Stainless steel powders for additive manufacturing

Abstract

To provide stainless steel powders for additive manufacturing, and methods of using the powders in additive manufacturing.SOLUTION: Exemplary alloys may comprise, by mass%, 13.25-14.75% chromium, 4.5-5.5% nickel, 0.11-0.17% carbon, 0.01-0.31% titanium, and the balance mass% of iron and incidental elements and impurities. Exemplary methods may include conducting additive manufacturing with an atomized alloy powder to generate a manufactured article, where the atomized alloy powder may comprise, by mass%, 13.25-14.75% chromium, 4.5-5.5% nickel, 0.11-0.17% carbon, 0.01-0.31% titanium, and the balance mass% of iron and incidental elements and impurities.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 274,141, filed on November 1, 2021, the entire contents of which are incorporated herein by reference. Government interests This invention was made with government support under Contract No. N68335-18-C-0020, granted by the United States Department of Defense (USDE). The U.S. Government has certain rights in this invention. Technical field This disclosure relates to materials, methods, and techniques for producing stainless steel alloy powders. More specifically, exemplary stainless steel alloy powders are suitable for additive manufacturing. [Background technology]

[0002] Additive manufacturing (AM) is a method of manufacturing components using an alternating layering process under the control of computer-aided design (CAD) information, rather than using traditional molds and dies. Additive manufacturing techniques such as Selective Laser Melting (SLM), also known as Powder Bed Laser Melting (LPBF), have matured considerably in recent years. Additive manufacturing offers the potential to reduce material usage, energy consumption, component costs, and manufacturing time by enabling the production of highly complex geometric net shapes without the use of molds or machining. Additive manufacturing allows for rapid component production, one-off production of hard-to-find parts, and production of parts that are difficult to manufacture by conventional means (such as complex geometric shapes that cannot be machined or cast). As a result, additive manufacturing can provide flexibility in parts production not only for end-users obtaining custom or replacement parts, but also for OEMs (original equipment manufacturers). [Overview of the Initiative]

[0003] The materials, methods, and techniques disclosed and intended herein relate to alloy steels particularly adapted for additive manufacturing applications. In some cases, the alloy steel may contain chromium, nickel, carbon, titanium, and the remainder iron, as well as incidental elements and impurities. In some cases, the alloy steel may contain chromium, nickel, carbon, titanium, vanadium, tungsten, molybdenum, and the remainder iron, as well as incidental elements and impurities.

[0004] In one embodiment, an alloy is disclosed. The example alloy may contain, by mass%, 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.11% to 0.17% carbon; 0.01% to 0.31% titanium; less than 0.01% copper; less than 0.01% manganese; less than 0.02% nitrogen; less than 0.04% oxygen; and the remainder by mass% iron, as well as incidental elements and impurities. In another embodiment, atomized alloy powders usable for additive manufacturing are disclosed. Exemplary atomized alloy powders may contain, by mass%, 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.11% to 0.17% carbon; 0.01% to 0.31% titanium; less than 0.01% copper; less than 0.01% manganese; less than 0.02% nitrogen; less than 0.04% oxygen; and the remainder by mass% iron, as well as incidental elements and impurities. In another embodiment, a method for using atomized alloy powder in additive manufacturing is disclosed. The exemplary method may include the steps of: receiving atomized alloy powder containing alloyed particles; carrying out additive manufacturing using the atomized alloy powder to produce a manufactured article, wherein the additive manufacturing is carried out under an argon (Ar) atmosphere; and removing the manufactured article. The exemplary alloyed particles may contain, by mass%, 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.11% to 0.17% carbon; 0.01% to 0.31% titanium; less than 0.01% copper; less than 0.01% manganese; less than 0.02% nitrogen; less than 0.04% oxygen; and the remainder by mass% iron, as well as incidental elements and impurities. In one embodiment, an alloy is disclosed. The example alloy may contain, by mass%, 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.11% to 0.15% carbon; 0.02% to 0.14% titanium; less than 0.01% copper; less than 0.01% manganese; less than 0.02% nitrogen; less than 0.04% oxygen; and the remainder by mass% iron, as well as incidental elements and impurities. In another embodiment, an additively manufactured article is disclosed. An exemplary additively manufactured article may be produced using a method comprising: receiving an atomized alloy powder containing alloyed particles; carrying out additive manufacturing using the atomized alloy powder to produce an additively manufactured article, wherein the additive manufacturing is carried out in an argon (Ar) atmosphere; and removing the additively manufactured article. The example alloyed particles and / or additively manufactured articles may contain, in mass%,: 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.13% to 0.17% carbon; 0.01% to 0.31% titanium; 0.01% to 0.21% vanadium; 0.4% to 0.6% tungsten; 0.4% to 0.6% molybdenum; less than 0.01% copper; less than 0.01% manganese; less than 0.02% nitrogen; less than 0.04% oxygen; and the remainder by mass% iron, as well as incidental elements and impurities.

[0005] To obtain some of the benefits of this disclosure, it is not particularly required that the materials, techniques, or methods relating to stainless steel alloy powders include all of the details characterized herein. Accordingly, the specific examples characterized herein are intended to be illustrative applications of the techniques described, and alternative methods are possible.

[0006] The patent or application file includes at least one color drawing. A copy of the published patent or patent application containing one or more color drawings will be provided by the authorities upon request and payment of the necessary fees. [Brief explanation of the drawing]

[0007] [Figure 1A]This is an optical microscope image of Experimental Alloy Example 1 in its as-built state, photographed parallel to the build plate (xy specimen). [Figure 1B] Figure 1A is an optical microscope image of experimental alloy example 1, taken perpendicular to the build plate (z specimen). [Figure 2] Figures 1A and 1B show electron beam backscatter diffraction (EBSD) images of experimental alloy example 1. [Figure 3] This is an electron beam backscatter diffraction (EBSD) image of experimental alloy example 2. [Figure 4] This graph compares the fatigue performance of a commercially available alloy with that of experimental alloy example 1 shown in Figures 1A, 1B, and 2. [Figure 5] This graph compares the corrosion performance of a commercially available alloy with experimental alloy example 1 shown in Figures 1A, 1B, and 2. [Figure 6] This graph compares the ambient toughness and stress corrosion cracking (SCC) resistance of a commercially available alloy with experimental alloy example 1 shown in Figures 1A, 1B, and 2. [Figure 7] Figure 6 is an optical microscope image of experimental alloy example 1. [Figure 8] Figure 6 shows an optical microscope image of experimental supplier C(Ar). [Figure 9] Figure 6 is an optical microscope image of experimental training material 17-4 (H1026). [Modes for carrying out the invention]

