纳米析出强化钢激光相变硬化工艺及组织性能研究  

Study on Laser Transformation Hardening Process and Microstructure and Mechanical Properties of 700MPa Grade Nano-scale Precipitate Strengthened Steel

作　　者：朱广江 王晓南[2,3] 陈长军[4] 张敏[4] 敬和民[1] 李佳叶 钱德宇 

机构地区：[1]安徽工业大学材料科学与工程学院,安徽马鞍山243002 [2]苏州大学沙钢钢铁学院,江苏苏州215021 [3]江苏大学江苏省光子制造科学与技术重点实验室,江苏镇江212013 [4]苏州大学机电工程学院激光加工中心,江苏苏州215021

出　　处：《应用激光》2015年第2期170-175,共6页Applied Laser

基　　金：国家自然科学基金青年基金资助项目(项目编号:51305285);江苏省基础研究计划(自然科学基金)青年基金资助项目(项目编号:BK20130315);江苏省光子制造科学与技术重点实验室开放基金资助项目(项目编号:GZ201304)

摘　　要：采用4kW光纤激光器对厚度为4．5mm的热轧700MPa级纳米析出强化钢进行激光相变硬化处理，主要研究激光功率、扫描速度对相变区组织、硬度及耐磨性的影响。结果表明，激光相变区呈“月牙形”，主要由三个部分组成，由外至内依次是表面微熔区、相变硬化区和过渡区，三个区域的组织依次分别为马氏体+粒状贝氏体、马氏体和细小马氏体+铁素体。激光相变硬化处理后相变硬化区和过渡区(统称“硬化层”)硬度得到提高，平均硬度比基体提高了40～80HV0．3。随着激光功率的增加或扫描速度的减小，硬化层深度逐渐增加，功率为3．5kw时硬化层深度达到1．1mm。当扫描速度为20mm／s，激光功率在2．0～3．5kW之间时，激光相变硬化后试样的耐磨性较基体提高了29％～44％。研究结果表明激光相变硬化可显著提高实验钢的表面硬度和耐磨性能。Abstract In this paper, hotrolled nanoscale precipkate strengthenedsteel was used forlaser transformationhardeningwitha thicknessof4,5 mmby4 kW fiber lase Theeffectsoflaserpowerandscanningspeedonmicrostructure, hardnessandwearresistancewereinvestiga-ted Resultsshowedthatlasertransformationzonewas crescent, mainlyconsistedofthreeparts, surfacemicromeltingzonefollowedbyphase transformation hardening zone and transition zone from the outside to the inside The microstructure were martensite+granularbainite martensite, and fine martensite-ferrite, respectivel The hardness of phase transformation hardening zone and transition zone(called hardenedlayer) were improved Comparedwithmatrix, averagehardnessofhardenedlayer was improved by 40～8) HV.Q3 Withincreasing laser power and decreasing scanning speed, the depth of the hardened layer increased gradually when laser power is 3. 5 kW, t hedepthofthehardenedlayerwasl-lmm Whenscanningspeedis23mm/s, thelaserpowerisbetween20-3.5 kW, comparedwithmatrix, thewear resistance of sample after laser transformation hardening was improved by 29%-44% The results showed that laser transformationhardening can significantly improve the surface hardness and wear resistance of experimental steel.

关 键 词：激光相变硬化 超高强钢 显微组织 硬度 耐磨性 马氏体 

分 类 号：TG141[一般工业技术—材料科学与工程]