激光修复300M钢的组织及力学性能研究

发布时间：2018-06-21 23:50

本文选题：激光成形修复 + 激光增材制造　；参考：《金属学报》2017年03期

【摘要】：采用激光立体成形技术进行了300M钢修复实验,利用XRD、SEM及动态散斑等手段研究了激光成形修复300M钢沉积态和热处理态的组织及力学性能特征。结果表明,300M钢基材区由马氏体、贝氏体及少量残余奥氏体组成;修复区由顶部的贝氏体组织,中部的马氏体和贝氏体的混合组织,到底部的回火马氏体组织呈现连续转变;热影响区则呈现为不均匀的马氏体组织。经过淬火+回火处理后,各区域的组织变得均匀,均为回火马氏体和贝氏体的混合组织。修复后沉积态试样的拉伸性能远低于锻件标准。但经过热处理后,修复试样的各项力学性能指标均有显著提高。应力-应变测试结果表明,沉积态和热处理态试样在弹性变形阶段的应变都是均匀增加的,而超过最大拉伸强度后,局部应变在修复区急剧增加。这与试样的组织协调变形能力及应变硬化指数有关。
[Abstract]:The repair experiments of 300M steel were carried out by using laser stereoscopic forming technology. The microstructure and mechanical properties of 300M steel repaired by laser forming were studied by means of XRDX SEM and dynamic speckle. The results show that the base area of the steel is composed of martensite, bainite and a small amount of retained austenite, and the repair zone is transformed continuously from the bainite structure at the top, the mixed structure of martensite and bainite from the middle to the tempering martensite at the bottom. The heat affected zone presents inhomogeneous martensite structure. After quenching and tempering, the microstructure of each region becomes uniform, all of them are mixed microstructure of tempered martensite and bainite. The tensile properties of the deposited specimens are much lower than the forging standard. However, after heat treatment, the mechanical properties of the repaired samples were improved significantly. The results of stress-strain test show that the strain of both deposited and heat treated specimens increases uniformly during elastic deformation, but when the maximum tensile strength exceeds the maximum tensile strength, the local strain increases sharply in the repair zone. This is related to the deformation capacity and strain hardening index of the specimen.
【作者单位】：西北工业大学凝固技术国家重点实验室;
【基金】：国家自然科学基金项目Nos.51323008、51475380和51501154 高等学校学科创新引智计划项目No.08040~~
【分类号】：TG142.1

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