Do you know how to pickling bearing ring white spot?

Do you know how to pickling bearing ring white spot? Wafangdian bearing ring processing technology for: car manufacture & rarr; Carburizing & rarr; High temperature tempering & rarr; Return the car processing & rarr; The secondary hardening & rarr; High temperature tempering & rarr; Coarse grinding & rarr; Pickling. 1. Coarse grinding bearing ring morphology and physical and chemical inspection method after pickling raceway and the guard should be evenly colored, defect ring after pickling plaques are mainly distributed in the race and gear side, as shown in figure 1. Respectively in the bearing ring taking samples, white spot and normal in the sample section of surface microstructure observation. Metallographic specimen after mechanical grinding and polishing corrosion in 4% nitric acid alcohol solution, with GX - olin and company 51 metallographic microscope observation of carburized layer microstructure and distribution of carbide shape, to determine whether the organization is qualified and carbide network exceeds bid. Application type ARL4460 direct reading spectrometer analysis of the chemical composition of the sample, to determine whether its composition is qualified. Using BUEHLER MICROMET type 5124 microhardness meter testing its hardness and depth of carburizing layer, determine its surface hardness and carburized layer depth of carburizing layer. 2. Carburizing layer tissue contrast high temperature carburizing bearing steel carburizing heat treatment after heat treatment, surface carburizing layer should be cryptocrystalline martensite, residual austenite and uniform distribution of carbide, can not have network carbide and massive carbide. Vertical profile control of raceway vitiligo and normal part respectively made metallographic specimen, the olin ba si GX - 51 metallographic microscope to observe microstructure and carbides in the race the two sample, color normal place of raceway surface microstructure of cryptocrystalline martensite, residual austenite and uniform distribution of carbide, carbide network and are not found in the thick carbide. According to the above analysis, the bearing ring material chemical composition of qualified; Raceway surface hardness of 60 HRC color normal place, the depth of carburizing layer 1. 28 mm, surface carbon content is 0. 91%; Surface hardness is 56 race white spot. 5 HRC, carburized layer depth of 0. 96 mm, the surface carbon content 0. 73%; Raceway white spot in the surface microstructure of cryptocrystalline martensite and retained austenite, and found no residual carbides, and the surface carbon content lower than normal, can determine the bearing ring raceway local regional low carbon content cause white spot after pickling. Spherical roller bearing ring raceway surface hardness is low, white spot area and the depth of carburizing layer, the contact fatigue life of bearing will be greatly reduced, peeling off in the use of the bearing process cause early failure.