Study On The Preparation Of GCr15-45 Steel Bimetal Composite By ESR Method And Its Heat Treatments

As one of the main consumption parts of the rolling mill,the roll consumes about 5%?15%of the total cost of steel rolling.It is an indispensable part of rolling production,and is called the "mother of the steel".In order to acquire a high wear resistance of its working layer,the traditional single material roll often contains high alloy contents.This not only increases the production cost of the roll,but also is not conducive to the high strength and toughness of the core and the roll neck,and is also not conducive to the improvement of the comprehensive performance of the roll.Due to the different material quality of the roll core and the working layer,through a reasonable material selection,we can achieve the excellent performance of the roller working layer,such as high wear resistance,high surface roughness resistance and internal strength and toughness.Based on this,combined with the advantage of ESR technology.a new process for preparing bimetal composite roll by electroslag remelting process has been developed,and the effects of diffferent heat treatment processes on the micro structure and properties of bimetal composite have been discussed,so as to provide reference and guidance for the industrial production.In this paper,GCrl5 steel and 45#steel are selected as the working layer and the of roll core respectively.By the using of the lining electroslag furnace,slag chute,pouring ingot mold and the advanced current carrying mold technology,GCr 15-45 composite ingot was produced by theelectroslag remelting method.Through the continuous exploration and summarization,we have not only mastered the technological characteristics of its technology,obtained the appropriate technological parameters,but also prepared a good bimetal composite ingot.(1)In order to analyze and understand the bonding quality of bimetal composite ingot more accurately and effectively,the cast ingot was anatomically analyzed.From the macro morphology of the cross section,double metal binding ring to interface with uniform,no defects;macro morphology of longitudinal section reflects the double metal binding changes with the interface temperature of electro slag melting system is gradually warming up to a stable process,therefore,the interface is a combination of continuous slag according to a good transition and finally stabilized.(2)In order to adjust the GCr15 hypereutectoid steel microstructure and organization for quenching,this paper explores the effects of different heating temperature,holding time,isothermal temperature and holding time under isothermal spheroidizing process meter impact power and other performance of GCr15-45#steel bimetal interface microstructure and hardness.As a comprehensive analysis about the uniformity of the spherical carbide uniformity in GCr15 steel and the elimination of the overheating Widmanstatten structure in 45#steel,it is benefite to chose the annealing process of heating the specimens to 820? and holding for 0.5 hours and what is followed by cooling the specimens to 720? in the furnace,holding for 5 hours,finally,when it cooled to 60? removed it from the furnace.(3)Based on the above annealing process,the effects of different quenching temperature,heat preservation time and tempering temperature on the microstructure and properties of bimetal composites were investigated.The comprehensive analysis indicates that the heat preservation time of quenching temperature at 850? holding for 0.5 hours,the tempering temperature is 150? and holding for 1.5 hours is appropriate.