Chapter 33: Other Welding Processes, Brazing and Soldering

Chapter 33: Other Welding Processes, Brazing and Soldering

33.1 Introduction

33.2 Other Welding and Cutting Processes

Electroslag Welding FIGURE 33-1 (a) Arrangement of equipment and workpieces for making a vertical weld by the electroslag process. (b) Cross section of an electroslag weld, looking through the water-cooled copper slide.

Electron Beam Welding FIGURE 33-2 Schematic diagram of the electron-beam welding process

Examples of Electron Beam Welding FIGURE 33-3 (Left to right) Electronbeam welds in 19-mm-thick 7079 aluminum and 102- mm-thick stainless steel. (Courtesy of Hamilton Standard Division of United Technologies Corporation, Hartford, CT.)

Process Summary of EBW

Examples of Laser Welding FIGURE 33-4 Laser butt weld of 3-mm (0.125-in.) stainless steel, made at 1.5 m/min with a 1250-watt laser. (Courtesy of Coherent, Inc., Santa Clara, CA.)

Process Summary of LBW

Comparison of Power Densities FIGURE 33-5 Comparison of the power densities of various welding processes. The high power densities of the electronbeam and laser-beam welding processes enable the production of deep, narrow welds with small heat-affected zones. Welds can be made quickly and at high travel speeds.

Schematic of Laser Beam Cutting FIGURE 33-6 Schematic of laser-beam cutting. The laser provides the heat, and the flow of assist gas propels the molten droplets from the cut.

Cutting Surface FIGURE 33-7 Surface of 6-mm-thick carbon steel cut with a 1250-watt laser at 1.8 m/min. (Courtesy of Coherent, Inc., Santa Clara, CA.)

Schematic of Flash Welding FIGURE 33-8 Schematic diagram of the flash-welding process. (a) Equipment and setup; (b) completed weld.

33.3 Surface Modification by Welding Related Processes

Schematic of a Metal Spray Gun FIGURE 33-9 Schematic diagram of an oxyacetylene metal-spraying gun. (Courtesy of Sulzer Metco, Winterthur, Switzerland.)

Plasma Arc Spray Gun FIGURE 33-10 Diagram of a plasma-arc spray gun. (Courtesy of Sulzer Metco, Winterthur, Switzerland.)

Comparison of Thermal Spray Deposition

33.4 Brazing

Joint Strength FIGURE 33-11 Typical variation of tensile strength with clearance in a butt-joint braze. (Courtesy of Handy & Harman, Rye, NY.)

Joint Clearance in Brazing FIGURE 33-12 When brazing dissimilar metals, the initial joint clearance should be adjusted for the different thermal expansions (here brass expands more than steel). Proper brazing clearances should exist at the temperature where the filler metal flows.

Common Joint Design FIGURE 33-13 The two most common types of braze joints are butt and lap. Butt offers uniform thickness across the joint, whereas lap offers greater bonding area and higher strength

Variations of Butt Joints FIGURE 33-14 Variations of the butt and lap configurations include the butt-lap and scarf. The four types are shown for both flat and tubular parts.

Common Joint Designs for Brazing FIGURE 33-15 Some common joint designs for assembling parts by brazing

Compatibility of Brazing Materials

Brazing Material Families

Furnace Assembly FIGURE 33-16 Two views of an array of furnace-brazed assemblies. (www.franklinbrazing.com

Schematic of Braze-Welding Process FIGURE 33-17 Schematic of the braze-welding process

33.5 Soldering

Solder Joints FIGURE 33-18 Some common designs for soldered joints.

Compatibility of Soldering

Common Solder

Wave Soldering FIGURE 33-19 Schematic of wave soldering