Experimental Research On Microstructure And Property Of Ring Cold Rolling After Heat Treatment

Cold ring rolling is a kind of continual local plastic forming technology under room temperature. The cold ring rolling realized net produce ring, which keeps the metal streamline in the ring body and increases the ring mechanical property. Compered with other producing craft, cold rolling craft greatly extends the life of bearing ring and is more efficient than traditional craft.The research of cold rolling and heat treatment of bearing steel was mainly on the shape of carbides and improvement of mechanical property after quenching and tempering.Based on the research of other people,research of microstucture and property of cold rolling,recrystallization,quenching and tempering was carried out on spheroidized ring by changing deformation amount.The effects of cold rolling craft on structure and mechanical property were reflected overall.This research has great practical value on impovement of ring's stability,durability and combination mechanical property.Microstructure and property of ring cold rolling was analyzed and discussed in this paper .the character of rings' microstucture in different deformation amount was oberseved and discussed.The microhardness of rings in different deformation was measured. The rules of change and distribution of microhardness were discussed.The results showed that there are smaller and more well-proportioned carbides in structure of ring with more deformation amount,and in which distribution of microhardness is more even.Then recrystallization annealing experiment was carried out in different temperature and time,fmish of recrystallization could be analyzed by the microhardness curve.The influence of second phase carbides on recrystallization was mainly discussed.The results showed the second phase hindered the process of recrystallization and improved temperature of recrystallization;The recrystallization of ring with small deformation amount could be finished in relative low temperature and long time.Quenching and tempering experiments were done in different temperature and time.The quenching and tempering microstructure of rings were analyzed in detail.The character of rings'quenching structure was analyzed through microhardness curve,and combination mechanical properties was discussed based on character of quenching structure.The results indicated that microhardness of ring with different deformation amount was mainly influnenced by proportion of martensite in structure. Homogeneity of alloy carbide resolved , thoughness of bearing ring could be improved and generation or extension of microcracks could be controlled by increasing deformation amount.Combination mechanical properties could be increased significantly during the process of tempering.