共查询到19条相似文献,搜索用时 203 毫秒
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为提高变速器锥盘使用寿命,以锥盘用38CrMoAl钢为研究材料,采用不同渗氮温度低氮氢比离子渗氮进行表面改性。利用光学显微镜、X射线衍射仪、显微硬度计、摩擦磨损试验机对渗氮后的38CrMoAl钢显微组织、物相、硬度、渗层脆性及耐磨性进行了测试和分析。结果表明:38CrMoAl钢经520℃,N2∶H2=1∶4和540℃,N_2∶H_2=1∶5离子渗氮后表层无白亮层生成,XRD分析表明表层无γ'-Fe4N相,说明离子渗氮时通过改变渗氮温度和氮氢比可以避免白亮层生成,只形成渗氮扩散层。研究还发现,渗氮层的脆性显著降低,韧性和耐磨性提高,为促进无白亮层离子渗氮技术更好地应用于变速器锥盘的表面改性提供了参考。 相似文献
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研究了渗氮工艺对精密数控机床主轴用38CrMoAl钢性能的影响。结果表明,经过渗氮处理后38CrMoAl钢表层的抗拉强度、硬度和耐磨性能均得到提高,但其韧性降低。而渗氮处理对材料心部影响不大。在一段式、二段式和三段式3种渗氮处理工艺中,三段式渗氮处理所得材料的综合性能最佳。 相似文献
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在不同氨水浓度的电解液中,采用液相等离子体渗透技术在38CrMoAl钢表面制备了渗氮层。采用光学显微镜(OM)、扫描电镜(SEM)和X射线衍射仪(XRD)等对渗氮层的显微组织、相组成进行了观察和分析,并采用Parstat2273电化学工作站测试了渗氮层的耐蚀性能,并对其显微硬度和耐磨性进行了测试,研究了氨水浓度对38CrMoAl钢液相等离子体渗氮显微组织与性能的影响。结果表明:随着氨水浓度的增大,渗氮层中的白亮层厚度呈增加趋势,分布着针状的氮化物和细小碳化物的扩散层厚度和渗氮层最大显微硬度值呈先增加后降低的趋势;当氨水浓度为60%时,渗氮层厚度达160μm,其中扩散层为112μm,渗氮层硬度最高为1023 HV0.1,约是基体硬度的3.5倍;渗氮层主要以Fe2N、Fe3N相等为主;渗氮层的耐磨性能和耐腐蚀优于基体。 相似文献
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稀土含量对38CrMoAl钢渗氮层性能的影响 总被引:1,自引:1,他引:0
为了克服38CrMoAl钢渗氮速度慢,渗层脆性大,稀土添加到渗氮气氛中只能作用于工件表面等缺点,研究了38CrMoAl钢中不同稀土添加量对渗氮层性能的影响,并初步分析了其影响机制。研究结果表明:稀土对38CrMoAl钢渗氮具有明显的催渗作用,且能提高渗层性能。原因是稀土加入钢中后,引起周围铁原子的点阵畸变,有利于氮原子的吸附和扩散,且稀土易与渗氮气氛中的氧结合,削弱了氧对渗氮的阻碍作用;同时稀土的晶粒细化、固溶体强化、微合金化也是其改善渗层性能的重要原因。 相似文献
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内孔等离子喷涂Ni45-15%Mo涂层与38CrMoAl渗氮层耐磨性研究 总被引:2,自引:0,他引:2
采用内孔等离子喷涂技术在内径矿150mm的发动机气缸套内表面38CrMoAl基体上,在开放条件下制备Ni45—15%Mo涂层,并与缸套内表面渗氮硬层,在边界润滑条件下进行了环块滑动摩擦磨损对比试验。对内孔喷枪的粒子飞行速度进行了在线监测研究,对喷涂层与渗氮层的显微组织、显微硬度、结合强度对耐磨性的影响进行了分析。结果表明,38CrMoAl基上内孔等离子喷涂层与渗氮层相比磨损量减小0.3mg,摩擦因数减小0.02,涂层摩擦偶件表面榀伤小于渗氛层偶件.涂层综合麾檫学件能优干渗氛层。 相似文献
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循环氮势快速离子渗氮 总被引:13,自引:2,他引:11
研究了循环氮势快速离子渗氮工艺机理和方法。对40Cr和38CrMoAl钢进行了离子湖氮。结果表明,与常规离子渗氮工艺相比,该工艺能显著地增加材料的渗氮层深度和耐磨性。 相似文献
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High chromium martensitic steels are designed to provide high corrosion resistance in combination with high strength. Some of these steel grades contain primary carbides for improving the wear resistance, e.g. the steel 440C. The present paper mainly deals with the effect of chemical composition and microstructure on the corrosion properties. Different experimental alloys were produced in the shape of small ingots. The influence of the alloying elements chromium, molybdenum, cobalt, and carbon on the corrosion properties was studied. The results can be summarized as follows: Chromium and molybdenum improve the corrosion resistance, however, only the content of these elements in solid solution in the steel matrix is effective. In case of cobalt the corrosion resistance decreases. The reason is the interaction between cobalt and carbon and its effect on the chromium content in the steel matrix. The calculated pitting resistant equivalent number of high chromium martensitic steels is only limited valid, because there is a major effect of carbide precipitation on the corrosion behaviour. Further investigations were focused on the heat treatment. Especially the effect of the tempering temperature of these steels was studied. The tempering temperature is most relevant for secondary hardening carbide precipitation, which lowers the chromium content of the matrix with detrimental influence on the corrosion properties. The carbide precipitation and chromium distribution was characterized by means of energy filtered transmission electron microscopy (EFTEM). 相似文献
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Kuksenova L. I. Lapteva V. G. Berezina E. V. Gerasimov S. A. Senatorski Ya. 《Metal Science and Heat Treatment》2004,46(1-2):32-35
The effect of the temperature of preliminary tempering and gas nitriding on the wear resistance and structure of surface layers of steel 38Kh2MYuA is investigated. Triboengineering and structural characteristics of nitrided layer including a layer with virtual absence of wear are obtained. Ways for optimizing nitriding modes are outlined. 相似文献
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