Alloy compositions and articles formed of such compositions

Abstract

To provide iron-based alloys with improved oxidation resistance, reduced retained delta ferrite, and / or improved rupture ductility.SOLUTION: The present invention provides a composition comprising: from about 10 wt.% to about 11 wt.% of chromium; no more than about 0.030 wt.% of aluminum; from about 0.08 wt.% to about 0.20 wt.% of carbon; from about 0.10 wt.% to about 0.60 wt.% of silicon; from about 0.05 wt.% to about 0.40 wt.% of vanadium; from about 0.01 wt.% to about 0.10 wt.% of titanium; no more than about 5 wt.% of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and the balance iron and residual elements.SELECTED DRAWING: Figure 1D

Description

[Background technology]

[0001] The field of the disclosure relates generally to compositions, and more specifically to alloy compositions and articles formed therewith, which have broad applicability in applications requiring alloys with improved oxidation resistance, reduced residual delta ferrite, and / or improved fracture ductility.

[0002] Iron-base alloys are commonly used in cast and wrought steel products. However, conventional iron-base alloys exhibit excessive oxidation and poor long-term fracture properties (such as delta ferrite and fracture ductility). While some iron-base alloys have improved one or two of these properties, no iron-base alloy maximizes all of these properties. This is especially true in the power generation industry where iron-base alloys operate at ever higher temperatures and pressures to increase the efficiency of various components, without including structural integrity.

[0003] However, chemical modifications aimed at improving oxidation, such as increasing chromium content, can increase the potential for delta ferrite and therefore reduce high-temperature rupture properties. Addition of tungsten can improve rupture performance, but increases the high-temperature oxidation rate. The use of aluminum to deoxidize hot metal has also been found to reduce the rupture ductility of iron-base alloys.

[0004] Thus, there is a need for iron-base alloys having improved oxidation resistance, reduced retained delta ferrite, and improved rupture ductility. Summary of the Invention

[0005] In one embodiment, a composition is provided that includes about 10% to about 11% by weight chromium, about 0.030% or less by weight aluminum, about 0.08% to about 0.20% by weight carbon, about 0.10% to about 0.60% by weight silicon, about 0.05% to about 0.40% by weight vanadium, about 0.01% to about 0.10% by weight titanium, 5% or less by weight manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt, with the balance being iron and remaining elements.

[0006] In another aspect, an article is provided comprising a composition comprising about 10% to about 11% by weight chromium, about 0.030% or less by weight aluminum, about 0.08% to about 0.20% by weight carbon, about 0.10% to about 0.60% by weight silicon, about 0.05% to about 0.40% by weight vanadium, about 0.01% to about 0.10% by weight titanium, up to 5% by weight manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt, with the balance being iron and remaining elements. [Brief description of the drawings]

[0007] These and other features, aspects, and advantages of the present disclosure can be better understood by reference to the following detailed description taken in conjunction with the accompanying drawings. These and other features of the present disclosure can be better understood by reference to the following detailed description taken in conjunction with the accompanying drawings. [Figure 1A] FIG. 13 shows exemplary simulated matrix phase results for comparative composition CE1. [Figure 1B] FIG. 13 shows exemplary simulated matrix phase results for comparative composition CE2. [Figure 1C] FIG. 13 shows exemplary simulated matrix phase results for comparative composition CE3. [Figure 1D] FIG. 1 shows exemplary simulated matrix phase results for composition IE1 of the present invention. [Figure 2A]FIG. 13 shows exemplary results of simulated hardenability for comparative composition CE1. [Figure 2B] FIG. 13 shows exemplary results of simulated hardenability for comparative composition CE2. [Figure 2C] FIG. 13 shows exemplary results of simulated hardenability for comparative composition CE3. [Figure 2D] FIG. 1 shows exemplary results of simulated hardenability for composition IE1 of the present invention. [Figure 3A] FIG. 1 shows exemplary results of simulated YS tempering for comparative and inventive compositions. [Figure 3B] FIG. 1 shows exemplary results of simulated UTS tempering for comparative and inventive compositions. [Figure 4] FIG. 1 shows exemplary simulated short term rupture results for comparative and inventive compositions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] It has now been discovered that compositions according to the present disclosure can be used in wrought and cast alloys. The compositions contain modified elemental contents of Cr, Al, Si, C, Al, Ti and V compared to other alloy compositions. The Cr content is particularly prominent. The compositions exhibit improved oxidation resistance, reduced retained delta ferrite and improved fracture ductility. The compositions according to the present disclosure can be widely applied in applications requiring alloys with improved oxidation resistance, reduced retained delta ferrite and / or improved fracture ductility.

