回火温度对550 MPa级高强钢屈强比和残余应力的影响  

Effect of tempering temperature on yield ratio and residual stress of 550 MPa high strength

作　　者：武凤娟 曲锦波 杨浩 Wu Fengjuan;Qu Jinbo;Yang Hao(Institute of Research of Iron and Steel,Shagang,Jiangsu Province,Zhangjiagang Jiangsu 215625,China)

机构地区：[1]江苏省(沙钢)钢铁研究院,江苏张家港215625

出　　处：《金属热处理》2024年第10期66-72,共7页Heat Treatment of Metals

摘　　要：采用显微组织分析、拉伸试验及应力检测等方法研究了不同回火温度(300、400、500、600、700℃)对550MPa级高强钢屈强比和残余应力的影响。结果表明,回火温度在300~500℃区间时,随着回火温度的升高,钢中弥散细小的析出物逐渐增加,M/A岛分解,位错密度降低;回火温度升高到600℃时,M/A岛完全分解,析出物数量最多,位错稀少;回火温度为700℃时,部分贝氏体组织发生再结晶,开始有较多的铁素体产生,且析出物聚集长大,位错几乎不可见。在300~700℃回火温度区间内,随着回火温度的升高,屈强比先升高后降低,钢中残余应力逐渐降低。经500℃回火后钢板的综合性能最优,屈强比为0.85,残余应力为13.98MPa。Effect of tempering temperature(300,400,500,600,700℃)on yield ratio and residual stress of 550 MPa high strength steel was studied by means of microstructure analysis,tensile test and stress measurement.The results show that with the increase of tempering temperature in the range of 300-500 ℃,the amount of dispersed and fine precipitates increases,the M/A constituents decompose and the dislocation density decreases gradually.When the tempering temperature rises up to 600 ℃,the amount of the precipitates reaches the maximum,while the M/A constituents completely decompose and only a small amount of dislocations exist.When the tempering temperature is 70o C,partial recrystallization of bainite occurs with the formation of more ferite,and the precipitates aggregate and coarsen and dislocations are almost invisible.With the tempering temperature increasing from 300 ℃ to 700℃,the yield ratio first increases and then decreases,while the residual stress decreases gradually.An excellent combination of yield ratio and residual stress is obtained after tempering at 500℃,with yield ratio of 0.85 and residual stress of 13.98 MPa.

关 键 词：回火温度 550MPa级高强钢 屈强比 残余应力 

分 类 号：TG156.5[金属学及工艺—热处理]