In the world of welding, mastering different welding processes is the key to achieving high-quality and efficient results. Whether you are a professional welder looking to enhance your skills or a novice eager to learn the ropes, understanding the practical tips and techniques of various welding methods is essential. In this comprehensive guide, we will explore the secrets of six major welding processes, providing you with valuable insights and actionable advice to help you become a proficient welder. Let's dive into the world of welding and unlock the skills that will set you apart in this challenging yet rewarding field.
01 MIG Welding
1. Maintain a welding wire stick-out of 1/4 to 3/8 inches (the length of the welding wire protruding from the welding gun tip).
2. Use a small-diameter welding wire for welding thin sheets; for welding thick plates, use a large-diameter welding wire and a high-current welding machine.
3. Use the correct welding wire for the workpiece. Stainless steel welding wire for stainless steel, aluminum welding wire for aluminum, and steel welding wire for steel.
4. Use the correct shielding gas. Carbon dioxide is very suitable for welding steel, but it may be too hot for welding thin sheets. A mixed gas of 75% argon and 25% carbon dioxide should be used for welding thinner materials. Only argon can be used for welding aluminum. When welding steel, you can also use a three-gas mixture (helium + argon + carbon dioxide).
5. To achieve the best control of the weld bead, keep the welding wire directly aligned with the joint edge of the molten pool.
6. When the welding operation is in an abnormal position (vertical welding, horizontal welding, overhead welding), maintain a smaller molten pool to achieve the best control of the weld bead and use the smallest diameter welding wire possible.
7. Ensure that the welding wire size you use matches the nozzle, liner, and drive roller.
8. Clean the welding gun liner and drive roller regularly to keep the welding gun nozzle free of spatter. If the welding gun nozzle is blocked or the wire feeding is not smooth, replace it.
9. Try to keep the welding gun straight during welding to avoid wire feeding problems.
10. Use both hands during welding operations to ensure the stability of the welding gun, and do this as much as possible. (This also applies to electrode welding, TIG welding, and plasma cutting.)
11. Adjust the tightness of the wire spool and drive roller of the wire feeder to just enough to feed the wire, not too tight.
12. When the welding wire is not in use, store it in a clean and dry place to avoid contamination and affect the welding effect.
13. Use a direct current electrode positive (DCEP) power source.
14. The drag (pull) welding gun technique can achieve deeper penetration and a narrower weld. The push welding gun technique can achieve shallower penetration and a wider weld.
02 Aluminum Welding
1. The most suitable welding gun for welding aluminum is the spool gun. If you cannot use this type of welding gun, try to use the shortest welding gun to keep it straight; only argon can be used as the shielding gas; only the push welding gun technique can be used when welding aluminum.
2. If you have wire feeding problems, you can try a conductive tip one size larger than the welding wire.
3. The most commonly used welding wire for welding aluminum is the softer standard welding wire. Another type is harder (easier to feed) and is mainly used for welding operations with higher hardness and strength requirements.
4. Before welding, do a good job of removing the oxide layer on the surface of the aluminum material. Use a special stainless steel brush to remove the oxide layer.
5. Fill the crater well at the end of welding to prevent cracks. One way is to keep the welding gun in the molten pool for a few seconds after welding.
03 Self-Shielded Flux-Cored Wire Welding
1. Use the pull (or drag) welding gun technique during welding.
2. Keep the welding wire clean and dry to achieve the best welding effect.
3. This welding is similar to electrode welding because the slag layer on the surface of the weld must be cleaned after welding. A chipping hammer and wire brush can be used for slag removal.
4. Self-shielded flux-cored wire welding does not require an extra shielding gas container. (The shielding agent is inside the welding wire.) This feature makes it very suitable for outdoor work because the shielding gas is easily blown away outdoors.
5. Self-shielded flux-cored wire welding is more difficult than MIG welding when welding thin sheets.
04 TIG Welding
1. Very suitable for thin sheet welding - a clean welding process can achieve a beautiful welding appearance.
2. Use argon as the shielding gas when welding steel and aluminum.
3. Use direct current electrode negative (DCEN) for welding steel and stainless steel, and use alternating current for welding aluminum.
4. Always use the push welding gun technique in TIG welding.
5. Match the size of the tungsten electrode with the size of the nozzle.
6. For welding aluminum - pure tungsten electrodes should be used. This allows the tungsten to easily form a spherical tip during AC welding.
7. For welding steel and stainless steel - tungsten electrodes containing 2% thorium should be used. The tungsten electrode should be sharpened when using direct current electrode positive welding.
05 Shielded Metal Arc Welding
1. Mostly use the drag welding gun technique.
2. Be prepared to prevent slag spatter.
3. Keep the electrode clean and dry - follow the manufacturer's recommendations.
4. Penetration: direct current electrode negative - maximum penetration, alternating current - medium penetration (may also have more spatter), direct current electrode positive - minimum penetration.
06 Resistance Welding
1. Resistance welding is not suitable for welding aluminum, copper, or copper alloys. It is only used for welding steel and stainless steel.
2. To obtain more heat (current output), use a shorter electrode arm.
3. If the welding machine has no heat control function, use the length of the electrode arm for control. For example, use a longer electrode arm when welding thin sheets that require low heat.
4. Note that a longer electrode arm may bend and you may also lose the pressure on the weld.
5. Ensure that there is no gap between the welded workpieces, otherwise the welding effect will be greatly affected.
6. Keep the two electrode arms aligned so that the electrodes are aligned with each other. Also, maintain an appropriate pressure, not too large or too small.
7. If you need a good appearance on one side of the workpiece after welding, you can grind (with a machine) the electrode side.
8. Clean the electrodes regularly, otherwise the output (current) will decrease. Also, put appropriate protective covers on the electrodes.
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