[0009] It has now been discovered that, in particular, increasing the chromium content from 8.5% to 9.5% and up to 11% significantly reduces the formation of inner and outer oxide layers in creep strength enhanced ferritic (CSEF) forged steel products. Increasing the chromium content also increases the chromium equivalent (CE) and can result in residual delta ferrite. Delta ferrite is a low creep resistance phase that leads to reduced long term rupture strength. Therefore, the amount of residual delta ferrite in the final product is typically less than 5%. The composition of the present disclosure optimizes the chemical composition of cast 10-11% chromium alloys to achieve improved oxidation performance while reducing the risk of premature fracture due to residual delta ferrite and insufficient rupture ductility.

[0010] The embodiments described herein overcome at least some of the shortcomings of known iron-base alloys. Exemplary embodiments described herein include a composition comprising about 10% to about 11% by weight chromium, about 0.030% or less by weight aluminum, about 0.08% to about 0.20% by weight carbon, about 0.10% to about 0.60% by weight silicon, about 0.05% to about 0.40% by weight vanadium, about 0.01% to about 0.10% by weight titanium, up to 5% by weight manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt, with the balance being iron and remaining elements.

[0011] In some embodiments, the composition may include chromium (Cr) in any suitable amount conducive to the compositions described herein. In some embodiments, the composition includes Cr. In some embodiments, the composition includes about 10% to about 11% by weight chromium. In some embodiments, the composition includes about 10.25% to about 11% by weight chromium.

[0012] In some embodiments, the composition comprises about 10.0 wt% or more Cr, about 10.1 wt% or more Cr, about 10.2 wt% or more Cr, about 10.3 wt% or more Cr, about 10.4 wt% or more Cr, about 10.5 wt% or more Cr, about 10.6 wt% or more Cr, about 10.7 wt% or more Cr, about 10.8 wt% or more Cr, or about 10.9 wt% or more Cr. In some embodiments, the composition comprises about 10.1 wt% or less Cr, about 10.2 wt% or less Cr, about 10.3 wt% or less Cr, about 10.4 wt% or less Cr, about 10.5 wt% or less Cr, about 10.6 wt% or less Cr, about 10.7 wt% or less Cr, about 10.8 wt% or less Cr, about 10.9 wt% or less Cr, or about 11.0 wt% or less Cr.

[0013] In some embodiments, the composition may include aluminum (Al) in an amount that is conducive to the compositions described herein. In some embodiments, the composition does not include aluminum. In some embodiments, the composition includes no more than 0.030% by weight aluminum. In some embodiments, the composition includes no more than 0.015% by weight aluminum.

[0014] In some embodiments, the composition comprises about 0.005% Al or more, about 0.010% Al or more, about 0.015% Al or more, about 0.020% Al or more, or about 0.025% Al or more, by weight. In some embodiments, the composition comprises about 0.010% Al or less, about 0.015% Al or less, about 0.020% Al or less, about 0.025% Al or less, by weight.

[0015] In some embodiments, the composition may contain any suitable amount of carbon (C) conducive to the compositions described herein. In some embodiments, the composition contains about 0.08% to about 0.20% by weight of carbon. In some embodiments, the composition contains about 0.12% to about 0.18% by weight of carbon.

[0016] In some embodiments, the composition comprises about 0.08% or more carbon, about 0.09% or more carbon, about 0.10% or more carbon, about 0.11% or more carbon, about 0.12% or more carbon, about 0.13% or more carbon, about 0.14% or more carbon, about 0.15% or more carbon, about 0.16% or more carbon, about 0.17% or more carbon, about 0.18% or more carbon, or about 0.19% or more carbon by weight. In some embodiments, the composition comprises about 0.09% or less by weight carbon, about 0.10% or less by weight carbon, about 0.11% or less by weight carbon, about 0.12% or less by weight carbon, about 0.13% or less by weight carbon, about 0.14% or less by weight carbon, about 0.15% or less by weight carbon, about 0.16% or less by weight carbon, about 0.17% or less by weight carbon, about 0.18% or less by weight carbon, about 0.19% or less by weight carbon, or about 0.20% or less by weight carbon.

[0017] In some embodiments, the composition may include any suitable amount of silicon (Si) conducive to the compositions described herein. In some embodiments, the composition includes about 0.10% to about 0.60% by weight of silicon. In some embodiments, the composition includes about 0.20% to about 0.40% by weight of silicon.

