From the analysis of the chemical composition of the broken roll, except for the high S content, the content of other elements is basically normal, and the macroscopic structure of the roll is not too abnormal. The author observed on the spot that there was a problem with the “cast iron” in the charge. The fractures of this batch of pig iron are white, and they are very brittle, with high S content and low C, Si and Mn contents. The main reason for the nickel-chromium-molybdenum infinite chilled cast iron roll breakage is the use of “recycled iron”. Many practices have proved that with “recycled iron” as the charge, the casted castings are prone to cracks and cracks. In order to solve the problem of broken rolls, the author suggests to make improvements in the roll ingredients, disable the “recycled iron”, and switch to the new iron produced by the blast furnace, so that the problem of the broken roll that has plagued the factory for nearly half a year has finally been completely solved. A similar situation occurs.