Abstract: Provided is maraging steel with which maraging steel that has been subjected to nitriding treatment has excellent fatigue strength and stable high strength. Maraging steel that has been subjected to nitriding treatment to a thickness of 0.5 mm or less and comprises, by mass %, 0.008% or less of C, 0.5% or less of Si, 0.5% or less of Mn, 0.5 to 1.5% of Cr, 16.0 to 22.0% of Ni, 3.0 to 7.0% of Co, and 3.0 to 7.0% of Mo is maraging steel further comprising, by mass %, 0.6 to 1.3% of Al and Fe and impurities as the balance, wherein the impurities are maintained at 0.01% or less of Ti, 0.01% or less of Nb, 0.01% or less of Ta, and 0.01% or less of W, the ratio of Al and Ti is Al/Ti>250, and by Vickers hardness, the surface hardness of the maraging steel is 800 to 1,050 HV and internal hardness of the maraging steel is 570 HV or less.

Abstract: Provided is a maraging steel strip which has such a composition that can reduce the content of TiN acting as the starting point of fatigue fracture in a high-cycle region, and the bending fatigue strength of which has been improved by the precipitation hardening effect yielded by precipitating coherent nitrides in the nitrided structure. A maraging steel strip produced by nitriding a managing steel which contains by mass, C: 0.01% or less, Si: 0.1% or less, Mn: 0.1% or less, P: 0.01% or less, S: 0.005% or less, Ni: 8.0 to 22.0%, Cr: 0.1 to 8.0%, Mo: 2.0 to 10.0%, Co: 2.0 to 20.0%, Ti: 0.1% or less, Al: 2.5% or less, N: 0.03% or less, and O: 0.005% or less, with the balance being Fe and unavoidable impurities, wherein Baker-Nutting orientation relationship with an orientation difference within 10° exists between the Cr nitride precipitated in the nitrided layer and the matrix martensite.

Abstract: To provide an inexpensive heat-resisting steel for engine valves by causing Fe-based heat-resisting steel to exhibit high temperature strength not inferior to that of Ni-based heat-resisting steel. A heat-resisting steel for engine valves excellent in high temperature strength containing, in % by mass, C: 0.20 to 0.50%, Si: 1.0% or less, Mn: 5.0% or less, P: 0.1 to 0.5%, Ni: 8.0 to 15.0%, Cr: 16.0 to 25.0%, Mo: 2.0 to 5.0%, Cu: 0.5% or less, Nb: 1.0% or less (including 0%), W: 8.0% or less (including 0%), N: 0.02 to 0.2%, B: 0.01% or less, and remnants of Fe and impurities, wherein the heat-resisting steel for engine valves satisfies formulae below: 442P(%)+12Mo(%)+5W(%)+7Nb(%)+328N(%)+171?300??Formula (1) ?38.13P(%)+1.06Mo(%)+0.13W(%)+9.64Nb(%)+13.52N(%)+4.83?0.12??Formula (2).

Abstract: Provided are: steel for solid oxide fuel cells, which is capable of ensuring sufficient oxidation resistance even if a predetermined amount of nitrogen is contained therein; and a member for solid oxide fuel cells, which uses the steel for solid oxide fuel cells. This steel for solid oxide fuel cells having excellent oxidation resistance contains, in mass %, 0.022% or less (including 0%) of C, 0.01-0.05% of N, 0.01% or less (including 0%) of 0, 0.15% or less (including 0%) of Al, 0.15% or less (including 0%) of Si, 0.1-0.5% of Mn, 22.0-25.0% of Cr, 1.0% or less (excluding 0%) of Ni, 1.5% or less (including 0%) of Cu, 0.02-0.12% of La and 0.01-1.50% of Zr with La+Zr being 0.03-1.60%, and 1.5-2.5% of W, with the balance made up of Fe and impurities. The ratio of Zr/(C+N) in mass % is preferably 10 or more.

Abstract: A piston ring material is provided which retains excellent mechanical properties and processability, which are required of piston ring materials, and has wearing resistance and scuffing resistance, which are sliding properties required of piston rings. The piston ring material, which is for use in internal combustion engines, contains, in terms of mass %, 0.3-0.8% carbon, 0.1-3.0% silicon, 0.1-3.0% manganese, 0.01-0.3% sulfur, 0.1-2.0% chromium, and 0.05-2.0% the sum of titanium and/or zirconium, with the remainder being iron and incidental impurities. The titanium and/or zirconium contained in the piston ring material and the sulfur contained therein satisfy the following relationship. [Ti (%)+½Zr (%)]/S (%)?5.0 Preferably, the material may contain one or more members selected from up to 1.0% copper, less than 3.0% molybdenum, up to 1.0% aluminum, and less than 2.0% nickel, in terms of mass %.

