Structure and Strength of Isothermally Heat-Treated Medium Carbon Ti-V Microalloyed Steel

Isothermal transformation characteristics of a medium carbon Ti-V microalloyed steel were investigated using light microscopy, scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), and by uniaxial compressive testing. Samples austenitized on 1100 °C isothermally treated in the range from 350 to 600 subsequently water quenched. The final microstructure samples held at consisted bainitic sheaves had yield strength, approximately 1000 MPa, which is attributed high dislocation density low bainite. At 400 450 °C, acicular ferrite became prevalent microstructure. It was also formed displacive mechanism, but lower, leading decrease strength 700 MPa. after heat treatment 500 coarse non-polygonal grains separated pearlite colonies, principally free grains, so that YS reached minimum value about heat-treated 550 both grain boundary intragranular ferrite, alongside some martensite. After s, austenite stable transformed martensite quenching. Therefore, presence increased approx. 800