[0018] In some embodiments, the composition comprises about 0.10 wt% or more Si, about 0.15 wt% or more Si, about 0.20 wt% or more Si, about 0.25 wt% or more Si, about 0.30 wt% or more Si, about 0.35 wt% or more Si, about 0.40 wt% or more Si, about 0.45 wt% or more Si, about 0.50 wt% or more Si, or about 0.55 wt% or more Si. In some embodiments, the composition comprises about 0.15 wt% or less Si, about 0.20 wt% or less Si, about 0.25 wt% or less Si, about 0.30 wt% or less Si, about 0.35 wt% or less Si, about 0.40 wt% or less Si, about 0.45 wt% or less Si, about 0.50 wt% or less Si, about 0.55 wt% or less Si, or about 0.60 wt% or less Si.

[0019] In some embodiments, the composition may include any suitable amount of vanadium (V) conducive to the compositions described herein. In some embodiments, the composition includes from about 0.05% to about 0.40% by weight of vanadium. In some embodiments, the composition includes from about 0.10% to about 0.30% by weight of vanadium.

[0020] In some embodiments, the composition comprises about 0.05 wt% or more V, 0.10 wt% or more V, about 0.15 wt% or more V, about 0.20 wt% or more V, about 0.25 wt% or more V, about 0.30 wt% or more V, or about 0.35 wt% or more V. In some embodiments, the composition comprises about 0.10 wt% or less V, about 0.15 wt% or less V, about 0.20 wt% or less V, about 0.25 wt% or less V, about 0.30 wt% or less V, about 0.35 wt% or less V, or about 0.40 wt% or less V.

[0021] In some embodiments, the composition may include titanium (Ti) in any suitable amount conducive to the compositions described herein. In some embodiments, the composition includes about 0.01% to about 0.10% by weight of titanium. In some embodiments, the composition includes about 0.015% to about 0.060% by weight of titanium.

[0022] In some embodiments, the composition comprises about 0.010 wt% or more Ti, about 0.015 wt% or more Ti, about 0.020 wt% or more Ti, about 0.025 wt% or more Ti, about 0.030 wt% or more Ti, about 0.035 wt% or more Ti, about 0.040 wt% or more Ti, about 0.045 wt% or more Ti, about 0.050 wt% or more Ti, or about 0.055 wt% or more Ti. In some embodiments, the composition comprises about 0.015 wt% or less Ti, about 0.020 wt% or less Ti, about 0.025 wt% or less Ti, about 0.030 wt% or less Ti, about 0.035 wt% or less Ti, about 0.040 wt% or less Ti, about 0.045 wt% or less Ti, about 0.050 wt% or less Ti, about 0.055 wt% or less Ti, or about 0.060 wt% or less Ti.

[0023] In some embodiments, the composition may include manganese (Mn) in any suitable amount conducive to the compositions described herein. In some embodiments, the composition includes about 0.10% to about 1.0% by weight of manganese. In some embodiments, the composition includes about 0.50% to about 1.0% by weight of manganese.

[0024] In some embodiments, the composition comprises about 0.10 wt% or more Mn, about 0.15 wt% or more Mn, about 0.20 wt% or more Mn, about 0.25 wt% or more Mn, about 0.30 wt% or more Mn, about 0.35 wt% or more Mn, about 0.40 wt% or more Mn, about 0.45 wt% or more Mn, about 0.50 wt% or more Mn, about 0.55 wt% or more Mn, about 0.60 wt% or more Mn, about 0.65 wt% or more Mn, about 0.70 wt% or more Mn, about 0.75 wt% or more Mn, about 0.80 wt% or more Mn, about 0.85 wt% or more Mn, about 0.90 wt% or more Mn, or about 0.95 wt% or more Mn. In some embodiments, the composition comprises about 0.15 wt% or less Mn, about 0.20 wt% or less Mn, about 0.25 wt% or less Mn, about 0.30 wt% or less Mn, about 0.35 wt% or less Mn, about 0.40 wt% or less Mn, about 0.45 wt% or less Mn, about 0.50 wt% or less Mn, about 0.55 wt% or less Mn, about 0.60 wt% or less Mn, about 0.65 wt% or less Mn, about 0.70 wt% or less Mn, about 0.75 wt% or less Mn, about 0.80 wt% or less Mn, about 0.85 wt% or less Mn, about 0.90 wt% or less Mn, about 0.95 wt% or less Mn, or about 1.0 wt% or less Mn.

[0025] In some embodiments, the composition may include any suitable amount of molybdenum (Mo) conducive to the compositions described herein. In some embodiments, the composition includes about 0.10% to about 1.0% by weight of molybdenum. In some embodiments, the composition includes about 0.50% to about 1.0% by weight of molybdenum.

