Abstract: The present invention provides a method for producing a low thermal expansion Ni-base superalloy, which includes: preparing an alloy including, by weight %, C: 0.15% or less, Si: 1% or less, Mn: 1% or less, Cr: 5 to 20%, at least one of Mo, W and Re, which satisfy the relationship Mo+½(W+Re): 17 to 27%, Al: 0.1 to 2%, Ti: 0.1 to 2%, Nb and Ta, which satisfy the relationship Nb+Ta/2: 1.5% or less, Fe: 10% or less, Co: 5% or less, B: 0.001 to 0.02%, Zr: 0.001 to 0.2%, a reminder of Ni and inevitable components; subjecting the alloy to a solution heat treatment under the condition of at a temperature of 1000 to 1200° C.; subjecting the alloy to either a carbide stabilizing treatment for making aggregated carbides on grain boundaries and stabilizing the carbides under the conditions of at a temperature of not less than 850° C. and less than 1000° C.

Abstract: The present invention relates to a Ni base alloy having sufficient strength at high temperatures and high corrosion resistance at high temperatures in a high-temperature composite corrosive environment in which chlorination or sulfidation occurs simultaneously with high-temperature oxidation, without excessive cooling or surface protection. According to the present invention, a Ni base alloy having high-temperature strength and corrosion resistance includes Cr in a range of from 25 to 40 weight %, Al in a range of from 1.5 to 2.5 weight %, C in a range of from 0.1 to 0.5 weight %, W of 15 weight % or less, Mn of 2.0 weight % or less, Si in a range of from 0.3 to 6 weight %, Fe of 5% or less, and Ni of rest except inevitable impurities. When strength at high temperatures is allowed to be small, W is in a range of from 0 to 8%, and Si is in a range of from 0.3 to 1% or from 1 to 6%. In order to enhance strength at high temperatures, W is in a range of from 8 to 15, and Si is in a range of from 0.

Abstract: A Ni-base alloy which has excellent resistance to permanent set at high temperature and which can be produced at low cost, a heat-resistant spring made of the Ni-base alloy, and a process for producing the spring. The Ni-base alloy of the present invention consists of 0.01 to 0.15 mass % of C, 2.0 mass % or less of Si, 2.5 mass % or less of Mn, 12 to 25 mass % of Cr, 5.0 mass % or less of Mo and/or 5.0 mass % or less of W on condition that Mo+W/2 does not exceed 5.0 mass % or less, 1.5 to 3.5 mass % of Ti, 0.7 to 2.5 mass % of Al, 20 mass % or less of Fe, and the balance of Ni and unavoidable impurities. The ratio of Ti/Al in terms of atomic percentage ranges from 0.6 to 1.5 and the total content of Ti and Al ranges from 4.0 to 8.5 atomic %.

Abstract: Disclosed is a nickel-base super heat resistant cast alloy, from which turbine wheels of automobile engines can be manufacture by casting. The alloy consists essentially of, by weight %, C: 0.02-0.50%, Si: up to 1.0%, Mn: up to 1.0%, Cr: 4.0-10.0%, Al: 2.0-8.0%, Co: up to 15.0%, W: 8.0-16.0%, Ta: 2.0-8.0%, Ti: up to 3.0%, Zr: 0.001-0.200% and B: 0.005-0.300% and the balance of Ni and inevitable impurities, provided that, [%Al]+[%Ti]+[%Ta], by atomic %, amounts to 12.0-15.5%, that it contains &ggr;/&ggr;′-eutectoid of, by area percentage, 1-15%, that it contains carbides of, by area percentage, 1-10%, and that the “M-value” determined by the alloy composition is in the range of 93-98. The turbine wheels withstand temperature increase of exhaust gas.

