精冲模具崩刃失效演变及机理分析  

Evolution and mechanism analysis of chipping failure for fine blanking die

作　　者：张祥林[1] 张丽筠 ZHANG Xiang-lin, ZHANG Li-yun(State Key Laboratory for Material Processing and Die ＆ Mould Technology, Huazhong University of Science anti Technology, Wuhan 430074, China)

机构地区：[1]华中科技大学材料成形与模具技术国家重点实验室

出　　处：《塑性工程学报》2018年第5期33-38,共6页Journal of Plasticity Engineering

基　　金：湖北省重大专项(2015BAA015);国家科技重大专项(2009ZX04014-073)

摘　　要：从精冲模具崩刃失效的观测出发,利用体式显微镜、光学显微镜、环境扫描电子显微镜等设备,清晰显示了薄壁冲头和齿形冲头崩刃刃口附近侧面和底部的微裂纹、凹坑和变形形貌;结合文献理论、生产体验和形貌图分析了崩刃失效的演变规律、崩刃失效机制等。结果表明：冲头应力集中的重载导致的塑性变形是侧面主裂纹萌生的主要根源,挤压和拉拔力促进了裂纹的扩展,主裂纹汇合引起崩刃失效。最后根据影响精冲模具崩刃失效的因素,由生产现场实用化的角度,从被加工零件材料及形状、模具材料及结构、模具受力平衡性等方面给出了延缓模具崩刃失效的有效措施。Proceeding from observation of chipping failure during fine blanking production,the body microscope,optical microscope,and environmental scanning electron microscope were used for morphology observation of micro cracks,pits and deformation on the side and bottom near chipping edge for thin-walled punch and gear punch. Based on the comparisons between reported theories,production experiences and the surface morphologies of failure punches,the evolution rules and mechanisms of the chipping failure behavior were analyzed and discussed. The results show that the plastic deformation,which is caused by the stress concentration around punch corner,contributes to the main crack on the side wall. Besides,the extrusion force and drawing force promote the extension and convergence of the main cracks,which thus result in the chipping failure. Finally,based on the influential factors of chipping failure,several effective proposals were provided for delaying the chipping failure from the view of practical production,such as the material and shape of part,the material and structure of die,and the force balance condition of die.

关 键 词：精冲 模具 崩刃 裂纹 

分 类 号：TG385.2[金属学及工艺—金属压力加工]