HC340/590DP钢的前横梁冲压开裂分析

Cracking analysis on front crossbeam in stamping process for HC340/590DP steel

HC340/590DP钢具有马氏体和铁素体双相组织,是汽车轻量化中用量最多的材质之一。通过组织分析发现HC340/590DP钢的扩孔翻边性能主要由材料中马氏体的分布形态所决定。马氏体呈连续链状集中分布在铁素体晶界处,将铁素体封闭于其中,有助于裂纹的扩展,而呈岛状、不连续分布的马氏体可以有效地阻止裂纹的扩展。通过降低原始材料的碳含量,适当提高退火温度,得到马氏体呈岛状不连续分布的材料。利用有限元模拟软件,引入翻边扩孔判断准则,模拟前横梁的成形过程,使用改善后的HC340/590DP材料,前横梁翻边扩孔的开裂风险由1.13降低到0.85,符合前横梁的成形要求,且得到了实际验证。

HC340/590DP steel with martensite and ferrite dual-phase structure is one of the more material for car lightweight.Through the tissue analysis,it is found that the flanging and reaming perforrnanee of HC340/590DP steel is mainly determined by the distribution of martensite in the material.Martensite eontinuously distributed in the ferrite grain boundaries whieh eneloses the ferrite therein contributes to the crack propagation.However,the island-shaped and discontinuous distributed martensite can prevent the crack from growing.By reducing the carbon content of material,and properly increasing the annealing temperature,the martensite is obtained in the form of islandshaped and discontinuous distribution.Furthermore,the forming process of front crossbeam was simulated by the numerical simulation software and the criterion of flanging and reaming.The cracking risk for flanging and reaming of front crossbeam is reduced from 1.13 to 0.85 with the improved HC340/590DP material.Thus,the forming requirements of front crossbeam was met,and the actual verification was obtained.