Cr12 Cryogenic Treatment Process Experimental Study

Extension of cold treatment is deep cryogenic treatment. Operating simply without damaging the workpiece and pollution is the best characteristic of treatment. The experiment shows deep cryogenic treatment could transform many mechanical properties and prolong service life of material, stable the demension of workpieces, improve the uniformity of material and could reduce the deformation of workpieces. Deep cryogenic treatment is a kind of green manufacturing of mining potential performance of materials.Cr12steel is a material of rolling that it is commonly used. In the course of making and using, the material suffered the various stress cyclely, leading to the materials susceptible to failure early that effects the precision and service life of die serious. Therefore, researching the reason of failure early, finding effective measures for prolonging roll’s life become an important task.Deep cryogenic treatment process of Cr12steel is studied by orthogonal experiment method in this paper, and effect of cryogenic treatment process on mechanical properties and microstructure of Cr12steel was investigated by hardness test, wear test and X-ray diffraction. Through the analysis of test, a reasonable deep cryogenic treatment process was determined, that opens up a new ways for prolonging service life of Cr12steel.Through the experimental analysis and practical inspection, the results show as follows.1)The hardness and wear resistance are improved after cryogenic treatment, and holding time is the most influencing factors in deep cryogenic treatment process of Cr12steel.2)Austenite in Crl2steel could not elmininate completely by deep cryogenic treatment, could not change to martensite completely. Meanwhile, the diffraction peaks of the martensite are increased, the diffraction peaks are widen after cryogenic treatment.3)The residual austenite transforms further to martensite during cryogenic treatment, and distributable carbides are precipitated from martensite. The grain of martensite of Crl2steel are uniformity, compact and refined after cryogenic treatment.4)According to the test results, a reasonable deep cryogenic treatment process was determined. In this experiment, cooling rate of4℃·min-1, cryogenic temperature of—130℃holding time of2h, heating rate of4℃·min1are reasonable deep cryogenic treatment process. SVM is used for predictive analysis, the results show that reansonable process that was predicted is the same as reasonable process that was determined.5)Roll of Crl2by using reasonable processing in this paper after discussing of deep cryogenic treatment were applicated to process practice in factory, the results show that roll’s effect in processing is better after deep cryogenic treatment.