Alloy compositions and articles formed from such compositions

Abstract

Compositions are described herein, and more particularly, to alloy compositions and articles formed from the alloy compositions. The alloy composition is widely used in applications requiring alloys with improved oxidation resistance, reduced residual delta ferrite, and / or improved ductility at break.

Description

Background Art

[0001] The field of the present disclosure relates generally to compositions, and more particularly to alloy compositions and articles formed therefrom. The alloy compositions are widely used in applications requiring alloys having improved oxidation resistance, reduced retained delta ferrite, and / or improved fracture ductility.

[0002] Iron-based alloys are commonly used in cast and wrought steel products. However, conventional iron-based alloys exhibit excessive oxidizability and poor long-term fracture properties such as delta ferrite and fracture ductility. Although some iron-based alloys have improved one or two of these properties, no iron-based alloy has maximized all of these properties. This is especially true in the power generation industry, where iron-based materials operate at higher temperatures and pressures in order to increase the efficiency of various components while excluding structural integrity.

[0003] However, chemical modifications aimed at improving oxidizability (e.g., higher chromium content) can increase the potential energy of delta ferrite, resulting in poorer high temperature fracture properties. Adding tungsten can improve fracture properties while increasing the high temperature oxidation rate. Deoxidation of molten iron with aluminum has also been shown to reduce fracture ductility in iron-based alloys.

[0004] Therefore, there is a need for iron-based alloys having improved oxidation resistance, reduced retained delta ferrite, and improved fracture ductility. Summary of the invention

[0005] In one aspect, a composition is provided, comprising about 10% to about 11% chromium by weight, no more than about 0.030% aluminum by weight, about 0.08% to about 0.20% carbon by weight, about 0.10% to about 0.60% silicon by weight, about 0.05% to about 0.40% vanadium by weight, about 0.01% to about 0.10% titanium by weight, no more than about 5% manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt by weight, and the balance being iron and residual elements.

[0006] In yet another aspect, an article is provided comprising a composition comprising about 10% to about 11% chromium by weight, no more than about 0.030% aluminum by weight, about 0.08% to about 0.20% carbon by weight, about 0.10% to about 0.60% silicon by weight, about 0.05% to about 0.40% vanadium by weight, about 0.01% to about 0.10% titanium by weight, no more than about 5% manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt by weight, and the balance being iron and residual elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features, aspects and advantages of the present disclosure will be better understood when the following detailed description is read with reference to the accompanying drawings, in which like characters refer to like parts throughout the several views, and in which:

[0008] Figure 1A Depicted are exemplary results for a simulated matrix phase for comparative composition CE1 according to the present disclosure.

[0009] Figure 1B Depicted are exemplary results for a simulated matrix phase for comparative composition CE2 according to the present disclosure.

[0010] Figure 1C Depicted are exemplary results for a simulated matrix phase for comparative composition CE3 according to the present disclosure.

[0011] Figure 1D Depicted are exemplary results for a simulated matrix phase for inventive composition IE1 according to the present disclosure.

[0012] Figure 2A Depicted are exemplary results of simulated hardenability of comparative composition CE1 according to the present disclosure.

[0013] Figure 2B Depicted are exemplary results of simulated hardenability of comparative composition CE2 according to the present disclosure.

[0014] Figure 2C Depicted are exemplary results of simulated hardenability of comparative composition CE3 according to the present disclosure.

[0015] Figure 2D Depicted are exemplary results of simulated hardenability of inventive composition IE1 according to the present disclosure.

[0016] Figure 3A Depicted are exemplary results of simulated YS tempering of comparative compositions and inventive compositions according to the present disclosure.

[0017] Figure 3B Depicted are exemplary results of simulated UTS tempering of comparative compositions and inventive compositions according to the present disclosure.

[0018] Figure 4 Depicted are exemplary results of simulated short-term fracture for comparative compositions and inventive compositions according to the present disclosure. DETAILED DESCRIPTION

[0019] It is surprisingly found in the present disclosure that the composition according to the present disclosure can be used for forging alloys and casting alloys. Compared with other alloy compositions, the composition includes changed Cr, Al, Si, C, Al, Ti and V element contents. The Cr content is particularly significant. The composition shows improved oxidation resistance, reduced residual delta ferrite and improved fracture ductility. The composition according to the present disclosure is widely applicable to applications where alloys with improved oxidation resistance, reduced residual delta ferrite and / or improved fracture ductility are required.

