Cast steel material for composite roll ring and preparation method thereof

The invention discloses a cast steel material for a composite roll ring. The cast steel material comprises the following chemical elements by mass percent: 0.8-0.9 % of carbon, 1.2-1.5% of tungsten, 1.5-2.5% of molybdenum, 1.5-2.5% of vanadium, 2.2-2.5% of chromium, 0.05-0.10% of niobium, 0.1% of rare earth, 0.004-0.007% of Mg, 0.02-0.05% of Al, not more than 0.030% of P, not more than 0.030% of S, and the balance of iron. A plurality of alloy elements such as rare earth, Al and niobium are added on the basis of high-carbon steel, the heat treatment temperature after casting is reasonably controlled in a secondary refining manner, and the raw materials are fed in batches, so that the alloy steel has the characteristics of high-speed steel, is heat-resisting, high in red hardness, good in matching of rigidity and tenacity, good in abrasive resistance, high in hardness, and impact resistant, and is applicable to a roll ring of a roller of a wire processing machine, low in cost and durable. A part of scrap iron is used as a raw material, so that the alloy is stable and uniform in quality.