终轧温度对Q420钢组织与力学性能的影响

Effects of Final Rolling Temperature on Microstructure and Mechanical Properties of Q420steel

以Q420低合金高强度钢为研究对象,采用相关的仪器设备和控轧控冷法,研究了终轧温度890℃和800℃对试验钢组织性能的影响.结果表明:两种终轧温度下试验钢的显微组织均为铁素体+粒状贝氏体.随着终轧温度的降低,实验钢的显微组织逐渐均匀细小化,Nb、Ti、V的碳氮化物析出数量逐渐增加,尺寸逐渐减小且趋于高度弥散,钢的强韧性都有不同程度的提高,而硬度却有所下降.当终轧温度降低到800℃时,实验钢的屈服强度、抗拉强度、延伸率、硬度分别高达672.13 MPa、775.06 MPa、22.74%、206.3 HV,试验钢的综合力学性能相对较佳.

Taking Q420 low-alloy high-strength steel as the research object, using the relevant equipment and controlled rolling and cooling method, the effect of finishing rolling temperature on the microstructure and properties of the test steel was studied at 890 and 800 respectively. The results show： the microstructure of the test steel is ferrite ＋ granular bainite in two kinds of final rolling temperature. With the decrease of the final rolling temperatur,the microstructure of the experimental steel was uniform and fine, carbonitride precipitates quantity of Nb,Ti,V gradually increased, size decreases and tends to be highly dispersed, the strength and toughness of steel are improved in different degree, and the hardness has declined. When the final rolling temperature is reduced to 800,the yield strength, tensile strength, elongation and hardness of the experimental steel were as high as 672.13 MPa, 775.06 MPa, 22.74%, 206.3 HV, the comprehensive mechanical properties of the test steel is relatively good.