MIG welding will be inefficient without the right MIG wire. Hence, it makes sense to invest in high-quality MIG wire for superior results and to avoid costly mistakes in pre-weld and post-weld operations, like forming, cutting, joint and surface preparation, painting and grinding, tacking, and cleaning. As long as you use the right MIG wire in metal inert gas welding, you can be sure of smoother and seamless results when joining metals together. MIG wires are also known as ‘MIG welding electrodes’, and they are chosen based on the metal that needs to be welded. Likewise, you need to consider the resistance to heat and abrasion, type of transfer, and position to be welded.
An MIG wire is typically classified with a code, which should let you know its suitability for MIG welding. The codes are used to identify the type of electrode. The rule of the thumb is to find ‘ER’ in the name of the product, so you know that it is suitable for MIG and TIG welding. ER70S-6 is an example of an electrode that is widely used for welding carbon steel, and it is typically used with shielding gas made of C25 (75 percent argon and 25 percent carbon dioxide) or 100 percent carbon dioxide. ER70S-3 is another commonly used MIG wire for mild steel. All MIG wires are designed and manufactured to meet a minimum tensile strength of 70,000 psi.
The right MIG wire will produce a clean base material without oxidation and grease. ER70S-3, for instance, is ideal for applications where silicon islands must not form on top of the weld to cause a glassy appearance. When paint is applied to the silicon island, it will later chip and flake off. Moreover, the silicon island may be identified as a slag inclusion on an x-ray, and the product may need to be reworked. ER70S-6 MIG wire is ideal for welding plates that have surface contaminants or mill scale. The wire comes with a deoxidiser, which prevents those issues. Deoxidisers absorb oxygen to make it oxidise into the arc as scale oxides. Hence, it can create a smooth transition from the base metal to the weld.