Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page 27-1 CHAPTER 27 Fusion-Welding Processes

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page 27-2 General Characteristics of Fusion Welding Processes

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page 27-3 Oxyacetylene Flames Used in Welding Figure 27.1 Three basic types of oxyacetylene flames used in oxyfuel-gas welding and cutting operations: (a) neutral flame; (b) oxidizing flame; (c) carburizing, or reducing, flame. The gas mixture in (a) is basically equal volumes of oxygen and acetylene.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page 27-4 Torch Used in Oxyacetylene Welding Figure 27.2 (a) General view of and (b) cross-section of a torch used in oxyacetylene welding. The acetylene valve is opened first; the gas is lit with a spark lighter or a pilot light; then the oxygen valve is opened and the flame adjusted. (c) Basic equipment used in oxyfuel-gas welding. To ensure correct connections, all threads on acetylene fittings are left-handed, whereas those for oxygen are right-handed. Oxygen regulators are usually painted green, acetylene regulators red.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page 27-5 Pressure-Gas Welding Figure 27.3 Schematic illustration of the pressure-gas welding process.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page 27-6 Shielded Metal-Arc Welding Figure 27.4 Schematic illustration of the shielded metal-arc welding process. About 50% of all large-scale industrial welding operations use this process. Figure 27.5 Schematic illustration of the shielded metal-arc welding operations (also known as stick welding, because the electrode is in the shape of a stick).

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page 27-7 Multiple Pass Deep Weld Figure 27.6 A deep weld showing the buildup sequence of individual weld beads.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page 27-8 Submerged-Arc Welding Figure 27.7 Schematic illustration of the submerged-arc welding process and equipment. The unfused flux is recovered and reused. Source: American Welding Society.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page 27-9 Gas Metal-Arc Welding Figure 27.8 Schematic illustration of the gas metal-arc welding process, formerly known as MIG (for metal inert gas) welding.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page Equipment Used in Gas Metal-Arc Welding Figure 27.9 Basic equipment used in gas metal-arc welding operations. Source: American Welding Society.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page Flux-Cored Arc-Welding Figure Schematic illustration of the flux-cored arc-welding process. This operation is similar to gas metal-arc welding, showing in Fig

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page Electrogas Welding Figure Schematic illustration of the electrogas welding process. Source: American Welding Society.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page Equipment for Electroslag Welding Figure Equipment used for electroslag welding operations. Source: American Welding Society.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page Designations for Mild Steel Coated Electrodes

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page Gas Tungsten-Arc Welding Figure The gas tungsten-arc welding process, formerly known as TIG (for tungsten inert gas) welding. Figure Equipment for gas tungsten-arc welding operations. Source: American Welding Society.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page Plasma-Arc Welding Figure Two types of plasma-arc welding processes: (a) transferred, (b) nontransferred. Deep and narrow welds can be made by this process at high welding speeds.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page Comparison of Laser-Beam and Tungsten-Arc Welding Figure Comparison of the size of weld beads in (a) electron-beam or laser-beam welding to that in (b) conventional (tungsten-arc) welding. Source: American Welding Society, Welding Handbook (8th ed.), 1991.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page Example of Laser Welding Figure Laser welding of razor blades.

Kalpakjian Schmid Manufacturing Engineering and Technology © 2001 Prentice-Hall Page Flame Cutting and Drag Lines Figure (a) Flame cutting of steel plate with an oxyacetylene torch, and a cross- section of the torch nozzle. (b) Cross-section of a flame-cut plate showing drag lines.