离焦量对DP780高强双相钢激光接头组织及性能的影响  

Effects of Defocusing Amount on Microstructure and Properties of DP780 Highstrength Dual-phase Steel Laser Joint

作　　者：刘鑫雨 孙有平[1,2,3] 何江美 周勇[1] 裴梦雨 LIU Xinyu;SUN Youping;HE Jiangmei;ZHOU Yong;PEI Mengyu(School of Mechanical and Automotive Engineering,Guangxi University of Science and Technology,Liuzhou 545006;Guangxi Earthmoving Machinery Collaborative Innovation Center,Liuzhou 545006;Guangxi Key Laboratory of Automobile Components and Vehicle Technology,Liuzhou 545006)

机构地区：[1]广西科技大学机械与汽车工程学院,柳州545006 [2]广西土方机械协同创新中心,柳州545006 [3]广西汽车零部件与整车技术重点实验室,柳州545006

出　　处：《特种铸造及有色合金》2025年第2期256-262,共7页Special Casting & Nonferrous Alloys

基　　金：广西科技基地和人才专项资助项目(桂科AD22080042);广西科技重大专项资助项目(桂科AA23062089);中央引导地方科技发展资金项目(桂科ZY24212053);柳州市科技计划资助项目(2024AA0203C001,2024AB0301D001)。

摘　　要：在激光功率为2000 W,焊接速度为18 mm/s条件下,选择不同离焦量对2 mm厚DP780高强双相钢进行激光焊接试验。采用金相显微组织观察、XRD、EBSD、拉伸试验和硬度测试等手段,探究在离焦量为−2 mm至+2 mm时不同变量对焊接接头的成形性和力学性能的影响。EBSD分析显示,焊接接头组织由4个区域组成,焊缝区存在粗大的板条马氏体,物相均为α相,XRD衍射峰显示尖锐形貌,强峰均为(110)、(200)、(211)。离焦量为−2 mm时,接头抗拉强度为770 MPa,伸长率为12.86%,属于良好焊接;焊接接头显微硬度呈“M”状分布,在回火软化区硬度最低。The laser welding test of DP780 high-strength dual-phase steel with thickness of 2 mm was carried out with different defocusing amounts under the laser power of 2000 W and welding speed of 18 mm/s.By means of metallo⁃graphic microstructure observation,XRD,EBSD,tensile test and hardness test,the influence of different variables on the formability and mechanical properties of welded joints at defocus from−2 mm to+2 mm was investigated.EBSD results reveal that welded joint is composed of four regions,and there exists thick lath martensite in the weld zone,which are allαphase.XRD diffraction peak presents sharp morphology,and the strong peaks are(110),(200)and(211).The tensile strength and elongation of joint is 770 MPa and 12.86%under defocus of−2 mm,respectively,indicating desirable welding.The microhardness of welded joint shows a“M”shape distribution,reaching the mini⁃mum value at tempering softening zone.

关 键 词：DP780 激光焊 显微组织 EBSD 力学性能 

分 类 号：TG442[金属学及工艺—焊接]