基于30CrMnSiNi2A钢小轴翻边断裂模式的有限元分析与优化

Finite element analysis and optimization based on flanging fracture mode of small shaft for 30CrMnSiNi2A steel

30CrMnSiNi2A钢锁钩小轴铆接翻边处出现断裂脱圈的现象,开裂率约为50%。通过对锁钩小轴进行断口宏观、微观的观察,尺寸检查,硬度检查,金相组织检查以及生产工艺复查,结合有限元计算模拟再现锁钩小轴铆接成形过程翻边处的塑性变形情况,确定了开裂原因,并给出了相应的优化方案。分析结果表明:翻边处内孔倒角结构不合理是导致小轴铆接过程中产生大应力裂纹及过载断裂脱圈的主要原因;较高的表面粗糙度对翻边裂纹起到了促进作用。基于模拟结果,对小轴内孔直径及圆角、内孔深度、内孔表面粗糙度进行优化,铆接翻边后通过目视及放大镜检查以及渗透检查均无裂纹产生。

The phenomenon of fracture and ring release at the riveting and flanging area of small shaft for 30 CrMnSiNi2 A steel shackle occurs,and the cracking rate is about 50%.Then,through the macro and micro observations of fracture,the size inspection,the hardness inspection,the metallographic structure inspection and the production process review for the small shaft of shackle,combined with finite element calculation,the plastic deformation at the flanging area during the riveting process for the small shaft of shackle was simulated and reproduced,and the cause of cracking was determined as well as the corresponding optimization plan was given.The analysis results show that the unreasonable chamfer structure of inner hole at the flanging area is the main reason for the large stress cracks and the overload fracture and ring release during the riveting process of small shaft,and the higher surface roughness promotes the flanging crack.Based on the simulation results,the diameter,fillet,depth and surface roughness of inner hole for small shaft were optimized,and after riveting and flanging,there was no cracks in the visual inspection,magnifying glass inspection and penetration inspection.