ALLOY COMPOSITIONS AND ARTICLES FORMED OF SUCH COMPOSITIONS

Abstract

 Described herein are compositions, and more particularly to alloy compositions and articles formed with the alloy compositions. The alloy compositions are broadly applicable in applications requiring alloys with improved oxidation resistance, reduced retained delta ferrite, and/or improved rupture ductility.

Description

BACKGROUND

[0001] The field of the disclosure relates generally to compositions, and more particularly to alloy compositions and articles formed with the alloy compositions. The alloy compositions are broadly applicable in applications requiring alloys with improved oxidation resistance, reduced retained delta ferrite, and/or improved rupture ductility.

[0002] Iron-based alloys are commonly used in cast and wrought steel products. However, conventional iron-based alloys exhibit excessive oxidation and poor long-term rupture characteristics such as delta ferrite and rupture ductility. Although some iron-based alloys have improved one or two of these characteristics, no iron-based alloys have maximized all of these characteristics. This is especially true in the power generation industry where iron-based materials operate at higher temperatures and pressures in order increase the efficiencies of various components while not comprising structural integrity.

[0003] However, chemical modifications intended to improve oxidation, such as higher chromium content, can increase the potential of delta ferrite, thereby resulting in poorer high temperature rupture properties. Additions of tungsten can improve rupture performance while increasing high temperature oxidation rates. The use of aluminum to de-oxidize the molten iron has also been shown to decrease rupture ductility in iron-based alloys.

[0004] Accordingly, there is a need for iron-based alloys that possess improved oxidation resistance, reduced retained delta ferrite, and improved rupture ductility.

BRIEF DESCRIPTION

[0005] In one aspect, a composition is provided. The composition includes 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, from 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 wt% of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt, and balance iron and residual elements.

[0006] In another aspect, an article including a composition is provided. The composition includes 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, from 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 wt% of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt, and balance iron and residual elements.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1A depicts exemplary results of the simulated matrix phase for a comparative composition CE1 in accordance with the present disclosure.

FIG. 1B depicts exemplary results of the simulated matrix phase for a comparative composition CE2 in accordance with the present disclosure.

FIG. 1C depicts exemplary results of the simulated matrix phase for a comparative composition CE3 in accordance with the present disclosure.

FIG. 1D depicts exemplary results of the simulated matrix phase for an inventive composition IE1 in accordance with the present disclosure.

FIG. 2A depicts exemplary results of the simulated hardenability for a comparative composition CE1 in accordance with the present disclosure.

FIG. 2B depicts exemplary results of the simulated hardenability for a comparative composition CE2 in accordance with the present disclosure.

FIG. 2C depicts exemplary results of the simulated hardenability for a comparative composition CE3 in accordance with the present disclosure.

FIG. 2D depicts exemplary results of the simulated hardenability for an inventive composition IE1 in accordance with the present disclosure.

FIG. 3A depicts exemplary results of the simulated YS tempering for comparative compositions and an inventive composition in accordance with the present disclosure.

FIG. 3B depicts exemplary results of the simulated UTS tempering for comparative compositions and an inventive composition in accordance with the present disclosure.

FIG. 4 depicts exemplary results of the simulated short-term rupture for comparative compositions and an inventive composition in accordance with the present disclosure.

DETAILED DESCRIPTION

[0008] It was discovered in the present disclosure that compositions according to the present disclosure could be used for wrought and cast alloys. The compositions include altered elemental content for Cr, Al, Si, C, Al, Ti, and V compared to other alloy compositions. The Cr content is especially distinct. The compositions exhibit improved oxidation resistance, reduced retained delta ferrite, and improved rupture ductility. Compositions according to the present disclosure are broadly applicable in applications requiring alloys possessing improved oxidation resistance, reduced retained delta ferrite, and/or improved rupture ductility.

[0009] It was particularly discovered in the present disclosure that increasing chromium content from 8.5% to 9.5% to as much as 11 % greatly reduces the formation of inner and outer oxide layers for Creep Strength Enhanced Ferritic (CSEF) wrought steel products. Increasing the chromium content also results in a higher Chrome Equivalent (CE) that can result in the possibility of retaining delta ferrite. Delta ferrite is a low creep resistant phase that will result in reduced long term rupture strength. Thus, the amount of retained delta-ferrite is generally less than 5% in the final product. Compositions according to the present disclosure optimize the chemistry of a cast 10-11% chromium alloy to achieve improved oxidation performance while reducing the risk of premature rupture failure due to retained delta ferrite and poor rupture ductility.

