第三代汽车钢温热成形工艺研究及性能评价  

Research on the Warm-hot Forming Process and Its Performance Evaluation for the Third-generation Automobile Steel

作　　者：李晓东[1] 韩硕[1] 王存宇[2,3] 常颖[1] 胡平[1] 董瀚[2] 

机构地区：[1]大连理工大学汽车工程学院,大连116024 [2]钢铁研究总院华东分院,北京100081 [3]太原钢铁(集团)有限公司,太原030003

出　　处：《机械工程学报》2017年第8期35-42,共8页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51571048);辽宁省自然科学基金(2014028001);中国博士后科学基金(2016M591425);中央高校基本科研业务费(DUT15QY09;DUT16ZD201)资助项目

摘　　要：中锰钢为最新的第三代汽车钢,其成形性和力学性能的改善是当前汽车轻量化领域的前沿课题。提出超细晶中锰钢的温热成形技术,通过科学优选奥氏体化温度、保温时间和成形温度作为工艺参数因子,采用正交试验和极差分析的方法,引入断裂韧度性能参数,综合评估抗拉强度、伸长率、撕裂强度及单位面积裂纹扩展能性能指标,得出温热成形中锰钢的最优工艺参数组合,即奥氏体化温度为810℃、保温时间为7 min、成形温度为550℃。并通过断口形貌和真实的汽车B柱冲压件,从微观结构和宏观性能角度验证了所得工艺参数的有效性。测试结果显示,当采用最优工艺参数组合时,具有均匀的断口形貌特征;微观结构具有细化的马氏体板条形貌,板条平均长度尺寸在2~3μm;宏观性能良好,抗拉强度均在1 400 MPa以上,具有较好的塑性和断裂韧度。研究结果表明,温热成形技术是有效的中锰钢冲压成形方法,为第三代汽车钢的温热成形实际应用起到积极的促进作用。As a third-generation automobile steel, the enhancement of mechanical properties and formability for the medium-Mn steel is becoming a cutting-edge topic. In this research, a warm-hot stamping process for the medium-Mn steel is proposed. The methods of orthogonal experiments, range analysis and comprehensive evaluation are used to investigate the optimal process parameters. The warm-hot stamping process with anstenization temperature of 810 ℃, soaking time of 7 minutes and deformation temperature of 550 ℃ are optimal. Tear tests show that the fracture morphologies are uniformly distributed and fine-grained martensite laths with the average size of 2-3 μm are observed when the optimal process parameters are applied. Moreover, an automotive B-pillar is warm-stamped to examine the new process. The excellent comprehensive performance including strength, plasticity and fracture toughness is achieved. As a result, the warm-hot forming process for the medium-Mn steel is proved to be effective and will promote the industrial application of the third-generation automobile steels.

关 键 词：中锰钢 塑性 撕裂强度 温热成形 正交试验 

分 类 号：TG156[金属学及工艺—热处理]