模具初始温度对高强钢厚板热成形的影响

Influence of initial temperature of die on hot forming of high-strength steel thick plate

研究厚板在热成形淬火过程中的微观组织分布及演变,对于获得理想力学性能的汽车厚板件具有重要意义。以6mm厚的22MnB5钢板为对象,建立了其热成形淬火过程马氏体相变有限元预测模型,分析了模具初始温度(20~80℃)厚板的马氏体组织分布和演变的影响。结果表明:当保压力为40MPa,保压时间为30s时,模具初始温度越高,板料的成形温度有着小幅度的升高,但温度分布的均匀性受模具初始温度的影响不大;马氏体转化率降低,马氏体的分布变化不大。从厚度方向看,随模具初始温度的升高,板料的温度升高,而马氏体转化率减小。综合而言,较低的模具初始温度有利于马氏体转化的充分性和转化效率。

The study of the microstructure distribution and evolution of thick plate during hot forming and quenching process is of great significance for obtaining ideal mechanical properties of automotive thick plate.Taking the 22 MnB5 steel plate with 6 mm thickness as an object,the finite element prediction model of martensite transformation during hot forming and quenching process has been established,while the influence of the distribution and evolution of the martensite structure of the thick plate at the initial temperature of the die(20-80℃)has been analyzed.The results show that when the holding pressure is 40 MPa and the holding time is 30 s,the higher the initial temperature of the die is,the initial temperature of the die increases slightly,but the uniformity of the temperature distribution has not greatly been affected by the initial temperature of the die;the transformation rate of tensite decreases,and the distribution of martensite does not change much.From the perspective of the thickness direction,as the initial temperature of the die increases,the temperature of the sheet metal increases,while the martensite conversion rate decreases.In summary,a lower initial die temperature is conducive to the adequacy and efficiency of martensite transformation.