[0020] It has been found in particular in the present disclosure that increasing the chromium content from 8.5% to 9.5% up to 11% greatly reduces the formation of inner and outer oxide layers for creep strength enhanced ferrite (CSEF) wrought steel products. Increasing the chromium content also results in a higher chromium equivalent (CE), which can lead to the possibility of residual delta ferrite. Delta ferrite is a low creep resistant phase that can result in reduced long term fracture strength. Therefore, the amount of residual delta-ferrite in the final product is typically less than 5%. The composition according to the present disclosure optimizes the chemistry of the cast 10-11% chromium alloy to achieve improved oxidation performance while reducing the risk of premature fracture failure due to retained delta ferrite and poor fracture ductility.

[0021] Embodiments described herein overcome at least some disadvantages of iron-based alloys. Exemplary embodiments described herein include a composition. The composition comprises about 10 wt % to about 11 wt % chromium, no more than about 0.030 wt % aluminum, about 0.08 wt % to about 0.20 wt % carbon, about 0.10 wt % to about 0.60 wt % silicon, about 0.05 wt % to about 0.40 wt % vanadium, about 0.01 wt % to about 0.10 wt % titanium, no more than about 5 wt % manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen and cobalt, and the remainder of iron and residual elements.

[0022] In some embodiments, the composition may include any suitable amount of chromium (Cr) that is beneficial to the compositions described herein. In some embodiments, the composition includes Cr. In some embodiments, the composition includes about 10 wt % to about 11 wt % chromium. In some embodiments, the composition includes about 10.25 wt % to about 11 wt % chromium.

[0023] In some embodiments, the composition comprises at least about 10.0 wt % Cr, at least about 10.1 wt % Cr, at least about 10.2 wt % Cr, at least about 10.3 wt % Cr, at least about 10.4 wt % Cr, at least about 10.5 wt % Cr, at least about 10.6 wt % Cr, at least about 10.7 wt % Cr, at least about 10.8 wt % Cr, or at least about 10.9 wt % Cr. In some embodiments, the composition comprises up to about 10.1 wt % Cr, up to about 10.2 wt % Cr, up to about 10.3 wt % Cr, up to about 10.4 wt % Cr, up to about 10.5 wt % Cr, up to about 10.6 wt % Cr, up to about 10.7 wt % Cr, up to about 10.8 wt % Cr, up to about 10.9 wt % Cr, or up to about 11.0 wt % Cr.

[0024] In some embodiments, the composition may include any suitable amount of aluminum (Al) that is beneficial 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 wt % aluminum. In some embodiments, the composition includes no more than 0.015 wt % aluminum.

[0025] In some embodiments, the composition comprises at least about 0.005 wt % Al, at least about 0.010 wt % Al, at least about 0.015 wt % Al, at least about 0.020 wt % Al, or at least about 0.025 wt % Al. In some embodiments, the composition comprises at most about 0.010 wt % Al, at most about 0.015 wt % Al, at most about 0.020 wt % Al, at most about 0.025 wt % Al, or at most about 0.030 wt % Al.

[0026] In some embodiments, the composition may include any suitable amount of carbon (C) that is beneficial to the compositions described herein. In some embodiments, the composition includes about 0.08 wt % to about 0.20 wt % carbon. In some embodiments, the composition includes about 0.12 wt % to about 0.18 wt % carbon.

[0027] In some embodiments, the composition comprises at least about 0.08 wt % carbon, at least about 0.09 wt % carbon, at least about 0.10 wt % carbon, at least about 0.11 wt % carbon, at least about 0.12 wt % carbon, at least about 0.13 wt % carbon, at least about 0.14 wt % carbon, at least about 0.15 wt % carbon, at least about 0.16 wt % carbon, at least about 0.17 wt % carbon, at least about 0.18 wt % carbon, or at least about 0.19 wt % carbon. In some embodiments, the composition comprises up to about 0.09 wt % carbon, up to about 0.10 wt % carbon, up to about 0.11 wt % carbon, up to about 0.12 wt % carbon, up to about 0.13 wt % carbon, up to about 0.14 wt % carbon, up to about 0.15 wt % carbon, up to about 0.16 wt % carbon, up to about 0.17 wt % carbon, up to about 0.18 wt % carbon, up to about 0.19 wt % carbon, or up to about 0.20 wt % carbon.

