| 摘要 |
PURPOSE:To improve seizure resistance, abrasion resistance and accident resistance by constituting the 1st outer layer, the 2nd outer layer and an inner layer of respectively specified contents of C, Si, Mn, P, S, Ni, Cr, Mo. CONSTITUTION:The working layer to be in contact with rolled materials is formed into two layers; the 1st and the 2nd outer layers, and the layer to be not in contact with rolled materials is formed as an inner layer, which layers are melt stuck to one body whereby a three-layered sleeve is made. The 1st outer layer is formed of the steel contg., by weight %, 2.2-3 C, 0.2-1.5 Si, 0.4-1.5 Mn, <0.1 P, <0.1 S, 2.5 Ni, 2-3.2 Cr, and >=1.5 Si, 0.2-2 Mo, the 2nd outer layer of the steel contg. 2-3.2 C, 0.3-1.5 Si, 0.4-1.5 Mn, <0.1 P, <0.1 S, 0.5- 3.5 Ni, 8-25 Cr, 0.5-2.5 Mo, and the inner layer of the steel contg. 1-2 C, 0.5- 3 Si, 0.2-1 Mn, <0.1 P, <0.1 Si, 0.1-2 Ni, 0.1-3 Cr, 0.1-1 Mo. |