[0010] The embodiments described herein overcome at least some of the disadvantages of known iron-based alloys. The exemplary embodiments described herein include a composition. The composition includes 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, from 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 wt% of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt, and balance iron and residual elements

[0011] In some embodiments, the composition may include any suitable amount of chromium (Cr) that facilitates the composition described herein. In some embodiments, the composition includes Cr. In some embodiments, the composition includes from about 10 wt% to about 11 wt% chromium. In some embodiments, the composition includes from about 10.25 wt% to about 11 wt% chromium.

[0012] In some embodiments, the composition includes 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 includes at most about 10.1 wt% Cr, at most about 10.2 wt% Cr, at most about 10.3 wt% Cr, at most about 10.4 wt% Cr, at most about 10.5 wt% Cr, at most about 10.6 wt% Cr, at most about 10.7 wt% Cr, at most about 10.8 wt% Cr, at most about 10.9 wt% Cr, or at most about 11.0 wt% Cr.

[0013] In some embodiments, the composition may include any suitable amount of aluminum (Al) that facilitates the composition 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.

[0014] In some embodiments, the composition includes 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 includes 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.

[0015] In some embodiments, the composition may include any suitable amount of carbon (C) that facilitates the composition described herein. In some embodiments, the composition includes from about 0.08 wt% to about 0.20 wt% carbon. In some embodiments, the composition includes from about 0.12 wt% to about 0.18 wt% carbon.

[0016] In some embodiments, the composition includes 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 includes at most about 0.09 wt% carbon, at most about 0.10 wt% carbon, at most about 0.11 wt% carbon, at most about 0.12 wt% carbon, at most about 0.13 wt% carbon, at most about 0.14 wt% carbon, at most about 0.15 wt% carbon, at most about 0.16 wt% carbon, at most about 0.17 wt% carbon, at most about 0.18 wt% carbon, at most about 0.19 wt% carbon, or at most about 0.20 wt% carbon.

[0017] In some embodiments, the composition may include any suitable amount of silicon (Si) that facilitates the composition described herein. In some embodiments, the composition includes from about 0.10 wt% to about 0.60 wt% silicon. In some embodiments, the composition includes from about 0.20 wt% to about 0.40 wt% silicon.

[0018] In some embodiments, the composition includes at least about 0.10 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 includes at most about 0.15 wt% Si, at most about 0.20 wt% Si, at most about 0.25 wt% Si, at most about 0.30 wt% Si, at most about 0.35 wt% Si, at most about 0.40 wt% Si, at most about 0.45 wt% Si, at most about 0.50 wt% Si, at most about 0.55 wt% Si, or at most about 0.60 wt% Si.

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

[0020] In some embodiments, the composition includes 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 includes 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.

[0021] In some embodiments, the composition may include any suitable amount of titanium (Ti) that facilitates the composition described herein. In some embodiments, the composition includes from about 0.01 wt% to about 0.10 wt% titanium. In some embodiments, the composition includes from about 0.015 wt% to about 0.060 wt% titanium.

[0022] In some embodiments, the composition includes 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 includes at most about 0.015 wt% Ti, at most about 0.020 wt% Ti, at most about 0.025 wt% Ti, at most about 0.030 wt% Ti, at most about 0.035 wt% Ti, at most about 0.040 wt% Ti, at most about 0.045 wt% Ti, at most about 0.050 wt% Ti, or at most about 0.055 wt% Ti, or at most about 0.060 wt% Ti.

[0023] In some embodiments, the composition may include any suitable amount of manganese (Mn) that facilitates the composition described herein. In some embodiments, the composition includes from about 0.10 wt% to about 1.0 wt% manganese. In some embodiments, the composition includes from about 0.50 wt% to about 1.0 wt% manganese.

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

[0025] In some embodiments, the composition may include any suitable amount of molybdenum (Mo) that facilitates the composition described herein. In some embodiments, the composition includes from about 0.10 wt% to about 1.0 wt% molybdenum. In some embodiments, the composition includes from about 0.50 wt% to about 1.0 wt% molybdenum.

[0026] In some embodiments, the composition includes 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 includes at most about 0.45 wt% Mo, at most about 0.50 wt% Mo, at most about 0.55 wt% Mo, at most about 0.60 wt% Mo, at most about 0.65 wt% Mo, at most about 0.70 wt% Mo, at most about 0.75 wt% Mo, at most about 0.80 wt% Mo, at most about 0.85 wt% Mo, at most about 0.90 wt% Mo, at most about 0.95 wt% Mo, at most about 1.0 wt% Mo, at most about 1.05 wt% Mo, at most about 1.1 wt% Mo, at most about 1.15 wt% Mo, or at most about 1.2 wt% Mo.

