Copyright Goodheart-Willcox Co., Inc. 153 Objectives After completing this chapter, you will be able to: ❑ Identify the characteristics of aluminum. ❑ Identify wrought material, castings, and tempers by their number systems or designations. ❑ Distinguish between heat-treatable or nonheat- treatable aluminum. ❑ Summarize the filler metal choices for various aluminum alloys. ❑ Recall joint preparation techniques, including preweld cleaning, weld backing, preheating, and tack welds. ❑ Select the correct power source, shielding gases, and electrodes for welding aluminum using ACHF, DCEN, and DCEP. ❑ Apply correct procedures for welding aluminum using ACHF. ❑ Apply correct procedures for welding aluminum using DCEN. ❑ Apply correct procedures for welding aluminum using DCEP. Key Terms artificially aged cold work crater dross ductility hot short keyhole method naturally aged solution heat-treated stabilized strain-hardened swaging temper wrought Introduction Aluminum is a widely used material in the manufacturing and fabrication industries because of its highly desirable characteristics. Aluminum is very light in comparison to steels, has a good strength- to-weight ratio, and is highly resistant to corrosion. There are several different types of aluminum, so identifying the particular type of material is impor- tant and sometimes diffi cult to do. Aluminum is an excellent material for many applications, but requires some slightly different welding techniques than those used on steel. Chapter 9 Manual Welding of Aluminum