Precision bearing the effect of alloying elements in steel rolling bearings

1. GCr15 bearing steel, the role of silicon in favorable for the formation of body centered cubic ferrite organization, not to form carbide in the steel, iron, on the left in the periodic table and mainly dissolved in iron. The diffusion coefficient of carbon in austenite, speed had little influence on the formation austenite, can increase point A1, relatively slow speed of the formation of austenite. Austenitic grain size of heated slightly hinder or doesn't work, can delay the pearlite phase transformation make the C curve moves to the right, the nose of the C curve to move to high temperature area, lower the Ms points, improve the stability of the supercooled austenite, thus reduce hardening critical cooling rate, improve the hardenability of steel. Can significantly slow down the martensite in low temperature decomposition, but does not slow down during 400 ~ 500 ℃ tempering martensite decompose, significantly hinder the accumulation of the carbide steel during tempering to eliminate all kinds of distortion of the role, and are generally delayed hardening steel alpha reply, recrystallization and carbide process, thus inhibiting the steel hardness, strength, enhanced the tempering stability of steel. Can improve recrystallization temperature of alpha phase, can make the steel tempering brittleness significantly enhanced, will change the every phase of steel group, and increase the quantity of pearlite. Main purpose is to increase the hardenability of steel, hardening parts after high temperature tempering all can obtain the comprehensive mechanics performance of the high and uniform, especially the showed high, significantly strengthened ferrite, than in a certain range can improve the toughness of steel. 2. GCr15 bearing steel in the role of chromium element can be closed in the gamma phase element, content reaches a certain amount of gamma phase region was closed, even if the phase diagram gamma area shrink into a very small range, more than the content of gamma to alpha phase transformation in the alloy, favorable for the formation of body centered cubic ferrite organization. Can form carbides in the steel, as a transition excessive group elements, is located in the left side of the iron in the periodic table, can reduce the eutectoid point carbon content of steel as well as the largest solid solubility of carbon in the gamma, a large number of join can make gamma phase disappears, got all the ferrite organization. Reinforcers form elements, reduce the diffusion coefficient of carbon in austenite, thus greatly delayed the pearlite to austenite transformation process, because of the special carbide formation is not easy to dissolve in the steel, makes the austenite formed at a slower pace, can increase point A1, relatively slow speed of the formation of austenite. Significant to promoting the alpha recrystallization temperature to high temperature, evident in the steel tempering brittleness, strong to prevent the further development of martensitic decomposition, can change the every phase of steel group, and increase the quantity of pearlite. All increase the hardenability of steel, hardening parts after high temperature tempering can obtain the comprehensive mechanics performance of the high and uniform, especially the showed high, significantly strengthened ferrite, than in a certain range can improve the toughness of steel. If special carbide formation dissolution difficulty, when heated, if the holding time is insufficient, will get a composition is highly uniform austenite. For heating the austenitic grain size has a secondary effect, can delay the pearlite phase transformation, the lower the Ms points, improve the stability of the supercooled austenite, thus reduce hardening critical cooling rate, improve the hardenability of steel. Significantly hinder the accumulation of the carbide steel during tempering to eliminate all kinds of distortion of the role, and are generally delayed hardening steel alpha reply, recrystallization and carbide process, thus inhibiting the steel hardness, strength, enhance 5. 3 GCr15 bearing steel manganese element in the gamma phase can be opened, the role of the district, if you reach a certain amount, can completely inhibit the alpha phase, and replace it with gamma phase, so if you r quenching to room temperature can easily obtain austenite. Can improve recrystallization temperature of alpha phase, make evident in steel tempering brittleness, will change the every phase of steel group, and increase the quantity of pearlite. Can form carbides in the steel, as a transition excessive group elements, is located in the left side of the iron in the periodic table, can reduce A1 and A3, a lot of can even make the A3 to below room temperature after China's entry into wto, the steel at room temperature austenitic organization, still has the transformation temperature can change the work analysis, and reduce the A1 point relatively increased the degree of superheat, also increase the speed of the formation of austenite, can make the refine pearlite, favour austenitic formation, the austenitic grain size is helpful when heated. Can delay the pearlite phase transformation, reduce Ms points, improve the stability of the supercooled austenite, thus reduce hardening critical cooling rate, improve the hardenability of steel. In order to increase the hardenability of steel, hardening parts after high temperature tempering all can obtain the comprehensive mechanics performance of the high and uniform, especially the showed high, significantly strengthened ferrite, than in a certain range can improve the toughness of steel.