INTEGRATED HIGH, MEDIUM AND LOW PRESSURE ROTOR FOR STEAM TURBINE AND ITS MANUFACTURE

摘要

PURPOSE:To obtain the titled rotor having superior strength at high and low temps. and superior toughness at low temp. by using a low alloy steel prepd. by adding specified percentages of C, Si, Mn, Cr, Co, Mo, V and Nb to Fe. CONSTITUTION:A low alloy steel consisting of, by weight, 0.15-0.3% C, =0.1% Si, =1.0% Mn, 0.5-1.5% Cr, 0.5-3.0% Co, 0.5-1.5% Mo, 0.15-0.3% V, 0.01- 0.1% Nb and the balance Fe with accompanying impurities is melted, cast, and forged to form a rotor-shaped rough body for a steam turbine. The rough body is austenitied by heating at 900-1,000 deg.C and quenched at a cooling rate at which a bainite structure is obtd. practically from the surface layer of the resulting rotor to the central part. The rough body is then tempered at 600-700 deg.C.