[0008] The materials, methods, and techniques disclosed and intended herein relate to stainless steel alloys. The alloys disclosed and intended herein are well suited for additive manufacturing applications. For example, atomized alloy powders usable for additive manufacturing may include alloy particles containing various alloys disclosed and intended herein. Generally, exemplary alloy powders may be designed to provide desirable properties and characteristics in the as-built state. Exemplary alloys typically have a copper-free composition. Exemplary alloys may have a microstructure that is primarily martensite in the as-built state and / or after stress relaxation and / or Stage I tempering. In some cases, exemplary alloys may contain more nickel than the 17-4 alloy composition. While not bound by any particular theory, it is theorized that increasing the nickel content can improve the toughness of the resulting manufactured article and / or address defects such as pores. In some cases, exemplary alloys utilize ε-carbide, which can impart strength through "self-tempering". In some cases, exemplary alloys may also contain molybdenum and tungsten, which can impart solid-solution strengthening and / or resistance to intergranular stress corrosion cracking. I. Exemplary alloy steel Exemplary alloy steels are described below with respect to examples of composition and quantities, phase and microstructural characteristics, and physical properties. As discussed elsewhere, the exemplary alloy steels are particularly suitable for powder-based additive manufacturing. In various embodiments, the exemplary alloys can have sufficient toughness to withstand printing and subsequent operations without significant heat treatment. In various embodiments, the exemplary alloys can have resistance to pores and surface irregularities by strengthening the matrix. In various embodiments, the exemplary alloys can have sufficient pitting corrosion resistance with high chromium content.

[0009] A. Exemplary ingredients and quantities The exemplary alloy steels disclosed and intended herein contain various components in various amounts. For example, the exemplary alloy steels may contain iron and one or more of chromium (Cr), nickel (Ni), carbon (C), and titanium (Ti). In some cases, the exemplary alloy steels may further contain vanadium (V), tungsten (W), and molybdenum (Mo). In some cases, the exemplary alloy steels may further contain one or more incidental elements and impurities such as silicon (Si), tantalum (Ta), copper (Cu), manganese (Mn), niobium (Nb), nitrogen (N), oxygen (O), phosphorus (P), and sulfur (S).

[0010] The exemplary alloy steel either does not contain copper or contains less than 0.01% by mass of copper. Copper is typically a strengthening agent in 17-4PH alloy since it forms a nano-dispersion of pure copper precipitates. However, these precipitates can only nucleate when sufficient tempering is used. Since this exemplary alloy is designed to be subjected only to the basic heat treatment for stress relaxation and tempering of martensite, copper is not a major factor for strength and thus is used in trace amounts or not at all. The exemplary alloy steel may have a higher carbon content compared to 17-4PH alloy. The high carbon content promotes the hardening of ε-carbide (Fe 2.4 C) particles and can toughen the material in Stage I tempering (e.g., up to 1 hour at 200 °C), which may be achieved via a "self-tempering" process, which may be the residual heating during build. In some cases, the exemplary alloy steel may contain small amounts of molybdenum and / or tungsten, which may improve the grain boundary binding force for corrosion resistance and resistance to intergranular fracture. In some cases, the exemplary alloy steel contains less than 0.01% by mass of molybdenum and / or less than 0.01% by mass of tungsten and / or less than 0.01% by mass of vanadium.

[0011] The example alloy steel may contain chromium. For example, the example alloy steel may contain 13.25% to 14.75% by mass of chromium (Cr). In various embodiments, the exemplary alloy steel may contain, by mass, 13.25% to 15% Cr; 13.25% to 14.75% Cr; 13.5% to 14.5% Cr; 13.25% to 13.75% Cr; 13.75% to 14.25% Cr; 14.25% to 14.75% Cr; 13.3% to 13.5% Cr; 13.5% to 13.7% Cr; 13.7% to 13.9% Cr; 13.9% to 14.1% Cr; 14.1% to 14.3% Cr; 14.3% to 14.5% Cr; or 14.5% to 14.7% Cr. In various embodiments, the exemplary alloy steel may contain, by mass, at least 13.25% Cr; at least 13.5% Cr; at least 13.75% Cr; at least 14.0% Cr; at least 14.25% Cr; or at least 14.5% Cr. In various embodiments, the exemplary alloy steel may contain, by mass, 14.75% or less Cr; 14.5% or less Cr; 14.25% or less Cr; 14.0% or less Cr; 13.75% or less Cr; or 13.5% or less Cr.

[0012] The exemplary alloy steel may contain nickel. For example, the exemplary alloy steel may also contain 4.5% to 5.5% by mass of nickel (Ni). In various embodiments, the exemplary alloy steel may contain, by mass, 4.5% to 5.3% Ni; 4.7% to 5.5% Ni; 4.5% to 5.1% Ni; 4.7% to 5.3% Ni; 4.9% to 5.5% Ni; 4.7% to 5.1% Ni; 4.9% to 5.3% Ni; 5.1% to 5.5% Ni; 4.5% to 4.7% Ni; 4.7% to 4.9% Ni; 4.9% to 5.1% Ni; 5.1% to 5.3% Ni; or 5.3% to 5.5% Ni. In various embodiments, the exemplary alloy steel may contain, by mass, at least 4.5% Ni; at least 4.75% Ni; at least 5.0% Ni; or at least 5.25% Ni. In various embodiments, the exemplary alloy steel may contain, by mass, 5.5% or less Ni; 5.25% or less Ni; 5.0% or less Ni; or 4.75% or less Ni.

[0013] The exemplary alloy steel may contain carbon. For example, the exemplary alloy steel may contain from 0.11% to 0.17% carbon (C) by mass. In various embodiments, the exemplary alloy steel may contain, by mass, 0.13% - 0.17% C; 0.13% - 0.16% C; 0.14% - 0.17% C; 0.13% - 0.15% C; 0.15% - 0.17% C; 0.11% - 0.15% C; or 0.14% - 0.16% C. In various embodiments, the exemplary alloy steel may contain, by mass, at least 0.11% C; at least 0.13% C; or at least 0.15% C. In various embodiments, the exemplary alloy steel may contain, by mass, C of 0.17% or less; C of 0.15% or less; or C of 0.13% or less.