Abstract: Disclosed is a low-thermal-expansion Ni-based super-heat-resistant alloy for a boiler, which has excellent high-temperature strength. The alloy can be welded without the need of carrying out any aging treatment. The alloy has a Vickers hardness value of 240 or less. The alloy comprises (by mass) C in an amount of 0.2% or less, Si in an amount of 0.5% or less, Mn in an amount of 0.5% or less, Cr in an amount of 10 to 24%, one or both of Mo and W in such an amount satisfying the following formula: Mo+0.5 W=5 to 17%, Al in an amount of 0.5 to 2.0%, Ti in an amount of 1.0 to 3.0%, Fe in an amount of 10% or less, and one or both of B and Zr in an amount of 0.02% or less (excluding 0%) for B and in an amount of 0.2% or less (excluding 0%) for Zr, with the remainder being 48 to 78% of Ni and unavoidable impurities.

Abstract: An alloy to be surface-coated, which can keep excellent hardness of 58HRC or above even when the amount of an alloying element added is reduced or even when the alloy is heated to a temperature of as high as 400 to 500° C.; and sliding members produced by forming a hard film on the surface of the alloy. An alloy to be surface-coated, the surface of which is to be covered with a hard film, which alloy contains by mass C: 0.5 to 1.2%, Si: 2.0% or below, Mn: 1.0% or below, Cr: 5.0 to 14.0%, Mo+1/2 W: 0.5 to 5.0%, and N: more than 0.015 to 0.1% with the balance being Fe and impurities, preferably such an alloy which contains by mass C: 0.6 to 0.85%, Si: 0.1 to 1.5%, Mn: 0.2 to 0.8%, Cr: 7.0 to 11.0%, Mo+1/2 W: 1.0 to 4.0%, and N: 0.04 to 0.08%.

Abstract: An electrode material to be used for producing an earth electrode of a spark plug has a chemical composition of 0.3 to 3.0 mass % of Si, 0.01 to 0.3 mass % of one or more elements selected from the group consisting of Y and rare earth elements, not more than 0.5 mass % of Ti, not more than 1.2 mass % of Fe, and one or both of not more than 0.20 mass % of Ca and not more than 0.08 mass % of Mg. The electrode material further contains C, Mn, Cr, Al, N, S, a remainder Ni, and incidental impurities. In a total content of C, Mn, Cr, Al, N and S, C is not more than 0.1 mass %, Mn is less than 0.5 mass %, Cr is less than 0.5 mass %, Al is not more than 0.3 mass %, N is not more than 0.05 mass %, and S is not more than 0.03 mass %.

Abstract: A nonmagnetic stainless steel which has a higher electrical resistivity than existing nonmagnetic alloys, a production process for producing the stainless steel, and a radio wave receiver. The receiver has a main case and rear cover constituted of a nonmagnetic stainless steel having an electrical resistivity as high as more than 100 ??·cm and consisting of C: not more than 0.1%, Si: 4.0-7.5%, Mn: not more than 2.0%, Ni: 25.5-30.0%, Cr: 15.0-20.0%, Mo: 0.1-3.0%, Cu: 0-2.0%, in mass % and the balance Fe and impurities. Even if some variable magnetic flux generated by a coil of an antenna runs through the main case and the rear cover, the receiving efficiency of the antenna can be prevented from being reduced by eddy current loss and a sufficient radio receiving sensitivity can be obtained. This nonmagnetic stainless steel is produced by hot and/or cold plastic working and subsequent solution treating conducted at 1,000-1,180° C.

Abstract: Disclosed is steel for a solid oxide fuel cell, which has excellent oxidation resistance, reduces Cr evaporation, has good electrical conductivity and has a thermal expansion coefficient similar to that of a ceramic component such as an electrolyte or an electrode. Specifically disclosed is steel for solid oxide fuel cells, which has excellent oxidation resistance and contains, in mass %, 0.1% or less of C, 0.2% or less of Al, 0.2% or less of Si, 0.4% or less of Mn, 16.0-28.0% of Cr, 1.5% or less of Ni, 1.0% or less of REM and/or Zr in total, 1.0-3.0% of W, and more than 0.2% but 4.0% or less of Cu, with the balance made up of Fe and unavoidable impurities.

