1.The selection of work roll material
     the work roll (R1) in the front section of roughing mill: the Work Roll in the front section of roughing mill must have strong toughness, wear resistance and hot cracking resistance. The hardness range is about HS40 -- 55. 60CrNiMo cast steel rolls are generallyused.
     After roughing work roll (R2) : After roughing work roll should be made of material with good heat resistance and crack resistance. General selection of semi-steel, high-chromium steel, high-speed steel and other materials.
     Front Work Roll (F1-4) : the Front Work Roll of finishing rolling has high temperature and heavy load. Cast semi-steel and High Chromium Centrifugal compound cast iron are generally used. High Chromium Centrifugal composite cast iron has high wear resistance and hot crack resistance, and can roll surface spot defects.
     Finishing Work Roll (F5-7) : The use of finishing work roll in the final stage of rolling has a very important impact on product quality and surface condition. The roll properties are mainly high hardness, wear resistance, indentation, anti-spalling and anti-hot cracking, the general selection of infinite hard cast iron (ordinary type, improved type) and other materials.
2.The choice of material of backup roll and vertical roll
      whether it is used for rough rolling or finishing rolling, requires good hot cracking resistance, wear resistance, fatigue resistance and high strength. Materials generally choose composite cast steel, alloy forged steel (CR3, CR5) and other materials.