[0014] The exemplary alloy steel may contain titanium. For example, the exemplary alloy steel may contain from 0.01% to 0.31% titanium (Ti) by mass. In various embodiments, the exemplary alloy steel may contain, by mass, (Ti) of from 0.01% to 0.28%; 0.04% to 0.31%; 0.01% to 0.15%; 0.02% to 0.14%; 0.15% to 0.31%; 0.01% to 0.1%; 0.1% to 0.2%; 0.2% to 0.31%; 0.07% to 0.18%; 0.13% to 0.22%; 0.18% to 0.26%; 0.01% to 0.06%; 0.06% to 0.11%; 0.11% to 0.16%; 0.16% to 0.21%; 0.21% to 0.26%; or 0.26% to 0.31%. In various embodiments, the exemplary alloy steel may contain, by mass, at least 0.01% Ti; at least 0.02% Ti; at least 0.10% Ti; at least 0.15% Ti; at least 0.20% Ti; or at least 0.25% Ti. In various embodiments, the exemplary alloy steel may contain, by mass, Ti of 0.31% or less; Ti of 0.25% or less; Ti of 0.20% or less; Ti of 0.15% or less; Ti of 0.10% or less; or Ti of 0.05% or less.

[0015] In some cases, the exemplary alloy steel may contain vanadium. For example, the exemplary alloy steel may contain, if present, 0.01% to 0.21% by mass of vanadium(V). In various embodiments, exemplary alloy steels may contain, by mass, 0.01% to 0.18% V; 0.04% to 0.21% V; 0.01% to 0.11% V; 0.11% to 0.21% V; 0.01% to 0.07% V; 0.07% to 0.14% V; 0.14% to 0.21% V; 0.06% to 0.10% V; 0.10% to 0.14% V; 0.14% to 0.18% V; 0.01% to 0.04% V; 0.04% to 0.07% V; 0.07% to 0.10% V; 0.10% to 0.13% V; 0.13% to 0.16% V; or 0.16% to 0.19% V. In various embodiments, the exemplary alloy steel may contain at least 0.01% V; at least 0.05% V; at least 0.10% V; or at least 0.15% V. In various embodiments, the exemplary alloy steel may contain 0.21% or less V; 0.15% or less V; 0.10% or less V; or 0.05% or less V.

[0016] In some cases, the exemplary alloy steel may contain tungsten. For example, the exemplary alloy steel may contain 0.4% to 0.6% by mass of tungsten (W), if present. In various embodiments, exemplary alloy steel may contain, by mass, 0.4% to 0.5% W; 0.5% to 0.6% W; 0.4% to 0.45% W; 0.45% to 0.5% W; 0.5% to 0.55% W; 0.55% to 0.6% W; 0.42% to 0.46% W; 0.48% to 0.52% W; 0.52% to 0.56% W; 0.40% to 0.43% W; 0.43% to 0.46% W; 0.46% to 0.49% W; 0.49% to 0.52% W; 0.52% to 0.55% W; 0.55% to 0.58% W; or 0.58% to 0.6% W. In various embodiments, the exemplary alloy steel may contain at least 0.4% W; at least 0.45% W; at least 0.5% W; or at least 0.55% W. In various embodiments, the exemplary alloy steel may contain 0.6% or less W; 0.55% or less W; 0.5% or less W; or 0.45% or less W.

[0017] In some cases, the exemplary alloy steel may contain molybdenum. For example, the exemplary alloy steel may contain 0.4% to 0.6% by mass of molybdenum (Mo), if present. In various embodiments, exemplary alloy steels may contain, by mass, 0.4% to 0.5% Mo; 0.5% to 0.6% Mo; 0.4% to 0.45% Mo; 0.45% to 0.5% Mo; 0.5% to 0.55% Mo; 0.55% to 0.6% Mo; 0.42% to 0.46% Mo; 0.48% to 0.52% Mo; 0.52% to 0.56% Mo; 0.40% to 0.43% Mo; 0.43% to 0.46% Mo; 0.46% to 0.49% Mo; 0.49% to 0.52% Mo; 0.52% to 0.55% Mo; 0.55% to 0.58% Mo; or 0.58% to 0.6% Mo. In various embodiments, the exemplary alloy steel may contain at least 0.4% Mo; at least 0.45% Mo; at least 0.5% Mo; or at least 0.55% Mo. In various embodiments, the exemplary alloy steel may contain 0.6% or less Mo; 0.55% or less Mo; 0.5% or less Mo; or 0.45% or less Mo.

[0018] In some cases, the exemplary alloy steels may contain one or more incidental elements and / or impurities. Incidental elements and impurities in the disclosed alloy steels include, but are not limited to, silicon, tantalum, copper, manganese, niobium, nitrogen, oxygen, phosphorus, and sulfur elements, or mixtures thereof, that are adhering to the raw materials. Incidental elements and impurities may be present in the alloys disclosed herein in a total amount of 0.1% by mass or less, 0.05% by mass or less, 0.01% by mass or less, or 0.001% by mass or less. In some cases, the example alloy steel may contain, by mass, 0.01% or less of silicon; 0.001% or less of silicon; or 0.0001% or less of silicon. In some cases, the example alloy steel may contain, by mass, 0.01% or less of tantalum; 0.001% or less of tantalum; or 0.0001% or less of tantalum. In some cases, the example alloy steel may contain, by mass, 0.01% or less of copper; 0.001% or less of copper; or 0.0001% or less of copper. In some cases, the example alloys may contain, by mass, 0.1% or less of manganese; 0.01% or less of manganese; or 0.001% or less of manganese. In some cases, the example alloy steel may contain, by mass, 0.01% or less of niobium; 0.005% or less of niobium; or 0.001% or less of niobium. In some cases, the example alloy steel may contain, by mass, 0.02% or less of nitrogen, 0.01% or less of nitrogen, 0.005% or less of nitrogen; or 0.001% or less of nitrogen. In some cases, the example alloy steel may contain, by mass, 0.04% or less of oxygen, 0.02% or less of oxygen, 0.01% or less of oxygen, 0.005% or less of oxygen, or 0.001% or less of oxygen. In some cases, the example alloy steel may contain, by mass, 0.01% or less of phosphorus; 0.005% or less of phosphorus; or 0.001% or less of phosphorus. In some cases, the example alloy steel may contain, by mass, 0.01% or less of sulfur; 0.005% or less of sulfur; or 0.001% or less of sulfur. It is understood that the alloys described herein may consist only of the above-mentioned components, may consist essentially of such components, or, in other embodiments, may include additional components.

