ALLOY COMPOSITIONS AND ARTICLES FORMED OF SUCH COMPOSITIONS

Description

BACKGROUND

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 and improved creep strength.

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 creep strength. 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.

However, chemical modifications intended to improve oxidation resistance, such as higher chromium content in an CA6NM alloy described in US Patent Publication No. 2009/0090767, can decrease creep strength in iron-based alloys. Likewise, chemical modifications intended to improve creep strength, such as by reducing chromium content, can decrease oxidation resistance in iron-based alloys.

Accordingly, there is a need for iron-based alloys that possess improved oxidation resistance and improved creep strength.

BRIEF DESCRIPTION

In one aspect, a composition is provided. The composition includes from about 11.1 wt % to about 11.6 wt % chromium, from about 0.005 wt % to about 0.25 wt % carbon, from about 0.1 wt % to about 2.0 wt % manganese, from about 0.1 wt % to about 1.0 wt % silicon, from about 0.4 wt % to about 2.0 wt % molybdenum, from about 0.005 wt % to about 0.5 wt % vanadium, from about 0.01 wt % to about 0.50 wt % niobium, from about 0.005 wt % to about 0.1 wt % nitrogen, from about 0.1 wt % to about 1.0 wt % nickel, from 0 wt % to about 0.04 wt % phosphorus, from 0 wt % to about 0.02 wt % sulfur, and iron.

In another aspect, an article including a composition is provided. The composition includes from about 11.1 wt % to about 11.6 wt % chromium, from about 0.005 wt % to about 0.25 wt % carbon, from about 0.1 wt % to about 2.0 wt % manganese, from about 0.1 wt % to about 1.0 wt % silicon, from about 0.4 wt % to about 2.0 wt % molybdenum, from about 0.005 wt % to about 0.5 wt % vanadium, from about 0.01 wt % to about 0.50 wt % niobium, from about 0.005 wt % to about 0.1 wt % nitrogen, from about 0.1 wt % to about 1.0 wt % nickel, from 0 wt % to about 0.04 wt % phosphorus, from 0 wt % to about 0.02 wt % sulfur, and iron.

BRIEF DESCRIPTION OF THE DRAWINGS

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. 1 depicts the creep strength and oxidation rate for a comparative stainless steel alloy composition including nominal 9% Cr chromium as well as molybdenum, vanadium, and niobium, a comparative CA6NM alloy composition, and a composition IE1 in accordance with the present disclosure.

FIG. 2 depicts the Larson-Miller parameter (LMP) per stress rupture strength for a comparative composition CE1 and a composition IE1 in accordance with the present disclosure.

FIG. 3 depicts photographs of thermal cycling studies of alloys formed from a comparative composition CE1 and a composition IE1 in accordance with the present disclosure

DETAILED DESCRIPTION

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 compared to other alloy compositions. The compositions surprisingly exhibit improved oxidation resistance and improved creep strength. Compositions according to the present disclosure are broadly applicable in applications requiring alloys possessing improved oxidation resistance and improved creep strength.

It was particularly discovered in the present disclosure that carefully controlling chromium content to be within the range of from about 11.1 wt % to about 11.6 wt % resulted in alloys with improved oxidation resistance and improved creep strength. Compositions according to the present disclosure therefore optimize the chemistry of a 11.1 wt %-11.6 wt % chromium alloy.

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 11.1 wt % to about 11.6 wt % chromium, from about 0.005 wt % to about 0.25 wt % carbon, from about 0.1 wt % to about 2.0 wt % manganese, from about 0.1 wt % to about 1.0 wt % silicon, from about 0.4 wt % to about 2.0 wt % molybdenum, from about 0.005 wt % to about 0.5 wt % vanadium, from about 0.01 wt % to about 0.50 wt % niobium, from about 0.005 wt % to about 0.1 wt % nitrogen, from about 0.1 wt % to about 1.0 wt % nickel, from 0 wt % to about 0.04 wt % phosphorus, from 0 wt % to about 0.02 wt % sulfur, and iron.

