3D printed high-carbon steel and method for producing it

Abstract

The present invention relates to a method for producing 3D printed products of iron-based alloys with narrow carbide area distribution and integrated HIP and hardening products.

Description

[Technical Field]

[0001] This invention relates to 3D printed products of iron-based alloys having high hardness. The 3D printed products are hardened using a furnace in which the products obtained from 3D printing are treated with hot isostatic pressure (HIP) and quenched. [Background technology]

[0002] Today, several different methods exist for preparing powder metallurgy materials. One of the main methods is PM-HIP (powder metallurgy isostatic pressing). This method involves spraying (granulating) metal powder, placing this powder into a container, sealing the container, and then exposing the sealed container for HIP to 1120-1150°C and 100 MPa for typically 3 hours, for example, according to a standard process. The result is typically a solidified material block that requires further processing.

[0003] The container can have different shapes, depending largely on the materials and form required for the final product. It could even be a standard cylindrical shape if the material is a rod for further manufacturing.

[0004] In the latter case, for example, for the manufacture of PM-HSS (powder metallurgy high-speed steel), the material block is then typically forged and rolled to the dimensions of the final bars. These bars are then typically softened and tempered, and then transported to stock. They are then transported to a workshop where soft machining is performed for the shapes of the required details, such as gear hobs. However, after soft machining, the gear hob semi-finished parts are hardened in a vacuum furnace and then tempered in another furnace. Finally, the hardened semi-finished parts can serve as a base for achieving the desired surface tolerances.

[0005] Typically, after machining a softened and tempered steel bar, the material is hardened. One of the most common hardening processes for PM-HSS involves heating to 1180°C, holding at that temperature for a specified time, and then cooling to 25-50°C, ensuring a minimum cooling rate of 7°C / s between 1000°C and 800°C. In this process, tempering is performed after hardening, and the material is repeatedly heated to 560°C with a holding time exceeding 1 hour (h), and cooled to less than 25°C between repetitions.

[0006] The temperature naturally depends on the type of alloy and the target hardness. Furthermore, if high-precision soft machining is performed, it is possible to add a stress relaxation step (typically 600-700°C over 2 hours (h), followed by slow cooling to 500°C, and then further cooling to 25°C).

[0007] The results of the PM-HIP process, besides powder quality, composition, forging, and rolling, are therefore the effects of temperature, pressure, and time.

[0008] The HIP process can also be used for 3D printed (additive-processed) metal alloys. In this case, the process can serve as a method for closing pores resulting from the 3D printing process. The process also serves to ensure the overall density component. After the HIP process on a 3D printed product, a conventional hardening process may be used thereafter.

[0009] The results of the 3D printing, HIP, and curing processes are, in this case, a consequence of temperature, pressure, and time, in addition to powder quality, composition, and 3D printing parameters. Nevertheless, this multi-step process is time-consuming. [Overview of the project] [Problems that the invention aims to solve]

[0010] The object of the present invention is to eliminate the drawbacks of the prior art. Accordingly, the present invention provides a method in which HIP and hardening are integrated, and the resulting material unexpectedly has improved mechanical properties compared to materials HIPed and hardened by conventional methods. The present invention also aims to provide a material or product having a more uniform carbide size or carbide area distribution. For example, the hardness of the material was improved by up to 12%, and wear studies revealed a 7.5% lower wear rate. Furthermore, even though the hardness increased, the toughness remained the same as that of samples processed by conventional methods. This is more pronounced in the case of alloys with a higher carbon content.

Means for Solving the Problems

[0011] In a first aspect, the present invention relates to a 3D printed product according to claim 1.

[0012] In a preferred embodiment, the present invention is a 3D printed product formed of an iron-based alloy comprising a metal matrix and carbide particles incorporated into the metal matrix; where the alloy has carbon: 1.0% to 5.0% by weight; chromium: 2.0% to 22.0% by weight; iron: the balance; and includes where the alloy has tungsten: 2% to 13% by weight; cobalt: 7% to 18% by weight; molybdenum: 1% to 10% by weight; vanadium: 3% to 8% by weight; and further includes at least two of the elements of where the alloy includes inevitable trace impurities; the maximum carbide area is less than 8 μm 2 and the average carbide area is less than 2 μm 2 and; and / or the carbide area distribution is 1.90 μm 2having a difference between the following d90 value and d10 value; and / or a carbide area distribution of 2.20 μm 2 having the following d90 value, relating to a 3D printed product.

