淬火温度对非均质淬火-配分钢组织和性能的影响

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partitioned Mn pearlite steel to obtain Mn-heterogeneous austenite, the effect of quenching temperature on the microstructure evolution and mechanical properties of the steel was systematically investigated. The results show that when high temperature austenite inherits the Mn distribution in Mn-rich cementite and Mn-poor ferrite in pearlite, ghost pearlite which consists of alternative Mn-enriched film retained austenite (RA) and Mn-depleted lath martensite can be obtained after quenching. With the increase of quenching temperature, the driving force of austenite-to-martensite transformation decreases, which leads to the decrease of ghost pearlite fraction and the increase of fraction and size of blocky RA. Due to the decrease of ghost pearlite fraction, the average width of martensite lath increases, resulting in the decreased yield strength. Moreover, the increased fraction and size of blocky RA ensure an increased uniform elongation by transformation-induced plasticity effect, whereas the transformation product (i. e., fresh martensite) is detrimental to the post-uniform elongation. Therefore, tuning the quenching temperature provides an effective strategy to tailor yield strength and uniform elongation while maintaining large ultimate tensile strength (about 1600 MPa) and total elongation (about 20%).