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 11.1 wt % to about 11.6 wt % chromium.

In some embodiments, the composition includes at least about 11.1 wt % Cr, at least about 11.15 wt % Cr, at least about 11.2 wt % Cr, at least about 11.25 wt % Cr, at least about 11.3 wt % Cr, at least about 11.35 wt % Cr, at least about 11.4 wt % Cr, at least about 11.45 wt % Cr, at least about 11.5 wt % Cr, or at least about 11.55 wt % Cr. In some embodiments, the composition includes at most about 11.15 wt % Cr, at most about 11.2 wt % Cr, at most about 11.25 wt % Cr, at most about 11.3 wt % Cr, at most about 11.35 wt % Cr, at most about 11.4 wt % Cr, at most about 11.45 wt % Cr, at most about 11.5 wt % Cr, at most about 11.55 wt % Cr, or at most about 11.6 wt % Cr.

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 0.005 wt % to about 0.25 wt % carbon. In some embodiments, the composition includes from about 0.1 wt % to about 0.16 wt % carbon.

In some embodiments, the composition includes at least about 0.005 wt % C, at least about 0.01 wt % C, at least about 0.02 wt % C, at least about 0.03 wt % C, at least about 0.04 wt % C, at least about 0.05 wt % C, at least about 0.06 wt % C, at least about 0.07 wt % C, at least about 0.08 wt % C, at least about 0.09 wt % C, at least about 0.10 wt % C, at least about 0.11 wt % C, at least about 0.12 wt % C, at least about 0.13 wt % C, at least about 0.14 wt % C, at least about 0.15 wt % C, at least about 0.16 wt % C, at least about 0.17 wt % C, at least about 0.18 wt % C, at least about 0.19 wt % C, at least about 0.20 wt % C, at least about 0.21 wt % C, at least about 0.22 wt % C, at least about 0.23 wt % C, or at least about 0.24 wt % C. In some embodiments, the composition includes at most about 0.01 wt % C, at most about 0.02 wt % C, at most about 0.03 wt % C, at most about 0.04 wt % C, at most about 0.05 wt % C, at most about 0.06 wt % C, at most about 0.07 wt % C, at most about 0.08 wt % C, at most about 0.09 wt % C, at most about 0.10 wt % C, at most about 0.11 wt % C, at most about 0.12 wt % C, at most about 0.13 wt % C, at most about 0.14 wt % C, at most about 0.15 wt % C, at most about 0.16 wt % C, at most about 0.17 wt % C, at most about 0.18 wt % C, at most about 0.19 wt % C, at most about 0.20 wt % C, at most about 0.21 wt % C, at most about 0.22 wt % C, at most about 0.23 wt % C, at most about 0.24 wt % C, or at most about 0.25 wt % C.

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 2.0 wt % manganese. In some embodiments, the composition includes from about 0.30 wt % to about 1.0 wt % manganese.

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, at least about 0.95 wt % Mn, at least about 1.0 wt % Mn, at least about 1.05 wt % Mn, at least about 1.10 wt % Mn, at least about 1.15 wt % Mn, at least about 1.20 wt % Mn, at least about 1.25 wt % Mn, at least about 1.30 wt % Mn, at least about 1.35 wt % Mn, at least about 1.40 wt % Mn, at least about 1.45 wt % Mn, at least about 1.50 wt % Mn, at least about 1.55 wt % Mn, at least about 1.60 wt % Mn, at least about 1.65 wt % Mn, at least about 1.70 wt % Mn, at least about 1.75 wt % Mn, at least about 1.80 wt % Mn, at least about 1.85 wt % Mn, at least about 1.90 wt % Mn, or at least about 1.95 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, at most about 1.0 wt % Mn, at most about 1.05 wt % Mn, at most about 1.10 wt % Mn, at most about 1.15 wt % Mn, at most about 1.20 wt % Mn, at most about 1.25 wt % Mn, at most about 1.30 wt % Mn, at most about 1.35 wt % Mn, at most about 1.40 wt % Mn, at most about 1.45 wt % Mn, at most about 1.50 wt % Mn, at most about 1.55 wt % Mn, at most about 1.60 wt % Mn, at most about 1.65 wt % Mn, at most about 1.70 wt % Mn, at most about 1.75 wt % Mn, at most about 1.80 wt % Mn, at most about 1.85 wt % Mn, at most about 1.90 wt % Mn, at most about 1.95 wt % Mn, or at most about 2.0 wt % Mn.