[0028] In some embodiments, the composition may include any suitable amount of silicon (Si) that is beneficial to the compositions described herein. In some embodiments, the composition includes about 0.10 wt % to about 0.60 wt % silicon. In some embodiments, the composition includes about 0.20 wt % to about 0.40 wt % silicon.

[0029] In some embodiments, the composition comprises at least about 0.01 wt % Si, at least about 0.15 wt % Si, at least about 0.20 wt % Si, at least about 0.25 wt % Si, at least about 0.30 wt % Si, at least about 0.35 wt % Si, at least about 0.40 wt % Si, at least about 0.45 wt % Si, at least about 0.50 wt % Si, or at least about 0.55 wt % Si. In some embodiments, the composition comprises up to about 0.15 wt % Si, up to about 0.20 wt % Si, up to about 0.25 wt % Si, up to about 0.30 wt % Si, up to about 0.35 wt % Si, up to about 0.40 wt % Si, up to about 0.45 wt % Si, up to about 0.50 wt % Si, up to about 0.55 wt % Si, or up to about 0.60 wt % Si.

[0030] In some embodiments, the composition may include any suitable amount of vanadium (V) that is beneficial to the compositions described herein. In some embodiments, the composition includes about 0.05 wt % to about 0.40 wt % vanadium. In some embodiments, the composition includes about 0.10 wt % to about 0.30 wt % vanadium.

[0031] In some embodiments, the composition comprises at least about 0.05 wt % V, 0.10 wt % V, at least about 0.15 wt % V, at least about 0.20 wt % V, at least about 0.25 wt % V, at least about 0.30 wt % V, or at least about 0.35 wt % V. In some embodiments, the composition comprises at most about 0.10 wt % V, at most about 0.15 wt % V, at most about 0.20 wt % V, at most about 0.25 wt % V, at most about 0.30 wt % V, at most about 0.35 wt % V, or at most about 0.40 wt % V.

[0032] In some embodiments, the composition may include any suitable amount of titanium (Ti) that is beneficial to the compositions described herein. In some embodiments, the composition includes about 0.01 wt % to about 0.10 wt % titanium. In some embodiments, the composition includes about 0.015 wt % to about 0.060 wt % titanium.

[0033] In some embodiments, the composition comprises at least about 0.010 wt % Ti, at least about 0.015 wt % Ti, at least about 0.020 wt % Ti, at least about 0.025 wt % Ti, at least about 0.030 wt % Ti, at least about 0.035 wt % Ti, at least about 0.040 wt % Ti, at least about 0.045 wt % Ti, at least about 0.050 wt % Ti, or at least about 0.055 wt % Ti. In some embodiments, the composition comprises up to about 0.015 wt. % Ti, up to about 0.020 wt. % Ti, up to about 0.025 wt. % Ti, up to about 0.030 wt. % Ti, up to about 0.035 wt. % Ti, up to about 0.040 wt. % Ti, up to about 0.045 wt. % Ti, up to about 0.050 wt. % Ti, or up to about 0.055 wt. % Ti, or up to about 0.060 wt. % Ti.

[0034] In some embodiments, the composition may include any suitable amount of manganese (Mn) that is beneficial to the compositions described herein. In some embodiments, the composition includes about 0.10 wt % to about 1.0 wt % manganese. In some embodiments, the composition includes about 0.50 wt % to about 1.0 wt % manganese.

[0035] In some embodiments, the composition comprises at least about 0.10 wt % Mn, at least about 0.15 wt % Mn, at least about 0.20 wt % Mn, at least about 0.25 wt % Mn, at least about 0.30 wt % Mn, at least about 0.35 wt % Mn, at least about 0.40 wt % Mn, at least about 0.45 wt % Mn, at least about 0.50 wt % Mn, at least about 0.55 wt % Mn, at least about 0.60 wt % Mn, at least about 0.65 wt % Mn, at least about 0.70 wt % Mn, at least about 0.75 wt % Mn, at least about 0.80 wt % Mn, at least about 0.85 wt % Mn, at least about 0.90 wt % Mn, or at least about 0.95 wt % Mn. In some embodiments, the composition comprises up to about 0.15 wt % Mn, up to about 0.20 wt % Mn, up to about 0.25 wt % Mn, up to about 0.30 wt % Mn, up to about 0.35 wt % Mn, up to about 0.40 wt % Mn, up to about 0.45 wt % Mn, up to about 0.50 wt % Mn, up to about 0.55 wt % Mn, up to about 0.60 wt % Mn, up to about 0.65 wt % Mn, up to about 0.70 wt % Mn, up to about 0.75 wt % Mn, up to about 0.80 wt % Mn, up to about 0.85 wt % Mn, up to about 0.90 wt % Mn, up to about 0.95 wt % Mn, or up to about 1.0 wt % Mn.

