miranda, R. et al. (2007). Welding with high power fiber lasers–a preliminary study. Materials & Design 28 (4): 1231–1237.
21 21 Xie, J. and Kar, A. (1999). Laser welding of thin sheet steel with surface oxidation. Welding Journal 78: 343s–348s.
22 22 Mazumder, J. Procedure development and practice considerations for laser‐beam welding. In: Welding, Brazing and Soldering, ASM Handbook, vol. 6, 874. Materials Park, OH: ASM International.
23 23 Rockstroh, T.J. and Mazumder, J. (1987). Spectroscopic studies of plasma during cw laser materials interaction. Journal of Applied Physics 61 (3): 917–923.
24 24 Seaman, F. Technical Paper MR77‐982, Role of Shielding Gas in Laser Welding. 1977, Society of Manufacturing Engineers: Dearborn, MI.
25 25 Hyatt, C.V., Magee, K.H., Porter, J.F. et al. (2001). Laser‐assisted gas metal arc welding of 25‐mm‐thick HY‐80 plate. Welding Journal 80 (7): 163s–172s.
26 26 Albright, C.E., Eastman, J., and Lempert, W. (2001). Low‐power lasers: assist arc welding. Welding Journal 80 (4): 55s–58s.
27 27 (1980). Welding Handbook, 7e, vol. 3, 44. Miami, Florida: American Welding Society.
28 28 Thomas, W.M. (1991). Friction stir butt welding. International Patent Application No. PCT/GB92, Patent Application No. 9125978.8, filed December 6, 1991.
29 29 Bhamji, I. et al. (2011). Solid state joining of metals by linear friction welding: a literature review. Materials Science and Technology 27 (1): 2–12.
30 30 Ushio, M., Matsuda, F., and Sadek, A.A. (1993). GTA welding electrode. In: International Trends in Welding Science and Technology (eds. S.A. David and J.M. Vitek), 405–409. ASM International, Materials Park, OH.
Further Reading
1 Arata, Y. (1985). Development of Ultra High Energy Density Heat Source and its Application to Heat Processing. Osaka, Japan: Okada Memorial Japan Society, New York, NY for the Promotion of Welding.
2 DebRoy, T., De, A., Bhadeshia, H.K.D.H. et al. (2012). Tool durability maps for friction stir welding of an aluminium alloy. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 468 (2147): 3552–3570.
3 Duley, W.W. (1999). Laser Welding. New York: Wiley.
4 Olson, D.L., Siewert, T.A., Liu, S., and Edwards, G.R. (1993). ASM Handbook: Welding, Brazing, and Soldering, vol. 6. Materials Park, OH: ASM International.
5 Schwartz, M.M. (1979). Metals Joining Manual. New York: McGraw‐Hill.
6 (1980). Welding Handbook, Vols. 1–3, 7e. Miami, FL: American Welding Society.
Problems
1 11.1 It has been suggested that compared to SMAW, the cooling rate is higher in GMAW and it is, therefore, more likely for heat‐affected zone cracking to occur in hardenable steels. What is the main reason for the cooling rate to be higher in GMAW than SMAW?
2 11.2 The diameter of the electrodes to be used in SMAW depends on factors such as the workpiece thickness, the welding position, and the joint design. Large electrodes, with their corresponding high currents, tend to produce large weld pools. When welding in the overhead or vertical position, should you use larger or smaller electrodes?
3 11.3 In GTAW the welding cable is connected to the tungsten electrode through a water‐cooled copper contact tube, as shown in Figure 1.12. Why is the tube positioned near the lower end of the electrode instead of the top?
4 11.4 Measurements of the axial temperature distribution along the GTAW electrode have shown that the temperature drops sharply from the electrode tip toward the contact tube. Why? For instance, with a 2.4‐mm‐diameter W–ThO2 electrode at 150 A, the temperature drops from about 3600 K at the tip to about 2000 K at 5 mm above the tip. Under the same condition but with a W‐La2O3 electrode, the temperature drops from about 2700 K at the tip to about 1800 K at 5 mm above the tip [30]. Which electrode can carry more current before melting, and why?
5 11.5 Experimental results show that in EBW the penetration depth of the weld decreases as the welding speed increases. Explain why. Under the same power and welding speed, do you expect a much greater penetration depth in aluminum or steel, and why?
6 11.6 How does the working distance in EBW affect the depth–width ratio of the resultant weld?
7 11.7 Consider EBW in the presence of a gas environment. Under the same power and welding speed, rank and explain the weld penetration for Ar, He, and air. The specific gravities of Ar, He, and air with respect to air are 1.38, 0.137, and 1, respectively, at 1 atm,