[0026] In some embodiments, the composition comprises about 0.40 wt% Mo or more, about 0.45 wt% Mo or more, about 0.50 wt% Mo or more, about 0.55 wt% Mo or more, about 0.60 wt% Mo or more, about 0.65 wt% Mo or more, about 0.70 wt% Mo or more, about 0.75 wt% Mo or more, about 0.80 wt% Mo or more, about 0.85 wt% Mo or more, about 0.90 wt% Mo or more, about 0.95 wt% Mo or more, about 1.0 wt% Mo or more, about 1.05 wt% Mo or more, about 1.1 wt% Mo or more, or about 1.15 wt% Mo or more. In some embodiments, the composition comprises up to about 0.45 wt% Mo, up to about 0.50 wt% Mo, up to about 0.55 wt% Mo, up to about 0.60 wt% Mo, up to about 0.65 wt% Mo, up to about 0.70 wt% Mo, up to about 0.75 wt% Mo, up to about 0.80 wt% Mo, up to about 0.85 wt% Mo, up to about 0.90 wt% Mo, up to about 0.95 wt% Mo, up to about 1.0 wt% Mo, up to about 1.05 wt% Mo, up to about 1.1 wt% Mo, up to about 1.15 wt% Mo, or up to about 1.2 wt% Mo.

[0027] In some embodiments, the composition may include any suitable amount of nickel (Ni) conducive to the compositions described herein. In some embodiments, the composition includes about 0.10% to about 1.0% by weight of nickel. In some embodiments, the composition includes about 0.50% to about 1.0% by weight of nickel.

[0028] In some embodiments, the composition comprises about 0.10 wt% or more Ni, about 0.15 wt% or more Ni, about 0.20 wt% or more Ni, about 0.25 wt% or more Ni, about 0.30 wt% or more Ni, about 0.35 wt% or more Ni, about 0.40 wt% or more Ni, about 0.45 wt% or more Ni, about 0.50 wt% or more Ni, about 0.55 wt% or more Ni, about 0.60 wt% or more Ni, about 0.65 wt% or more Ni, about 0.70 wt% or more Ni, about 0.75 wt% or more Ni, about 0.80 wt% or more Ni, about 0.85 wt% or more Ni, about 0.90 wt% or more Ni, or about 0.95 wt% or more Ni. In some embodiments, the composition comprises about 0.15 wt% or less Ni, about 0.20 wt% or less Ni, about 0.25 wt% or less Ni, about 0.30 wt% or less Ni, about 0.35 wt% or less Ni, about 0.40 wt% or less Ni, about 0.45 wt% or less Ni, about 0.50 wt% or less Ni, about 0.55 wt% or less Ni, about 0.60 wt% or less Ni, about 0.65 wt% or less Ni, about 0.70 wt% or less Ni, about 0.75 wt% or less Ni, about 0.80 wt% or less Ni, about 0.85 wt% or less Ni, about 0.90 wt% or less Ni, about 0.95 wt% or less Ni, or about 1.0 wt% or less Ni.

[0029] In some embodiments, the composition may include any suitable amount of niobium (Nb) conducive to the compositions described herein. In some embodiments, the composition includes about 0.01% to about 0.12% by weight of niobium. In some embodiments, the composition includes about 0.05% to about 0.10% by weight of niobium.

[0030] In some embodiments, the composition comprises about 0.01 wt% or more Nb, about 0.02 wt% or more Nb, about 0.03 wt% or more Nb, about 0.04 wt% or more Nb, about 0.05 wt% or more Nb, about 0.06 wt% or more Nb, about 0.07 wt% or more Nb, about 0.08 wt% or more Nb, about 0.09 wt% or more Nb, about 0.10 wt% or more Nb, or about 0.11 wt% or more Nb. In some embodiments, the composition comprises about 0.02 wt% or less Nb, about 0.03 wt% or less Nb, about 0.04 wt% or less Nb, about 0.05 wt% or less Nb, about 0.06 wt% or less Nb, about 0.07 wt% or less Nb, about 0.08 wt% or less Nb, about 0.09 wt% or less Nb, about 0.010 wt% or less Nb, about 0.11 wt% or less Nb, or about 0.12 wt% or less Nb.

[0031] In some embodiments, the compositions may contain any suitable amount of nitrogen (N) conducive to the compositions described herein. In some embodiments, the compositions contain about 0.01% to about 0.10% by weight of nitrogen. In some embodiments, the compositions contain about 0.03% to about 0.07% by weight of nitrogen.

