The present invention refers to the chemical composition of a wire for hardfacing tool joints of oil drilling pipes, known in the industry as hardbanding. This wire has in its microstructure the formation of graphite to reduce the coefficient of friction and maintain hardness, aiming to protect the drilling pipe and the well casing pipe.

A seal member includes a γ′ precipitation-hardening alloy, in which the γ′ 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.

A seal member includes a γ′ precipitation-hardening alloy, in which the γ′ 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.

An iron-based alloy includes, in weight percent, carbon from about 0.75 to about 2 percent; manganese from about 0.1 to about 1 percent; silicon from about 0.1 to about 1 percent; chromium from about 3 to about 6 percent; nickel up to about 4 percent; vanadium from about 1 to about 3 percent; molybdenum from about 4 to about 7 percent; tungsten from about 4 to about 7 percent; cobalt from about 4 to about 7 percent; boron up to about 0.1 percent; nitrogen from about 0.001 to about 0.15 percent, aluminum from about 0.001 to about 0.6 percent, copper from about 0.1 to about 1 percent, sulfur up to about 0.3 percent, phosphorus up to about 0.3 percent, up to about 5 percent total of tantalum, titanium, hafnium and zirconium; iron from about 65 to about 80 percent; and incidental impurities. The alloy is suitable for use in elevated temperature applications such as in valve seat inserts for combustion engines.

An iron-based alloy includes, in weight percent, carbon from about 0.75 to about 2 percent; manganese from about 0.1 to about 1 percent; silicon from about 0.1 to about 1 percent; chromium from about 3 to about 6 percent; nickel up to about 4 percent; vanadium from about 1 to about 3 percent; molybdenum from about 4 to about 7 percent; tungsten from about 4 to about 7 percent; cobalt from about 4 to about 7 percent; boron up to about 0.1 percent; nitrogen from about 0.001 to about 0.15 percent, aluminum from about 0.001 to about 0.6 percent, copper from about 0.1 to about 1 percent, sulfur up to about 0.3 percent, phosphorus up to about 0.3 percent, up to about 5 percent total of tantalum, titanium, hafnium and zirconium; iron from about 65 to about 80 percent; and incidental impurities. The alloy is suitable for use in elevated temperature applications such as in valve seat inserts for combustion engines.

The stainless steel contains 0.0001 mass % or more and 0.15 mass % or less of C, 0.30 mass % or more and 2.0 mass % or less of Si, 0.1 mass % or more and 15 mass % or less of Mn, 5 mass % or more and 30 mass % or less of Ni, 0.0001 mass % or more and 0.01 mass % or less of S, 16 mass % or more and 25 mass % or less of Cr, 0 mass % or more and 5 mass % or less of Mo, 0 mass % or more and 0.005 mass % or less of Al, 0 mass % or more and 0.0010 mass % or less of Mg, 0.0010 mass % or more and 0.0060 mass % or less of 0, and 0.0001 mass % or more and 0.5 mass % or less of N, and at least includes an inclusion with an equivalent circle diameter of 5 μm or more, having the average composition of 5 mass % or more of MnO, 20 mass % or more of Cr.sub.2O.sub.3+Al.sub.2O.sub.3, 1 mass % or more of Al.sub.2O.sub.3, and 5 mass % or less of Ca0. The number density of the inclusion having the composition is 0.5 inclusions/mm.sup.2 or less.

The stainless steel contains 0.0001 mass % or more and 0.15 mass % or less of C, 0.30 mass % or more and 2.0 mass % or less of Si, 0.1 mass % or more and 15 mass % or less of Mn, 5 mass % or more and 30 mass % or less of Ni, 0.0001 mass % or more and 0.01 mass % or less of S, 16 mass % or more and 25 mass % or less of Cr, 0 mass % or more and 5 mass % or less of Mo, 0 mass % or more and 0.005 mass % or less of Al, 0 mass % or more and 0.0010 mass % or less of Mg, 0.0010 mass % or more and 0.0060 mass % or less of 0, and 0.0001 mass % or more and 0.5 mass % or less of N, and at least includes an inclusion with an equivalent circle diameter of 5 μm or more, having the average composition of 5 mass % or more of MnO, 20 mass % or more of Cr.sub.2O.sub.3+Al.sub.2O.sub.3, 1 mass % or more of Al.sub.2O.sub.3, and 5 mass % or less of Ca0. The number density of the inclusion having the composition is 0.5 inclusions/mm.sup.2 or less.

The martensitic stainless steel seamless pipe according to the present disclosure has a chemical composition containing, in mass %, C: 0.001 to 0.050%, Si: 0.05 to 1.00%, Mn: 0.05 to 2.00%, P: 0.030% or less, S: 0.0100% or less, Al: 0.005 to 0.100%, N: 0.020% or less, Ni: 1.00 to 9.00%, Cr: 8.00 to 16.00%, Cu: 3.50% or less, Mo: 1.00 to 5.00%, W: 0.01 to 0.30%, V: 0.010 to 1.500%, and Co: 0.001 to 0.500%, and also containing one or more elements selected from the group consisting of Ca, Mg, B, and rare earth metal, with the balance being Fe and impurities, and has a yield strength of 655 MPa or more.

The martensitic stainless steel material according to the present disclosure consists of C: less than 0.030%, Si: 1.00% or less, Mn: 0.05 to 2.00%, Cr: 11.50 to 14.00%, Ni: 5.00 to 7.50%, Mo: 1.10 to 3.50%, Cu: 0.50 to 3.50%, Co: 0.01 to 0.30%, Al: 0.001 to 0.100%, N: 0.001 to 0.100%, and the balance: Fe and impurities. The microstructure is composed of retained austenite in an amount of 0 to 15 vol%, and ferrite in an amount of 0 to 10 vol%, with the balance being martensite. The yield strength is 862 MPa or more, and a number density of Cu precipitates is 3.0 x 10.sup.21 to 50.0 x 10.sup.21 /m.sup.3.

The martensitic stainless steel material according to the present disclosure consists of C: less than 0.030%, Si: 1.00% or less, Mn: 0.05 to 2.00%, Cr: 11.50 to 14.00%, Ni: 5.00 to 7.50%, Mo: 1.10 to 3.50%, Cu: 0.50 to 3.50%, Co: 0.01 to 0.30%, Al: 0.001 to 0.100%, N: 0.001 to 0.100%, and the balance: Fe and impurities. The microstructure is composed of retained austenite in an amount of 0 to 15 vol%, and ferrite in an amount of 0 to 10 vol%, with the balance being martensite. The yield strength is 862 MPa or more, and a number density of Cu precipitates is 3.0 x 10.sup.21 to 50.0 x 10.sup.21 /m.sup.3.