G115钢模拟热影响区界面组织演变研究  

Mechanism of interfacial microstructure evolution of G115 steel in simulated heat affected zone

作　　者：江骏东 马庆爽 陈乐利 罗锐[3] 李会军[4] 高秋志 JIANG Jundong;MA Qingshuang;CHEN Leli;LUO Rui;LI Huijun;GAO Qiuzhi(School of Resources and Materials,Northeastern University at Qinhuangdao,Qinhuangdao 066004,Hebei,China;School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China;School of Materials Science&Engineering,Jiangsu University,Zhenjiang 212013,Jiangsu,China;School of Materials Science&Engineering,Tianjin University,Tianjin 300354,China)

机构地区：[1]东北大学秦皇岛分校资源与材料学院,河北秦皇岛066004 [2]东北大学材料科学与工程学院,沈阳110819 [3]江苏大学材料科学与工程学院,江苏镇江212013 [4]天津大学材料科学与工程学院,天津300354

出　　处：《材料工程》2024年第11期91-106,共16页Journal of Materials Engineering

基　　金：国家自然科学基金钢铁联合研究基金重点项目(U1960204);国家自然科学基金面上项目(51871042,52171107);中央高校基本科研业务费(N2123010);河北省“三三三人才工程”项目(B20221001);江苏省先进结构材料与应用技术重点实验室开放基金(ASMA202002)。

摘　　要：采用EBSD(electron backscatter diffraction),HRTEM(high resolution transmission electron microscopy)等表征手段,研究峰值温度及焊接热输入对G115钢焊接模拟热影响区界面微观组织演变的影响。结果表明:细晶焊接热影响区组织中M23C6碳化物尺寸相比粗晶及临界焊接热影响区组织更为细小,仅为100 nm左右,析出强化作用明显。峰值温度提高使得小角度晶界数量有所提升,从而增加晶界强化效果。粗晶区组织几何位错密度最高为3.19×10^(14)m^(-2);临界焊接热影响区位错的回复、细小MX析出相的钉扎与亚晶的出现保证了材料的强度。对于细晶焊接热影响区组织,焊接热输入的提升使得位错发生湮灭,亚晶的形成受到抑制,从而促进马氏体板条亚结构转变为马氏体块状亚结构,屈服强度由1115 MPa下降到947 MPa。当焊接热输入为14.4 kJ/cm时,细晶焊接热影响区组织兼具良好的强度和韧性。The microstructure evolution of the interface in the simulated heat affected zone(HAZ)of G115 steel was characterized by electron backscatter diffraction(EBSD)and high resolution transmission electron microscopy(HRTEM).The results show that the size of precipitated M23C6 in the fine grain zone is smaller than that in the coarse grain and the critical zone,which is only about 100 nm,and the precipitation strengthening effect is obvious.With the increase in peak temperature,the number of small angle grain boundary increases,hence the grain boundary strengthening effect increases.The highest geometrical dislocation density is 3.19×10^(14)m^(-2)in the coarse-grained zone.The recovery of the critical dislocation,the pinning of the fine MX precipitates and the appearance of the subgrains make the G115 steel maintain the durable strength for a long time at high-temperature.For the microstructure of the fine grain zone,the increase of welding heat input promotes the transformation of martensitic lath substructure into martensite block substructure,the dislocations are annihilated,the formation of subgrain is inhibited,and the yield strength decreases from 1115 MPa to 947 MPa.When the welding heat input is 14.4 kJ/cm,the microstructure of the fine grain welding heat affected zone has both good strength and toughness.

关 键 词：G115钢 焊接热模拟 位错强化 亚结构强化 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TB31[金属学及工艺—金属材料]