切割工艺对1.5GPa级超高强度钢扩孔性能的影响  

Influence of cutting process on hole expansion performance of 1.5GPa ultra-high strength steel

作　　者：刘张 申逸菲 闵峻英[1] 侯勇[1] 叶又[2] 侯泽然 林建平[1] LIU Zhang;SHEN Yi-fei;MIN Jun-ying;HOU Yong;YE You;HOU Ze-ran;LIN Jian-ping(School of Mechanical Engineering,Tongji University,Shanghai 201804,China;Pan Asia Technical Automotive Center Co.,Ltd.,Shanghai 202106,China)

机构地区：[1]同济大学机械与能源工程学院,上海201804 [2]泛亚汽车技术中心有限公司,上海202106

出　　处：《塑性工程学报》2022年第5期202-210,共9页Journal of Plasticity Engineering

基　　金：国家科技部“十三五”重点研发计划课题(2017YFB0304403)。

摘　　要：针对QP1500和TBF1470两种1.5 GPa级超高强度钢,分别研究了激光切割和线切割两种切割工艺对其扩孔性能的影响。结果表明,QP1500对切割工艺更为敏感,采用激光切割加工边部时扩孔性能显著降低,而TBF1470对切割工艺并不敏感。通过分析切割边部显微硬度和EBSD结果发现,采用激光切割时,试样边部经历局部高温并迅速冷却至室温的过程会产生大量淬火态马氏体组织,这是导致QP1500边部硬度提高从而扩孔性能降低的主要原因。通过基于数字图像相关技术的拉伸实验,进一步研究了切割工艺对QP1500和TBF1470单向拉伸性能的影响。结果表明,采用激光切割时QP1500试样的总伸长率和断裂应变较采用线切割时分别减小了11.59%和44.44%,而TBF1470单向拉伸性能几乎不受影响。采用180℃/20 min烘烤工艺对QP1500激光切割试样进行处理后,单向拉伸性能显著提升,达到与线切割试样相持的水平。The influence of laser cutting and wire cutting on the hole expansion performance of two kinds of 1.5 GPa ultra-high strength steels QP1500 and TBF1470 was studied.The results show that QP1500 is more sensitive to cutting process,and the hole expansion performance is significantly reduced when the laser cutting is used for the edge,while TBF1470 is insensitive to cutting process.By analyzing the microhardness and EBSD results of the cutting edge,it is found that a large amount of quenched martensite are produced in the process of local high temperature and rapid cooling to room temperature at the edge of specimens under laser cutting,which is the main reason for the increase of the edge microhardness of QP1500 and the decrease of hole expansion performance.The tensile experiment based on digital image correlation technology was used to further study the influence of the cutting process on the uniaxial tensile properties of QP1500 and TBF1470.The results show that the total elongation and fracture strain of QP1500 specimens are reduced by 11.59%and 44.44%,respectively compared with wire cutting specimen,while the uniaxial tensile properties of TBF1470 are almost unaffected.The uniaxial tensile properties of QP1500 under laser cutting were significantly improved after baking at 180℃/20 min,almost reaching the level of wire cutting specimens.

关 键 词：超高强度钢 激光切割 线切割 扩孔 边部开裂 

分 类 号：TH142.2[一般工业技术—材料科学与工程]