焊后热处理对T91钢TLP连接接头组织与力学性能的影响  

Effect of post-welding heat treatment on microstructure and mechanical properties of T91 steel TLP bonded joint

作　　者：李报[1] 陈思杰[1] 刘毅辉 

机构地区：[1]河南理工大学材料科学与工程学院,河南焦作454000 [2]中国电建集团河南工程公司,河南郑州450000

出　　处：《金属热处理》2017年第10期56-60,共5页Heat Treatment of Metals

基　　金：河南省科技厅产学研合作项目(152107000049);中国电力建设股份公司科技项目(DJ-TGYY-2014-08)

摘　　要：利用光学显微镜、扫描电镜对热处理前后T91钢管TLP连接接头的组织、主要元素分布、拉伸断口形貌进行分析;利用电子万能力学试验机、夏比摆锤冲击试验机、显微硬度计对接头热处理前后的力学性能进行测定及分析。结果表明,焊态下,T91钢焊缝金属为未充分扩散的中间层,显微硬度较高,约为348 HV0.5;母材为马氏体+残留奥氏体。经焊后热处理,焊缝与母材组织相似,均为回火马氏体;焊缝硬度值与母材区相近,约为223 HV0.5;另外,焊后热处理接头室温抗拉强度及冲击吸收能量增大,分别为660 MPa和52 J;180°弯曲试验试样完好。焊后热处理前T91钢焊接接头室温拉伸断口形貌为河流花样及扇形花样,属于脆性断裂,经热处理后T91钢焊接接头室温拉伸断口形貌为等轴韧窝,为韧性断裂。Microstructure,element distribution and fracture morphology of T91 steel TLP bonded joint before and after post-welding heat treatment（ PWHT） were analyzed by means of OM and SEM. Mechanical properties were investigated by electronic universal testing machine,Charpy test device and microhardness tester. The results show that before PWHT,the weld-metal zone is interlayer without adequate diffusion,and the microhardness is higher,about 348 HV0. 5; the microstructure of the matrix is martensite and retained austenite. After PWHT,the microstructure of welding seam is similar to the matrix; welding seam micro-hardness is similar to the matrix,as about 223 HV0. 5.Furthermore,after PWHT,the tensile strength and impact absorbed energy at room temperature of the joint are increased to 660 MPa and52 J respectively,and the samples of 180° bending test are without any cracks. Fracture morphology of the welded joint is river pattern and fan-shaped patterns before PWHT,characterized with brittle fracture. After PWHT,the fracture morphology of the welded joint is dimple patterns,and belongs to ductile fracture.

关 键 词：T91钢管 TLP连接 焊后热处理 显微组织 力学性能 

分 类 号：TG453.9[金属学及工艺—焊接] TG162.8