Carbon Equivalent to Assess Hardenability of Steel and Prediction of HAZ Hardness Distribution

Abstract

A practical method to predict HAZ hardness distribution was studied by considering the effect of prior austenite grain sizes on hardenability and that of tempering. For 400 to 490MPa grade steels, hardness distribution between fusion and Ac 3 lines can be fairly well predicted by introducing the effect of grain sizes to the maximum HAZ hardness prediction method. For boron added 780MPa grade steel, since the maximum hardness is obtained at the area a little bit away from the fusion line, the present method cannot predict its HAZ hardness well. Hardness at Ac 1 line can be evaluated with the tempering parameter.