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 free-cutting Ni-base heat-resistant alloy excellent in the high-temperature strength and corrosion resistance was proposed. The alloy contains Ni as a major component, 0.01 to 0.3 wt % of C and 14 to 35 wt % of Cr, and further contains at least one element selected from Ti, Zr and Hf in a total amount of 0.1 to 6 wt %, and S in an amount of 0.015 to 0.5 wt %. The alloy has dispersed in the matrix thereof a machinability improving compound phase, where such phase contains any one of Ti, Zr and Hf as a major constituent of the metal elements, essentially contains C and either S or Se as a binding component for such metal elements. The alloy also satisfies the relations of WTi+0.53WZr+0.27WHf>2WC+0.75WS and WC>0.37WS, where WTi represents Ti content (wt %), WZr represents Zr content (wt %), WHf represents Hf content (wt %), WC represents C content (wt %) and WS represents S content (wt %).

Abstract: The present invention relates to a Ni base alloy having sufficient strength at high temperatures and high corrosion resistance at high temperatures in a high-temperature composite corrosive environment in which chlorination or sulfidation occurs simultaneously with high-temperature oxidation, without excessive cooling or surface protection. According to the present invention, a Ni base alloy having high-temperature strength and corrosion resistance includes Cr in a range of from 25 to 40 weight %, Al in a range of from 1.5 to 2.5 weight %, C in a range of from 0.1 to 0.5 weight %, W of 15 weight % or less, Mn of 2.0 weight % or less, Si in a range of from 0.3 to 6 weight %, Fe of 5 % or less, and Ni of rest except inevitable impurities. When strength at high temperatures is allowed to be small, W is in a range of from 0 to 8 %, and Si is in a range of from 0.3 to 1 % or from 1 to 6 %. In order to enhance strength at high temperatures, W is in a range of from 8 to 15, and Si is in a range of from 0.

Abstract: A precipitation hardened Co—Ni based heat-resistant alloy is composed of, all by weight, not more than 0.05% of C; not more than 0.5% of Si; not more than 1.0% of Mn; 25 to 45% of Ni; 13 to 22% of Cr; 10 to 18% of Mo or 10 to 18% of Mo+½W; 0.1 to 5.0% of Nb; 0.1 to 5.0% of Fe; and further at least one kind of 0.007 to 0.10% of REM; 0.001 to 0.010% of B; 0.0007 to 0.010% of Mg and 0.001 to 0.20% of Zr; the balance of substantially Co and inevitable impurities, and Co3Mo or Co7Mo6 is precipitated in boundaries between a fine twin structure and a parent phase.

Abstract: A Co—Ni base heat-resistant alloy is composed of, all by weight: not more than 0.05 mass % of C; not more than 0.5 mass % of Si; not more than 1.0 mass % of Mn; 25 to 45 mass % of Ni; 13 to less than 18 mass % of Cr; 7 to 20 mass % of Mo+½W of one kind or more of Mo and W; 0.1 to 3.0 mass % of Ti; 0.1 to 5.0 mass % of Nb; 0.1 to 5.0 mass % of Fe, with the balance of substantially Co and inevitable impurities.

Abstract: ABSTRACT OF DISCLOSURE Disclosed is a heat resistant cast steel having not only good heat resistance but also good thermal fatigue resistance, which is suitable as the material for engine parts, particularly, such as exhaust gas manifold and turbo-housing, which are repeatedly exposed to such a high temperature as 900° C. or higher. The heat resistant cast steel comprises, by weight percent, C: 0.2-1.0%, Ni: 8.0-45.0%, Cr: 15.0-30.0%, W: up to 10% and Nb: 0.5-3.0%, provided that [%C]-0.13[%Nb]: 0.05-0.95%, the balance being Fe and inevitable impurities, and the cast structure contains dispersed therein, by atomic percent, MC-type carbides: 0.5-3.0% and M23C6-type carbides: 0.5-10.0%. The matrix of the steel is an austenitic phase mainly composed of Fe—Ni—Cr and the steel has the mean coefficient of thermal expansion in the range from room temperature to 1050° C. up to 20.0×10−4 and a tensile strength in the temperature range up to 1050° C.

