Microstructure and Mechanical Properties of Friction Stir Welded 1.5GPa Martensitic High-Strength Steel Plates

作     者：Pengcheng Zhu Lin Zhang Zhaochang Li KHLo Jianfeng Wang Yufeng Sun Shaokang Guan Pengcheng Zhu;Lin Zhang;Zhaochang Li;K.H.Lo;Jianfeng Wang;Yufeng Sun;Shaokang Guan

作者机构：School of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450001China BAIC Group Off-Road Vehicle Co.LtdBeijing 101300China Department of Electromechanical EngineeringFaculty of Science and TechnologyUniversity of MacaoMacaoChina Henan Key Laboratory of Advanced Magnesium AlloysZhengzhou 450002China 

出 版 物：《Acta Metallurgica Sinica(English Letters)》 (金属学报（英文版）)

年 卷 期：2022年第35卷第7期

页      面：1079-1089页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：supported by the Henan provincial Joint Fund of the National Natural Science Foundation of China (Grant No.U2004170) the Natural Science Foundation of Henan Province (No.202300410474) 

主　　题：Martensitic steel Friction stir welding Heat-aff ected zone Microstructure Mechanical properties 

摘      要：In this study, 2.4 mm thick high-strength martensitic steel plates with a tensile strength of 1500 MPa were friction stir welded at various welding speeds of 40, 60, 80, 100, 120 mm/min and a constant rotation speed of 300 rpm. Sound joints could be obtained when the welding speed was 40, 60 and 80 mm/min, while a kissing bond was found in the joint welded at 100 and 120 mm/min. It was revealed that the peak temperature exceeded A C3(the end temperature at which all ferrite transformed to austenite when the steel was heated) for all the welding conditions and martensitic structures were fi nally formed in the stir zone of the joints. A signifi cant decrease in hardness was located in the heat-aff ected zone, which had a transitional microstructure from tempered martensite near base metal to a mixed structure containing hard martensite, soft ferrite and bainite near stir zone. For the sound joints, the specimen was fractured in the heat-aff ected zone during tensile tests and the highest tensile strength could reach about 1058 MPa.