高强钢厚板热成形的入模温度研究

Research on input temperature for hot forming of highstrength steel thick plate

针对6 mm厚的22MnB5钢板,建立了热成形淬火过程马氏体相变过程的有限元模型,分析了入模温度对厚板的温度和马氏体组织分布的影响。结果表明:当保压压力为40 MPa、保压时间为30 s时,入模温度越高,马氏体的转化率越低;入模温度在600~750℃时,马氏体的分布均匀性逐渐变差,高于750℃后,马氏体分布的均匀性没有明显变化;沿板料厚度方向,随入模温度的升高,马氏体分布均匀性有所好转,但马氏体转化率降低。因此较低的入模温度有利于提高马氏体转化的充分性、分布均匀性及转化效率。

A finite element model for predicting martensitic transformation of 6 mm 22MnB5 steel plate during hot forming and quenching process was established.The effect of die temperature on the temperature and martensitic microstructure distribution of the thick plate was analyzed.The results showed that when the holding pressure was 40 MPa and the holding time was 30 s,the high⁃er the input temperature,the lower the conversion rate of martensite.The distribution uniformity of martensite became worse when the temperature was from 600~750℃,but did not change signif⁃icantly when the temperature was higher than 750℃;Along the thickness direction of the sheet,the distribution uniformity of martensite was improved with the increase of die entry temperature,but the conversion rate of martensite decreased.Therefore,lower input temperature was benefi⁃cial to improve the sufficiency,distribution uniformity and conversion efficiency of martensite transformation.