高强度钢-普通钢拼焊板热冲压成形机理研究

Hot Stamping Mechanism of High Strength Steel-Common Steel Tailor Welded Blanks

目的研究高强度钢-普通钢拼焊板热冲压成形机理。方法对高强度22MnB5钢-Q235钢拼焊板高温力学性能及U形热弯曲件的微观组织和力学性能进行实验研究,对高温下拼焊板协调变形进行数值分析,研究拼焊板高温力学性能和热弯曲件微观组织、力学性能的影响机制及拼焊板热变形协调机制。结果焊缝与拉伸方向平行时,800℃下拼焊板伸长率不高,两侧母材形变量相差较大;900℃和950℃下,两种母材形变量接近。焊缝与拉伸方向垂直时伸长率较低。热弯曲件“软”、“硬”区抗拉强度差为500~1000 MPa,伸长率差为5%~20%。结论焊缝与拉伸平行时拼焊板塑性较好,温度越高焊缝两侧变形较一致,焊缝与拉伸垂直时拼焊板力学性能主要取决于“软”区母材的性能。揭示了高强度22MnB5钢-Q235钢拼焊板热冲压成形机理。

The work aims to study the hot stamping mechanism of high strength steel-common tailor welded blanks.Experiment was carried out to study the high-temperature mechanical properties of 22MnB5 steel-Q235 steel TWBs and the microstructure and mechanical properties of U-shaped hot bended parts.Numerical analysis of compatible deformation of TWBs at high temperature was conducted to study the influencing mechanism for high-temperature mechanical properties of TWBs and microstructure and mechanical properties of hot bended parts and the coordination mechanism of hot deformation of TWBs.When the welding seam was parallel to the tensile direction,the elongation of TWBs was not high at the temperature of 800℃,and the deformation of the base metal on both sides of welding seam was quite different.At the temperature of 900℃and 950℃,the deformation of the two base metals was close.The elongation was lower when the welding seam was perpendicular to the tensile direction.The difference in tensile strength between“soft”and“hard”zones of hot bended parts was about 500~1000 MPa,and the difference in elongation was about 5%~20%.When the welding seam is parallel to the tensile direction,the plasticity of the TWBs is better.The higher the temperature is,the more consistent the deformation on both sides of the welding seam is.When the welding seam is perpendicular to the tensile direction,the mechanical properties of the TWBs mainly depend on the properties of the base metal in the“soft”zone.The hot stamping mechanism of high strength 22MnB5 steel-Q235 steel tailor welded blanks is revealed.