MCG 4340 Lecture Notes - Lecture 1: Shielding Gas, Electrical Resistance And Conductance

• School: University of Ottawa
• Department: Mechanical Engineering
• Course: MCG 4340
• Professor: Catherine Mavriplis

Document Summary

Since most utility trailers for cars are made from steel, the mig (gmaw) welding process would be the best. Edges must be bevelled to provide accessibility for welding and ensure the weld"s soundness and strength. However this uses more filler material: with mig welding, co2 can be used as a shielding gas and it is cheap. C-25 gas is preferable since it creates a more stable arc, good control over the weld pool, and overall better appearance of the weld. It is suitable for application with high current on heavy base metal: a shielding gas is typically not used when stick welding. The weld doesn"t oxidize because there is a flux coating on the electrode that vaporizes, producing a gas shield. Yes, aluminum can be spot welded except that because of its low electrical resistance, it needs a high current for it to heat up sufficiently.