[0019] The exemplary alloy steel may have a chromium-to-nickel ratio of 2.4 to 3.3 by mass. In various examples, the exemplary alloy steel may have a chromium-to-nickel ratio of 2.4 to 2.9; 2.6 to 3.3; 2.7 to 2.9; 2.75 to 2.85; or 2.8 to 2.9 by mass. In various examples, the exemplary alloy steel may have a chromium-to-nickel ratio of 2.4 or more; 2.6 or more; 2.8 or more; 3.0 or more; or 3.2 or more by mass. In various examples, the exemplary alloy steel may have a chromium-to-nickel ratio of 3.3 or less; 3.1 or less; 2.9 or less; 2.7 or less; or 2.5 or less by mass.

[0020] The example alloy steel may contain the above components in various combinations of amounts. For example, the example alloy steel may contain, by mass, 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.13% to 0.17% carbon; 0.01% to 0.31% titanium; 0.01% to 0.21% vanadium; 0.4% to 0.6% tungsten; 0.4% to 0.6% molybdenum; less than 0.01% copper; less than 0.01% manganese; less than 0.01% niobium; less than 0.02% nitrogen; less than 0.04% oxygen; and the remainder by mass % iron, as well as incidental elements and impurities. In some cases, the example alloy steel may contain, by mass, 13.75% to 14.25% chromium; 4.75% to 5.25% nickel; 0.14% to 0.16% carbon; 0.10% to 0.20% titanium; 0.07% to 0.14% vanadium; 0.45% to 0.55% tungsten; and 0.45% to 0.55% molybdenum; less than 0.01% manganese; less than 0.01% niobium; less than 0.02% nitrogen; less than 0.04% oxygen; and the remainder by mass % iron, as well as incidental elements and impurities. In some cases, the example alloy steel may contain, by mass, 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.11% to 0.15% carbon; 0.02% to 0.14% titanium; less than 0.01% copper; less than 0.01% manganese; less than 0.02% nitrogen; less than 0.04% oxygen; and the remainder by mass % iron, as well as incidental elements and impurities. Other amounts are intended.

[0021] B. Exemplary Phases and Nanostructure Properties Exemplary alloys, after additive manufacturing (also known as "as-built") and Stage I tempering, can have a variety of phases and microstructural properties in powder form. Stage I tempering may involve placing the printed article in a heated environment for a given time. For example, Stage I tempering may be carried out at 100°C to 250°C for 30 minutes to 4 hours. As an example, Stage I tempering may be carried out at 200°C for 1 hour. In some cases, after additive manufacturing, the exemplary alloy may have a predominantly martensitic structure. The exemplary alloy may also contain trace amounts of δ-ferrite and γ-austenite. Exemplary alloys, after additive manufacturing, may have a microstructure in which more than 60% (phase fraction) is martensite; more than 65% is martensite; more than 70% is martensite; more than 95% is martensite; more than 98% is martensite; or more than approximately 99% is martensite. In various examples, exemplary alloys, after additive manufacturing, may have a microstructure in which 60% to 72% is martensite; 60% to 66% is martensite; or 66% to 72% is martensite. Exemplary alloys, after additive manufacturing, may have a microstructure in which less than 20% (phase fraction) is δ-ferrite; less than 18% is δ-ferrite; less than 16% is δ-ferrite; less than 14% is δ-ferrite; less than 12% is δ-ferrite; or less than 1% is δ-ferrite. Exemplary alloys, after additive manufacturing, may have a microstructure in which less than 30% (phase fraction) is γ-austenite; less than 25% is γ-austenite; less than 20% is γ-austenite; less than 18% is γ-austenite; or less than 1% is γ-austenite. The example alloys, after undergoing an additive manufacturing process, may have a microstructure in which less than 40% (phase fraction) of δ-ferrite and γ-austenite; less than 30% of δ-ferrite and γ-austenite; less than 20% of δ-ferrite and γ-austenite; less than 5% of δ-ferrite and γ-austenite; or less than 2% of δ-ferrite and γ-austenite. The exemplary alloy is subjected to an additive manufacturing process and / or Stage I tempering (which may be carried out at 200°C for 1 hour), and then Fe 2.4 It may have a microstructure containing C particles (also called ε-carbide).

[0022] C. Exemplary Mechanical Properties Exemplary alloys, after additive manufacturing (also known as "as-built") and Stage I tempering, can possess a variety of mechanical properties in powder form. The following various mechanical properties are described for xy specimens (where the long axis of the tensile specimen was parallel to the build plate) and z specimens (where the long axis of the tensile specimen was perpendicular to the build plate), and were tested under tension. The example alloys can have various yield strength characteristics in their as-built form, meaning that no aging or solution heat treatment has been performed after the additive manufacturing process.

