回火温度对600MPa级低碳贝氏体钢组织和力学性能的影响  

Effect of tempering temperature on the microstructure and mechanical properties of 600 MPa grade low carbon bainitic steel

作　　者：陈林恒[1] 康永林[1] 黎先浩[1] 温德智[2] 刘国民[2] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]湖南涟源钢铁集团有限公司,娄底417009

出　　处：《北京科技大学学报》2009年第8期983-987,共5页Journal of University of Science and Technology Beijing

摘　　要：利用扫描电镜(SEM)、透射电镜(TEM)等实验方法,研究了不同回火温度对屈服强度600MPa级Fe-Mn-Nb-B系低碳贝氏体高强钢组织和性能的影响.结果表明:回火温度对屈服强度和抗拉强度均有较大影响.各回火温度下的低碳贝氏体钢性能与回火前相比,屈服强度均有不同程度的升高,而抗拉强度则均有不同程度的下降;600℃回火时屈服强度比回火前高出105MPa.随着回火温度的升高,屈服强度先上升后又略有下降并在600℃时达到最大值,抗拉强度下降明显,伸长率略有升高,屈强比升高.分析认为:回火前后力学性能的变化主要与回火后有更多弥散的尺寸在20nm以下的新的细小粒子析出以及马氏体占绝大多数的大块M/A岛的分解和发生位错多边形的回复有关.The effects of tempering temperature on the microstructure and mechanical properties of 600 MPa grade low carbon bainitic steel belonged to Fe-Mn-Nb-B series were investigated by utilizing scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results show that tempering temperature has considerable influence on both the yield strength and the tensile strength. The yield strength increases with increasing tempering temperature while the tensile strength has an adverse law. In comparison with the as-received steel, the yield strength of the steel tempered at 600℃ increases 105 MPa. With the increase in tempering temperature, the yield strength increase first and has a slight decline after it reaches the highest point at 600℃, the tensile strength decreases significantly, the elongation increases slightly and the yield ratio increases also. Through analysis it is concluded that the major change of mechanical properties after tempering has a connection with dispersive precipitates with the size of less than 20 nm, the decomposition of large M/A islands in which martensite has a large proportion and the reversion of dislocations and polygon ferrite.

关 键 词：低碳贝氏体钢 回火温度 析出 M/A岛 

分 类 号：TG142.2[一般工业技术—材料科学与工程] TG156.5[金属学及工艺—金属材料]