Abstract: A piston ring material that when formed into a piston ring product, maintains excellent properties, and that at the production of piston ring rod, realizes excellent processability and shape stability. There is provided a piston ring material for internal combustion engine comprising, by mass, 0.5 to less than 0.7% C, 1.0% or less Si, 1.0% or less Mn, 12.0 to 16.0% Cr, 3.0% or less Mo and/or W (Mo+½W), 0.02 to 0.14% N and the balance Fe and unavoidable impurities, wherein the relationship of contained C, N and Cr satisfies the formulae: 25?43.22C (%)+42.45N (%)?0.02Cr (%)?40, and 0.15?0.92C (%)+0.67N (%)?0.03Cr (%)?0.30.

Abstract: Provided is a coated-surface sliding part having excellent adhesion of a hard coating, and a method for producing the same part. The coated-surface sliding part is a sliding part wherein a hard coating is formed by physical deposition on the surface of a base material formed from, by mass percent, C 0.5 to 0.8%, Si 0.1 to 1.5%, Mn 0.2 to 1.0%, Cr 8.0 to 13.5%, Mo and/or W 0.5 to 4.0% in terms of (Mo+ 1/2 W), and N 0.01 to 0.1%, with the remainder being Fe and impurities. The physically deposited coating is a titanium metal coating further covered by a diamond-like carbon coating. The method for producing a coated-surface part involves sputtering in order to apply the physically deposited coating, which consists of the titanium metal coating and then the diamond-like carbon coating which forms the surface layer, to the surface of the base material having the aforementioned composition. The base material is preferably subjected to argon gas bombardment prior to application of the physically deposited coating.

Abstract: To provide an inexpensive heat-resisting steel for engine valves by causing Fe-based heat-resisting steel to exhibit high temperature strength not inferior to that of Ni-based heat-resisting steel. A heat-resisting steel for engine valves excellent in high temperature strength containing, in % by mass, C: 0.20 to 0.50%, Si: 1.0% or less, Mn: 5.0% or less, P: 0.1 to 0.5%, Ni: 8.0 to 15.0%, Cr: 16.0 to 25.0%, Mo: 2.0 to 5.0%, Cu: 0.5% or less, Nb: 1.0% or less (including 0%), W: 8.0% or less (including 0%), N: 0.02 to 0.2%, B: 0.01% or less, and remnants of Fe and impurities, wherein the heat-resisting steel for engine valves satisfies formulae below: 442P(%)+12Mo(%)+5W(%)+7Nb(%)+328N(%)+171?300??Formula (1) ?38.13P(%)+1.06Mo(%)+0.13W(%)+9.64Nb(%)+13.52N(%)+4.83?0.

Abstract: Provided is a maraging steel strip which has such a composition that can reduce the content of TiN acting as the starting point of fatigue fracture in a high-cycle region, and the bending fatigue strength of which has been improved by the precipitation hardening effect yielded by precipitating coherent nitrides in the nitrided structure. A maraging steel strip produced by nitriding a managing steel which contains by mass, C: 0.01% or less, Si: 0.1% or less, Mn: 0.1% or less, P: 0.01% or less, S: 0.005% or less, Ni: 8.0 to 22.0%, Cr: 0.1 to 8.0%, Mo: 2.0 to 10.0%, Co: 2.0 to 20.0%, Ti: 0.1% or less, Al: 2.5% or less, N: 0.03% or less, and O: 0.005% or less, with the balance being Fe and unavoidable impurities, wherein Baker-Nutting orientation relationship with an orientation difference within 10° exists between the Cr nitride precipitated in the nitrided layer and the matrix martensite.

Abstract: Provided is an Ni-base alloy excellent in strength, ductility and other properties through the resolution of micro-segregation. Also provided is a process for manufacturing an Ni-base alloy containing by mass C: 0.15% or less, Si: 1% or less, Mn: 1% or less, Cr: 10 to 24%, Mo+(½)W (where Mo may be contained either alone or as an essential component): 5 to 17%, Al: 0.5 to 1.8%, Ti: 1 to 2.5%, Mg: 0.02% or less, and either B: 0.02% or less and/or Zr: 0.2% or less at an Al/(Al+0.56Ti) ratio of 0.45 to 0.70 with the balance consisting of Ni and impurities, which comprises subjecting, at least one time, an Ni-base alloy material which is prepared by vacuum melting and has the above composition to homogenization heat treatment at 1160 to 1220° C. for 1 to 100 hours. The Mo segregation ratio of the alloy is controlled to 1 to 1.17 by the homogenization heat treatment.

