摘要
以HC950/1300HS热成形钢为研究对象,分析了车身烘烤工艺对力学性能、断裂失效及零件承载能力等的影响。将热冲压处理后的材料在温度为175℃的加热箱内保温20 min模拟车身烘烤工艺;对比了两种工艺下材料强度和断后伸长率的变化;基于Swift和Hockett-Sherby组合硬化模型,以胀形试验与仿真模型获得的承载力-位移曲线拟合度最高作为目标,获取了最优外延有效应力-塑性应变曲线;基于MMC失效模型设计了5种不同形式的失效试样,采用试验和仿真相结合获取各失效形式试样的应力三轴度和极限失效应变,拟合获得断裂失效曲线,分析烘烤工艺的影响;采用静态三点弯曲加载试验分析烘烤工艺对热成形钢前防撞梁承载特性的影响。结果表明,烘烤工艺处理后,屈服强度增加约40 MPa,抗拉强度降低约130 MPa,断后伸长率降低约1%;剪切和单拉状态之间的失效应变降低,材料更容易发生失效,而单拉和双拉状态之间的失效应变则升高,在碰撞过程中材料更不容易发生失效;仿真分析结果表明,所搭建的硬化模型精度较高,误差控制在5%以内;烘烤工艺后,热成形前防撞梁的最大承载能力提升了约7.98%,而对应位移则减小了3.93%,承载特性出现明显变化。表明烘烤工艺对热成形钢承载能力的影响较大,设计过程中需予以考虑。
Taking HC950/1300HS hot forming steel as the research objects,the influence of body baking process on mechanical proper-ties,fracture failure and bearing capacity of parts was analyzed.The material after hot stamping treatment was heated in heating box at 175℃for 20 min to simulate the body baking process.The variation of material strength and elongation after fracture under the two kinds of processes was compared.Based on the Swift and Hockett-Sherby combined hardening model,the optimal epitaxial effective stress-plas-tic strain curves were obtained with the highest fitting degree of bearing force-displacement curves obtained by bulging test and simulation model as the goal.Based on the MMC failure model,five different forms of failure specimens were designed.The stress triaxiality and ulti-mate failure strain of each failure form of specimen were obtained combining test and simulation.The fracture failure curves were obtained by fitting,and the influence of baking process was analyzed.The influence of baking process on the bearing characteristics of hot forming steel front anti-collision beam was analyzed by static three-point bending loading tests.The results show that after baking process treatment,the yield strength increases by about 40 MPa,the tensile strength decreases by about 130 MPa,and the elongation after fracture decreases by about 1%.The failure strain between the shear state and the single tensile state is reduced,and the material is more prone to failure,while the failure strain between the single tensile state and the double tensile state increases,and the material is less prone to failure during colli-sion process.The simulation analysis results show that the accuracy of the established hardening model is high,and the error is controlled within 5%.After baking process,the maximum bearing capacity of the hot forming front anti-collision beam increases by about 7.98%,while the corresponding displacement decreases by 3.93%,and the bearing characteristics changes significantly.It shows that the baking process has a great influence on the bearing capacity of hot forming steel,which needs to be considered in the design process.
作者
陈享姿
CHEN Xiang-zi(Automotive Engineering School,Changsha Vocational&Technical College,Changsha 410217,China)
出处
《塑性工程学报》
北大核心
2025年第6期115-122,共8页
Journal of Plasticity Engineering
基金
湖南省教育厅科学研究项目(23C1120)
湖南省教育科学“十四五”规划课题(XJK24CZY076)。
关键词
热成形钢
烘烤工艺
前防撞梁
力学性能
断裂失效
hot forming steel
baking process
front anti-collision beam
mechanical property
fracture failure
