PAWŁOWSKI Bogdan AGH University of Science and Technology

Spoluautoři KRAWCZYK Janusz, BAŁA Piotr

The influence of shrinkage caused by austenitic transformation on thermal fatigue of mill rolls made of four different cast steels: G200CrNiMo4-3-3 (roll campaign 4 095 Mg), G200NiSiCr8-4-4 (roll campaign 1 561 Mg), G200SiCrNi4-4 (roll campaign 2 578 Mg) and G120CrNiMo4-3-3 (roll campaign 2 116 Mg) was investigated. The samples were taken from the work surface perpendicular (or close to it) to the axis of the rolls. The dimensional changes (shrinkage) associated with the austenitic transformation were determined by dilatometric examinations. A number of parameters that describe the susceptibility to thermal fatigue of investigated rolls was determined, including the greatest observed crack depth Gmax, average crack depth G, average crack path length L, average distance between cracks and other. It was found that the shrinkage associated with the formation of austenite appears to be a main factor contributing to the nucleation and growth of thermal fatigue cracks in cast steel rolls.