锻压技术

A柱加强板热冲压延迟开裂机理

英文标题：Mechanism of delayed fracture for Apillar in hot stamping

作者：余海燕蒋忠伟

分类号：U461

出版年,卷(期):页码：2017,42(3):40-43

摘要：

针对某车型超高强度硼钢A柱加强板热冲压成形后小翻边易发生延迟开裂的问题,进行了变薄率、化学成分、断面硬度、残余应力和断裂面扫描电镜等试验，对延迟开裂的原因进行了详细地讨论，并提出了改进措施。研究结果表明，开裂面呈韧窝形态，翻边圆角处发生氢脆现象。小翻边部位在热冲压时圆角处的应力集中导致镀层开裂,且放置一段时间后氢原子积聚形成氢分子易从开裂的镀层间隙处释放,形成该零件的延迟开裂。通过增加露点控制以有效降低氢的导入，可以避免氢脆的发生。

For the delayed fracture of flanging after hot stamping of ultra high strength boron steel Apillar, experiments of thickness thinning rate, chemical composition, section hardness, residual stress and SEM observation were conducted, and the causes were discussed and the improvement measures were suggested. The results show that the crack surface is in dimple shape and the hydrogen embrittlement phenomenon occurs at the flanging fillet. Furthermore, the stress concentration at the flanging fillet during hot stamping leads to coating cracking,and it produces the delayed fracture of part because the gathered hydrogen atoms forming hydrogen molecules are easy to release from the coating gap after the part which is placed a period of time. Thus, the hydrogen embrittlement can be avoided by increasing dew point to deduce the introduction of hydrogen effectively.

基金项目：

余海燕(1976-),女，博士，教授蒋忠伟(1981-)，男，硕士，中级工程师

参考文献：

［1］褚武扬.氢损伤与滞后断裂[M]. 北京：冶金工业出版社, 2000.Zhu W Y. Hydrogen Damage and Delayed Fracture[M].Beijing: Metallurgical Industry Press, 2000.
［2］庄百亮，单忠德，姜超. 热冲压成形工艺技术及其在车身上的应用[J]. 金属加工：热加工, 2010,(21): 62-64. Zhuang B L, Shan Z D, Jiang C. Hot stamping technology and application in vehicle body[J]. Metal Working:Hot Forming, 2010,(21): 62-64.
［3］李辉平，赵国群，张雷,等. 超高强度钢板热冲压及模内淬火工艺发展现状[J]. 山东大学学报:工学版, 2010, 40(3):69-74.Li H P, Zhao G Q, Zhang L, et al. The development status of hot stamping and quenching of ultra-high-strength steel[J]. Journal of Shandong University:Engineering Science Edition,2010, 40(3):69-74.
［4］马宁,张宗华,胡平,等.热成形金属复合材料的微观结构及力学行为研究[J]. 材料工程,2011,(5):88-92.Ma N, Zhang Z H, Hu P, et al. Microstructure and mechanical behavior of new type multi-layer metallic composite material in hot forming[J]. Materials Engineering, 2011,(5):88-92.
［5］谭志耀.超高强度钢板热冲压成形基础研究[D]. 上海：同济大学, 2006.Tan Z Y. The Basic Study on Hot Stamping of Ultra-High-Strength Steel[D]. Shanghai: Tongji University, 2006.
［6］林建平, 王立影, 田浩彬,等. 超高强度钢板热冲压成形研究与进展[J]. 热加工工艺, 2008, 37(21):140-144. Lin J P, Wang L Y, Tian H B, et al. Research and development of hot forming of ultra high strength steel[J]. Hot Working Technology, 2008, 37(21):140-144.
［7］骆锐,周华祥,吴沁. 高强度钢板的研究与应用[J].热加工工艺,2010,39(14):28-30.Lu R, Zhou H X, Wu Q. Research and application of high strength steel[J]. Technology of Hot Working, 2010, 39 (14):28-30.
［8］谷诤巍, 孟佳, 李欣,等. 超高强钢热成形奥氏体化加热参数的优化[J]. 吉林大学学报:工学版, 2011,(S2):194-197. Gu Z W, Meng J, Li X, et al. Research on optimization of the heating parameters of the ultrahighstrength steels austenization in hot stamping process[J]. Journal of Jilin University:Engineering Science Edition, 2011,(S2):194-197.
［9］马宁, 胡平, 闫康康,等. 高强度硼钢热成形技术研究及其应用[J]. 机械工程学报, 2010, 46(14):68-72.Ma N, Hu P, Yang K K, et al. Research and application of the technology of hot forming high strength boron steel[J].Journal of Mechanical Engineering, 2010, 46(14):68-72.
［10］袁新泉,冷松. 影响氢脆断口形貌因素的研究[J]. 航空材料,1986,(4): 32-33.

Yuan X Q, Leng S. Study on the influence factors of the hydrogen embrittlement fracture morphology[J]. Aerospace Material, 1986, (4): 32-33.

服务与反馈：

【本网站尚未开通全文下载服务】【加入收藏】