Welding Metallurgy for the Structural Engineer - Part 1 [N43]

Welding Metallurgy is just an academic concept of little interest to the Structural Engineer until... your project involves retrofitting an structure build in the 20s... or you experience an unexplained cracking problem... or you're asked to approve the use of a new or unlisted steel... or your project demands unusual mechanical properties (such as high notch toughness in the weld metal)... or your structure will be exposed to cold temperature service. When such situations arise, an understanding of welding metallurgy may be tool that will solve your problem. In this practical session, ferrous metallurgy is reviewed and then contrasted to welding metallurgy. The role of carbon, alloys, sulfur and phosphorous on weldability are discussed. Carbon equivalent equations are described. Heat affected zones and the role of heat input on mechanical properties are reviewed. The three major types of weld cracks are described, as well as the causes and cures for each. Hot cracking and cold cracking are discussed. Lamellar tearing and its causes are similarly covered. Finally, AISC and AWS specifications that address welding metallurgy issues are summarized.

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