Investigation Of Infinite Chill Spherical-graphite Cast Iron Rollers

It is very significant for the economic benefit of PangGang Group Corporation to raise the ability of self-providing of rollers, reduce the consumption of rollers and extend the applications of V-Ti pig iron. This article is aimed at developing the manufacture technology of iron rollers containing Cr-Mo-V. After analyzing the working feature of rollers, the chemical composition and processing were designed. Experiment indicated that the rollers had good properties when their composition was 3.4~3.6%C, 1.3~1.6%Si, 0.1~0.2%P, 0.5~0.8%Mn, 0.2~0.4%Cr, 0.2~0.3%Mo, 0.9~1.1%Cu, S≤0.03%, 0.04~0.06%Re, 0.04~0.06%Mg, and when V-Ti pig iron was used as raw material, Re-Mg alloy was used as spheroidizer and spheroidizing treatment was conducted between 1270oC and 1300oC. Mechanical properties of rollers with above composition were:σb≥300MPa, hardness=63～68HSD in the surfaces of the rollers. Hardness disparity within 150mm from roller surface was 10.3～11.8HSD . Metallurgical observation showed that there was not black slag on the fracture surface, and the micro-constitution was composed of fine carbide, pearlite and a little graphite. Some tiny particles of carbide containing vanadium and titanium were founded under SEM. During rolling process, no roller breakage and peel off took place. The roller life was longer than that of the same-type rollers that was bought. The general consumption of rollers reduced from 3.87Kg/t to 3.69Kg/t. The tested rollers can instead of the rollers that was bought.