Job Description. Key Responsibilities. Selects type and size of metals or other related materials and equipment according to specifications. Selects equipment and plans layouts, assembly, and welding, applying knowledge of geometry, physical properties of metal machining, weld shrinkage and welding techniques. May be required to use Gas-Metal Arc, Flux-Cored Arc, Gas-Tungsten Arc, Submerged Arc, or Shielded Metal Arc welding processes. Lays out, ...