Abstract: A low cost, economical and less resource-consuming heat resistant alloy for use as material of engine valve is disclosed, while the alloy has excellent mechanical properties at high temperature and excellent toughness after heated for a long time that conventional heat resistant alloys have not had. The alloy consists essentially of, in mass percent, C of 0.01 to 0.15%, Si of 0.01 to 0.8%, Mn of 0.01 to 0.8, Cr of 14 to 17%, Mo of more than 3.0% but equal to or less than 5.0%, Al of 1.6 to 2.5%, Ti of 1.5 to 3.0%, Nb or Nb+Ta of 0.5 to 2.0%, Ni of 50 to 60%, B of 0.001 to 0.015%, at least one of Mg of 0.001 to 0.015% and Ca of 0.001 to 0.015%, and the balance being Fe, wherein value A defined by 0.293[Ni]?0.513[Cr]?1.814[Mo] is 2.0 to 5.8, value B defined by [Al]/([Al]+[Ti]+[Nb]+[Ta]) is 0.45 to 0.65, and value C defined by [Al]+[Ti]+[Nb]+[Ta] is 6.2 to 7.6, wherein brackets mean atomic % of each element in the alloy.

Abstract: An exhaust valve for automobile engines, which is durable at such a high temperature as 900° C., and exhibits high fatigue strength and high oxidation resistance is disclosed. The exhaust valve is made of a Ni-based alloy consisting essentially of, by weight %. C: 0.01-0.15%, Si: up to 2.0%, Mn: up to 1.0%, P: up to 0.02%, S: up to 0.01%, Co: 0.1-15%, Cr: 15-25%, one or two of Mo: 0.1-10% and W: 0.1-5% in such amount that Mo+½ W; 3-10%, Al: 1.0-3.0%, Ti: 2.0-3.5%, provided that, by atomic %, Al+Ti: 6.3-8.5% and Ti/Al ratio: 0.4-0.8, and further, by weight %, B: 0.001-0.01%, Fe: up to 3%, and the balance of Ni and inevitable impurities by hot forging to give the form of an exhaust valve and subjecting to solid solution at 1000-1200° C. and aging at 700-950° C.

Abstract: A low cost, economical and less resource-consuming heat resistant alloy for use as material of engine valve is disclosed, while the alloy has excellent mechanical properties at high temperature and excellent toughness after heated for a long time that conventional heat resistant alloys have not had. The alloy consists essentially of, in mass percent, C of 0.01 to 0.15%, Si of 0.01 to 0.8%, Mn of 0.01 to 0.8, Cr of 14 to 17%, Mo of more than 3.0% but equal to or less than 5.0%, Al of 1.6 to 2.5%, Ti of 1.5 to 3.0%, Nb or Nb+Ta of 0.5 to 2.0%, Ni of 50 to 60%, B of 0.001 to 0.015%, at least one of Mg of 0.001 to 0.015% and Ca of 0.001 to 0.015%, and the balance being Fe, wherein value A defined by 0.293[Ni]?0.513[Cr]?1.814[Mo] is 2.0 to 5.8, value B defined by [Al]/([Al]+[Ti]+[Nb]+[Ta]) is 0.45 to 0.65, and value C defined by [Al]+[Ti]+[Nb]+[Ta] is 6.2 to 7.6, wherein brackets mean atomic % of each element in the alloy.

Abstract: Disclosed is a heat resistant alloy for exhaust valves, in which Ni-content is constrained to at maximum 62% due to the material cost, while the strength is maintained equal or better to those of conventional alloys and the strength is kept even after use at high temperature for a long period of time. The alloy has the composition essentially consisting of, by weight %, C: 0.01-0.2%, Si: up to 1.0%, Mn: up to 1.0%, P: up to 0.02%, S: up to 0.01%, Ni: 30-62%, Cr: 13-20%, W: 0.01-3.00%, Mo: up to 2.0%, provided that Mo+0.5 W: 1.0-2.5%, Al: 0.7% or higher and less than 1.6%, Ti: 1.5-3.0%, Nb: 0.5-1.5%, B: 0.001-0.010%, provided that [% Ti]/[% Al]: 1.6 or more to less than 2.0, and the balance of Fe and inevitable impurities. Optional components are I) at least one of Mg: 0.001-0.030%, Ca: 0.001-0.030% and Zr: 0.001-0.100%, II) Cu: up to 2.0%, and III) V: 0.005-1.00%.

Abstract: A secondary hardening type high temperature wear-resistant sintered alloy body comprising 0.4 to 15 wt. % of at least one species of metal carbide forming element which is selected from the group consisting of W, Mo, V, Ti, Nb, Ta and B; 5 to 35 wt. % of at least one species of austenite forming element which is selected from the group consisting of Ni, Co, Cu, and Cr; 0.2 to 1.2 wt. % of C; and 0.04 to 0.2 wt. % of Al consisting essentially the remainder of Fe, wherein the alloy body contains an austenite phase which is capable of martensitic transformation.

Abstract: A secondary hardening type high temperature wear-resistant sintered alloy body comprising 0.4 to 15 wt. % of at least one species of metal carbide forming element which is selected from the group consisting of W, Mo, V, Ti, Nb, Ta and B; 5 to 35 wt. % of at least one species of austenite forming element which is selected from the group consisting of Ni, Co, Cu, and Cr; 0.2 to 1.2 wt. % of C; and 0.04 to 0.2 wt % of the remainder consisting essentially of Fe wherein the alloy body contains an austenite phase which is capable of martensitic transformation.