[0023] For example, an exemplary alloy in as-built form may have a 0.2% elastic offset yield strength of 1030 MPa to 1470 MPa for a z specimen. In various embodiments, an exemplary alloy in as-built form may have yield strengths of 1030 MPa to 1045 MPa; 1033 MPa to 1041 MPa; 1400 MPa to 1470 MPa; 1400 MPa to 1435 MPa; 1435 MPa to 1470 MPa; 1440 MPa to 1460 MPa; or 1445 MPa to 1465 MPa for a z specimen. In various embodiments, an exemplary alloy in as-built form may have yield strengths of at least 1030 MPa; at least 1037 MPa; at least 1400 MPa; at least 1430 MPa; at least 1445 MPa; at least 1455 MPa; or at least 1460 MPa for a z specimen. In various implementations, exemplary alloys in as-built form may have yield strengths of 1460 MPa or less; 1455 MPa or less; 1445 MPa or less; 1435 MPa or less; 1420 MPa or less; or 1400 MPa or less for z-test specimens. Exemplary alloys in as-built form may have a 0.2% elastic offset yield strength of approximately 950 MPa to approximately 1140 MPa for xy specimens. In various embodiments, exemplary alloys in as-built form may have yield strengths of 950 MPa to 1000 MPa; 1000 MPa to 1050 MPa; 960 MPa to 1040 MPa; 1120 MPa to 1140 MPa; 1125 MPa to 1135 MPa; or 1130 MPa to 1134 MPa for xy specimens. In various embodiments, exemplary alloys in as-built form may have yield strengths of at least 950 MPa; at least 970 MPa; at least 990 MPa; at least 1010 MPa; at least 1030 MPa; at least 1045 MPa; at least 1125 MPa; or at least 1130 MPa for xy specimens. In various implementations, the alloys described as-built may have yield strengths of 1135 MPa or less; 1133 MPa or less; 1040 MPa or less; 1020 MPa or less; 1000 MPa or less; 980 MPa or less; or 960 MPa or less for xy test specimens. Exemplary alloys in as-built form may have an elongation of 11% to 21% for xy specimens. In various embodiments, exemplary alloys in as-built form may have an elongation of 11% to 21%; 11% to 15%; 15% to 18%; 18% to 21%; 15% to 17%; 17% to 19%; or 19% to 21% for xy specimens. In various embodiments, exemplary alloys in as-built form may have an elongation of at least 11%; at least 15%; at least 17%; at least 19%; or at least 20% for xy specimens. In various embodiments, exemplary alloys in as-built form may have an elongation of 20% or less; 18% or less; 16% or less; or 12% or less for xy specimens. Exemplary alloys in as-built form may have hardness values ​​of 44HRC to 50HRC. In various embodiments, exemplary alloys in as-built form may have hardnesses of 44HRC to 47HRC; 47HRC to 50HRC; 44HRC to 46HRC; 46HRC to 48HRC; or 48HRC to 50HRC. In various embodiments, exemplary alloys in as-built form may have hardnesses of at least 44HRC; at least 46HRC; or at least 48HRC. In various embodiments, exemplary alloys in as-built form may have hardnesses of 49HRC or less; 47HRC or less; or 45HRC or less. Exemplary alloys in as-built form have room-temperature toughness (K) of 185-235. IC ) may have. In various embodiments, exemplary alloys in as-built form have room-temperature toughness (K) of 185-235; 185-195; 225-235; 190-230; 190-210; or 210-230. IC ) may have. In various embodiments, exemplary alloys in as-built form have room-temperature toughness (K) of at least 185; at least 190; at least 195; at least 200; at least 205; at least 210; at least 215; at least 220; at least 225; or at least 230. IC ) may have. In various examples, exemplary alloy steels have a room temperature toughness (K) of 235 or less; 230 or less; 225 or less; 220 or less; 215 or less; 210 or less; 205 or less; 200 or less; 195 or less; or 190 or less. IC ) may have. Exemplary alloys in as-built form may have pitting potentials greater than 0 mV SCE. In various examples, exemplary alloys in as-built form may have pitting potentials of 0 mV SCE or greater; 5 mV SCE or greater; 10 mV SCE or greater; 15 mV SCE or greater; 20 mV SCE or greater; 25 mV SCE or greater; or 30 mV SCE or greater.

[0024] II. Exemplary Preparation Methods for Alloy Powders The exemplary alloy steels disclosed and intended herein may be secondarily processed into various feedstock forms suitable for the additive manufacturing system in question. For example, the exemplary alloy steels disclosed and intended herein may be secondarily processed into atomized alloy powders using available atomization techniques, such as inert gas spraying. The resulting atomized alloy powders can be used in powder bed melting or directed energy deposition systems. An exemplary method for producing atomized alloy powders includes the step of melting elemental metal feedstock or a feedstock that has been pre-alloyed to produce a desired chemical. In some combinations of elements disclosed above, the atomization process should occur when the temperature of the desired chemical reaches a temperature above which there is no solid material in the molten material. The example atomized alloy powder may have particles sized to suit specific applications and / or manufacturing systems. In some embodiments, the example atomized alloy powder contains particles having a diameter of 15 μm to 45 μm.

[0025] Exemplary manufacturing method The exemplary alloy steels disclosed and intended herein can be used in additive manufacturing systems. Additive manufacturing is a method of forming parts in layers by selectively melting a metal using a computer-controlled energy source (e.g., a laser, electron beam, welding torch, etc.). Additive manufacturing is also defined in ASTM F2792-12a, "Standard Terminology for Additively Manufacturing Technologies." Exemplary additive manufacturing methods include: direct metal laser sintering (DMLS), which uses a laser to sinter a powder medium at precisely controlled locations; laser wire deposition, which melts a wire-like feed material with a laser, then deposits and solidifies it at precise locations to form a product; electron beam melting; laser-processed net shaping; and direct metal deposition. Generally, additive manufacturing technologies offer flexibility in free-form fabrication without geometric constraints, rapid material processing times, and innovative joining techniques. A suitable additive manufacturing system is the EOSINT M280 direct metal laser sintering (DMLS) additive manufacturing system, available from EOS GmbH (Robert-Stirling-Ring 1,82152 Krailling / Munich, Germany). In some implementations, articles containing the illustrated alloy steels disclosed and intended are manufactured using direct metal laser sintering (DMLS). During the illustrated process, atomized alloy powder may be spread in a bed-like manner, and a laser is used to selectively melt and dissolve the area of ​​the bed. The manufactured article can be formed in an alternating layering manner by continuously spreading and melting multiple powder layers. In some implementations, the exemplary method may include a step of preheating the build plate of the additive manufacturing system. In some cases, the build plate may be preheated to about 40°C. In some cases, the build plate may be preheated to about 175°C to about 200°C; 180°C to 190°C; 190°C to 200°C; 180°C to 185°C; 185°C to 190°C; 190°C to 195°C; 195°C to 200°C; 178°C to 182°C; 179°C to 181°C; 180°C to 182°C; or about 180°C. In various examples, the build plate may be preheated to 175°C or higher; 180°C or higher; 185°C or higher; 190°C or higher; or 195°C or higher. In various examples, the build plate may be preheated to 200°C or lower; 195°C or lower; 190°C or lower; 185°C or lower; or 180°C or lower. In some cases, the article may be ready for use after additive manufacturing. In some cases, various post-processing operations may be performed after the build process. For example, the as-built article may be subjected to basic heat treatment for stress relief. For example, the as-built article may be subjected to Stage I tempering, which involves placing the article in an environment of 200°C for up to 1 hour. For example, the as-built article may be placed in an environment of 300°C to 700°C for 1 to 4 hours. Typically, solution heat treatment and aging are commonly used for precipitation-hardening martensitic stainless steel grades ("PH steel grades"), examples of which include 17-4PH and 15-5PH. Various alloys of the present disclosure typically do not undergo solution heat treatment and aging, which can result in time and cost savings. Examples of how atomized alloy powder can be used in additive manufacturing include a variety of operations. For example, the exemplary method may include the step of receiving atomized alloy powder containing alloyed particles. The alloyed particles may contain the components in the amounts detailed above. The method may also include the step of carrying out additive manufacturing using the atomized alloy powder to produce a manufactured article. In some cases, the additive manufacturing may be carried out under an argon (Ar) atmosphere. The manufactured article may then be removed from the additive manufacturing system. In some cases, the manufactured article may be subjected to one or more post-treatment operations, such as heat treatment and tempering, as described above.