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 1.0 wt % silicon. In some embodiments, the composition includes from about 0.20 wt % to about 0.60 wt % silicon.

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, at least about 0.55 wt % Si, at least about 0.60 wt % Si, at least about 0.65 wt % Si, at least about 0.70 wt % Si, at least about 0.75 wt % Si, at least about 0.80 wt % Si, at least about 0.85 wt % Si, at least about 0.90 wt % Si, or at least about 0.95 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, at most about 0.60 wt % Si, at most about 0.65 wt % Si, at most about 0.70 wt % Si, at most about 0.75 wt % Si, at most about 0.80 wt % Si, at most about 0.85 wt % Si, at most about 0.90 wt % Si, at most about 0.95 wt % Si, or at most about 1.0 wt % Si.

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 0.40 wt % to about 2.0 wt % molybdenum. In some embodiments, the composition includes from about 0.80 wt % to about 1.1 wt % molybdenum.

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, at least about 1.15 wt % Mo, at least about 1.20 wt % Mo, at least about 1.25 wt % Mo, at least about 1.30 wt % Mo, at least about 1.35 wt % Mo, at least about 1.40 wt % Mo, at least about 1.45 wt % Mo, at least about 1.50 wt % Mo, at least about 1.55 wt % Mo, at least about 1.60 wt % Mo, at least about 1.65 wt % Mo, at least about 1.70 wt % Mo, at least about 1.75 wt % Mo, at least about 1.80 wt % Mo, at least about 1.85 wt % Mo, at least about 1.90 wt % Mo, or at least about 1.95 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, at most about 1.20 wt % Mo, at most about 1.25 wt % Mo, at most about 1.30 wt % Mo, at most about 1.35 wt % Mo, at most about 1.40 wt % Mo, at most about 1.45 wt % Mo, at most about 1.50 wt % Mo, at most about 1.55 wt % Mo, at most about 1.60 wt % Mo, at most about 1.65 wt % Mo, at most about 1.70 wt % Mo, at most about 1.75 wt % Mo, at most about 1.80 wt % Mo, at most about 1.85 wt % Mo, at most about 1.90 wt % Mo, at most about 1.95 wt % Mo, or at most about 2.0 wt % Mo.

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 0.005 wt % to about 0.50 wt % vanadium. In some embodiments, the composition includes from about 0.17 wt % to about 0.25 wt % vanadium.

In some embodiments, the composition includes at least about 0.005 wt % V, at least about 0.01 wt % V, at least about 0.02 wt % V, at least about 0.03 wt % V, at least about 0.04 wt % V, at least about 0.05 wt % V, 0.10 wt % V, at least about 0.15 wt % V, at least about 0.17 wt % V, at least about 0.20 wt % V, at least about 0.25 wt % V, at least about 0.30 wt % V, at least about 0.35 wt % V, at least about 0.40 wt % V, or at least about 0.45 wt % V. In some embodiments, the composition includes at most about 0.01 wt % V, at most about 0.02 wt % V, at most about 0.03 wt % V, at most about 0.04 wt % V, at most about 0.05 wt % V, 0.10 wt % V, at most about 0.15 wt % V, at most about 0.17 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, at most about 0.40 wt % V, or at most about 0.45 wt % V, or at most about 0.50 wt % V.

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 0.50 wt % niobium. In some embodiments, the composition includes from about 0.05 wt % to about 0.10 wt % niobium.