[0032] In some embodiments, the composition comprises about 0.01 wt% or more N, about 0.02 wt% or more N, about 0.03 wt% or more N, about 0.04 wt% or more N, about 0.05 wt% or more N, about 0.06 wt% or more N, about 0.07 wt% or more N, about 0.08 wt% or more N, or about 0.09 wt% or more N. In some embodiments, the composition comprises about 0.02 wt% or less N, about 0.03 wt% or less N, about 0.04 wt% or less N, about 0.05 wt% or less N, about 0.06 wt% or less N, about 0.07 wt% or less N, about 0.08 wt% or less N, about 0.09 wt% or less N, or about 0.010 wt% or less N.

[0033] In some embodiments, the compositions may include any suitable amount of copper (Cu) conducive to the compositions described herein. In some embodiments, the compositions include about 0.05% to about 0.25% by weight of copper. In some embodiments, the compositions include about 0.10% to about 0.20% by weight of copper.

[0034] In some embodiments, the composition comprises about 0.05 wt% or more Cu, about 0.06 wt% or more Cu, about 0.07 wt% or more Cu, about 0.08 wt% or more Cu, about 0.09 wt% or more Cu, about 0.10 wt% or more Cu, about 0.11 wt% or more Cu, about 0.12 wt% or more Cu, about 0.13 wt% or more Cu, about 0.14 wt% or more Cu, about 0.15 wt% or more Cu, about 0.16 wt% or more Cu, about 0.17 wt% or more Cu, about 0.18 wt% or more Cu, about 0.19 wt% or more Cu, about 0.20 wt% or more Cu, about 0.21 wt% or more Cu, about 0.22 wt% or more Cu, about 0.23 wt% or more Cu, or about 0.24 wt% or more Cu. In some embodiments, the composition comprises about 0.06 wt% or less Cu, about 0.07 wt% or less Cu, about 0.08 wt% or less Cu, about 0.09 wt% or less Cu, about 0.10 wt% or less Cu, about 0.11 wt% or less Cu, about 0.12 wt% or less Cu, about 0.13 wt% or less Cu, about 0.14 wt% or less Cu, about 0.15 wt% or less Cu, about 0.16 wt% or less Cu, about 0.17 wt% or less Cu, about 0.18 wt% or less Cu, about 0.19 wt% or less Cu, about 0.20 wt% or less Cu, about 0.21 wt% or less Cu, about 0.22 wt% or less Cu, about 0.23 wt% or less Cu, about 0.24 wt% or less Cu, or about 0.25 wt% or less Cu.

[0035] In some embodiments, the compositions may include any suitable amount of iron (Fe) conducive to the compositions described herein. In many embodiments, the compositions include a balance of iron. In these embodiments, the amount of iron is sufficient to bring the total weight percent of the composition to 100 weight percent.

[0036] In some embodiments, the composition comprises about 84 wt% or more Fe, about 85 wt% or more Fe, or about 86 wt% or more Fe. In some embodiments, the composition comprises about 85 wt% or less Fe, about 86 wt% or less Fe, or about 87 wt% or less Fe.

[0037] In some embodiments, the composition may include contaminant elements. As used herein, contaminant elements include elements that may be inherently present in the composition and that substantially alter the material properties of the composition. In some embodiments, contaminant elements are not required in the composition and do not provide any benefit to the composition.

[0038] In some embodiments, the composition comprises a balance of iron and residual elements. As used herein, residual elements include elements that may be inherently present in the composition, but that do not substantially change the material properties of the composition if appropriately limited.

[0039] In these embodiments, the amount of iron and residual elements is sufficient to bring the total weight percent of the composition to 100 weight percent.

[0040] In some embodiments, the compositions may contain manganese (Mn), phosphorus (P), sulfur (S), molybdenum (Mo), tungsten (W), nickel (Ni), niobium (Nb), nitrogen (N), copper (Cu), boron (B), zirconium (Zr), arsenic (As), tin (Sn), antimony (Sb), lead (Pb), hydrogen (H), and cobalt (Co) in amounts conducive to the compositions described herein. In some embodiments, the compositions contain 5% or less by weight of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt.

[0041] In some embodiments, the composition comprises chromium, carbon, silicon, vanadium, titanium, manganese, molybdenum, nickel, niobium, nitrogen, copper, and iron. In some embodiments, the composition further comprises one or more elements selected from the group consisting of aluminum (Al), phosphorus (P), sulfur (S), tungsten (W), boron (B), zirconium (Zr), arsenic (As), tin (Sn), antimony (Sb), lead (Pb), hydrogen (H), cobalt (Co), and combinations thereof.