[0026] IV. Experimental Examples Various experimental alloys were prepared. The results are discussed below. In some cases, the experimental alloys were evaluated in comparison to commercially available alloys.

[0027] As an experimental example, 100 kg of Ar atomized powder heat was obtained (Alloy Example 1). The specified target composition range and the measurement results of the chemical properties of the powder are shown in Table 1 below for Alloy Example 1 and Alloy Example 2. [Table 1]

[0028] The following various commercially available alloys were tested: Supplier A (Supplier A(Ar)) atomized under an argon atmosphere, Supplier B (Supplier B(Ar)) atomized under an argon atmosphere, Supplier C (Supplier C(Ar / N2)) which is a blend of 50% Supplier C alloy atomized under an argon atmosphere and 50% Supplier C alloy atomized under a nitrogen atmosphere, and Supplier C (Supplier CN2) atomized under a nitrogen atmosphere. The elemental composition of each is shown in Table 2 below. [Table 2]

[0029] The powder of alloy example 1 was subjected to various flow behaviors and particle size distributions and compared with commercially available powders. The results are shown in Table 3 below. [Table 3]

[0030] Metallurgical specimens obtained from alloy example powders were characterized by optical-electron microscopy, X-ray diffraction, and electron backscatter diffraction (EBSD). For alloy example 1, experimental coupons were fabricated on a build plate preheated to 40°C using an EOS M290 instrument (obtained from EOS North America (Novi, Michigan)). The build process included bidirectional beam scanning at a scanning rotation angle of 67°. All coupons were fabricated using the same build parameters (laser power 195W, scanning speed 750mm / s, hatch spacing 0.1mm, layer thickness 40μm). For alloy example 2, experimental coupons were fabricated on a build plate preheated to 180°C using an EOS M290 instrument (obtained from EOS North America (Novi, Michigan)). The build process included bidirectional beam scanning at a scanning rotation angle of 67°. All coupons were fabricated using the same build parameters (laser power 195W, scanning speed 750mm / s, hatch spacing 0.1mm, layer thickness 40μm).

[0031] Optical microscope images were taken of the as-built specimen. The images are shown in Figure 1A (xy specimen, parallel to the build plate) and Figure 1B (z specimen, perpendicular to the build plate). As shown in Figures 1A and 1B, alloy example 1 mainly has a martensitic microstructure. Using the method outlined in Vunnam, Swathi, Abhinav Saboo, Chantal Sudbrack, and Thomas L. Starr, "Effect of powder chemical composition on the as-built microstructure of 17-4 PH stainless steel processed by selective laser melting," Additive Manufacturing 30 (2019):100876, the ferrite phase (yellow), martensite phase (blue), and austenite phase (red) were identified and quantified using EBSD image quality maps. Figure 2 shows the EBSD image used for phase analysis of alloy example 1. Figure 3 shows the EBSD image used for phase analysis of alloy example 2. As shown in Figure 3, in alloy example 2, ferrite is invisible (less than 1%), austenite (red) is invisible, and 99% is martensite.

[0032] Table 4 below shows the total phase fractions for as-built alloy example 1 and as-built alloy example 2. [Table 4]

[0033] Tensile and hardness tests were also performed on alloy example 1 and alloy example 2. The results are shown in Tables 5 and 6 below. Coupons prepared from Ar atomized powder were subjected to the following two heat treatments: (1) solution treatment and H900 (where "H900" is a heat treatment at 482°C (900°F) for 1 hour), and (2) direct H900 hardening without solution treatment. Only commercially available powders were heat-treated - no post-treatment was applied to the samples of alloy example 1 and alloy example 2.

[0034] Wire EDM flat "dumbbell-shaped" (dog bone) test specimens were cut from as-built and heat-treated coupons. Commercially available 17-4PH forging rods were purchased to be used as baselines. These forging rods were already solution-treated upon receipt (Condition A). The long axis of the tensile test specimens was either horizontal (XY) or perpendicular (Z) to the build plate and tested under tension. Three tests were performed for each combination of powder and heat treatment. Hardness was measured using a Wilson Instruments Rockwell 500 hardness tester.

[0035] As shown in Tables 5 and 6, the as-built properties of alloy example 1 and alloy example 2 both exceed those of commercially available 17-4PH powder. As shown in Tables 5 and 6, the as-built properties of alloy example 1 and alloy example 2 are equal to the ultimate tensile strength of aged (h900) commercially available powder. [Table 5] [Table 6]

[0036] The fatigue performance of supplier C(Ar)(2) (15.6 mass% Cr, 4.03 mass% Ni, 0 mass% Mo, 0.33 mass% Nb+Ta, 0.01 mass% C, 0.01 mass% N, 3.89 mass% Cu, 0.24 mass% Mn, and 0.29 mass% Si, remainder Fe) was compared with that of alloy example 1. Fatigue performance was tested using ASTM E466-15 (2015). The test conditions were R=-1 (tested under fully reversible tensile-compressive conditions) and 10 Hz. The results for the as-built alloy are shown in Figure 4. These results show that alloy example 1 exhibited superior fatigue properties at all stress amplitudes compared to supplier C(Ar)(2) alloy. 7 This indicates a higher fatigue limit during the cycle.

[0037] The corrosion test was carried out using potentiodynamic scanning with a 3.5% NaCl solution and a scanning rate of 0.5 mV / s. The results averaged over 5 scans are shown in Fig. 5 and Table 7 (below), together with the various powders described in Table 2 above. The results in Fig. 5 show that Alloy Example 1 has a relatively high pitting potential compared to the commercial alloys tested.

Table 7

[0038] The lower limit stress intensity factor for the initiation of environmentally induced hydrogen stress cracking was also tested for Alloy Example 1, Alloy Example 2, and various commercial powders. The tests were carried out at applied potentials of -1.1 V and -0.3 V (near the open circuit potential (OCP)) using ASTM F1624-12 (2018). The results are shown in Table 8 below. As shown in Table 8, both Alloy Example 1 and Alloy Example 2 have very high room-temperature toughness (or K IC ), and have approximately the same KISCC value in a corrosive environment.

