热处理温度对1000 MPa级高强钢熔敷金属组织和性能的作用机制  

Mechanism of heat treatment temperature on microstructure and properties in deposited metal of 1000 MPa grade high strength steel

作　　者：于庭祥 冯伟 陈波 张庆素 周宝金 刘鑫 刘满雨 YU Tingxiang;FENG Wei;CHEN Bo;ZHANG Qingsu;ZHOU Baojin;LIU Xin;LIU Manyu(Harbin Well Welding Co.,Ltd.,Harbin,150006,China;Harbin Welding Institute Limited Company,Harbin,150028,China)

机构地区：[1]哈尔滨威尔焊接有限责任公司,哈尔滨150006 [2]中国机械总院集团哈尔滨焊接研究所有限公司,哈尔滨150028

出　　处：《焊接学报》2024年第6期97-104,112,共9页Transactions of The China Welding Institution

基　　金：黑龙江省重点研发计划项目(2022ZX04A01)。

摘　　要：采用丝级埋弧焊方法制备1000 MPa级高强钢熔敷金属,利用SEM、EBSD、XRD和TEM等微观分析方法研究了焊后热处理温度(500~620℃)对1000 MPa级高强钢熔敷金属组织演变的影响,并通过拉伸和冲击试验评估其力学性能.结果表明,随着热处理温度升高,1000 MPa级高强钢熔敷金属抗拉强度和屈服强度对比焊态(as welded,AW)先升高后降低,熔敷金属热处理后比AW韧性降低.1000 MPa级高强钢熔敷金属在540℃热处理时获得较好强韧匹配效果,抗拉强度1030MPa,屈服强度970 MPa,-40℃冲击韧性58 J.1000 MPa级高强钢熔敷金属在500~620℃热处理过程中M/A组元中的A逐渐分解为碳化物和铁素体,M在620℃热处理时生成逆转变奥氏体并保留至室温.碳化物对于位错具有钉扎作用,但随热处理温度升高碳化物对位错的钉扎作用减弱,位错通过滑移和攀移不断减少.熔敷金属析出的碳化物对位错的钉扎作用强于位错滑移的软化作用时,熔敷金属强度提高,碳化物对位错的钉扎作用弱于位错滑移的软化作用时基体组织软化,熔敷金属强度降低.析出的碳化物导致位错塞积,产生的应力集中区域成为裂纹源,使热处理态熔敷金属韧性低于AW.1000 MPa high strength steel deposited metal is prepared by wire submerged arc welding.The effect of post-weld heat treatment temperature(500~620℃)on the microstructural evolution in deposited metal of 1000 MPa grade high strength steels has been investigated using microanalytical methods such as SEM,EBSD,XRD and TEM.Evaluate their mechanical properties by tensile and impact tests.The results show that with the increase of heat treatment temperature,1000MPa grade high-strength steel deposited metal tensile strength and yield strength of heat-treated state than the AW first increase and then reduce.The heat-treated state deposited metal toughness is lower than the AW.The strength and toughness matching effect of 1000 MPa grade high strength steel deposited metal is good at 540℃heat treatment,the tensile strength is 1030 MPa,the yield strength is 970 MPa,and the impact toughness is 58 J at−40℃.1000 MPa grade high strength steel fused metal in 500~620℃heat treatment process in the M/A group element A gradually decomposed into carbides and ferrite.During heat treatment at 620℃,reverse austenite is generated and retained to room temperature.Carbide for dislocations has a pinning effect,but with the increase of heat treatment temperature carbide on the dislocation of the pinning effect is weakened,dislocations through the slip and climb constantly reduced.Deposited metal precipitation of carbide on the dislocation pinning effect is stronger than the softening effect of dislocation slip,the deposited metal strength,carbides on the dislocation pinning effect is weaker than the softening effect of dislocation slip when the matrix microstructure softens,the deposited metal strength is reduced.The precipitated carbide leads to dislocation plugging,and the stress concentration area becomes the crack source,which makes the toughness of the heat-treated deposited metal lower than the AW.

关 键 词：1000 MPa级高强钢 熔敷金属 焊后热处理 埋弧焊 碳化物 

分 类 号：TG423[金属学及工艺—焊接]