The Effect of Deformation and Cooling Parameters on Microstructural Evolution of Low-carbon Bainitic Steels

摘要

A low carbon Mn-Cr-Mo low-alloy steel was adopted to investigate the effect of deformation a.nd cooling rate on internedrate transformation and on the volume traction, morphology and distribution of M-A constituents through thermal-simulation experiment. The result shows that with increasing cooling rate, the micro structure transforms from no-parallel acicular feuite to straight and slim lath bainite,and the volume fraction and size of the M-A constituents decreases,whose shape changes from irregularly infra-granular to regularly along bainitic laths or blocks. With increasing strain of austenite, the length of the bainitic lath decreases and the acicular ferrite tends to be formed. Meanwhile, the volume fraction of M-A constituents increases,The characterstics of bainite and the volume fraction of M-A constituents with increasing strain may be related to the enhancement of mechanical stability of the deformed austenite