Table 8

[0039] Fig. 6 shows a graph comparing the room-temperature toughness and stress corrosion cracking (SCC) resistance of a commercial alloy and Experimental Alloy Example 1. The K IC (room-temperature toughness) test was carried out in accordance with ASTM E399-22. The KISCC test was carried out in accordance with ASTM F1624-12 (2018). Fig. 7 is an optical micrograph of Experimental Alloy Example 1 shown in Fig. 6, from which intergranular cracking can be seen. Fig. 8 is an optical micrograph of Supplier C (Ar) shown in Fig. 6, from which intragranular cracking can be seen. Fig. 9 is an optical micrograph of Experimental Forged 17-4 (H1026) shown in Fig. 6, from which intergranular cracking can be seen. The crack surfaces in Figs. 7, 8, and 9 are horizontal in the build direction (z direction). As shown in Figures 6, 7, 8, and 9, alloy example 1 has improved toughness while maintaining a strength level comparable to both supplier C(Ar) and forging 17-4(H1025). Alloy example 1 has a similar K ISCC It has a value and a preferred (pseudo-cleavage) fracture mode. Alloy Example 1 also shows enhanced resistance to grain boundary embrittlement.

[0040] In relation to the descriptions of numerical ranges in this specification, each number interposing within such range is intended to be of the same precision. For example, for the range 6 to 9, the numbers 7 and 8 are intended in addition to 6 and 9, and for the range 6.0 to 7.0, the values ​​6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9 and 7.0 are intended. In another embodiment, when a pressure range is described as being between atmospheric pressure and another pressure, the pressure being atmospheric pressure is explicitly intended. It is understood that the above detailed description and accompanying examples are merely illustrative and should not be considered limitations on the scope of this disclosure. Various changes and modifications to the disclosed embodiments will be obvious to those skilled in the art. Such changes and modifications may include, but are not limited to, those relating to chemical structure, substituents, derivatives, intermediates, synthesis, composition, formulation, or method of use, and may be made without departing from the spirit and scope of this disclosure.

[0041] For completeness, various aspects of this technology are presented in the following numbered embodiments. Embodiment 1. In mass percent: 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.11% to 0.17% carbon; 0.01% to 0.31% titanium; and Remaining mass % of iron, plus incidental elements and impurities An alloy containing [a specific component]. Embodiment 2. In mass percent: Copper content of 0.01% or less; Manganese content of 0.01% or less; 0.02% or less of nitrogen; Oxygen content of 0.04% or less; Niobium less than 0.01%; and Silicon content of 0.01% or less The alloy according to Embodiment 1, including the alloy described above. Embodiment 3. In mass percent: 13.75% to 14.25% chromium; 4.75% to 5.25% nickel; 0.14% to 0.16% carbon; 0.12% to 0.18% titanium; 0.01% to 0.21% vanadium; 0.4%~0.6% tungsten; and 0.4% to 0.6% molybdenum The alloy according to Embodiment 2, including the alloy described above. Embodiment 4. In mass percent: 13.75% to 14.25% chromium; 4.75% to 5.25% nickel; 0.11% to 0.15% carbon; and 0.02%~0.14% titanium The alloy according to Embodiment 2, including the alloy described above. Embodiment 5. After undergoing additive manufacturing processes, without aging or solution heat treatment, The microstructure consists of less than 20% δ-ferrite and less than 30% γ-austenite; Hardness values ​​of 44-50 HRC; For the xy test specimens, the elongation was 15% to approximately 21%; For the xy test specimen, the yield strength was approximately 1000 MPa, The alloy according to Embodiment 3, having the following characteristics. Embodiment 6. After undergoing additive manufacturing processes, without aging or solution heat treatment, The microstructure consists of less than 1% δ-ferrite, less than 1% γ-austenite, and approximately 99% martensite; For the xy test specimens, the elongation was 10% to 14%; For the xy test specimens, the yield strength was 1125 MPa to 1135 MPa, The alloy according to Embodiment 4, having the following characteristics. Embodiment 7. After additive manufacturing and / or aging, Fe 2.4 An alloy according to any one of embodiments 1 to 6, having a microstructure containing C particles. Embodiment 8. The alloy according to any one of Embodiments 1 to 7, wherein the ratio of chromium to nickel is 2.7 to 2.9 by mass. Embodiment 9. Atomized alloy powder that can be used in additive manufacturing, In mass percent: 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.11% to 0.17% carbon; 0.01% to 0.31% titanium; Copper content of 0.01% or less; Manganese content of 0.01% or less; 0.02% or less of nitrogen; Oxygen less than 0.04%; and Remaining mass % of iron, plus incidental elements and impurities alloy particles Atomized alloy powder containing [this ingredient]. Embodiment 10. The alloy particles are, by mass%, 13.75% to 14.25% chromium; 4.75% to 5.25% nickel; 0.12%~0.14% carbon; and 0.06% to 0.10% titanium; Niobium less than 0.01%; and Silicon content of 0.01% or less Atomized alloy powder according to Embodiment 9, including the following: Embodiment 11. The alloy particles are, by mass%, 13.75% to 14.25% chromium; 4.75% to 5.25% nickel; 0.13% to 0.17% carbon; 0.13% to 0.17% titanium; 0.4% to 0.6% molybdenum; 0.05% to 0.15% vanadium; 0.4% to 0.6% tungsten; Niobium less than 0.01%; and Silicon content of 0.01% or less Atomized alloy powder according to Embodiment 9, including the following: Embodiment 12. After undergoing additive manufacturing processes, without aging or solution heat treatment, The microstructure consists of less than 30% δ-ferrite and γ-austenite, and the xy specimens exhibit an elongation of 15% to approximately 21%; Hardness values ​​of 44-50 HRC; The atomized alloy powder according to embodiment 12, having the properties of the atomized alloy powder described in embodiment 12. Embodiment 13. Atomized alloy powder according to any one of Embodiments 9 to 12, having a yield strength of approximately 1000 MPa to approximately 1140 MPa for xy test specimens after an additive manufacturing process, without aging or solution heat treatment. Embodiment 14. A method for using atomized alloy powder in additive manufacturing, A step of receiving atomized alloy powder containing alloyed particles, wherein the alloyed particles are in mass %: 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.13% to 0.17% carbon; 0.01% to 0.31% titanium; Niobium less than 0.01%; Silicon content of 0.01% or less; Copper content of 0.01% or less; Manganese content of 0.01% or less; 0.02% or less of nitrogen; and Oxygen less than 0.04%; and A step comprising the remaining mass % of iron, along with incidental elements and impurities, A step of producing a manufactured article by performing additive manufacturing using the above-mentioned atomized alloy powder, wherein the additive manufacturing is performed under an argon (Ar) atmosphere. The step of removing the manufactured goods, Methods that include... Embodiment 15. The alloyed particles, in mass%, are: 13.75% to 14.25% chromium; 4.75% to 5.25% nickel; 0.14% to 0.16% carbon; 0.12% to 0.18% titanium; 0.01% to 0.21% vanadium; 0.4%~0.6% tungsten; and 0.4% to 0.6% molybdenum; The method according to Embodiment 14, including the method described in Embodiment 14. Embodiment 16. The alloyed particles, in mass%, are: 13.75% to 14.25% chromium; 4.75% to 5.25% nickel; 0.11% to 0.15% carbon; and 0.02% to 0.14% titanium; The method according to Embodiment 14, including the method described in Embodiment 14. Embodiment 17. The finished product is: Microstructure consisting of less than 30% δ-ferrite and γ-austenite; Hardness values ​​of 44-50 HRC; For the xy test specimens, the elongation was 15% to approximately 21%; The method according to embodiment 16, wherein the method is characterized by having the following features. Embodiment 18. The process further includes the step of preheating the build plate to a temperature of 175°C to 200°C; The finished product is: The microstructure consists of less than 1% δ-ferrite, less than 1% γ-austenite, and approximately 99% martensite; For the xy test specimens, the elongation was 10% to 14%; For the xy test specimens, the yield strength was 1125 MPa to 1135 MPa, The method according to embodiment 17, wherein the method is characterized by having the following features. Embodiment 19. The method according to any one of embodiments 14 to 18, wherein the alloyed particles have a chromium-to-nickel ratio of 2.7 to 2.9 by mass. Embodiment 20. The finished product is: Room temperature toughness (K) of 185-235 IC ); and Pitting potential greater than 0mV SCE The method according to any one of embodiments 14 to 19, having the characteristics of: Embodiment 21. A manufactured article produced using the method described in any one of Embodiments 14 to 20.

