Study On Manufacturing Technologies Of Centrifugal Casting High Speed Steel Roll

High-speed steel (HSS) roll containing high carbon, tungsten and vanadium has been optimizing developed. In view of the manufacturing Technologies of Centrifugal Casting High Speed Steel Roll, the modification and heat treatment of HSS roll have been studied intensively. Combining with the PLS algorithm of pattern recognition and BPN algorithm of neural net, the model in protecting process in the heat treatment of compound HSS roll was developed based on the MATLAB commercial software. High quality of HSS roll has been successfully manufactured.The carbides and matrix of cast HSS modified by potassium and rare earth (RE) were fined and broken network eutectic carbides were achieved, and many little lumps and grain carbides were produced as well. When modified HSS roll was heated at 1050℃, network eutectic carbides disappeared and many spherical carbides came out. The mechanical properties and wear resistances of modified HSS roll were distinctly improved, modification was bound to increase the thermal conductivity and decrease the hot expansion coefficient of HSS roll.The heat treatment of HSS roll was different from that of common high-speed tool steel. Fog quenching at 1025-1075℃ and tempering at 500-550℃, HSS roll turned out to have excellent mechanical properties and wear resistance. Two times temper was able to satisfy the requirement of HSS roll, while three times temper decreased the hardness of HSS roll.With the controlling technique of roll inner layer cooling, compound roll of different structures and hardness at inner layer and outer layer were obtained under heat treatment conditions. With the utilization of PLS and BPN algorithm to learn samples collected among the heat insulation plate thickness, the plate thermal coefficient, the coating thickness, the coating thermal coefficient and the inner layer hardness of HSS roll, the neural network model in protecting process was obtained in the heat treatment of compound HSS roll. Themodel could be used to predict the effects of insulting materials parameters on the inner layer hardness of roll during heat treatment for Centrifugal Casting High Speed Steel Roll. The neural network model turned out to be precise, efficient and great reliable in the application.The hardness of HSS roll was over 66 HRC, the depth of hardened layer excesses 30 mm, the variation of hardness in the roll surface was smaller than 1.5 HRC, and the wear resistance of HSS roll was better than that of high chromium cast iron roll and high nickel chromium indefinite hilled cast iron roll, close to that of powder metallurgy (PM) hard alloy roll.