Abstract: A seal member includes a ?? precipitation-hardening alloy, in which the ?? precipitation-hardening alloy has a component composition of, in mass %: Ni: from 40 to 62%; Cr: from 13 to 20%; Ti: from 1.5 to 2.8%; Al: from 1.0 to 2.0% (provided that Ti/Al: 2.0 or less); Nb: 2.0% or less; Ta: 2.0% or less (provided that Nb+Ta: from 0.2 to 2.0%); B: from 0.001 to 0.010%; W: 3.0% or less; and Mo: 2.0% or less (provided that Mo+(1/2)W: from 1.0 to 2.5%), and optionally, C: 0.08% or less; Si: 1.0% or less; Mn: 1.0% or less; P: 0.02% or less; and S: 0.01% or less, with the balance being Fe and inevitable impurities, and in which the seal member has a hardness of 250 Hv or more, and includes a cold-rolled microstructure obtained by a cold rolling.

Abstract: The present invention relates to an Ni-based superalloy for hot forging, containing, in terms of % by mass, C: more than 0.001% and less than 0.100%, Cr: 11% or more and less than 19%, Co: more than 5% and less than 25%, Fe: 0.1% or more and less than 4.0%, Mo: more than 2.0% and less than 5.0%, W: more than 1.0% and less than 5.0%, Nb: 0.3% or more and less than 4.0%, Al: more than 3.0% and less than 5.0%, Ti: more than 1.0% and less than 3.0%, and Ta: 0.01% or more and less than 2.0%, with the balance being unavoidable impurities and Ni, in which the component composition satisfies the following two relationships: 3.5?([Ti]+[Nb]+[Ta])/[Al]×10<6.5 and 9.5?[Al]+[Ti]+[Nb]+[Ta]<13.0.

Abstract: The present invention relates to a maraging steel containing, in terms of mass %, 0.10?C?0.35, 9.0?Co?20.0, 1.0?(Mo+W/2)?2.0, 1.0?Cr?4.0, a certain amount of Ni, a certain amount of Al, and V+Nb?0.60, with the balance being Fe and inevitable impurities, in which in a case of V+Nb?0.020, the amount of Ni is 6.0?Ni?9.4 and the amount of Al is 1.4?Al?2.0, and in a case of 0.020<V+Nb?0.60, the amount of Ni is 6.0?Ni?20.0 and the amount of Al is 0.50?Al?2.0.

Abstract: The present invention relates to a method for producing a precipitation strengthened Ni-based superalloy material having a predetermined composition, containing a blooming forging step of performing a forging at a temperature range of from Ts to Tm and performing an air cooling to form a billet having an average crystal grain size of #1 or more, an overaging thermal treatment step of heating and holding the billet at a temperature range of from Ts to Ts+50° C. and slowly cooling it to a temperature of Ts or lower, and a crystal grain fining forging step of performing another forging at a temperature range of from Ts?150° C. to Ts and performing another air cooling, in which Ts is from 1,030° C. to 1,100° C., and an overall average crystal grain size is #8 or more after the crystal grain fining forging step.

Abstract: The present invention relates to a maraging steel containing, in terms of mass %, 0.20?C?0.35, 9.0?Co?20.0, 1.0?(Mo+W/2)?2.0, 1.0?Cr?4.0, and a certain amount of Ni, with the balance being Fe and inevitable impurities, in which in a case where the contents of V and Nb satisfy V+Nb?0.020 mass %, the amount of Ni is 6.0?Ni?9.4, and in which in a case where the contents of V and Nb satisfy 0.020 mass %<V+Nb?0.60 mass %, the amount of Ni is 6.0?Ni?16.0.

Abstract: The present invention relates to a maraging steel containing, in terms of mass %, 0.20?C?0.35, 9.0?Co?20.0, 1.0?(Mo+W/2)?2.0, 1.0?Cr?4.0, and a certain amount of Ni, with the balance being Fe and inevitable impurities, in which in a case where the contents of V and Nb satisfy V+Nb?0.020 mass %, the amount of Ni is 6.0?Ni?9.4, and in which in a case where the contents of V and Nb satisfy 0.020 mass %<V+Nb?0.60 mass %, the amount of Ni is 6.0?Ni?16.0.

Abstract: The present invention relates to a method for producing a precipitation strengthened Ni-based superalloy material having a predetermined composition, containing a blooming forging step of performing a forging at a temperature range of from Ts to Tm and performing an air cooling to form a billet having an average crystal grain size of #1 or more, an overaging thermal treatment step of heating and holding the billet at a temperature range of from Ts to Ts+50° C. and slowly cooling it to a temperature of Ts or lower, and a crystal grain fining forging step of performing another forging at a temperature range of from Ts?150° C. to Ts and performing another air cooling, in which Ts is from 1,030° C. to 1,100° C., and an overall average crystal grain size is #8 or more after the crystal grain fining forging step.

