基于复相组织精细调控的硼钢高强韧热冲压工艺  

High strength and toughness hot stamping process of boron steel based on fine control of multiphase structure

作　　者：谢光驹 宋燕利[1,2,3] 路珏[1,2,3] 郝川川 刘鹏 XIE Guang-ju;SONG Yan-li;LU Jue;HAO Chuan-chuan;LIU Peng(Hubei Key Laboratory of Advanced Technology for Automotive Components,Wuhan University of Technology,Wuhan 430070,China;Hubei Collaborative Innovation Center for Automotive Components Technology,Wuhan University of Technology,Wuhan 430070,China;Hubei Research Center for New Energy&Intelligent Connected Vehicle,Wuhan University of Technology,Wuhan 430070,China;Dongfeng(Wuhan)Industry Co.,Ltd.,Wuhan 430040,China)

机构地区：[1]武汉理工大学现代汽车零部件技术湖北省重点实验室,湖北武汉430070 [2]武汉理工大学汽车零部件技术湖北省协同创新中心,湖北武汉430070 [3]武汉理工大学湖北省新能源与智能网联车工程技术研究中心,湖北武汉430070 [4]东风(武汉)实业有限公司,湖北武汉430040

出　　处：《塑性工程学报》2022年第2期35-46,共12页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(51975440);湖北省重点研发计划(2020BAB143);新能源汽车科学与关键技术学科创新引智基地(B17034);教育部创新团队发展计划项目(IRT_17R83)。

摘　　要：为解决强韧性协调困难问题,以B1500HS硼钢为研究对象,开展基于复相组织精细调控的硼钢高强韧热冲压工艺研究。以加热温度、保温时间和成形温度为设计因素,进行多指标综合评分的正交试验设计,开展平模强韧化热冲压试验;通过单向拉伸试验、Kahn试验和夏比摆锤冲击试验获得成形后构件的强度、塑性和韧性指标,采用OM、SEM对试样微观组织、形貌分布及断口形貌进行表征,揭示了微观组织对热冲压构件强韧性的影响规律,获得了高强韧性热冲压构件的相组成和形貌的最佳匹配。结果表明:加热温度900℃、保温时间1 min和成形温度750℃时,试样抗拉强度、断后伸长率、撕裂强度、单位面积裂纹形核功和冲击韧性值相较于常规热冲压试样分别提升8.42%、57.00%、5.31%、14.75%和27.87%。此时复相组织中粒状贝氏体(约8%)及块状铁素体(约10%)提升了构件韧性;而细小致密的板条马氏体(约82%)及贝氏体中的细小、均匀分布的球状M-A岛提升了组织强度。To solve the problem that it is difficult to coordinate the strength and toughness, taking B1500 HS boron steel as the research object, the high strength and toughness hot stamping process of boron steel based on fine control of multiphase structure was studied. Taking heating temperature, holding time and forming temperature as design factors, the orthogonal test design of multi-index comprehensive score was carried out, and the strengthening and toughening flat die hot stamping test was carried out. The strength, plasticity and toughness of the formed components were obtained by uniaxial tensile tests, Kahn tests and Charpy pendulum impact tests. The microstructure, morphology distribution and fracture morphology of the samples were characterized by OM and SEM, the effect of microstructure on the strength and toughness of hot stamped components was revealed, and the best matching of phase composition and morphology of hot stamped components with high strength and toughness was obtained. The results show that when the heating temperature is 900 ℃, the holding time is 1 min and the forming temperature is 750 ℃, compared with conventional hot stamped components, the tensile strength, elongation after fracture, tear strength, nucleation energy of carck in unit area and impact toughness are increased by 8.42%, 57.00%, 5.31%, 14.75% and 27.87%, respectively. At this time, the granular bainite(about 8%) and massive ferrite(about 10%) in the multiphase structure improves the toughness of components, while the fine and dense lath martensite(about 82%) and the fine and uniformly distributed spherical M-A islands in bainite enhances the microstructure strength.

关 键 词：B1500HS硼钢 平模热冲压 复相组织 强韧性 

分 类 号：U461[机械工程—车辆工程]