Claims

1. 1. An atomized alloy powder usable for additive manufacturing, comprising: In % by weight: 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.11% to 0.17% carbon; 0.01% to 0.31% titanium; not more than 0.01% copper; not more than 0.01% manganese; not more than 0.02% nitrogen; 0.04% or less oxygen; containing not more than 0.01% sulfur; and the ratio of chromium to nickel, by mass, is between 2.4 and 3.3; alloy particles, with the balance being iron and incidental elements and impurities. and An atomized alloy powder having a microstructure that is less than 30% delta-ferrite and gamma-austenite and more than 70% martensite.

2. The alloy particles comprise, in mass %, 13.75% to 14.25% chromium; 4.75% to 5.25% nickel; 0.12% to 0.14% carbon; and 0.06% to 0.10% titanium; not more than 0.01% niobium; and Less than 0.01% silicon The atomized alloy powder of claim 1 , comprising:

3. The alloy particles comprise, in mass %, 13.75% to 14.25% chromium; 4.75% to 5.25% nickel; 0.13% to 0.17% carbon; 0.13% to 0.17% titanium; 0.4% to 0.6% molybdenum; 0.05% to 0.15% vanadium; 0.4% to 0.6% tungsten; not more than 0.01% niobium; and Less than 0.01% silicon The atomized alloy powder of claim 1 , comprising:

4. The powder has been subjected to an additive manufacturing process and has not been subjected to aging or solution heat treatment, and the atomized alloy powder is For xy specimens, an elongation of 15% to about 21%; and a hardness value of 44-50 HRC; The atomized alloy powder according to claim 3, having

5. The atomized alloy powder of claim 1, wherein the powder has been subjected to an additive manufacturing process and has not been subjected to aging or solution heat treatment, and the atomized alloy powder has a yield strength of about 1000 MPa to about 1140 MPa for an x-y test specimen.

6. 1. A method of using atomized alloy powder in additive manufacturing, comprising: Receiving the atomized alloy powder including alloyed particles, the alloyed particles comprising, in weight percent: 13.25% to 14.75% chromium; 4.5% to 5.5% nickel; 0.13% to 0.17% carbon; 0.01% to 0.31% titanium; not more than 0.01% niobium; not more than 0.01% silicon; not more than 0.01% copper; not more than 0.01% manganese; not more than 0.02% nitrogen; not more than 0.01% sulfur; containing not more than 0.04% oxygen; and the ratio of chromium to nickel, by mass, is between 2.4 and 3.3; The balance is % by mass of iron and incidental elements and impurities. and performing additive manufacturing using the atomized alloy powder to produce a manufactured article, wherein the additive manufacturing is performed under an argon (Ar) atmosphere; removing an article of manufacture having a microstructure that is less than 30% delta-ferrite and gamma-austenite and more than 70% martensite; A method comprising:

7. The alloyed particles comprise, in weight percent: 13.75% to 14.25% chromium; 4.75% to 5.25% nickel; 0.14% to 0.16% carbon; 0.12% to 0.18% titanium; 0.01% to 0.21% vanadium; 0.4% to 0.6% tungsten; and 0.4% to 0.6% molybdenum; The method of claim 6, comprising:

8. The alloyed particles comprise, in weight percent: 13.75% to 14.25% chromium; 4.75% to 5.25% nickel; 0.11% to 0.15% carbon; and 0.02% to 0.14% titanium; The method of claim 6, comprising:

9. The finished article of manufacture comprises: a hardness value of 44-50 HRC; For xy specimens, elongation of 15% to about 21%; 9. The method of claim 8, comprising:

10. further comprising preheating the build plate to a temperature of 175°C to 200°C; The finished article of manufacture comprises: a microstructure that is less than 1% δ-ferrite, less than 1% γ-austenite, and about 99% martensite; For xy specimens, elongation of 10% to 14%; For the x-y specimens, a yield strength of 1125 MPa to 1135 MPa; 10. The method of claim 9, comprising:

11. 7. The method of claim 6, wherein the alloyed particles have a chromium to nickel ratio, by mass, of 2.7 to 2.

9.

12. The finished article of manufacture comprises: Room temperature toughness (K) of 185-235 IC ); and Pitting potential above 0 mV SCE 9. The method of claim 8, comprising:

Images