Abstract: A piston ring material is provided which retains excellent mechanical properties and processability, which are required of piston ring materials, and has wearing resistance and scuffing resistance, which are sliding properties required of piston rings. The piston ring material, which is for use in internal combustion engines, contains, in terms of mass %, 0.3-0.8% carbon, 0.1-3.0% silicon, 0.1-3.0% manganese, 0.01-0.3% sulfur, 0.1-2.0% chromium, and 0.05-2.0% the sum of titanium and/or zirconium, with the remainder being iron and incidental impurities. The titanium and/or zirconium contained in the piston ring material and the sulfur contained therein satisfy the following relationship. [Ti (%)+½Zr (%)]/S (%)?5.0 Preferably, the material may contain one or more members selected from up to 1.0% copper, less than 3.0% molybdenum, up to 1.0% aluminum, and less than 2.0% nickel, in terms of mass %.

Abstract: An alloy to be surface-coated, which can keep excellent hardness of 58HRC or above even when the amount of an alloying element added is reduced or even when the alloy is heated to a temperature of as high as 400 to 500° C.; and sliding members produced by forming a hard film on the surface of the alloy. An alloy to be surface-coated, the surface of which is to be covered with a hard film, which alloy contains by mass C: 0.5 to 1.2%, Si: 2.0% or below, Mn: 1.0% or below, Cr: 5.0 to 14.0%, Mo+1/2 W: 0.5 to 5.0%, and N: more than 0.015 to 0.1% with the balance being Fe and impurities, preferably such an alloy which contains by mass C: 0.6 to 0.85%, Si: 0.1 to 1.5%, Mn: 0.2 to 0.8%, Cr: 7.0 to 11.0%, Mo+1/2 W: 1.0 to 4.0%, and N: 0.04 to 0.08%.

Abstract: Disclosed is a low-thermal-expansion Ni-based super-heat-resistant alloy for a boiler, which has excellent high-temperature strength. The alloy can be welded without the need of carrying out any aging treatment. The alloy has a Vickers hardness value of 240 or less. The alloy comprises (by mass) C in an amount of 0.2% or less, Si in an amount of 0.5% or less, Mn in an amount of 0.5% or less, Cr in an amount of 10 to 24%, one or both of Mo and W in such an amount satisfying the following formula: Mo+0.5 W=5 to 17%, Al in an amount of 0.5 to 2.0%, Ti in an amount of 1.0 to 3.0%, Fe in an amount of 10% or less, and one or both of B and Zr in an amount of 0.02% or less (excluding 0%) for B and in an amount of 0.2% or less (excluding 0%) for Zr, with the remainder being 48 to 78% of Ni and unavoidable impurities.

Abstract: A maraging steel for metallic belts which has a composition capable of being reduced in the content of TiN serving as a starting point for fatigue fracture in a high-cycle-rate region. The composition facilitates nitriding to heighten the surface hardness. The steel has a nitrided surface layer having increased compressive residual stress and hence improved flexural fatigue strength. In the steel, former austenite crystal grains have been reduced in size in order to secure higher strength and higher ductility. The maraging steel consists of, by mass %, up to 0.01% C, up to 0.1% Si, up to 0.1% Mn, up to 0.01% P, up to 0.005% S, 17.0-22.0% Ni, 0.1-4.0% Cr, 3.0-7.0% Mo, from more than 7.0 to 20.0% Co, up to 0.1% Ti, up to 2.5% Al, up to 0.03% N, up to 0.005% 0, up to 0.01% B (exclusive zero), and the balance of Fe and unavoidable impurities, wherein Co/3+Mo+4Al is 8.0-15.0%.

Abstract: A piston ring material that when formed into a piston ring product, maintains excellent properties, and that at the production of piston ring rod, realizes excellent processability and shape stability. There is provided a piston ring material for internal combustion engine comprising, by mass, 0.5 to less than 0.7% C, 1.0% or less Si, 1.0% or less Mn, 12.0 to 16.0% Cr, 3.0% or less Mo and/or W (Mo+1/2W), 0.02 to 0.14% N and the balance Fe and unavoidable impurities, wherein the relationship of contained C, N and Cr satisfies the formulae: 25?43.22C (%)+42.45N (%)?0.02Cr (%)<40, and 0.15 <0.92C (%)+0.67N (%)?0.03Cr (%)<0.30.