ZHAl66-6-3-2 aluminum brass ZHAl66-6-3-2 high-strength copper rod…

An image analyzer was used for microstructure observation.The results show that increasing the solid solution temperature will reduce the strength of high temperature resistant bearing steel, while improving the plasticity and impact properties, but the change in hardness is not significant.The microstructure of high-temperature resistant bearing steel after high-temperature solution and tempering treatment is mainly lath martensite, and also includes a small amount of retained austenite and a certain amount of carbides.Due to the increase in solid solution temperature, the martensite lath gradually changes from short and thick to long and thin, which is beneficial to improving the plasticity and impact properties of high-temperature bearing steel.Higher solid solution temperature will also cause the austenite grains of high temperature resistant bearing steel to gradually grow and coarsen, resulting in a reduction in the strength of high temperature resistant bearing steel.Swedish OVAKO is a bearing steel smelted by die casting. The oxygen mass fraction of its ordinary grade (B grade) bearing steel is controlled at (4-6)×10-6, the mass fraction of titanium is (8-12)×10-6. Ultra-high purity bearing steel is its isotropic bearing steel, namely (IQ steel).
Its mass fraction of oxygen is (3-4)×10-6, the mass fraction of sulfur is 10-5. Because its ultimate fatigue strength and toughness are basically the same in all directions such as rolling and radial directions, it is called isotropic bearing steel.·By comparing the metallurgical quality of SANYO and OVAKO bearing steels, it can be seen that oxygen content and titanium content are two key control indicators for measuring the metallurgical quality of bearings.From the perspective of inclusions, bearing steel companies mainly start by reducing the oxygen content, and achieve the purpose of reducing the inclusion content and reducing the size of the inclusions by minimizing the oxygen content.Swedish bearing steel companies focus on controlling the shape and distribution of inclusions. The production status of bearing steel in these two countries represents the current level of bearing steel production quality and the future development direction of bearing steel chemical metallurgy.Domestic advanced bearing steel manufacturers represented by Xingcheng Special Steel, Baosteel Special Steel, Northeast Special Steel, Jiangsu Suzhou Steel, Nanjing Steel Works, etc. have the characteristics of high quality (certification) and large output.