Simulation of radial forging conditions by third hits hot compression tests

Radial forging conditions of ultra-high strength 32CrMoV1210 steel was investigated by using multi-pass hot compression tests. Compression continuous cooling transformation (CCCT) diagram after final deformation pass was plotted and compared with CCT diagram in order to identify the effects of deformation on transformation behavior. Comparison between these two diagrams showed that prior deformation increased martensite start temperature, Ms from 45 to 85 °C. The microstructural observation illustrated that application of prior deformation leads to finer lath martensite. It also showed that when deformation temperatures decreased, the grain size and its distributions became finer and inhomogeneous, respectively.