Analysis on Crack Propagation Property of High Speed Steel Type White Cast Iron Roll in Hot Strip Rolling

Recently high-speed steel type white cast iron roll was developed and shows high wear -resistance and are widely used in hot strip rolling. However a crack caused with rolling accident in roll surface propagate rapidly and damage a roll performance. Then the investigation for crack propagation was carried out by numerical analysis with finite-element method and crack propagation test. The results concrete as follows; (1) Crack propagates by contact with buck-up roll by means of shear mode (mode II) . ( 2) Ordinary thermal crack less than 1 mm in length does not propagate, but abnormal mechanical crack more 1.3 mm in length caused by rolling accident propagate even under normal rolling condition. ( 3) Compressive residual stress of roll is not a accelerate factor for propagation of crack.