Hole Expansion Properties of High Strength Automobile Steel Plates with Different Microstructures
-
摘要: 对热轧铁素体贝氏体双相钢FB60、铁素体马氏体双相钢DP600和铁素体珠光体钢SPFH590等三种汽车用高强钢板进行了扩孔试验, 利用光学显微镜观察了扩孔裂纹的萌生和扩展, 研究了不同钢的扩孔性能及开裂机理。结果表明:FB60钢的扩孔性能最优, DP600钢的最差; SPFH590钢与FB60钢具有相同的屈强比, 但其扩孔性能却不及FB60钢的; 组织对扩孔性能的影响与扩孔裂纹的萌生和扩展有关, FB60钢的裂纹萌生于铁素体内以及铁素体与贝氏体晶界, 绕过贝氏体穿过铁素体扩展; SPFH590钢的裂纹萌生于铁素体与珠光体边界、珠光体内铁素体与渗碳体界面和铁素体内, 极易沿铁素体与渗碳体片层扩展; DP600钢的裂纹萌生于铁素体与马氏体晶界, 并沿晶界扩展。Abstract: Hole expansion tests were conducted for hot-rolled ferrite-bainite dual phase steel FB60, ferrite-martensite dual phase steel DP600 and ferrite-pearlite steel SPFH590. Optical microscope was used to observe formation and propagation of expansion cracks and analyze the hole expansion property and cracking mechanism of the steels. The results show that the FB60 steel exhibits the best hole expansion property, and DP600 steel exhibits the worst hole expansion property. However, the yield ratio of SPFH590 steel was equal to that of FB60 steel, but the hole expansion rate of SPFH590 steel less than that of FB60 steel. The effect of microstructure on hole expansion property was related to the formation and propagation of expansion cracks. The cracks formed not only at ferrite-bainite interfaces but also within ferrite grains in FB60 steel, and propagated along the phase interface between ferrite and bainite and by cutting off ferrite grains. The expansion cracks formed at ferrite-pearlite interfaces, ferrite-cementite interfaces within pearlite and within ferrite grains in SPFH590 steel, and propagated easily along the ferrite-cementite interface. The cracks formed at ferrite-martensite interfaces in DP600 steel, and propagated along the phase interface between ferrite and martensite.
-
Keywords:
- high strength steel /
- ferrite-pearlite steel /
- hole expansion /
- crack propagation
-
-
[1] 蔡明晖, 丁桦, 张建苏, 等.铁素体/贝氏体双相钢的变形和断裂特性［J］.材料研究学报, 2009, 23（1）:83-88. [2] 康永林.现代汽车板工艺及成形理论与技术［M］.北京:冶金工业出版社, 2009:130-145. [3] TAKAHASHI M. Development of high strength steels for automobiles［J］.Nippon Steel Technical Report, 2003, 88:8-12. [4] HYUN D I, OAK S M, KANG S S, et al. Estimation of hole flange ability for high strength steel plates［J］. Journal of Materials Processing Technology, 2002, 130/131:9-13. [5] 陈继平, 董玉庆, 钱健清, 等.热轧马氏体和贝氏体双相钢扩孔性能及机理［J］.中南大学学报(自然科学版), 2014, 45(2):395-400. [6] 董春明, 张红梅, 刘振宇, 等.终轧温度对热轧双相钢微观形貌的影响［J］.机械工程材料, 2007, 31（3）:17-19. [7] BARBACKI A. The role of bainite in shaping mechanical properties of bainite［J］. Journal of Materials Processing Technology, 1995, 53: 57-60. [8] XU Ping-guang, FANG Hong-sheng, BAI Ping-zhe, et al. New duplex microstructure of grain boundary allotriomorphic ferrite/granular bainite［J］. Journal of Iron and Steel Research International, 2002:9(2):33-38. [9] 李龙, 丁桦, 杜林秀, 等.仿晶界型铁素体/贝氏体低碳锰钢的组织和力学性能［J］.金属学报, 2006, 42(11):1227-1232. [10] 李龙, 丁桦, 温景林, 等.铁素体和贝氏体复相组织低碳钢的力学特性［J］.材料研究学报, 2007, 21(5):517-522. [11] 王卫卫, 丁桦, 唐正友, 等.铁素体贝氏体钢的扩孔性能［J］.钢铁研究学报, 2009, 21（6）:48-52. [12] 蔡明晖, 丁桦, 张建苏, 等.经济型铁素体/贝氏体高扩孔钢的组织与性能［J］.钢铁, 2008, 43（8）:77-85. [13] 谷海容, 张建, 杨兴亮, 等.高扩孔型铁素体/贝氏体双相钢组织性能研究［J］.武汉科技大学学报, 2011, 34（6）:419-423. [14] 方圆, 刘雅政, 周乐育, 等.马氏体体积分数对热轧双相钢形变位错结构和断裂的影响［J］.钢铁, 2009, 44（8）:89-92. [15] ERDOGAN M. The effect of new ferrite content on the tensile fracture behavior of dual phase steels［J］.Journal of Materials Science, 2002, 37: 3623-3630. [16] HASEGAWA K, KAWAMURA K, URABE T, et al. Effects of microstructure on stretch-flange-formability of 980 MPa grade cold-rolled ultra-high strength steel sheets［J］. ISIJ International, 2004, 44(3): 603-609. [17] 刘禹门.铁素体珠光体钢的变形与断裂［J］.金属热处理学报, 1982, 3（1）:1-10. [18] 黄孝瑛, 郭薇, 潘天喜, 等.珠光体钢微观结构和断裂过程的TEM研究［J］.金属学报, 1987, 23（3）:200-204.
计量
- 文章访问数: 6
- HTML全文浏览量: 0
- PDF下载量: 2
下载:
