回火温度对N合金化耐蚀塑料模具钢组织与性能的影响  

Effect of tempering temperature on microstructure and properties of N-alloyed corrosion resistant plastic die steel

作　　者：谢官利 迟宏宵[2] 李祖来[1] 马党参[2] 周健[2] 樊译 欧阳伟豪 XIE Guan-li;CHI Hong-xiao;LI Zu-lai;MA Dang-shen;ZHOU Jian;FAN Yi;OUYANG Wei-hao(School of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;Institute of Special Steels,Center Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]钢铁研究总院特殊钢研究所,北京100081

出　　处：《材料热处理学报》2022年第3期99-107,共9页Transactions of Materials and Heat Treatment

摘　　要：采用光学显微镜、扫描电镜、能谱仪、透射电镜、拉伸试验、冲击试验、盐雾腐蚀试验和相分析试验等研究了低温(240℃)和高温(500℃)回火对N合金化耐蚀塑料模具钢组织与性能的影响。结果表明:试验钢的组织均主要为回火马氏体,均析出了M_(3)C型碳化物。高温回火后试验钢的位错上析出了纳米级的M(CN)型碳氮化物以及M_(23)C_(6)碳化物,表明回火温度的升高可以促进氮化物的析出。低温回火和高温回火后试验钢的冲击吸收能量分别为32.4 J和10.4 J,断后伸长率变化不大,但是高温回火后试验钢的屈服强度与抗拉强度略有提升,并且大量碳氮化物在位错形核,增加了试验钢的解理断裂倾向。试验钢的腐蚀形式主要为点蚀,其低温回火后的耐腐蚀性远大于高温回火,腐蚀速率分别为0.005 g/(m^(2)·h)和0.026 g/(m^(2)·h);低温回火与高温回火后试验钢的自腐蚀电位分别为-0.08 V和-0.125 V,且后者的钝化膜极易破裂,这是由于在高温回火过程中,高合金含量的碳化物大量析出,且大多为富铬的M_(3)C或M_(23)C_(6)型碳化物,从而形成较多贫铬区,导致试验钢的耐腐蚀性能降低。Effect of tempering at low temperature(240℃)and high temperature(500℃)on microstructure and properties of N-alloyed corrosion resistant plastic die steel was studied by means of optical microscope,scanning electron microscopy,energy dispersive spectrometer analysis,transmission electron microscopy,tensile test,impact test,salt spray corrosion test and phase analysis test.The results show that the microstructure of the experimental steel is mainly tempered martensite,and M_(3)C-type carbides are precipitated.After tempering at high temperature,nano M(CN)carbonitrides and M_(23)C_(6)carbide precipitate on the dislocation of the experimental steel,indicating that the increase of tempering temperature can promote the precipitation of nitride.The impact absorbed energy of the experimental steel tempered at low temperature and high temperature is 32.4 J and 10.4 J,respectively,and the elongation after breaking changes little.However,after tempering at high temperature,the yield strength and tensile strength of the experimental steel are slightly improved,and a large number of carbonitrides nucleate in dislocations,which increases the cleavage fracture tendency of the experimental steel.The corrosion form of the experimental steel is mainly pitting corrosion,and its corrosion resistance after low-temperature tempering is much higher than that after high-temperature tempering,the corrosion rates are 0.005 g/(m^(2)·h)and 0.026 g/(m^(2)·h),respectively.After tempering at low temperature and high temperature,the self-corrosion potential of the experimental steel is-0.08 V and-0.125 V,respectively,and the passive film of the latter is very easy to crack.This is because during high temperature tempering,a large number of carbides with high alloy content precipitate,and most of them are chromium rich M_(3)C or M_(23)C_(6)carbides,resulting in the formation of more chromium depletion areas,resulting in the reduction of corrosion resistance of the experimental steel.

关 键 词：耐蚀塑料模具钢 氮合金化 碳氮化物 盐雾腐蚀 

分 类 号：TG142.3[一般工业技术—材料科学与工程]