[0036] In some embodiments, the composition may include any suitable amount of molybdenum (Mo) that is beneficial to the compositions described herein. In some embodiments, the composition includes about 0.10 wt % to about 1.0 wt % of molybdenum. In some embodiments, the composition includes about 0.50 wt % to about 1.0 wt % of molybdenum.

[0037] In some embodiments, the composition comprises at least about 0.40 wt % Mo, at least about 0.45 wt % Mo, at least about 0.50 wt % Mo, at least about 0.55 wt % Mo, at least about 0.60 wt % Mo, at least about 0.65 wt % Mo, at least about 0.70 wt % Mo, at least about 0.75 wt % Mo, at least about 0.80 wt % Mo, at least about 0.85 wt % Mo, at least about 0.90 wt % Mo, at least about 0.95 wt % Mo, at least about 1.0 wt % Mo, at least about 1.05 wt % Mo, at least about 1.1 wt % Mo, or at least about 1.15 wt % Mo. 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.

[0038] In some embodiments, the composition may include any suitable amount of nickel (Ni) that is beneficial to the compositions described herein. In some embodiments, the composition includes about 0.10 wt % to about 1.0 wt % nickel. In some embodiments, the composition includes about 0.50 wt % to about 1.0 wt % nickel.

[0039] In some embodiments, the composition comprises at least about 0.10 wt % Ni, at least about 0.15 wt % Ni, at least about 0.20 wt % Ni, at least about 0.25 wt % Ni, at least about 0.30 wt % Ni, at least about 0.35 wt % Ni, at least about 0.40 wt % Ni, at least about 0.45 wt % Ni, at least about 0.50 wt % Ni, at least about 0.55 wt % Ni, at least about 0.60 wt % Ni, at least about 0.65 wt % Ni, at least about 0.70 wt % Ni, at least about 0.75 wt % Ni, at least about 0.80 wt % Ni, at least about 0.85 wt % Ni, at least about 0.90 wt % Ni, or at least about 0.95 wt % Ni. In some embodiments, the composition comprises up to about 0.15 wt % Ni, up to about 0.20 wt % Ni, up to about 0.25 wt % Ni, up to about 0.30 wt % Ni, up to about 0.35 wt % Ni, up to about 0.40 wt % Ni, up to about 0.45 wt % Ni, up to about 0.50 wt % Ni, up to about 0.55 wt % Ni, up to about 0.60 wt % Ni, up to about 0.65 wt % Ni, up to about 0.70 wt % Ni, up to about 0.75 wt % Ni, up to about 0.80 wt % Ni, up to about 0.85 wt % Ni, up to about 0.90 wt % Ni, up to about 0.95 wt % Ni, or up to about 1.0 wt % Ni.

[0040] In some embodiments, the composition may include any suitable amount of niobium (Nb) that facilitates the compositions described herein. In some embodiments, the composition includes about 0.01 wt % to about 0.12 wt % niobium. In some embodiments, the composition includes about 0.05 wt % to about 0.10 wt % niobium.

[0041] In some embodiments, the composition includes at least about 0.01 wt % Nb, at least about 0.02 wt % Nb, at least about 0.03 wt % Nb, at least about 0.04 wt % Nb, at least about 0.05 wt % Nb, at least about 0.06 wt % Nb, at least about 0.07 wt % Nb, at least about 0.08 wt % Nb, at least about 0.09 wt % Nb, at least about 0.10 wt % Nb, or at least about 0.11 wt % Nb. In some embodiments, the composition includes up to about 0.02 wt % Nb, up to about 0.03 wt % Nb, up to about 0.04 wt % Nb, up to about 0.05 wt % Nb, up to about 0.06 wt % Nb, up to about 0.07 wt % Nb, up to about 0.08 wt % Nb, up to about 0.09 wt % Nb, up to about 0.010 wt % Nb, up to about 0.11 wt % Nb, or up to about 0.12 wt % Nb.