[0027] In some embodiments, the composition may include any suitable amount of nickel (Ni) that facilitates the composition described herein. In some embodiments, the composition includes from about 0.10 wt% to about 1.0 wt% nickel. In some embodiments, the composition includes from about 0.50 wt% to about 1.0 wt% nickel.

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

[0029] In some embodiments, the composition may include any suitable amount of niobium (Nb) that facilitates the composition described herein. In some embodiments, the composition includes from about 0.01 wt% to about 0.12 wt% niobium. In some embodiments, the composition includes from about 0.05 wt% to about 0.10 wt% niobium.

[0030] 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 at most about 0.02 wt% Nb, at most about 0.03 wt% Nb, at most about 0.04 wt% Nb, at most about 0.05 wt% Nb, at most about 0.06 wt% Nb, at most about 0.07 wt% Nb, at most about 0.08 wt% Nb, at most about 0.09 wt% Nb, at most about 0.010 wt% Nb, at most about 0.11 wt% Nb, or at most about 0.12 wt% Nb.

[0031] In some embodiments, the composition may include any suitable amount of nitrogen (N) that facilitates the composition described herein. In some embodiments, the composition includes from about 0.01 wt% to about 0.10 wt% nitrogen. In some embodiments, the composition includes from about 0.03 wt% to about 0.07 wt% nitrogen.

[0032] In some embodiments, the composition includes 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 includes 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.

[0033] In some embodiments, the composition may include any suitable amount of copper (Cu) that facilitates the composition described herein. In some embodiments, the composition includes from about 0.05 wt% to about 0.25 wt% copper. In some embodiments, the composition includes from about 0.10 wt% to about 0.20 wt% copper.

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

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

[0036] In some embodiments, the composition includes at least about 84 wt% Fe, at least about 85 wt% Fe, or at least about 86 wt% Fe. In some embodiments, the composition includes at most about 85 wt% Fe, at most about 86 wt% Fe, or at most about 87 wt% Fe.

[0037] In some embodiments, the composition may include tramp elements. As used herein, tramp elements include elements that may be inherently present in the composition and substantially alter the material properties of the composition. In some embodiments, tramp elements are not necessary in the composition and provide no benefit to the composition.

[0038] In some embodiments, the composition includes balance iron and residual elements. As used herein, residual elements include elements that may be inherently present in the composition but do not substantially alter 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 wt%.

[0040] 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 facilitates the composition described herein. In some embodiments, the composition includes 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.

[0041] In some embodiments, the composition includes chromium, carbon, silicon, vanadium, titanium, manganese, molybdenum, nickel, niobium, nitrogen, copper, and iron. In some embodiments, the composition further includes 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.

[0042] 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 wt% 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 wt% of phosphorus, sulfur, tungsten, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and/or cobalt

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

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

[0045] In some embodiments, the composition may have a martensite start temperature that facilitates the use of the composition described herein. In some embodiments, the composition has a martensite start temperature in a range of from about 450 °F to about 550 °F.

[0046] In some embodiments, the composition may have a martensite 90% temperature that facilitates the use of the composition described herein. In some embodiments, the composition has a martensite 90% temperature in a range of from about 250 °F to about 350 °F.

[0047] Also described herein is an article including the composition. Generally, the composition may be included in any suitable article known in the art that facilitates the use of the composition described herein.

[0048] In some embodiments, the article is produced using, but not limited to only using, a wrought process and/or a cast process. In some embodiments, the article is produced using a cast process.

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

[0050] In some embodiments, the article is a component of a turbine such as, but not limited to only being, 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, compressor blades, compressor vanes, guide vanes, retaining rings, and a combination thereof.

[0051] In some embodiments, the article is a component of a turbine such as, but not limited to only being, 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 intermediate pressure rotor, a packing head, a diaphragm casing, and a combination thereof.

[0052] In some embodiments, the article is a component of a turbo charger component. In some embodiments, the article is a component of an automobile.

[0053] In some embodiments, the article is configured to be used at a max operating temperature of 750 °C.

[0054] Further aspects of the present disclosure are provided by the subject matter of the following clauses:

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;

from 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 wt% of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and

balance iron and residual elements.

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

3. The composition according to any preceding clause, wherein the composition comprises no more than 0.015 wt% aluminum.

4. The composition according to any preceding clause, wherein the composition comprises from about 0.12 wt% to about 0.18 wt% carbon.

