| 摘要 |
PURPOSE:To improve the strength and toughness of a stainless steel used as the material of a long vane for a low pressure steam turbine by quenching the steel and tempering it twice under different conditions. CONSTITUTION:A long vane for a low pressure steam turbine is made of a stainless steel having a composition contg. 0.07-0.15% C, 0.15-0.32% Si, 0.40- 1.00% Mn, 2.5-3.5% Ni, 10.0-13.0% Cr, 1.6-2.4% Mo, 0.3-0.5% V and 0.02- 0.05% N (C+N=0.11-0.23%). The vane is held at 1,010+ or -25 deg.C austenitizing temp. for 2hr, and it is quenched. The quenched vane is tempered by holding at 570+ or -25 deg.C for 3hr, and it is further tempered at 475+ or -25 deg.C for 5hr. The strength and toughness of the vane are considerably improved. |
