Welding techniques for the six major welding processes

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01 MIG welding: Keep the wire rod extended at 1/4–3/8 inch (the length of the wire extending from the gun tip). 02 Use a wire with a small diameter when welding thin sheets； Large-diameter welding wires and high-current welders are used when welding thick plates. 03 Use the correct welding wire to weld the workpiece. Stainless steel welding wire is used for welding stainless steel, aluminum welding wire is used for welding aluminum, and steel welding wire is used for welding steel. 04 Use the correct shielding gas. Carbon dioxide is very suitable for welding steel, but it may generate too high a temperature when used for welding thin sheets; a mixture of 75% argon and 25% carbon dioxide should be used to weld thinner materials. Argon can only be used for welding aluminum. When welding steel, you can also use a mixed gas composed of 3 gases (helium + argon + carbon dioxide). 05 To achieve the best control over the weld bead, the welding wire should be kept directly aligned with the edge where the molten pool meets. 06 When welding is performed in an abnormal position (upward welding, horizontal welding, downward welding), a smaller weld pool should be maintained to achieve optimal control over the weld bead, and the wire with the smallest diameter should be used as much as possible. 07 Ensure that the size of the welding wire you use is compatible with the electrode holder, liner tube, and drive roller. 08 Regularly clean the weld gun liner and drive roller to keep the weld gun tip free of spatter. If the welding torch tip is clogged or wire feeding is not smooth, replace it. 09 Try to keep the welding torch straight during welding to avoid wire feeding issues. 10 Use both hands simultaneously during welding to ensure the stability of the welding torch; try to do this as much as possible. (This also applies to stick welding, TIG welding, and plasma cutting.) 11 Adjust the tension of the wire reel and drive roller on the wire feeder to a level that is just sufficient for feeding the wire; it should not be too tight. 12 When not in use, store the welding wire in a clean and dry place to prevent contamination from affecting the welding quality. 13 Use a DC reverse-polarity DCEP power supply. 14 The drag (pull) welding torch technique enables deeper penetration and narrower welds. The push gun technique allows for a shallower penetration and a wider weld bead. 02 Aluminum Welding 01 The most suitable welding torch for aluminum is a drawn-wire type torch; if you cannot use such a torch, try to use the shortest one possible in order to keep it straight ； Only argon can be used as the shielding gas ； When welding aluminum, only the push gun technique can be used. 02 If you encounter issues with wire feeding, you can try using a contact tip that is one size larger than the welding wire. 03 The most commonly used welding wire for welding aluminum is a softer standard welding wire. The other type is harder (easier to feed the wire), and it is mainly used in welding operations where higher hardness and strength are required. 04 Before starting welding, it is necessary to remove the oxide layer from the surface of the aluminum material; use a special stainless steel brush to do this. 05 Fill the weld pool at the end of welding to prevent cracks. One method is to keep the welding torch in the molten pool for a few seconds after welding. 03 Self-protecting flux-cored wire welding 01 Use the pull (or drag) gun technique during welding. 02 Keep the welding wire clean and dry to achieve optimal welding results. 03 This type of welding is similar to stick welding, as the slag layer on the surface of the weld must be removed after welding is completed. A slag hammer and wire brush can be used for slag removal. 04 Self-shielding flux-cored wires do not require an additional shielding gas cylinder. (The protective agent is inside the welding wire). This feature makes it highly suitable for use in outdoor operations, as protective gases are easily dispersed when used outdoors. 05 Self-shielding flux-cored wires are more difficult to use for welding thin sheets compared to MIG welding. 04 TIG welding 01 Highly suitable for welding thin sheets – a clean welding process yields an attractive weld appearance. 02 Argon is used as a shielding gas when welding steel and aluminum. 03 Use DC positive polarity (DCEN) to weld steel and stainless steel, and use AC to weld aluminum. 04 The push gun technique is always used in TIG welding. 05 Match the size of the tungsten electrode to that of the nozzle sleeve. 06 Welding aluminum – pure tungsten electrodes should be used. This allows the tungsten to easily form a spherical tip during arc welding. 07 Welding steel and stainless steel — Tungsten electrodes containing 2% thorium should be used. The tungsten electrode should be sharpened when welding with a direct current positive pole. 05 Stick Arc Welding 01 The drag gun technique is used most of the time. 02 Be prepared to prevent weld slag splashing. 03 Keep the welding rod clean and dry—follow the manufacturer’s recommendations. 04 Penetration: Negative DC current – maximum penetration; AC current – moderate penetration (with possible excessive spatter); Positive DC current – minimum penetration. 06 Resistance welding 01 Resistance welding is not suitable for welding aluminum, copper, or copper alloys. And it is only used for welding steel and stainless steel. 02 To obtain higher heat (current output), shorter electrode arms should be used. 03 If it is a welder without a heat control function, the length of the electrode arm should be used for control. For example, longer electrode arms are used when welding thin sheets that require low heat. 04 Be aware that longer electrode arms may bend, and you might also lose the pressure applied to the weld. 05 It is necessary to ensure that there are no gaps between the welded pieces; otherwise, the welding quality will be significantly affected. 06 Keep the two electrode arms aligned so that the electrodes are aligned with each other. Also, maintain an appropriately adjusted pressure – neither too high nor too low. 07 If you need a good appearance on one side of the workpiece after welding, you can grind (using a machine) the side where the electrode is located. 08 Clean the electrodes regularly; otherwise, the output (current) will decrease. Appropriate protective covers should also be placed on the electrodes.