Effect of Aluminum, Nitrogen and Silicon Content on the Toughness of C-Mn Steel Weld Heat Affected Zone

Abstract

In the present study, the effect of aluminum, silicon, and nitrogen content on the microstructure and toughness of the weld heat affected zone (HAZ) of tensile strength, 400-500MPa grade steels was investigated. The change in phase fraction, precipitate distribution as a function of peak temperature and cooling time were analyzed to clarify the effect of each alloying element on the microstructural changes and toughness of the weld HAZ. The optimal aluminum, nitrogen, and silicon content was determined by impact toughness and the microstructure of the simulated coarse grained heat affected zone (CGHAZ) concerning appropriate ferrite and bainite fraction, minimization of a cementite, a martensite-austenite (M-A) constituent distribution, and free nitrogen in a matrix.