[0042] In some embodiments, the composition is free of phosphorus (P), sulfur (S), tungsten (W), boron (B), zirconium (Zr), arsenic (As), tin (Sn), antimony (Sb), lead (Pb), hydrogen (H), and / or cobalt (Co). In some embodiments, the composition contains 0.5% or less by weight of phosphorus, sulfur, tungsten, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and / or cobalt. In some embodiments, the composition contains 0.25% or less by weight of phosphorus, sulfur, tungsten, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and / or cobalt.

[0043] In some embodiments, the composition is an alloy composition, hi some embodiments, the composition is a wrought composition and / or a cast composition.

[0044] In some embodiments, the composition may have a freezing range conducive to the use of the compositions described herein. The freezing range is defined as the difference between the liquidus temperature and the solidus temperature. In some embodiments, the composition has a freezing range of less than about 200° F. In some embodiments, the composition has a freezing range of less than about 175° F.

[0045] In some embodiments, the composition can have a martensite start temperature conducive to the use of the compositions described herein, hi some embodiments, the composition has a martensite start temperature in the range of about 450° F. to about 550° F.

[0046] In some embodiments, the composition can have a martensite 90% temperature conducive to the uses of the compositions described herein, hi some embodiments, the composition has a martensite 90% temperature in the range of about 250° F. to about 350° F.

[0047] Also described herein are articles that include the compositions. Generally, the compositions can be included in any suitable article known in the art that facilitates the use of the compositions described herein.

[0048] In some embodiments, the article is manufactured using, but not limited to, a forging process and / or a casting process. In some embodiments, the article is manufactured using a casting process.

[0049] In some embodiments, the article is a turbine component, hi some embodiments, the turbine is a gas turbine or a steam turbine.

[0050] In some embodiments, the article is a turbine component such as, but not limited to, a nozzle, a shroud, a splash plate, a combustor component, a diffuser case, an inner diffuser case, a compressor case, an inner compressor case, a splitter, an inner barrel, a turbine shell, a compressor blade, a compressor vane, a guide vane, a retaining ring, and combinations thereof.

[0051] In some embodiments, the article is a turbine component such as, but not limited to, an inner casing for an in-case steam turbine high pressure rotor, an inner casing for an in-case steam turbine intermediate pressure rotor, an outer casing for an in-case steam turbine high pressure rotor, an outer casing for an in-case steam turbine high pressure rotor, an outer casing for an in-case steam turbine intermediate pressure rotor, a packing head, a diaphragm casing, and combinations thereof.

[0052] In some embodiments, the article is a part of a turbocharger component, hi some embodiments, the article is a part of an automobile.

[0053] In some embodiments, the article is configured for use at a maximum operating temperature of 750°C.

