High Purity Gcr15 Bearing Steel Microstructure Evolution And Control Process

Purity and homogeneity of structure is an important factor for fatigue life in high carbon chromium bearing steel GCr15. Improve the carbide morphology and distribution of benefits and thus increase organizational uniformity GCr15 steel bearings to extend life after the oxygen content and inclusion have been well-controlled circumstances,. Use of high-purity GCrl5 bearing steel as test steel, systematic research to prepare the organization and the spheroidization annealing process of the carbide evolution were investigated. By IAS8 metallographic analysis software and computing on the carbide particle size, shape and distribution of quantitative characterization; good spheroidizing annealing is better for improving the quality of bearing steel GCr15 cutting and fatigue properties.Through the study of this issue show that:1) High-purity GCr15 bearing steel mesh, ribbon carbide is not obvious, the rating is less than 1 grade; center fluid analysis the maximum size of about 50 X 30μm, the average pearlite lamellar spacing of 0.144nm; carbide annealing uniform preparation organizations, can promote speed and quality of spheroidizing annealing.2) The use of image analysis software to calculate payments IAS8 annealed test steel on the carbon number per unit area, particle size, size and roundness of annealed carbide ball and characterized the quality of this method a more accurate assessment of carbon and can be applied to actual production.3) The use of the same spheroidizing annealing to prepare the organization of the annealing process using three different study found that a species of annealing the system to be between 0.1-0.5μm diameter particles of the total 66.87 percent, in the three kinds of systems by accounted for the largest percentage; 1μm particles larger than 8.61% of the total, the proportion of the three systems, the smallest; particle roundness of 0.87, with an average particle size of 0.27μm, the system shows a spheroidizing annealing is the best results.4) Well-prepared organizationφ70mm bearing steel rods through a. spheroidizing treatment particle size smaller, uniform distribution and the roundness is good, that can be shortened 3.5 hours to achieve the same effect, improve the efficiency of the annealing, and better for fast spheroidizing.5) The cutting performance was superior after annealing before annealing. In the same cutting parameters before and after annealing under the same specifications as the steel test steel after annealing was found on the tool wear is small, easy to get a small chip off, cutting surface finish is better, no scratches and cutting burr, etc., when use up shorter time.6) L1o is 4.36 X 107 in a spheroidizing annealing system for test steel, fatigue performance is better than isothermal annealing and continuous annealing; and the number of high-cycle fatigue spalling pits relatively shallow, morphology round the whole.