heat up Method
cross bearing steel quenched martensite by the quenching , a small amount of undissolved carbides and the second about 12 % to 14 % of residual austenite . Quenched martensite and residual austenite is stable organization during tempering martensite decomposition volume contraction of the steel , and the decomposition of the residual austenite volume swell of the steel .
As the tempering temperature increased, the amount of decomposition of the residual austenite increases , the hardness required to ensure the process conditions, an appropriate increase in the tempering temperature , the residual austenite decomposition into the larger specific volume of martensite organizations can work volume increases accordingly , that the relative increase in the outer diameter grinding , using this method can make the bearing ring defects in the normal China bearing manufacturer conditions as scrap parts was saved.
This method for a large amount of retained austenite thick , heavy workpieces ( especially for self-aligning roller bearings ) effect was significant. The actual production of different specifications, different sizes, different thicknesses of parts developed different tempering process , to ensure the hardness and deformation under the premise that organizational change sufficiently to produce large rose -shaped , with a corresponding increase in the amount of grinding , save waste .
Three chemical deposition method
For dimensional tolerances beyond the design standard bearing parts , chemical deposition method can be used to save . The principle of chemical deposition through a variety of chemical raw materials of the chemical reaction of the surface of the part evenly certain thickness of metal coating , by attaching the metal layer and tempered to ensure hardness of the original parts and mechanical performance of the same . Chemical deposition only increased the size of the parts , without changing the shape of the part tolerances , the tolerance for dimensional tolerances of parts , by chemical deposition is an effective way to save , at present , the maximum thickness of up to about 0.1mm unilateral deposition .
