| 摘要 |
PURPOSE:To obtain the titled steel plate having superior resistance to weld crack, erosion and creep by providing a specified composition consisting of C, Si, Mn, Cu, Ni, Cr, Mo, sol. Al, B, N and Fe and a structure contg. a proper percentage of bainite. CONSTITUTION:This normalized low-carbon steel plate for a boiler or a pressure vessel having high strength and tougness consists of, by weight, 0.01-0.12% C, 0.05-1.0% Si, 0.20-1.50% Mn, 0.05-0.19% Cu, 0.05-0.40% Ni, 0.05-0.39% Cr, >0.45-1.0% Mo, 0.005-0.10% sol. Al, 0.0003-0.0020% B, <=0.005% N and the balance Fe with inevitable impurities, satisfies a formula C+0.17Mn<=0.28%, and has <=0.23% PCM defined by a formula PCM=C+Si/30+(Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B%. The steel plate contains 20-85% bainite in the normalized structure and has superior resistance to weld crack, erosion and creep.
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