Abstract: The present invention relates to an Ni-based superalloy for hot forging, containing, in terms of % by mass, C: more than 0.001% and less than 0.100%, Cr: 11% or more and less than 19%, Co: more than 5% and less than 25%, Fe: 0.1% or more and less than 4.0%, Mo: more than 2.0% and less than 5.0%, W: more than 1.0% and less than 5.0%, Nb: 2.0% or more and less than 4.0%, Al: more than 3.0% and less than 5.0%, and Ti: more than 1.0% and less than 3.0%, with the balance being unavoidable impurities and Ni, in which the component composition satisfies the following two relationships: 3.5?([Ti]+[Nb])/[Al]×10<6.5 and 9.5?[Al]+[Ti]+[Nb]<13.0.

Abstract: Provided is a maraging steel excellent in fatigue characteristics, including, in terms of % by mass: C: ?0.015%, Ni: from 12.0 to 20.0%, Mo: from 3.0 to 6.0%, Co: from 5.0 to 13.0%, Al: from 0.01 to 0.3%, Ti: from 0.2 to 2.0%, O: ?0.0020%, N: ?0.0020%, and Zr: from 0.001 to 0.02%, with the balance being Fe and unavoidable impurities.

Abstract: The present invention relates to a method for producing a precipitation strengthened Ni-based superalloy material having a predetermined composition, containing a blooming forging step of performing a forging at a temperature range of from Ts to Tm and performing an air cooling to form a billet having an average crystal grain size of #1 or more, an overaging thermal treatment step of heating and holding the billet at a temperature range of from Ts to Ts+50° C. and slowly cooling it to a temperature of Ts or lower, and a crystal grain fining forging step of performing another forging at a temperature range of from Ts?150° C. to Ts and performing another air cooling, in which Ts is from 1,030° C. to 1,100° C., and an overall average crystal grain size is #8 or more after the crystal grain fining forging step.

Abstract: The present invention relates to a method for producing a precipitation strengthened Ni-based superalloy material having a predetermined composition, containing a blooming forging step of performing a forging at a temperature range of from Ts to Tm and performing an air cooling to form a billet having an average crystal grain size of #1 or more, an overaging thermal treatment step of heating and holding the billet at a temperature range of from Ts to Ts+50° C. and slowly cooling it to a temperature of Ts or lower, and a crystal grain fining forging step of performing another forging at a temperature range of from Ts?150° C. to Ts and performing another air cooling, in which Ts is from 1,030° C. to 1,100° C., and an overall average crystal grain size is #8 or more after the crystal grain fining forging step.

Abstract: The object of the present invention is to provide a heat-resistant steel for exhaust valves, having relatively small Ni content, high mechanical characteristics (for example, tensile strength, fatigue strength, wear resistance and hardness) at high temperature, and excellent oxidation resistance. The present invention provides a heat-resistant steel for exhaust valves, which includes: 0.45?C<0.60 mass %, 0.30<N<0.50 mass %, 19.0?Cr<23.0 mass %, 5.0?Ni<9.0 mass %, 8.5?Mn<10.0 mass %, 2.5?Mo<4.0 mass %, 0.01?Si<0.50 mass %, and 0.01?Nb<0.30 mass %, with the balance being Fe and unavoidable impurities, in which the steel satisfies 0.02?Nb/C<0.70 and satisfies 4.5?Mo/C<8.9.

Abstract: The present invention relates to an Ni-based superalloy for hot forging, containing, in terms of % by mass, C: more than 0.001% and less than 0.100%, Cr: 11% or more and less than 19%, Co: more than 5% and less than 25%, Fe: 0.1% or more and less than 4.0%, Mo: more than 2.0% and less than 5.0%, W: more than 1.0% and less than 5.0%, Nb: 0.3% or more and less than 4.0%, Al: more than 3.0% and less than 5.0%, Ti: more than 1.0% and less than 3.0%, and Ta: 0.01% or more and less than 2.0%, with the balance being unavoidable impurities and Ni, in which the component composition satisfies the following two relationships: 3.5?([Ti]+[Nb]+[Ta])/[Al]×10<6.5 and 9.5?[Al]+[Ti]+[Nb]+[Ta]<13.0.

Abstract: The present invention relates to an Ni-based superalloy for hot forging, containing, in terms of % by mass, C: more than 0.001% and less than 0.100%, Cr: 11% or more and less than 19%, Co: more than 5% and less than 25%, Fe: 0.1% or more and less than 4.0%, Mo: more than 2.0% and less than 5.0%, W: more than 1.0% and less than 5.0%, Nb: 2.0% or more and less than 4.0%, Al: more than 3.0% and less than 5.0%, and Ti: more than 1.0% and less than 3.0%, with the balance being unavoidable impurities and Ni, in which the component composition satisfies the following two relationships: 3.5?([Ti]+[Nb])/[Al]×10<6.5 and 9.5?[Al]+[Ti]+[Nb]<13.0.