[0042] In some embodiments, the composition may include any suitable amount of nitrogen (N) that is beneficial to the compositions described herein. In some embodiments, the composition includes about 0.01 wt % to about 0.10 wt % nitrogen. In some embodiments, the composition includes about 0.03 wt % to about 0.07 wt % nitrogen.

[0043] In some embodiments, the composition comprises at least about 0.01 wt % N, at least about 0.02 wt % N, at least about 0.03 wt % N, at least about 0.04 wt % N, at least about 0.05 wt % N, at least about 0.06 wt % N, at least about 0.07 wt % N, at least about 0.08 wt % N, or at least about 0.09 wt % N. In some embodiments, the composition comprises at most about 0.02 wt % N, at most about 0.03 wt % N, at most about 0.04 wt % N, at most about 0.05 wt % N, at most about 0.06 wt % N, at most about 0.07 wt % N, at most about 0.08 wt % N, at most about 0.09 wt % N, or at most about 0.010 wt % N.

[0044] In some embodiments, the composition may include any suitable amount of copper (Cu) that is beneficial to the compositions described herein. In some embodiments, the composition includes about 0.05 wt % to about 0.25 wt % copper. In some embodiments, the composition includes about 0.10 wt % to about 0.20 wt % copper.

[0045] In some embodiments, the composition comprises at least about 0.05 wt % Cu, at least about 0.06 wt % Cu, at least about 0.07 wt % Cu, at least about 0.08 wt % Cu, at least about 0.09 wt % Cu, at least about 0.10 wt % Cu, at least about 0.11 wt % Cu, at least about 0.12 wt % Cu, at least about 0.13 wt % Cu, at least about 0.14 wt % Cu, at least about 0.15 wt % Cu, at least about 0.16 wt % Cu, at least about 0.17 wt % Cu, at least about 0.18 wt % Cu, at least about 0.19 wt % Cu, at least about 0.20 wt % Cu, at least about 0.21 wt % Cu, at least about 0.22 wt % Cu, at least about 0.23 wt % Cu, or at least about 0.24 wt % Cu. In some embodiments, the composition comprises up to about 0.06 wt % Cu, up to about 0.07 wt % Cu, up to about 0.08 wt % Cu, up to about 0.09 wt % Cu, up to about 0.10 wt % Cu, up to about 0.11 wt % Cu, up to about 0.12 wt % Cu, up to about 0.13 wt % Cu, up to about 0.14 wt % Cu, up to about 0.1 % Cu, up to about 0.5 wt. % Cu, up to about 0.16 wt. % Cu, up to about 0.17 wt. % Cu, up to about 0.18 wt. % Cu, up to about 0.19 wt. % Cu, up to about 0.20 wt. % Cu, up to about 0.21 wt. % Cu, up to about 0.22 wt. % Cu, up to about 0.23 wt. % Cu, up to about 0.24 wt. % Cu, or up to about 0.25 wt. % Cu.

[0046] In some embodiments, the composition may include any suitable amount of iron (Fe) that is beneficial to the composition described herein. In many embodiments, the composition includes a surplus of iron. In these embodiments, the amount of iron is sufficient to bring the total weight percentage of the composition to 100 weight %.

[0047] In some embodiments, the composition comprises at least about 84 wt % Fe, at least about 85 wt % Fe, or at least about 86 wt % Fe. In some embodiments, the composition comprises up to about 85 wt % Fe, up to about 86 wt % Fe, or up to about 87 wt % Fe.

[0048] In some embodiments, the composition may include impurity elements. As used herein, impurity elements include elements that may be inherently present in the composition and significantly change the material properties of the composition. In some embodiments, the impurity elements are not necessary in the composition and do not provide benefits to the composition.

[0049] 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 properly restricted.

[0050] 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.

[0051] In some embodiments, the composition may include any suitable amount of 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) that is beneficial to the compositions described herein. In some embodiments, the composition includes no more than about 5% by weight of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt.

[0052] 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 at least one element 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.

[0053] In some embodiments, the composition does not include 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 includes no more than 0.5% by weight of phosphorus, sulfur, tungsten, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and / or cobalt. In some embodiments, the composition includes no more than 0.25% by weight of phosphorus, sulfur, tungsten, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and / or cobalt.

