Microstructures and mechanical properties of a modified high-C–Cr bearing steel with nano-scaled bainite
Microstructures and mechanical properties of a modified high-C–Cr bearing steel with nano-scaled bainite
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DOI：
10.1016/j.msea.2014.12.121
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发表时间：
2015-03
期刊：
影响因子：
6.4
通讯作者：
Jiali Zhao;T. Wang;B. Lv;F. Zhang
中科院分区：
文献类型：
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作者：
Jiali Zhao;T. Wang;B. Lv;F. Zhang
研究了一种新型贝氏体轴承钢在950 °C × 40 min等温淬火后在200 °C × 2 h、6 h、12 h和72 h低温等温淬火的组织和力学性能。在200 °C等温淬火6 h、12 h和72 h后，获得了贝氏体铁素体片厚约50±15 nm的纳米贝氏体组织。组织中除纳米级贝氏体铁素体片外，还存在少量残余奥氏体和未溶碳化物。在200 ℃等温72 h时，残余奥氏体体积分数为7.2%。200 °C等温72 h试样的抗拉强度达到2373 MPa，比200 °C等温2 h试样的抗拉强度高出上级，后者的组织几乎为全马氏体。等温72 h和2 h试样的失重值分别为0.0100 g和0.0273 g，耐磨性是等温2 h试样的1.7倍。由于低温贝氏体具有良好的强度和耐磨性，这种低温等温淬火技术可能是一种有潜力的轴承制造技术。
The microstructures and mechanical properties of a novel bainitic bearing steel subjected to austenitizing at 950 °C for 40 min followed by low-temperature austempering at 200 °C for 2 h, 6 h, 12 h and 72 h were studied. Nano-bainite microstructure with bainitic ferrite plate thickness about 50±15 nm was obtained by austempering at 200 °C for 6 h, 12 h and 72 h. Besides nano-scaled bainitic ferrite plates, there were small amount of retained austenite and undissolved carbides in the microstructure. The volume fraction of retained austenite is 7.2% in the samples austempered at 200 °C for 72 h. The ultimate tensile strength of samples austempered at 200 °C for 72 h reaches 2373 MPa, which is superior to the sample austempered at 200 °C for 2 h, whose microstructure is almost full martensite. The weight loss values are 0.0100 g and 0.0273 g for samples austempered for 72 h and 2 h respectively and the wear resistance of the sample austempered for 72 h is about 1.7 times higher than that for 2 h. Because of the excellent strength and wear resistance of the low-temperature bainite, this low-temperature austempering could be a potential technology for manufacturing bearings.