5. The composition according to any preceding clause, wherein the composition comprises from about 0.20 wt% to about 0.40 wt% silicon.

6. The composition according to any preceding clause, wherein the composition comprises from about 0.10 wt% to about 0.30 wt% vanadium.

7. The composition according to any preceding clause, wherein the composition comprises from about 0.015 wt% to about 0.060 wt% titanium.

8. The composition according to any preceding clause, 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;

from 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 wt% of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and

balance iron and residual elements.

9. The composition according to any preceding clause, 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 any preceding clause, 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 according to any preceding clause, wherein the composition has a freezing range less than about 200 °F.

12. The composition according to any preceding clause, wherein the composition has a freezing range less than about 175 °F.

13. The composition according to any preceding clause, wherein the composition has a martensite start temperature in a range of from about 450 °F to about 550 °F.

14. The composition according to any preceding clause, wherein the composition has a martensite 90% temperature in a range of from about 250 °F to about 350 °F.

15. The composition according to any preceding clause, wherein the composition is a wrought composition and/or a cast composition.

16. An article comprising a composition, the 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;

from 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 wt% of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and

balance iron and residual elements.

17. The 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 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 intermediate pressure rotor, a packing head, a diaphragm casing, and a combination thereof.

18. The article according to any preceding clause, 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 case, an inner diffuser case, a compressor case, an inner compressor case, a splitter, an inner barrel, a turbine shell, compressor blades, compressor vanes, guide vanes, retaining rings, and a combination thereof.

19. The article according to any preceding clause, wherein the composition comprises:

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;

from 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 wt% of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and

balance iron and residual elements.

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

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

from about 0.40 wt% to about 1.2 wt% molybdenum.

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

EXAMPLES

[0056] Without further elaboration, it is believed that one skilled in the art using the preceding description can utilize the present invention to its fullest extent. The following Examples are, therefore, to be construed as merely illustrative, and not limiting of the disclosure in any way whatsoever. The starting material for the following Examples may not have necessarily been prepared by a particular preparative run whose procedure is described in other Examples. It also is understood that any numerical range recited herein includes all values from the lower value to the upper value. For example, if a range is stated as 10-50, it is intended that values such as 12-30, 20-40, or 30-50, etc., are expressly enumerated in this specification. These are only examples of what is specifically intended, and all possible combinations of numerical values between and including the lowest value and the highest value enumerated are to be considered to be expressly stated in this application.

Example 1. Compositions.

[0057] Compositions according to the present disclosure are shown in the below table. CE1 and CE5 are comparative examples in wrought form. CE2, CE3, and CE4 are comparative examples in casting form. IE1 is an inventive example in casting form. "max" means the maximum amount of the element, "min" means the minimum amount of the element, and "N/A" means the element is not present.

Table 1. Tested compositions.

	Wt (%)
Element	CE1	CE2	CE3	CE4	CE5	IE1
Carbon	0.08-0.13	0.10-0.16	0.11-0.14	0.08-0.12	0.1-0.14	0.12-0.18
Manganese	0.20-0.50	0.3-1.0	0.80-1.0	0.3-0.6	0.15-0.45	0.5-1.0
Phosphorus	0.020 max	0.020 max	0.015 max	0.025 max	0.02 max	0.020 max
Sulfur	0.005 max	0.010 max	0.010 max	0.01 max	0.01 max	0.010 max
Silicon	0.15-0.45	0.20-0.60	0.20-0.30	0.20-0.50	0.4-0.6	0.20-0.40
Chromium	10.0-11.0	8.5-11.0	9.0-10.0	8.0-9.5	11.0-12.0	10.25-11.00
Molybdenum	0.40-0.60	0.8-1.1	1.4-1.6	0.85-1.05	0.2-0.4	0.6-0.8
Tungsten	0.05 max	N/A	N/A	N/A	1.3-1.7	0.05 max
Nickel	0.25 max	0.30-0.70	0.1-0.25	0.4 max	0.1-0.4	0.5-1.0
Vanadium	0.18-0.25	0.17-0.25	0.18-0.23	0.18-0.25	0.2-0.3	0.1-0.3
Niobium	0.02-0.06	0.05-0.10	0.05-0.08	0.06-0.10	N/A	0.05-0.10
Nitrogen	0.030-0.070	0.03-0.07	0.020-0.04	0.03-0.07	N/A	0.03-0.07
Copper	0.10 max	N/A	0.2 max	N/A	N/A	0.1-0.2
Aluminum	0.020 max	N/A	0.01-0.025	0.02 max	N/A	0.015 max
Boron	0.001	N/A	0.008-0.013	N/A	0.003-0.006	0.001 max
Titanium	0.01 max	N/A	0.015 max	0.01 max	N/A	0.015-0.060
Zirconium	0.01 max	N/A	N/A	0.01 max	N/A	0.01 max
Arsenic	0.010 max	N/A	0.005 max	N/A	N/A	0.005 max
Tin	0.010 max	N/A	0.005 max	N/A	N/A	0.005 max
Antimony	0.003 max	N/A	0.0035 max	N/A	N/A	0.003 max
Lead	N/A	N/A	N/A	N/A	N/A	0.003 max
Hydrogen	N/A	N/A	0.003 max	N/A	N/A	0.003 max
Cobalt	N/A	N/A	0.9-1.1	N/A	N/A	N/A
Iron	balance	balance	balance	balance	balance	balance
Total	100	100	100	100	100	100

