| 摘要 |
PURPOSE:To manufacture forged steel for heat resistant pressure vessel having good creep rupture strength and superior toughness, by forging steel contg. specified quantities of Cr, Mo, V, Nb, B, etc., heating, then applying acceleratedly cooling and tempering. CONSTITUTION:Steel composed of, by weight 0.02-0.02% C, <=0.10% Si, <=1.0% Mn, <=0.015% P, <=0.010% S, 3-6% Cr, 0.5-2.0% Mo, 0.1-0.3% V, 0.02-0.2% Nb, 0.001-0.04% B, <=0.020% total Al, 0.005-0.02% Ti, <=0.020% total N and the balance Fe with inevitable impurity is forged. Next, it is heated to 1,020-1,100 deg.C to enter carbides, etc., of Nb, Mo, V, Cr, B into solid soln. in ground iron, successively cooled by about 1 deg.C/sec, then temper treated at >=600 deg.C to highly toughen and finely precipitate carbonitride. |