[0054] In some embodiments, the composition is an alloy composition. In some embodiments, the composition is a wrought composition and / or a cast composition.

[0055] In some embodiments, the composition may have a solidification range that is beneficial to the use of the composition described herein. The solidification range is defined as the difference between the liquidus and solidus temperatures. In some embodiments, the composition has a solidification range of less than about 200°F. In some embodiments, the composition has a solidification range of less than about 175°F.

[0056] In some embodiments, the composition can have a martensite start temperature that facilitates use of the compositions described herein. In some embodiments, the composition has a martensite start temperature in a range of about 450°F to about 550°F.

[0057] In some embodiments, the composition may have a 90% Martensite Temperature that facilitates use of the compositions described herein. In some embodiments, the composition has a 90% Martensite Temperature in the range of about 250°F to about 350°F.

[0058] Also described herein is an article comprising the composition. Generally speaking, the composition can be contained in any suitable article known in the art that facilitates the use of the composition described herein.

[0059] In some embodiments, the article is produced using (but not limited to only using) a forging process and / or a casting process. In some embodiments, the article is produced using a casting process.

[0060] In some embodiments, the article is a component of a turbine. In some embodiments, the turbine is a gas turbine or a steam turbine.

[0061] In some embodiments, the article is a component of a turbomachine, such as, but not limited to, only nozzles, shrouds, splash plates, combustor components, diffuser housings, inner diffuser housings, compressor housings, inner compressor housings, splitters, inner barrels, turbine housings, compressor blades, compressor airfoils, guide vanes, shroud rings, and combinations thereof.

[0062] In some embodiments, the article is a component of a turbine, such as, but not limited to, an inner shell for a high-pressure rotor of a steam turbine in a shell, an inner shell for an intermediate-pressure rotor of a steam turbine in a shell, an outer shell for a high-pressure rotor of a steam turbine in a shell, an outer shell for an intermediate-pressure rotor of a steam turbine in a shell, a packing head, a diaphragm housing, and combinations thereof.

[0063] In some embodiments, the article is a component of a turbocharger component. In some embodiments, the article is a component of an automobile.

[0064] In some embodiments, the article is configured for use at a maximum operating temperature of 750°C.

[0065] Other aspects of the disclosure are provided by the subject matter of the following clauses:

[0066] 1. A composition comprising:

[0067] from about 10 wt % to about 11 wt % chromium;

[0068] no more than about 0.030 wt. % aluminum;

[0069] from about 0.08 wt % to about 0.20 wt % carbon;

[0070] about 0.10 wt % to about 0.60 wt % silicon;

[0071] from about 0.05 wt. % to about 0.40 wt. % vanadium;

[0072] from about 0.01 wt % to about 0.10 wt % titanium;

[0073] no more than about 5 weight percent manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and

[0074] The balance is iron and residual elements.

[0075] 2. The composition according to the preceding clause, wherein the composition comprises from about 10.25 wt % to about 11 wt % chromium.

[0076] 3. A composition according to any preceding clause, wherein the composition comprises no more than about

[0077] 0.015 wt% aluminum.

[0078] 4. A composition according to any preceding clause, wherein the composition comprises from about 0.12 wt % to about 0.18 wt % carbon.

[0079] 5. A composition according to any preceding clause, wherein the composition comprises from about 0.20 wt % to about 0.40 wt % silicon.

[0080] 6. A composition according to any preceding clause, wherein the composition comprises from about 0.10 wt. % to about 0.30 wt. % vanadium.

[0081] 7. A composition according to any preceding clause, wherein the composition comprises from about 0.015 wt % to about 0.060 wt % titanium.

[0082] 8. A composition according to any preceding clause, comprising:

[0083] from about 10.25 wt % to about 11 wt % chromium;

[0084] No more than about 0.015 wt. % aluminum;

[0085] from about 0.12 wt % to about 0.18 wt % carbon;

[0086] about 0.20 wt % to about 0.40 wt % silicon;

[0087] from about 0.10 wt. % to about 0.30 wt. % vanadium;

[0088] from about 0.015 wt % to about 0.060 wt % titanium;

[0089] no more than about 5 weight percent manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and

[0090] The balance is iron and residual elements.

[0091] 9. A composition according to any preceding clause, further comprising:

[0092] from about 0.10 wt % to about 1.0 wt % manganese; and / or

[0093] From about 0.40 wt. % to about 1.2 wt. % molybdenum.

