| 摘要 |
PURPOSE:To obtain a width sizing die for hot slab excellent in wear resistance and heat crack resistance by specifying a composition consisting of C, Si, Mn, Ni, Cr, Co, Mo, V, Nb, and Fe and also specifying the structure of matrix. CONSTITUTION:In a die used at the time of subjecting a hot slab to edging over the whole length and working to the prescribed width, the chemical composition of this slab is regulated so that it consists of, by weight, 0.15-0.35% C, 0.1-1.5% Si, 0.2-1.5% Mn, <=1.0% Ni, 0.8-2.5% Cr, <=1.0% Co, >1.5-5.0% Mo, further <=1.0% V and/or Nb, and the balance essentially Fe. Further, the matrix structure of this slab is regulated so that bainite comprises >=80% by area ratio. This structure can be obtained by applying hardening from an austenite region of about 900-1050 deg.C and successive tempering at about 600-670 deg.C to the die with the above alloy composition. By this method, the long-life width sizing die for hot slab combining wear resistance with heat crack resistance can be obtained. |