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, at least about 0.15 wt % Nb, at least about 0.20 wt % Nb, at least about 0.25 wt % Nb, at least about 0.30 wt % Nb, at least about 0.35 wt % Nb, at least about 0.40 wt % Nb, or at least about 0.45 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 0.10 wt % Nb, at most about 0.15 wt % Nb, at most about 0.20 wt % Nb, at most about 0.25 wt % Nb, at most about 0.30 wt % Nb, at most about 0.35 wt % Nb, at most about 0.40 wt % Nb, at most about 0.45 wt % Nb, or at most about 0.50 wt % Nb.

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 0.005 wt % to about 0.10 wt % nitrogen. In some embodiments, the composition includes from about 0.03 wt % to about 0.06 wt % nitrogen.

In some embodiments, the composition includes at least about 0.005 wt % N, 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 0.01 wt % N, 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.

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 0.30 wt % to about 0.7 wt % nickel.

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.

In some embodiments, the composition may include any suitable amount of phosphorus (P) that facilitates the composition described herein. In some embodiments, the composition does not include phosphorus. In some embodiments, the composition includes up to 0.02 wt % phosphorus.

In some embodiments, the composition includes at least about 0.001 wt % P, at least about 0.002 wt % P, at least about 0.003 wt % P, at least about 0.004 wt % P, at least about 0.005 wt % P, at least about 0.006 wt % P, at least about 0.007 wt % P, at least about 0.008 wt % P, at least about 0.009 wt % P, at least about 0.010 wt % P, at least about 0.011 wt % P, at least about 0.012 wt % P, at least about 0.013 wt % P, at least about 0.014 wt % P, at least about 0.015 wt % P, at least about 0.016 wt % P, at least about 0.017 wt % P, at least about 0.018 wt % P, or at least about 0.019 wt % P. In some embodiments, the composition includes at most about 0.002 wt % P, at most about 0.003 wt % P, at most about 0.004 wt % P, at most about 0.005 wt % P, at most about 0.006 wt % P, at most about 0.007 wt % P, at most about 0.008 wt % P, at most about 0.009 wt % P, at most about 0.010 wt % P, at most about 0.011 wt % P, at most about 0.012 wt % P, at most about 0.013 wt % P, at most about 0.014 wt % P, at most about 0.015 wt % P, at most about 0.016 wt % P, at most about 0.017 wt % P, at most about 0.018 wt % P, at most about 0.019 wt % P, or at most about 0.020 wt % P.

In some embodiments, the composition may include any suitable amount of sulfur(S) that facilitates the composition described herein. In some embodiments, the composition does not include sulfur. In some embodiments, the composition includes up to 0.01 wt % sulfur.

In some embodiments, the composition includes at least about 0.001 wt % S, at least about 0.002 wt % S, at least about 0.003 wt % S, at least about 0.004 wt % S, at least about 0.005 wt % S, at least about 0.006 wt % S, at least about 0.007 wt % S, at least about 0.008 wt % S, or at least about 0.009 wt % S. In some embodiments, the composition includes at most about 0.002 wt % S, at most about 0.003 wt % S, at most about 0.004 wt % S, at most about 0.005 wt % S, at most about 0.006 wt % S, at most about 0.007 wt % S, at most about 0.008 wt % S, or at most about 0.009 wt % S, or at most about 0.010 wt % S.

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 %.

In some embodiments, the composition includes at least about 80 wt % Fe, at least about 81 wt % Fe, at least about 82 wt % Fe, at least about 83 wt % Fe, at least about 84 wt % Fe, at least about 85 wt % Fe, at least about 86 wt % Fe, at least about 87 wt % Fe, or at least about 88 wt % Fe.

In some embodiments, the composition includes at most about 81 wt % Fe, at most about 82 wt % Fe, at most about 83 wt % Fe, at most about 84 wt % Fe, at most about 85 wt % Fe, at most about 86 wt % Fe, at most about 87 wt % Fe, at most about 88 wt % Fe, or at most about 89 wt % Fe.

