摘要
采用5kWCO2激光器对65Mn弹簧钢进行焊接处理.利用光学显微镜(OM)、X射线衍射仪(XRD)、扫描电镜(SEM)、显微硬度仪、电子万能试验机及残余应力测定仪对激光焊接接头的显微组织、硬度、抗拉强度、拉伸断口和残余应力进行了研究.结果表明,65Mn弹簧钢经激光焊接后,焊缝中心区组织为等轴晶,近中心区为枝状晶和胞状晶的混合组织,边缘区为少量的胞状晶;在热影响区(HAZ)中,过热区主要是由粗大的针状马氏体组成,相变重合区主要是由较细小的针状马氏体组成,在部分相变区主要由铁素体+珠光体组成.焊接接头主要由α-Fe,Fe3C和FeSi等相组成.焊缝区和HAZ的硬度最高值分别为720HV和770HV,从HAZ到基材硬度明显下降;焊接接头的抗拉强度平均值为475MPa,焊缝中心区的残余应力平均值为105MPa,热影响区的应力平均值为-60MPa.
To obtain excellent welding joint,65Mn spring steel was welded by 5 kW CO2 laser welding equipment.Microstructure,tensile strength,tensile fracture and residual stress of this joint were investigated by means of OM,XRD,SEM,microhardness testing machine,electronic universal testing machine and residual stress test machine.The experimental results indicate that the fine equiaxised crystal,dendrite crystal and cell grain are formed from welding central zone to edge zone,respectively.In the HAZ,the over-heated zone is mainly comprised of coarse acicular martensite.Recrystalline zone mainly consistes of fine acicular martensite.The part transforming zone is comprised of ferrite and pearlite.The welding joint mainly consists of fine α-Fe,Fe3C and FeSi.The highest hardness value of welding zone and HAZ is 720 HV and 770 HV,respectively.The hardness decreases significantly from HAZ to base metal.The average tensile strength of welding joints is approximately 475 MPa.The average residual stress in welding zone is 105 MPa,and the average residual stress in HAZ is-60 MPa.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2009年第9期105-108,共4页
Transactions of The China Welding Institution
关键词
弹簧钢
65MN钢
激光焊接
组织
性能
spring steel
65Mn
laser welding
microstructure
properties