Table 2. N/Al ratio.

	Wt (%)
Ratio	CE1	CE2	CE3	CE4	CE5	IE1
N/Al	4.0 min	N/A	N/A	N/A	N/A	N/A

Example 2. Simulated Matrix Phase.

[0058] The properties of the compositions according to the present disclosure were simulated to determine expected physical properties. The simulated matrix phase properties are shown in the below table and Figures 1A-1D.

[0059] Freezing range can often be used as a relative predictor of castability. A tighter freezing range generally has less shrinkage tendency and may also be less prone to solidification hot tears. CE2 and IE1 exhibit similar simulated freezing range temperatures, and therefore should exhibit similar castability.

Table 3. Critical Solidification Temperatures.

	Temperature (°F)
Phase	CE1	CE2	CE3	IE1
Liquidus	2735	2725	2716	2716
Solidus	2575	2552	2472	2545
Freezing range	160	173	244	171

Example 3. Simulated Hardenability.

[0060] The simulated martensite hardenability properties are shown in Figures 2A-2D. Ms is the martensite start temperature. M50 is the 50% martensite transformed temperature. M90 is the 90% martensite transformed temperature. HRC is the Rockwell C Hardness.

[0061] All four simulated compositions showed exceptional hardenability. It was observed that IE1 martensite start temperature is about 500 °F and martensite 90% temperature is about 300 °F. IE1 castings should achieve 100% martensite even in very thick sections during quenching/cooling. Bainite/ferrite/pearlite noses are pushed to very long times.

Example 4. Simulated Tempering.

[0062] The simulated tempering properties are shown in Figures 3A-3B. Figure 3A depicts the predicted yield strengths and Figure 3B depicts the ultimate tensile strengths. It was observed that all four simulated compositions show similar tempering responses. Tempering may be used to balance strength and toughness.

Example 5. Simulated Short-term Rupture.

[0063] The simulated short-term rupture properties are shown in Figure 4. It was observed that IE1 has similar short-term rupture properties as CE1.

[0064] It was discovered herein that compositions according to the present disclosure could be used for wrought and/or cast alloys. The compositions exhibit improved oxidation resistance, reduced retained delta ferrite, and improved rupture ductility. Compositions according to the present disclosure are broadly applicable in applications requiring alloys with improved oxidation resistance, reduced retained delta ferrite, and/or improved rupture ductility.

[0065] Unless otherwise indicated, approximating language, such as "generally," "substantially," and "about," as used herein indicates that the term so modified may apply to only an approximate degree, as would be recognized by one of ordinary skill in the art, rather than to an absolute or perfect degree. Accordingly, a value modified by a term or terms such as "about," "approximately," and "substantially" is not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Additionally, unless otherwise indicated, the terms "first," "second," etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, for example, a "second" item does not require or preclude the existence of, for example, a "first" or lower-numbered item or a "third" or higher-numbered item.

[0066] Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. Moreover, references to "some embodiments" in the above description are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.

[0067] 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 devices or systems and performing any incorporated methods. 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 with insubstantial differences from the literal languages 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;

from 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 wt% of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and

balance 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 of 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;

from 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 wt% of manganese, phosphorus, sulfur, molybdenum, tungsten, nickel, niobium, nitrogen, copper, boron, zirconium, arsenic, tin, antimony, lead, hydrogen, and cobalt; and

balance iron and residual elements.

9. The composition of 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 of 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 freezing range less than about 200 °F.

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

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

14. The composition of claim 1, wherein the composition has a martensite 90% temperature in a range of from 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.

Drawing