Webcryptocrystalline martensite, uniform fine-grained carbides, and a small amount of retained austenite, Rockwell hardness was 56 HRC. Figure 3 is a photograph of the microstructure of the HT4 and HT5 specimens after tempering. The tempering at 180℃ is tempered at low temperature to obtain tempered martensite with a hardness of 58.5 HRC. WebApr 10, 2024 · As shown in OM images (Fig. 5 a, c), the matrix of the two bearings is common cryptocrystalline martensite microstructure. It cannot be seen the traditional martensite decay phenomenon occurred in the subsurface regions [ 34 ], such as dark etching regions (DERs) [ 35, 36] or white etching bands (s) [ 36, 37 ].

Effect of Carbon Concentration Gradient on Multi-Level Composite ...

WebFeb 1, 2011 · The martensite in steel can nucleate in the austenite crystal grain interior as well as along the austenite crystal grain boundary. It is proposed that the volumetric strain energy in... WebSep 1, 2024 · This paper mainly studies the effect of different heat treatment conditions on the microstructure and property of 9SiCr steel. The results show that 920°C normalizing + 860°C quenching + 220°C tempering, and ultimately get cryptocrystalline martensite, uniform fine-grained carbides and a small amount of retained austenite. download subtitle indonesia moana

Material factors of affecting bearing life- NSK SKF NTN TIMKEN …

WebAfter quenching, it contains 70% cryptocrystalline martensite and 20% to 25% retained austenite. During the cooling process, the medium temperature stays or the slow cooling will cause thermal stabilization of austenite, which will reduce the MS point and increase the amount of retained austenite. WebThis tissue is called cryptocrystalline martensite. When the temperature is further increased, the T8 steel is quenched at 860 ° C. At this time, the microstructure is martensite M+, and retained austenite Ar, and a large amount of undissolved cementite Fe3C. At this time, the martensite structure is needle-like. WebTo sum up, the undissolved carbides GCr15 steel after quenching at about 7% of retained austenite (cryptocrystalline martensite, the average carbon content of about 0.55%) is the best organization in about 9%. Moreover, when the original tissue carbide is small, evenly distributed, reliable control of the level of microstructure, is conducive ... clausinay