[0094] 10. A composition according to any preceding clause, further comprising:

[0095] from about 0.50 wt % to about 1.0 wt % manganese; and / or

[0096] From about 0.60 wt. % to about 0.80 wt. % molybdenum.

[0097] 11. The composition of any preceding clause, wherein the composition has a solidification range of less than about 200°F.

[0098] 12. A composition according to any preceding clause, wherein the composition has less than about

[0099] Freezing range of 175°F.

[0100] 13. The composition of any preceding clause, wherein the composition has a martensite start temperature of about 450°F to about 550°F.

[0101] 14. The composition of any preceding clause, wherein the composition has a 90% martensite temperature of about 250°F to about 350°F.

[0102] 15. A composition according to any preceding clause, wherein the composition is a wrought composition and / or a cast composition.

[0103] 16. An article comprising a composition comprising:

[0104] from about 10 wt % to about 11 wt % chromium;

[0105] no more than about 0.030 wt. % aluminum;

[0106] from about 0.08 wt % to about 0.20 wt % carbon;

[0107] about 0.10 wt % to about 0.60 wt % silicon;

[0108] from about 0.05 wt. % to about 0.40 wt. % vanadium;

[0109] from about 0.01 wt % to about 0.10 wt % titanium;

[0110] no more than about 5 weight percent manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and

[0111] The balance is iron and residual elements.

[0112] 17. An article according to the preceding clause, wherein the article is a component of a turbine selected from the group consisting of an inner casing for a high pressure rotor of a steam turbine in a casing, an inner casing for an intermediate pressure rotor of a steam turbine in a casing, an outer casing for a high pressure rotor of a steam turbine in a casing, an outer casing for an intermediate pressure rotor of a steam turbine in a casing, a packing head, a diaphragm housing and combinations thereof.

[0113] 18. An article according to any of the preceding clauses, wherein the article is a component of a turbine selected from the group consisting of: a nozzle, a shroud, a splash plate, a combustor component, a diffuser shell, an inner diffuser shell, a compressor shell, an inner compressor shell, a splitter, an inner barrel, a turbine shell, a compressor blade, a compressor airfoil, a guide vane, a guard ring, and combinations thereof.

[0114] 19. An article according to any preceding clause, wherein the composition comprises:

[0115] from about 10.25 wt % to about 11 wt % chromium;

[0116] No more than about 0.015 wt. % aluminum;

[0117] from about 0.12 wt % to about 0.18 wt % carbon;

[0118] about 0.20 wt % to about 0.40 wt % silicon;

[0119] from about 0.10 wt. % to about 0.30 wt. % vanadium;

[0120] from about 0.015 wt % to about 0.060 wt % titanium;

[0121] no more than about 5 weight percent manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and

[0122] The balance is iron and residual elements.

[0123] 20. The article according to any preceding clause, wherein the composition further comprises:

[0124] from about 0.10 wt % to about 1.0 wt % manganese; and / or

[0125] from about 0.40 wt % to about 1.2 wt % molybdenum;

[0126] References to “one embodiment” in the above description are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0127] Example

[0128] Without further detailed description, it is believed that those skilled in the art can make the most of the present invention using the foregoing description. Therefore, the following examples are to be construed as illustrative only and not to limit the present disclosure in any way. The starting materials for the following examples may not necessarily be prepared by a specific preparation run, the procedures of which are described in other embodiments. It should also be understood that any numerical range described herein includes all values ​​from the lower limit to the upper limit. For example, if the range is stated as 10 to 50, it is intended to explicitly list values ​​such as 12 to 30, 20 to 40, or 30 to 50 in this specification. These are only examples of specific intent, and all possible combinations of numerical values ​​between and including the lowest and highest values ​​listed are considered to be explicitly stated in the present application.

[0129] Example 1. Composition

[0130] Compositions according to the present disclosure are shown in the following table. CE1 and CE5 are comparative examples in wrought form. CE2, CE3 and CE4 are comparative examples in cast form. IE1 is an inventive example in cast form. "max" indicates the maximum amount of the element, "min" indicates the minimum amount of the element, and "N / A" indicates that the element is not present.

[0131] Table 1. Tested compositions .

[0132]

[0133] Table 2. N / Al ratio .

[0134]

[0135] Example 2. Simulated matrix phase .

