摘要:
采用TEM、SEM技术和光学显微分析等方法,研究了终轧温度对Si-Mn系热轧双相钢组织与力学性能的影响。试验结果表明,随着终轧温度降低,铁素体晶粒尺寸减小且大小差异性增加,马氏体体积分数下降,贝氏体体积分数升高。当终轧温度为860℃时,强化相主要为马氏体,抗拉强度较高且屈强比低,第二相主要成分为Nb (C、N)且尺寸较大;当终轧温度为743℃时,强化相主要为贝氏体,屈服强度较高且塑性较好,第二相主要成分为复合碳氮化合物Nb (Ti) CN且尺寸较小。综合分析表明,合理控制终轧温度可使热轧双相钢获得不同比例的强化相和不同成分的第二相,从而控制其力学性能。
关键词:
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双相钢 /
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热轧 /
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终轧温度 /
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组织形貌 /
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力学性能
Abstract:
The effect of finishing rolling temperature on the microstructure and mechanical properties of Si-Mn-Nb hot-rolled dual-phase steel were investigated by using TEM,SEM technology and optical microscopy.The results showed that with finishing rolling temperature decreasing,the size of ferrite grains decreased and the size differences increased,the volume fraction of martensite decreased and the volume fraction of bainite increased.When the finishing temperature was 860 ℃,the microstructure of strengthening phase was mainly martensite,the tensile strength was higher and the yield ratio was lower,the second phase was mainly composed of Nb（C,N） and its size was larger.When the finishing temperature was 743℃,the microstructure of strengthening phase was mainly bainite,the yield strength was higher and the plasticity was good,the second phase was mainly composed of Nb（Ti） CN carbonitride compound and its size was smaller. Comprehensive analysis shows that the different proportions of the strengthening phase and the second phase of different components was obtained through reasonable control of the final rolling temperature,thus the controlling of mechanical properties can be obtained as well.
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