[0054] Additional aspects of the disclosed technology are set forth in the following embodiments section. [Embodiment 1] about 10% to about 11% by weight chromium; about 0.030% by weight or less of aluminum; about 0.08% to about 0.20% by weight carbon; about 0.10 wt.% to about 0.60 wt.% silicon; about 0.05% to about 0.40% by weight vanadium, about 0.01% to about 0.10% by weight titanium; 5% by weight or less of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen and cobalt, Remaining iron and residual elements A composition comprising: [Embodiment 2] The composition of embodiment 1, wherein the composition comprises about 10.25% to about 11% by weight of chromium. [Embodiment 3] The composition of embodiment 1 or embodiment 2, wherein said composition comprises 0.015% by weight or less of aluminum. [Embodiment 4] The composition of any one of the preceding embodiments, wherein the composition comprises about 0.12% to about 0.18% by weight of carbon. [Embodiment 5] The composition of any one of the preceding embodiments, wherein the composition comprises from about 0.20% to about 0.40% by weight of silicon. [Embodiment 6] The composition of any one of the first through fifth embodiments, wherein the composition comprises about 0.10% to about 0.30% by weight of vanadium. [Embodiment 7] The composition of any one of the preceding embodiments, wherein the composition comprises about 0.015% to about 0.060% by weight of titanium. [Embodiment 8] about 10.25% to about 11% by weight chromium; about 0.015% by weight or less of aluminum; about 0.12% to about 0.18% by weight carbon; about 0.20 wt.% to about 0.40 wt.% silicon; about 0.10% to about 0.30% by weight vanadium, about 0.015% to about 0.060% by weight titanium; 5% by weight or less of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen and cobalt, Remaining iron and residual elements The composition of any one of the preceding embodiments, comprising: [Embodiment 9] about 0.10% to about 1.0% by weight manganese, and / or About 0.40% to about 1.2% by weight of molybdenum The composition of any one of the preceding embodiments, further comprising: [Embodiment 10] about 0.50% to about 1.0% by weight manganese, and / or About 0.60% to about 0.80% by weight of molybdenum The composition of any one of the preceding embodiments, further comprising: [Embodiment 11] The composition of any one of the preceding embodiments, wherein the composition has a freezing range of less than about 200° F. [Embodiment 12] The composition of any one of embodiments 1 through 11, wherein the composition has a freezing range of less than about 175°F. [Embodiment 13] The composition of any one of paragraphs 1 through 12, wherein the composition has a martensite start temperature in the range of about 450°F to about 550°F. [Embodiment 14] The composition of any one of paragraphs 1 to 13, wherein the composition has a martensite 90% temperature in the range of about 250°F to about 350°F. [Embodiment 15] The composition of any one of paragraphs 1 to 14, wherein the composition is a forging composition and / or a cast composition. [Embodiment 16] An article comprising a composition, the composition comprising: about 10% to about 11% by weight chromium; about 0.030% by weight or less of aluminum; about 0.08% to about 0.20% by weight carbon; about 0.10 wt.% to about 0.60 wt.% silicon; about 0.05% to about 0.40% by weight vanadium, about 0.01% to about 0.10% by weight titanium; 5% by weight or less of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen and cobalt, Remaining iron and residual elements Including, articles. [Embodiment 17] The article of embodiment 16, wherein the article is a turbine component selected from the group consisting of an inner casing for a steam turbine high pressure rotor in a case, an inner casing for a steam turbine intermediate pressure rotor in a case, an outer casing for a steam turbine high pressure rotor in a case, an outer casing for a steam turbine intermediate pressure rotor in a case, a packing head, a diaphragm casing, and combinations thereof. [Embodiment 18] The article of embodiment 16 or embodiment 17, wherein the article is a turbine component selected from the group consisting of a nozzle, a shroud, a splash plate, a combustor component, a diffuser case, an inner diffuser case, a compressor case, an inner compressor case, a splitter, an inner barrel, a turbine shell, a compressor blade, a compressor vane, a guide vane, a retaining ring, and combinations thereof. [Embodiment 19] The composition, about 10.25% to about 11% by weight chromium; about 0.015% by weight or less of aluminum; about 0.12% to about 0.18% by weight carbon; about 0.20 wt.% to about 0.40 wt.% silicon; about 0.10% to about 0.30% by weight vanadium, about 0.015% to about 0.060% by weight titanium; 5% by weight or less of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen and cobalt, Remaining iron and residual elements The article of any one of claims 16 to 18, comprising: [Embodiment 20] The composition, about 0.10% to about 1.0% by weight manganese, and / or About 0.40% to about 1.2% by weight of molybdenum The article of any one of embodiments 16 through 19, further comprising:

[0055] References to "some embodiments" in the above description are not intended to be interpreted as excluding the existence of additional embodiments that also comprise the recited features. EXAMPLES

[0056] Without further explanation, it is believed that a person skilled in the art can utilize the present invention to the fullest extent from the above description. The following examples are merely illustrative and do not limit the present disclosure. The starting materials in the following examples are not necessarily prepared by the specific preparations whose procedures are described in other examples. In addition, the numerical ranges described in this specification include all values ​​from the lower limit to the upper limit. For example, if a range is described as 10 to 50, values ​​such as 12 to 30, 20 to 40, and 30 to 50 are explicitly described in this specification. These are only examples of what is specifically intended, and it is understood that all possible combinations of numerical values ​​between the described lower limit and upper limit are explicitly described in this application.

[0057] Example 1. Composition Compositions according to the present disclosure are shown in the table below. CE1 and CE5 are comparative examples in wrought form. CE2, CE3 and CE4 are comparative examples in cast form. IE1 is an example in cast form. "max" means the upper limit of the element, "min" means the lower limit of the element, and "N / A" means the element is not present.

[0058] [Table 1]

[0059] [Table 2]

[0060] Example 2. Simulated matrix phase The properties of compositions according to the present disclosure were simulated to determine expected physical properties, and the simulated matrix phase properties are shown in the table below and in Figures 1A-1D.

[0061] The freezing range can often be used as a relative predictor of castability. A narrower freezing range generally results in less tendency to shrink and less susceptible to solidification hot cracking. CE2 and IE1 have similar simulated freezing range temperatures and are expected to show similar castability.

[0062] [Table 3]

[0063] Example 3. Simulated hardenability The simulated martensite hardenability properties are shown in Figures 2A-2D. Ms is the martensite start temperature. M50 is the 50% martensite transformation temperature. M90 is the 90% martensite transformation temperature. HRC is Rockwell C hardness.

