Research into in-service deterioration of ball-rolling rolls

Abstract

This work features research findings on causes of deterioration occurring in ball-rolling rolls. The causes of such deterioration may originate not only in the excessive loads application and the use of bottleneck operating parameters but also in the specific process being implemented and the equipment used to heat-treat the rolling rolls. The deterioration occurring in roll flanges having a relatively small thickness was used to demonstrate that, to prevent the deterioration of ball-rolling roll flanges, the mill design must accommodate the minimum allowable flange widths obtained as a function of maximum allowable loads and the roll pass calculations. The next example of roll deterioration involved the use of a gas furnace to implement the heating stage of the quench hardening process for rolls made of 35KhGSA steel, which, as a result, developed roll deterioration. The use of rolls of the same steel grade, which were heat-treated in an arc furnace prior to being quenched, has been shown to deliver long-lasting positive results evidenced by many years of their operation. Rolls made of 5KhNM steel have also been shown to respond well to the heat treatment preceding the quenching process, but this time, the treatment was implemented in a gas furnace.