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.

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.

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

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

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.

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

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

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.

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.

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

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

1. A composition comprising:

• • from about 11.1 wt % to about 11.6 wt % chromium;
  • from about 0.005 wt % to about 0.25 wt % carbon;
  • from about 0.1 wt % to about 2.0 wt % manganese;
  • from about 0.1 wt % to about 1.0 wt % silicon;
  • from about 0.4 wt % to about 2.0 wt % molybdenum;
  • from about 0.005 wt % to about 0.5 wt % vanadium;
  • from about 0.01 wt % to about 0.50 wt % niobium;
  • from about 0.005 wt % to about 0.1 wt % nitrogen;
  • from about 0.1 wt % to about 1.0 wt % nickel;
  • from 0 wt % to about 0.04 wt % phosphorus;
  • from 0 wt % to about 0.02 wt % sulfur; and
  • iron.

2. The composition according to the preceding clause, wherein the composition comprises at least about 11.15 wt % chromium.

3. The composition according to any preceding clause, wherein the composition comprises at least about 11.2 wt % chromium.

4. The composition of according to any preceding clause, wherein the composition comprises at least about 11.25 wt % chromium.

5. The composition according to any preceding clause, wherein the composition comprises at least about 11.3 wt % chromium.

6. The composition according to any preceding clause, wherein the composition comprises at most about 11.55 wt % chromium.

7. The composition according to any preceding clause, wherein the composition comprises at most about 11.5 wt % chromium.

8. The composition according to any preceding clause, wherein the composition comprises at most about 11.45 wt % chromium.

9. The composition according to any preceding clause, wherein the composition comprises at most about 11.4 wt % chromium.

10. The composition according to any preceding clause, comprising:

• • from about 11.1 wt % to about 11.6 wt % chromium;
  • from about 0.1 wt % to about 0.16 wt % carbon;
  • from about 0.3 wt % to about 1.0 wt % manganese;
  • from about 0.2 wt % to about 0.6 wt % silicon;
  • from about 0.8 wt % to about 1.1 wt % molybdenum;
  • from about 0.17 wt % to about 0.25 wt % vanadium;
  • from about 0.05 wt % to about 0.1 wt % niobium;
  • from about 0.03 wt % to about 0.06 wt % nitrogen;
  • from about 0.3 wt % to about 0.7 wt % nickel;
  • from 0 wt % to about 0.02 wt % phosphorus;
  • from 0 wt % to about 0.01 wt % sulfur; and
  • balance iron and residual elements.

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

12. An article comprising a composition, the composition comprising:

• • from about 11.1 wt % to about 11.6 wt % chromium;
  • from about 0.005 wt % to about 0.25 wt % carbon;
  • from about 0.1 wt % to about 2.0 wt % manganese;
  • from about 0.1 wt % to about 1.0 wt % silicon;
  • from about 0.4 wt % to about 2.0 wt % molybdenum;
  • from about 0.005 wt % to about 0.5 wt % vanadium;
  • from about 0.01 wt % to about 0.50 wt % niobium;
  • from about 0.005 wt % to about 0.1 wt % nitrogen;
  • from about 0.1 wt % to about 1.0 wt % nickel;
  • from 0 wt % to about 0.04 wt % phosphorus;
  • from 0 wt % to about 0.02 wt % sulfur; and
  • iron.

13. The article according to the preceding clause, wherein the composition is a wrought composition, a forged composition, and/or a cast composition.

14. The article according to any 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.

15. 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.

