Abstract: Steel having excellent vibration-damping properties and weldability includes about 0.02 wt % or less of C, about 0.02 wt % or less of Si, and about 0.08 wt % or less of Mn. This steel also includes about 0.05 to 1.5 wt % of Cu, about 1.0 to 7.0 wt % of Al, about 0.008 wt % or less of N, and Fe and incidental impurities which together constitute the remaining wt %.

Abstract: A high toughness, ultra high-strength steel having an excellent stress corrosion cracking resistance with a yield stress of not less than 110 kgf/mm.sup.2, which comprises 0.06-0.20 wt % of C, not more than 0.35 wt % of Si, 0.05-1.0 wt % of Mn, 8-11 wt % of Ni, 0.2-2.5 wt % of Cr, 0.7-2.5 wt % of Mo, 0.05-0.2 wt % of V, 0.01-0.08 wt % of Al, not more than 0.005 wt % of N, not more than 0.003 wt % of O, provided that the value of Al (%).times.N (%).times.10.sup.4 is not more than 1.5, and the balance being substantially Fe and inevitable impurities.

Abstract: A novel low C-Cr-Mo steel having an excellent weldability and a high erosion-corrosion resistance under wet steam, which consists of, in % by weight, 0.02-0.14% of C, not more than 0.90% of Si, 0.30-0.80% of Mn, 0.70-1.60% of Cr, 0.40-0.70% of Mo and the remainder being substantially Fe. This novel steel is a very excellent material for fabricating the portions in the feed-water heater, for example, for a nuclear power generation plant, the portions being used under wet steam condition. The above described weldability and erosion-corrosion resistance can be improved by additionally adding the second components of Cu, N, or B, the third components of Nb or V or the fourth components of Al, Ti or Zr in the respectively defined amounts.

Abstract: A Cr-Mo steel which is suitable for use as extremely thick plates of 75 mm or greater for pressel vessels of oil refinery, coal liquefaction and coal gasification equipment. The Cr-Mo steel includes 0.09 to 0.17 wt % of carbon, 0.03 to 0.50 wt % of silicon, 0.45 to 0.70 wt % of manganese, 1.80 to 3.40 wt % of chromium, 0.80 to 1.20 wt % of molybdenum, 0.035 to 0.1 wt % of aluminum and 0.0010 to 0.0040 wt % of boron and the balance iron and impurities inevitably mixed in steel-making processes. The Cr-Mo steel of such compositions is highly excellent in high-temperature strength, toughness and hydrogen attack resistance.

Abstract: A weldable steel excellent in the toughness of the bond in a single layer welding with a large heat-input more than 60,000 J/cm, which contains 0.03 to 0.22% of carbon, 0.02 to 0.80% of silicon and 0.40 to 2.00% of manganese in coexistance of 0.005 to 0.1% of rare earth metal and 0.0005 to 0.01% of boron, the remainder being substantially iron. Said weldable steel can be further improved by containing at least one of not more than 0.1% of niobium, not more than 0.1% of vanadium, not more than 0.5% of copper, not more than 1.0% of nickel, not more than 0.8% of chromium, not more than 0.5% of molybdenum, not more than 0.1% of selenium, not more than 0.1% of aluminum, not more than 0.1% of titanium and not more than 0.1% of zirconium.

Abstract: A novel low C-Cr-Mo steel having an excellent weldability and a high erosion-corrosion resistance under wet steam, which consists of, in % by weight, 0.02-0.14% of C, not more than 0.90% of Si, 0.30-0.80% of Mn, 0.70-1.60% of Cr, 0.40-0.70% of Mo and the remainder being susbtantially Fe. This novel steel is a very excellent material for fabricating the portions in the feed-water heater, for example, for a nuclear power generation plant, the portions being used under wet steam condition. The above described weldability and erosion-corrosion resistance can be improved, by additionally adding the second components of Cu, N, or B, the third components of Nb or V or the fourth components of Al, Ti or Zr in the respectively defined amounts.