Some Investigations on the Thermal Shock Crack of Cold Strip Mill Work Roll Materials

Abstract

Slipping, pitching and other behaviors of roll for cold strip mill, especially work roll bring about thermal shock cracks on this surface in their service condition, which will affect roll life.
This paper discribes on the investigation as to the influence of material compositions and heat treatment cunditions on the thermal shock crack depth and shows the superior of 3-5 % Cr-Mo steel containing more chromium than ordinal 1-2 % Cr-Mo Steel. The practical rolling mill use of new type roll of 3-5 % Cr-Mo steel proved the extremely extended roll life.
A thermal shock testing machine which utilizing frictional heat generated by contacting rotating disc and test specimen was developed for the present investigation and qauntitative measure of crack depth in the test specimen due to the thermal shock was introduced for the evaluation of roll materials.