ロール用強靱型鋳鋼の機械的性質におよぼす合金元素の影響

抄録

(I) The effects of further additions of Ni, Cr, V and Nb on the mechanical properties at room and elevated temperatures of conventional Ni-Cr-Mo cast steel material (SNI) have been investigated.
The following results were obtained:
(1) Vanadium addition improves the elongation and reduction of area of Ni-Cr-Mo cast steel at elavated temperatures.
(2) Interaction effect of chromium with nickel improves the toughness and strength of the cast steel.
(3) Niobium addition decreases the toughness.
(4) The addition of 0.4% V, 0.75% Cr and 0.5% Ni to the conventional Ni-Cr-Mo cast steel used for roll is effective in increasing the fatigue strength and toughness and this new material seems to be suitable for slabbing and heavy plate rougher mill roll.
(II) The effects of further addition of 3.0% Ni and reduction of 0.1% C to the new material at room and elevated temperatures have been investigated and the following results were obtained:
(I) 0.4%C-1.25%Cr-4.0%Ni-0.5%Mo-0.4%V cast steel has higher tensile and fatigue strength (Δδβ=23kg/mm², Δδw10⁶=8kg/mm²) than new 0.5%C-1.25%Cr-1.0%Ni-0.5%Mo-0.4%V cast steel has.
(2) The individual effects of chromium and nickel on the toughness are small, but the interaction effect of these two elements seems to improve the toughness under the temperature of 100°C.