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I. Overview of Aluminum Alloy Welding Aluminum alloy welding: refers to the process of welding aluminum alloy materials. Aluminum alloys are highly strong and lightweight. The main welding processes are manual TIG welding (gas tungsten arc welding), automatic TIG welding, and MIG welding (metal inert gas welding), along with the base material, welding wire, shielding gas, and welding equipment. II. Welding Methods for Aluminum Alloys 1. Tungsten Inert Gas Welding Tungsten inert gas welding is primarily used for aluminum alloys and is a good welding method; however, the equipment required for this process is complex, making it unsuitable for use in outdoor conditions. 2. Resistance spot welding and seam welding: These welding methods can be used to weld thin aluminum alloy sheets with a thickness of less than 5 mm. However, the equipment used for welding is relatively complex, with high welding current and high productivity, making it particularly suitable for the mass production of parts and components. 3. Pulse TIG welding: Pulse TIG welding can significantly improve stability during the welding process; parameters can be adjusted to control arc power and weld shape. It results in minimal deformation of the welded parts and a small heat-affected zone, making it particularly suitable for thin sheets, welding in all positions, as well as for welding heat-sensitive alloys such as wrought aluminum, hard aluminum, and super-hard aluminum. 4. Friction Stir Welding: Friction stir welding has been increasingly used, primarily in the field of lightweight metal structures such as aluminum alloys and magnesium alloys. Its advantage lies in the fact that the welding temperature is lower than the melting point of the materials, which helps to avoid defects such as cracks and pores that can occur with fusion welding. III. Scope of testing for the welding procedure qualification of aluminum and aluminum alloys 1. Butt welding of copper and aluminum pipes in the refrigeration industry, as well as welding of copper pipes with galvanized pipes, stainless steel pipes, and aluminum pipes together. 2. Welding of copper and aluminum terminals, copper and aluminum leads, and copper and aluminum busbars in the power transformation industry. 3. Welding of radiator tubes, motors, and busbars in the electronics and electrical industry. 4. It is also used in production and daily life for faucets, coupling connectors, accompanying nuts, and so on. IV. Process Evaluation Procedure for Aluminum Alloy Welding 1. Welding process evaluation 2. Identification of items for welding process evaluation 3. Drafting of the welding process plan 4. Welding process evaluation tests 5. Preparation of the welding process evaluation report 6. Preparation of welding procedure specifications (process cards, work instruction sheets) V. Inspection Items for Welding Process Evaluation of Aluminum Alloys (I) Main items 1. Type and specification of welding materials: Article 4.3.1 – Check product certification documents, Chinese markings, and inspection reports (100% inspection) 2. Re-inspection of welding materials: Article 4.3.2 – Check re-inspection reports (100% inspection) 3. Material compatibility: Article 5.2.1 – Check quality certificates and baking records (100% inspection) 4. Welder’s certificates: Article 5.2.2 – Check welder’s qualification certificates, their scope of approval, and validity period (for all welders) 5. Welding process evaluation: Article 5.2.3 – Check welding process evaluation reports (100% inspection) 6. Internal defects: Article 5.2.4 – Check weld flaw detection records (100% inspection) 7. Dimensions of composite welds: Article 5.2.5 – Conduct visual inspections and random measurements using weld gauges (check all relevant data; for similar welds, conduct random inspections on 10% with a minimum of 3 samples) 8. Detection of surface defects in welds: Article 5.2.6 – Conduct visual inspections or use magnifying glasses, weld gauges, and steel rulers; if necessary, employ penetrant testing or magnetic particle testing