16. The article according to any preceding clause, wherein the composition comprises at least about 11.15 wt % chromium.

17. The article according to any preceding clause, wherein the composition comprises at least about 11.2 wt % chromium.

18. The article according to any preceding clause, wherein the composition comprises at most about 11.55 wt % chromium.

19. The article according to any preceding clause, wherein the composition comprises at most about 11.5 wt % chromium.

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

• • from about 11.1 wt % to about 11.6 wt % chromium;
  • from about 0.1 wt % to about 0.16 wt % carbon;
  • from about 0.3 wt % to about 1.0 wt % manganese;
  • from about 0.2 wt % to about 0.6 wt % silicon;
  • from about 0.8 wt % to about 1.1 wt % molybdenum;
  • from about 0.17 wt % to about 0.25 wt % vanadium;
  • from about 0.05 wt % to about 0.1 wt % niobium;
  • from about 0.03 wt % to about 0.06 wt % nitrogen;
  • from about 0.3 wt % to about 0.7 wt % nickel;
  • from 0 wt % to about 0.02 wt % phosphorus;
  • from 0 wt % to about 0.01 wt % sulfur; and
  • balance iron and residual elements.

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

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

Compositions according to the present disclosure are shown in the below table. CE1 is a comparative stainless steel alloy composition including nominal 9% Cr chromium as well as molybdenum, vanadium, and niobium, and IE1 is an inventive example. The only chemical difference between these examples is their respective chromium contents. “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 (%)	Wt (%)
	Element	CE1	IE1
	Carbon	0.1-0.16	0.1-0.16
	Manganese	0.3-1.0	0.3-1.0
	Silicon	0.2-0.6	0.2-0.6
	Chromium	8.5-11.0	11.1-11.6
	Molybdenum	0.8-1.1	0.8-1.1
	Vanadium	0.17-0.25	0.17-0.25
	Niobium	0.05-0.1	0.05-0.1
	Nitrogen	0.03-0.06	0.03-0.06
	Nickel	0.3-0.7	0.3-0.7
	Phosphorus	0.02 max	0.02 max
	Sulfur	0.01 max	0.01 max
	Iron	balance	balance
	Total	100	100

Example 2. Simulations

The properties of the compositions according to the present disclosure were simulated to determine expected physical properties. The simulated properties are shown in FIG. 1 as compared to the properties of CE1 and a comparative CA6NM alloy composition having chromium in an amount between 11.5 wt % and 14.0 wt %. In FIG. 1, it is observed that the composition according to the present disclosure has an improved creep strength and a lower oxidation rate compared to the comparative compositions.

Example 3. Physical Measurements

The properties of the compositions according to the present disclosure were also measured to determine physical properties. The measured properties of cast alloys including a comparative composition and a composition according to the present disclosure are shown in FIGS. 2-3.

In FIG. 2, it is observed that the composition according to the present disclosure has a higher relative LMP per stress rupture strength compared to the comparative composition. The results are normalized to the performance of the comparative composition. The LMP measures time until stress rupture, and therefore it is demonstrated that the composition according to the present disclosure has improved stress rupture performance and creep strength.

In FIG. 3, it is observed that the composition according to the present disclosure has a higher oxidation resistance compared to the comparative composition. Cast alloys composed of CE1 or IE1 were made and evaluated over the indicated number of thermal cycles at 1200° F. CE1 showed black oxides covering the whole surface of the cast alloy as soon as 400 cycles, and this oxide layer started to spall in subsequent cycles. By 800 cycles, the complete layer spalled and a new oxidation cycle subsequently started. In contrast, IE1 showed an initial protective oxide layer that survived all 1000 cycles without spalling oxides. It is therefore demonstrated that the composition according to the present disclosure has improved oxidation resistance.

It was discovered herein that compositions according to the present disclosure could be used for wrought and cast alloys. The compositions include altered elemental content for Cr compared to other alloy compositions. The compositions surprisingly exhibit improved oxidation resistance and improved creep strength. Compositions according to the present disclosure are broadly applicable in applications requiring alloys possessing improved oxidation resistance and improved creep strength.

Definitions

As used herein, references to “example embodiment” or “one embodiment” or “some embodiments” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

When introducing elements of various embodiments disclosed herein, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. The term “comprising” may alternatively be read to mean “consisting of” or “consisting essentially of”.

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.

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.

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.