1.MIG Welding
MIG is a welding method that covers the welding part with inert gas to stabilize the arc and prevent changes in welding quality. It uses arc heat to melt the metal in the welding part and feeds the welding rod to connect the weld. It is also generally called semi-automatic welding, covered gas arc welding or Carbon dioxide arc welding, etc.
(1) Use small diameter welding wire when welding thin plates; use large diameter welding wire and high current welding machine when welding thick plates.
(2) Use the correct welding wire to weld the workpiece. Stainless steel welding wire welds stainless steel, aluminum welding wire welds aluminum, and steel welding wire joins steel.
(3) Use the correct protective gas. Carbon dioxide is very suitable for welding steel, but the temperature may be too high for welding thin plates. A mixture of 75% argon and 25% carbon dioxide should be used to weld thinner materials. For welding aluminum, only argon gas can be used. A mixture of 3 gases (helium + argon + carbon dioxide) can also be used when welding steel.
(4) To achieve the best effect of controlling the weld bead, the welding wire should be kept directly aligned with the bonding edge of the molten pool.
(5) Try to keep the welding gun straight when welding to avoid wire feeding problems. When the welding operation is in an abnormal position (vertical welding, horizontal welding, overhead welding), the molten pool should be kept small to achieve optimal control of the weld bead, and the smallest diameter welding wire should be used as much as possible.
(6) Make sure the size of the welding wire you use matches the nozzle, liner, and drive roller.
(7) Clean the welding gun liner and driving roller frequently to keep the welding gun mouth free of spatter. If the welding gun mouth is clogged or the wire feed is not smooth, replace it.
(8) When the welding wire is not in use, keep it in a clean and dry place to avoid contamination that may affect the welding effect.
2.TIG Welding
TIG, also known as tungsten inert gas welding, is an arc welding method that uses non-melting tungsten electrodes for welding. When performing GTAW welding, the welding area is shielded from atmospheric pollution with a shielding gas (inert gases such as argon are commonly used), and solder (filler metal) is usually used together. During welding, energy is provided by an electric arc that conducts through highly ionized gas (i.e., plasma) and metal vapor as a constant current welding power source.
(1) Very suitable for thin plate welding - a clean welding process can achieve a beautiful welding appearance.
(2) Use argon as a protective gas when welding steel and aluminum.
(3) Use DC positive polarity (DCEN) to weld steel and stainless steel, and use AC to weld aluminum.
(4) The push gun technique has always been used in TIG welding.
(5) Welding aluminum materials - pure tungsten electrodes should be used. In this way, tungsten can easily form a spherical tip during AC welding.
(6) Welding steel and stainless steel - Tungsten electrodes containing 2% thorium should be used. The tungsten electrode should be sharpened during DC positive welding.
3. Resistance Welding
Resistance welding refers to a method that uses the resistance heat generated by current passing through the weldment and the contact point as a heat source to locally heat the weldment and apply pressure at the same time for welding. When welding, there is no need for filler metal, high productivity, small deformation of the weldment, and easy automation. There are four main methods, namely spot welding, seam welding, projection welding and butt welding. Resistance welding is not suitable for welding aluminum, copper or copper alloys, but only for welding steel and stainless steel.
(1) To obtain greater heat (current output), shorter electrode arms should be used.
(2) If it is a welding machine without heat control function, the length of the electrode arm should be used for control. For example, longer electrode arms are used when welding thin plates that require low heat.
(3) Make sure there is no gap between the welding workpieces, otherwise the welding effect will be greatly affected.
(4) Keep the two electrode arms aligned so that the electrodes are aligned with each other. Also keep the pressure adjusted appropriately, not too much or too little.
(5) If you need a certain side of the workpiece to have a good appearance after welding, you can use a machine to grind the electrode side.
(6) Clean the electrodes frequently, otherwise the output current will decrease. Appropriate protective covers should also be worn on the electrodes.
