Influence of Initial Pearlite Morphology on the Microstructure Evolution During Heat Treatment of 1.0C–1.5Cr Steel

Effect of initial pearlite morphology on the microstructure evolution during spheroidization annealing and subsequent hardening treatment was studied in hot-rolled 1.0C–1.5Cr bearing steel. The ferrite-to-austenite transformation in spheroidization annealing can be accelerated by refining the pearlite interlamellar spacing and pearlite colony size. Decreasing interlamellar spacing is also beneficial to increasing the number density of undissolved cementite, leading to the refining of final spheroidized cementite. During the re-austenitizing process of hardening treatment, the smaller initial spheroidized cementite leads to faster cementite dissolution and finer undissolved cementite particles. The prior austenite grain size after hardening treatment can also be decreased by refining the initial pearlite microstructure.