Progress of NbCN precipitation in HSLA steels as determined by electrical resistivity measurements

Abstract

The residual resistivity of HSLA steel, complemented by the (200) X-ray diffraction line broadening, has been used to determine the amount of Nb remaining in solid solution in the ferrite after various heat-treatments of the parent austenite. The solubility of Nb in the austenite, the isothermal precipitation kinetics of NbCN in undeformed austenite, and the influence of the cooling rate on the NbCN precipitation during the γ → α transformation have been measured on two commercial steels of different carbon and Nb contents. The results are comparable to those previously reported in the literature and illustrate the potential use of the proposed method.