Abstract: A Ni-base alloy which has excellent resistance to permanent set at high temperature and which can be produced at low cost, a heat-resistant spring made of the Ni-base alloy, and a process for producing the spring. The Ni-base alloy of the present invention consists of 0.01 to 0.15 mass % of C, 2.0 mass % or less of Si, 2.5 mass % or less of Mn, 12 to 25 mass % of Cr, 5.0 mass % or less of Mo and/or 5.0 mass % or less of W on condition that Mo+W/2 does not exceed 5.0 mass % or less, 1.5 to 3.5 mass % of Ti, 0.7 to 2.5 mass % of Al, 20 mass % or less of Fe, and the balance of Ni and unavoidable impurities. The ratio of Ti/Al in terms of atomic percentage ranges from 0.6 to 1.5 and the total content of Ti and Al ranges from 4.0 to 8.5 atomic %.

Abstract: A free-cutting Ni-base heat-resistant alloy excellent in the high-temperature strength and corrosion resistance was proposed. The alloy contains Ni as a major component, 0.01 to 0.3 wt % of C and 14 to 35 wt % of Cr, and further contains at least one element selected from Ti, Zr and Hf in a total amount of 0.1 to 6 wt %, and S in an amount of 0.015 to 0.5 wt %. The alloy has dispersed in the matrix thereof a machinability improving compound phase, where such phase contains any one of Ti, Zr and Hf as a major constituent of the metal elements, essentially contains C and either S or Se as a binding component for such metal elements. The alloy also satisfies the relations of WTi+0.53WZr+0.27WHf>2WC+0.75WS and WC>0.37WS, where WTi represents Ti content (wt %), WZr represents Zr content (wt %), WHf represents Hf content (wt %), WC represents C content (wt %) and WS represents S content (wt %).

Abstract: A method for producing an exhaust valve is described, comprising subjecting a raw material of a specified heat resisting alloy to solid solution treatment; forming a head portion of the exhaust valve from the solution treated raw material through cold working or warm working; joining a stem portion made of martensitic heat resisting steel to said head portion of the exhaust valve; and subjecting the head portion and the stem portion joined with each other to aging treatment.

Abstract: A martensitic heat resisting steel having improved heat resistance, which consists by weight percentage of 0.35%.ltoreq.C.ltoreq.0.60%, 1.0%.ltoreq.Si.ltoreq.2.5%, 0.1%.ltoreq.Mn<1.5%, 7.5%.ltoreq.Cr.ltoreq.13.0%, one or both of 1.0%.ltoreq.Mo.ltoreq.3.0% and 1.0%.ltoreq.W.ltoreq.3.0% so that 1.5%.ltoreq.(Mo+0.5W).ltoreq.3.0%, optionally 0.1%.ltoreq.Nb+Ta.ltoreq.1.0%, 0.1%.ltoreq.V.ltoreq.1.0% and S.ltoreq.0.1%, and the remainder is substantially Fe.

Abstract: A heat resisting alloy for use in exhaust valves low in price and excellent in the cold workability and possible to be formed into valve shapes through the cold or warm working, which consists by weight percentage of C: 0.01.about.0.1%, Si.ltoreq.2%, Mn.ltoreq.2%, Cr: 12.about.25%, Nb+Ta: 0.2.about.2.0%, Ti.ltoreq.3.5%, Al: 0.5.about.3.0%, Ni: 25.about.45%, Cu: 0.1.about.5.0%, optionally at least one element selected from W.ltoreq.3%, Mo.ltoreq.3%, and V.ltoreq.1% with (1/2W+Mo+V).ltoreq.3%, Co.ltoreq.5% with Ni+Co: 25.about.45%, Ca+Mg: 0.001.about.0.01%, one or both of B.ltoreq.0.01% and Zr: 0.001.about.0.1%, and the balance of Fe and incidental impurities.