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采用热模拟实验方法研究了铌对Si--Mn系弹簧钢相变特征的影响,分析了NbC的形变诱导析出行为.结果表明:弹簧钢中添加微量铌,推迟了珠光体转变,马氏体转变的最小冷却速率由5℃.s-1变为3℃.s-1;细化了珠光体,改变了珠光体组织形貌,渗碳体片层变薄、形状变得不规则,出现弯曲、断续;含铌弹簧钢在850℃变形时发生了NbC的形变诱导析出,NbC的析出位置为珠光体中的铁素体片层内、珠光体球团边界和位错处,析出物颗粒直径为10～15nm,形状近似球形.
The effect of niobium on the phase transformation of Si - Mn spring steel was studied by means of thermal simulation experiment, and the deformation induced precipitation behavior of NbC was analyzed.The results show that the addition of trace niobium to spring steel delayed the pearlite transformation and the martensite The minimum cooling rate of transformation changed from 5 ℃ .s-1 to 3 ℃ .s-1. The pearlite was refined, the pearlite structure was changed, the cementite sheet became thinner, the shape became irregular, Bending and discontinuous. NbC deformation induced precipitation occurs when the Nb-containing spring steel is deformed at 850 ℃. The precipitating position of NbC is within the ferrite sheet in the pearlite, at the boundary of the pearlite pellet and at the dislocation, Diameter of 10 ~ 15nm, approximately spherical shape.