Abstract: The present invention provides a hot-forgeable Ni-based superalloy excellent in high temperature strength, including, in terms of % by mass: C: more than 0.001% and less than 0.100%, Cr: 11.0% or more and less than 19.0%, Co: 0.5% or more and less than 22.0%, Fe: 0.5% or more and less than 10.0%, Si: less than 0.1%, Mo: more than 2.0% and less than 5.0%, W: more than 1.0% and less than 5.0%, Mo+½W: 2.5% or more and less than 5.5%, S: 0.010% or less, Nb: 0.3% or more and less than 2.0%, Al: more than 3.00% and less than 6.50%, and Ti: 0.20% or more and less than 2.49%, with the balance being Ni and unavoidable impurities, in which (Ti/Al)×10 is 0.2 or more and less than 4.0 in terms of atomic ratio, and in which Al+Ti+Nb is 8.5% or more and less than 13.0% in terms of atomic %.

Abstract: The present invention provides a maraging steel containing: 0.10?C?0.30 mass %, 6.0?Ni?9.4 mass %, 11.0?Co?20.0 mass %, 1.0?Mo?6.0 mass %, 2.0?Cr?6.0 mass %, 0.5?Al?1.3 mass %, and Ti?0.1 mass %, with the balance being Fe and unavoidable impurities, and satisfying 1.00?A?1.08, in which A is 0.95+0.35×[C]?0.0092×[Ni]+0.011×[Co]?0.02×[Cr]?0.001×[Mo], where [C] indicates a content (mass %) of C, [Ni] indicates a content (mass %) of Ni, [Co] indicates a content (mass %) of Co, [Cr] indicates a content (mass %) of Cr, and [Mo] indicates a content (mass %) of Mo, respectively. The maraging steel has a tensile strength of 2,300 MPa or more and is also excellent in the toughness/ductility and fatigue characteristics.

Abstract: The present invention relates to a maraging steel containing, in terms of mass %, 0.20?C?0.35, 9.0?Co?20.0, 1.0?(Mo+W/2)?2.0, 1.0?Cr?4.0, and a certain amount of Ni, with the balance being Fe and inevitable impurities, in which in a case where the contents of V and Nb satisfy V+Nb?0.020 mass %, the amount of Ni is 6.0?Ni?9.4, and in which in a case where the contents of V and Nb satisfy 0.020 mass %<V+Nb?0.60 mass %, the amount of Ni is 6.0?Ni?16.0.

Abstract: The present invention relates to a maraging steel containing, in terms of mass %, 0.10?C?0.35, 9.0?Co?20.0, 1.0?(Mo+W/2)?2.0, 1.0?Cr?4.0, a certain amount of Ni, a certain amount of Al, and V+Nb?0.60, with the balance being Fe and inevitable impurities, in which in a case of V+Nb?0.020, the amount of Ni is 6.0?Ni?9.4 and the amount of Al is 1.4?Al?2.0, and in a case of 0.020<V+Nb?0.60, the amount of Ni is 6.0?Ni?20.0 and the amount of Al is 0.50?Al?2.0.

Abstract: The present invention aim at providing a steel for steam turbine blades which is excellent in terms of strength and toughness. The steel of the present invention has a composition which contains, in terms of % by mass, 0.02-0.10% of C, up to 0.25% of Si, 0.001-0.10% of Mn, up to 0.010% of P, up to 0.010% of S, 8.5-10.0% of Ni, 10.5-13.0% of Cr, 2.0-2.5% of Mo, 0.001-0.010% of N, 1.15-1.50% of Al, less than 0.10% of Cu, up to 0.20% of Ti, and the remainder being incidental impurities and Fe, and which satisfies 6.0?Ni/Al?8.0, 9.0?Nieq?11.0 and 17.0?Creq?19.0, in which Nieq=[Ni]+0.11[Mn]?0.0086([Mn]2)+0.44[Cu]+18.4[N]+24.5[C] Creq=[Cr]+1.21[Mo]+0.48[Si]+2.2[Ti]+2.48[A1].

Abstract: The present invention relates to a high-hardness hardfacing alloy powder, containing: 0.5<C?3.0 mass %, 0.5?Si?5.0 mass %, 10.0?Cr?30.0 mass %, and 16.0<Mo?40.0 mass %, with the balance being Co and unavoidable impurities, wherein a total amount of Mo and Cr satisfies 40.0?Mo+Cr?70.0 mass %. The high-hardness hardfacing alloy powder according to the present invention may further contain at least one element selected from the group consisting of: Ca?0.03 mass %, P?0.03 mass %, Ni?5.0 mass % and Fe?5.0 mass %. The high-hardness hardfacing alloy powder according to the present invention can be employed for build-up welding of a face part of a valve used in various internal combustion engines, automotive engines, steam turbines, heat exchangers, heating furnaces and the like.