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利用光学显微镜(OM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)以及拉伸和冲击试验等方法研究了V(0.03%-0.12%)(质量分数,下同)、Si含量(0.32%-0.89%)对中碳(0.54%)珠光体车轮钢显微组织及力学性能的影响。结果表明:提高V含量细化了实验钢的奥氏体晶粒尺寸、珠光体团尺寸及其片层间距,并且提高了铁素体体积分数。随着V含量的提高,由于VC沉淀强化和细化晶粒的作用,室温屈服强度和-20℃冲击韧性得到改善;但软相(先共析铁素体)增多,室温抗拉强度降低。提高Si含量显著降低了铁素体体积分数和细化了珠光体片层间距,略细化奥氏体晶粒和珠光体团尺寸;Si也促进VC的析出但作用很小。Si主要以固溶强化和细化片层间距的方式提高屈服强度和抗拉强度。结合适中含量的V(0.07%-0.08%)微合金化和较高含量的Si(0.8%-0.9%)合金化,可以使中碳珠光体钢获得较好的强韧性匹配。
V (0.03% -0.12%) (mass fraction, the same below), Si content (0.32%) was studied by optical microscope (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and tensile and impact tests. % -0.89%) on the microstructure and mechanical properties of medium carbon (0.54%) pearlite wheel steel. The results show that increasing V content refined austenite grain size, pearlite size and lamellar spacing of experimental steels, and increased ferrite volume fraction. With the increase of V content, the room temperature yield strength and the impact toughness at -20 ℃ are improved due to the effect of VC precipitation strengthening and grain refinement. However, the soft phase (proeutectoid ferrite) increases and the room temperature tensile strength decreases. Increasing the Si content significantly decreased the volume fraction of ferrite and refined the pearlite lamella spacing, slightly refining the size of austenite grains and pearlite groups; Si also promoted the precipitation of VC with little effect. Si mainly increases the yield strength and the tensile strength by solid solution strengthening and refining of the sheet spacing. In combination with moderate content of V (0.07% -0.08%) microalloying and high content of Si (0.8% -0.9%) alloying, can make the carbon pearlite steel get better strength and toughness matching.