[0064] All four compositions simulated showed excellent hardenability. The IE1 martensite start temperature was about 500°F and the martensite 90% temperature was about 300°F. The IE1 casting appears to achieve 100% martensite even in very thick sections during quench / cool. The bainite / ferrite / pearlite nose is extruded for a very long time.

[0065] Example 4. Simulated tempering The simulated temper properties are shown in Figures 3A-B. Figure 3A shows the predicted yield strength and Figure 3B shows the ultimate tensile strength. It was observed that all four simulated compositions showed similar temper response. Tempering can be used to balance strength and toughness.

[0066] Example 5. Simulated short-term fracture The simulated short-term fracture properties are shown in Figure 4. It was observed that IE1 had similar short-term fracture properties to CE1.

[0067] It has now been found that compositions according to the present disclosure can be used in wrought and / or cast alloys, which exhibit improved oxidation resistance, reduced retained delta ferrite and improved fracture ductility. The compositions according to the present disclosure are broadly applicable to applications requiring alloys with improved oxidation resistance, reduced retained delta ferrite and / or improved fracture ductility.

[0068] Unless otherwise stated, in this specification, approximation expressions such as "approximately", "substantially" and "about" indicate that the modified term is not absolute or exact, but merely approximate as would be obvious to one of ordinary skill in the art. Thus, values ​​modified with terms such as "approximately", "substantially" and "about" are not limited to their exact numerical values. In at least some cases, approximation expressions correspond to the accuracy of the instrument that measures the value. Furthermore, unless otherwise stated, terms such as "first", "second" and the like are merely appended in this application and do not impose numerical, positional or hierarchical requirements on what they are appended to. Furthermore, for example, "second" does not require or exclude the presence of, for example, "first" or less or "third" or more.

[0069] Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. References herein to "some embodiments" should not be interpreted as excluding the existence of additional embodiments that possess the recited features. Consistent with the principles of the invention, a feature shown in one drawing may be referenced and / or claimed in combination with a feature shown in another drawing.

[0070] The present specification has been described by way of examples to disclose the invention, including the best mode thereof, and to enable those skilled in the art to practice the invention, including making and using the apparatus or system and practicing the method. The patentable scope of the invention is defined by the claims, and may include other examples that are obvious to those skilled in the art. Such other examples are within the scope of the claims if they have elements that are not literally different from the claims, or have equivalent elements that are only insubstantial different from the claims.

Claims

1. about 10% to about 11% by weight chromium; up to about 0.030% by weight aluminum; about 0.08% to about 0.20% by weight carbon; about 0.10 wt.% to about 0.60 wt.% silicon; about 0.05% to about 0.40% by weight vanadium; about 0.01% to about 0.10% by weight titanium; 5% by weight or less of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; Remaining iron and residual elements A composition comprising:

2. The composition of claim 1 , wherein the composition comprises from about 10.25% to about 11% by weight chromium.

3. 10. The composition of claim 1, wherein the composition comprises no more than 0.015 weight percent aluminum.

4. The composition of claim 1 , wherein the composition comprises about 0.12% to about 0.18% by weight carbon.

5. The composition of claim 1 , wherein the composition comprises about 0.20% to about 0.40% by weight silicon.

6. The composition of claim 1, wherein the composition comprises from about 0.10% to about 0.30% by weight vanadium.

7. The composition of claim 1 , wherein the composition comprises about 0.015% to about 0.060% by weight titanium.

8. about 10.25% to about 11% by weight chromium; up to about 0.015% by weight aluminum; about 0.12% to about 0.18% by weight carbon; about 0.20 wt.% to about 0.40 wt.% silicon; about 0.10 wt. % to about 0.30 wt. % vanadium; about 0.015% to about 0.060% by weight titanium; 5% by weight or less of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; The composition of claim 1 comprising the balance iron and remaining elements.

9. from about 0.10% to about 1.0% by weight manganese, and / or About 0.40% to about 1.2% by weight molybdenum The composition of claim 1 further comprising:

10. from about 0.50% to about 1.0% by weight manganese, and / or about 0.60% to about 0.80% by weight molybdenum The composition of claim 1 further comprising:

11. 10. The composition of claim 1, wherein the composition has a freezing range of less than about 200°F.

12. 10. The composition of claim 1, wherein the composition has a freezing range of less than about 175°F.

13. The composition of claim 1 , wherein the composition has a martensite start temperature in the range of about 450° F. to about 550° F.

14. 10. The composition of claim 1, wherein the composition has a martensite 90% temperature in the range of about 250°F to about 350°F.

15. The composition of claim 1 , wherein the composition is a forging composition and / or a casting composition.

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