[0136] The properties of the compositions according to the present disclosure were simulated to determine the expected physical properties. The simulated matrix phase properties are shown in the following table and Figures 1A-1D middle.

[0137] The solidification range can generally be used as a relative predictor of castability. Tighter solidification ranges generally have less tendency to shrink and may also be less prone to solidification hot tearing. CE2 and IE1 exhibit similar simulated solidification range temperatures and therefore should exhibit similar castability.

[0138] Table 3. Critical curing temperature .

[0139]

[0140] Example 3. Simulated hardenability .

[0141] Simulated martensite hardenability properties 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 the Rockwell C hardness.

[0142] All four simulated compositions showed excellent hardenability. The IE1 martensite start temperature was observed to be about 500°F and the 90% martensite temperature was about 300°F. Even in very thick sections during quenching / cooling, the IE1 casting should obtain 100% martensite. The bainite / ferrite / pearlite nose is pushed for a long time.

[0143] Example 4. Simulated tempering .

[0144] The simulated tempering properties are shown in Figure 3A-3B middle. Figure 3A plots the predicted yield strength, Figure 3B The ultimate tensile strength is plotted. It is observed that all four simulated compositions show similar tempering responses. Tempering can be used to balance strength and toughness.

[0145] Example 5. Simulated short-term fracture .

[0146] The simulated short-term fracture properties are shown in Figure 4 It was observed that IE1 has similar short-term breaking properties as CE1.

[0147] It is found herein that the compositions according to the present disclosure can be used for wrought and / or cast alloys. The compositions exhibit improved oxidation resistance, reduced retained delta ferrite, and improved fracture ductility. The compositions according to the present disclosure are widely suitable for use in applications where alloys having improved oxidation resistance, reduced retained delta ferrite, and / or improved fracture ductility are desired.

[0148] Unless otherwise indicated, approximate language as used herein, such as "substantially", "substantially" and "about" indicate that as those of ordinary skill in the art will recognize, the terms so modified may apply only to approximate degrees, rather than absolute or perfect degrees. Therefore, the values ​​modified by one or more terms (such as "about", "approximately" and "substantially") are not limited to the specified exact values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value. In addition, unless otherwise indicated, the terms "first", "second" etc. are only used as marks in this article, and are not intended to impose order, position or hierarchical requirements on the items to which these terms are related. In addition, for example, the reference to the "second" item does not require or exclude the existence of, for example, the "first" or lower numbered items or the "third" or higher numbered items.

[0149] Although specific features of various embodiments of the present invention may be shown in some drawings and not in other drawings, this is for convenience only. In addition, references to "some embodiments" in the above description are not intended to be interpreted as excluding the existence of additional embodiments that also include the described features. In accordance with the principles of the present invention, any feature of a drawing may be referenced and / or claimed in conjunction with any feature of any other drawing.

[0150] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any device or system and performing any combined method. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. A composition comprising: from about 10 wt % to about 11 wt % chromium; no more than about 0.030 wt. % aluminum; from about 0.08 wt % to about 0.20 wt % carbon; about 0.10 wt % to about 0.60 wt % silicon; from about 0.05 wt. % to about 0.40 wt. % vanadium; from about 0.01 wt % to about 0.10 wt % titanium; no more than about 5 weight percent manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and The balance is iron and residual elements.

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

3. The composition of claim 1, wherein the composition comprises no more than 0.015 wt. % aluminum.

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

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

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

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

8. The composition according to claim 1, comprising: from about 10.25 wt % to about 11 wt % chromium; No more than about 0.015 wt. % aluminum; from about 0.12 wt % to about 0.18 wt % carbon; about 0.20 wt % to about 0.40 wt % silicon; from about 0.10 wt. % to about 0.30 wt. % vanadium; from about 0.015 wt % to about 0.060 wt % titanium; no more than about 5 weight percent manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and The balance is iron and residual elements.

9. The composition according to claim 1, further comprising: from about 0.10 wt % to about 1.0 wt % manganese; and / or From about 0.40 wt. % to about 1.2 wt. % molybdenum.

10. The composition according to claim 1, further comprising: from about 0.50 wt % to about 1.0 wt % manganese; and / or From about 0.60 wt. % to about 0.80 wt. % molybdenum.

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

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

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

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

15. The composition of claim 1, wherein the composition is a wrought composition and / or a cast composition.

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