TD Machine Shop Policies & Procedures. Welding Procedure Specifications. A WPS is a document that describes how welding is to be carried out in production.
They are recommended for all welding operations and many application codes and standards make them mandatory What information should they include? Sufficient details to enable any competent person to apply the information and produce a weld of acceptable quality. How to Weld - MIG Welding. MIG welding was developed in the 1940's and 60 years later the general principle is still very much the same.
MIG welding uses an arc of electricity to create a short circuit between a continuously fed anode (+ the wire-fed welding gun) and a cathode ( - the metal being welded). The heat produced by the short circuit, along with a non-reactive (hence inert) gas locally melts the metal and allows them to mix together. Once the heat is removed, the metal begins to cool and solidify, and forms a new piece of fused metal.