[0013] In a second aspect, the present invention is a method for producing a 3D printed product, comprising: a. providing a powder of an iron-based alloy, the iron-based alloy further comprising carbon and inevitable amounts of impurities; b. 3D printing a product from the iron-based alloy in a freeform fabrication apparatus having a chamber, the 3D printing being performed in a vacuum; c. subjecting the product obtained in step b to i. placing the product in a furnace; ii. heating the product to a first temperature of at least 850 °C and increasing the pressure in the furnace to a first pressure of at least 80 MPa, and holding the product at the first temperature and the first pressure for a first holding time; iii. heating the product to a second temperature of at least 950 °C and holding the product at the second temperature and a second pressure for a second holding time; iv. quenching the product to a third temperature and decreasing the pressure in the furnace to a third pressure, and holding the product at the third temperature and the third pressure for a third holding time; v. performing a temperature cycle by heating the product to a fourth temperature and increasing the pressure in the furnace to a fourth pressure, and holding the product at the fourth temperature and the fourth pressure for a fourth holding time, and then decreasing the temperature of the product to a fifth temperature to treat by relating to a method for producing a 3D printed product comprising.

[0014] In a third aspect, the present invention relates to a product obtained by the method of the present invention.

[0015] In one embodiment, the product obtained by the method of the present invention is obtained by a method in which the first temperature is 1120 to 1150°C and the first pressure is about 100 MPa. Preferably, the first holding time is preferably 3 hours (h).

[0016] In another embodiment, the product obtained by the present invention has a hardness measured using a 2 kg Vickers indenter on a sample that has been ground and polished, according to a standard material analysis method by finish grinding with SiC P4000 in accordance with SS-EN ISO 6507.

[0017] An advantage of the present invention is that the resulting product has a hardness (HV2kg) that is at least 5% higher, preferably 7% higher, and more preferably 10% higher than the corresponding 3D printed product that is processed using conventional HIP and heat treatment.

[0018] All embodiments described herein are applicable to all aspects unless otherwise specified. Preferred embodiments of the present invention are specified in the dependent claims. [Brief explanation of the drawing]

[0019] [Figure 1] Wear rates for material 280 under different heat treatments. The figure shows the unexpectedly low wear volume of integrated HIP and hardened material 280-5 compared to conventional HIP and heat-treated material 280-4. Both use a hardening temperature of 1180°C followed by tempering at 560°C for 3 × 1 hour (h). At the final sliding distance (31m) in the test, the measured wear rates were 0.0055 mm³ for 280-4 and 0.0051 mm³ for 280-5, respectively. This corresponds to a 7.5% reduction in wear rate. [Figure 2] a) SEM images of material 150 after conventional HIP and curing (WD=7.6mm, EHT=10.00kV, magnification 10.00KX), and b) after integrated HIP and curing according to the present invention (WD=6.7mm, EHT=10.00kV, magnification 10.00KX). [Figure 3] a) SEM image of material 150 with marked carbide edges after conventional HIP and curing, and b) after integrated HIP and curing according to the present invention. [Figure 4] a) SEM images of material 280 after conventional HIP and curing (WD=7.5mm, EHT=10.00kV, magnification 10.00KX), and b) after integrated HIP and curing according to the present invention (WD=5.9mm, EHT=10.00kV, magnification 10.00KX). [Figure 5] a) SEM image of material 280 with marked carbide edges after conventional HIP and curing, and b) after integrated HIP and curing according to the present invention. [Figure 6] a) SEM images of material 290 after conventional HIP and curing (WD=6.3mm, EHT=10.00kV, magnification 10.00KX), and b) after integrated HIP and curing according to the present invention (WD=4.5mm, EHT=10.00kV, magnification 10.00KX). [Figure 7] a) SEM image of material 290 with marked carbide edges after conventional HIP and curing, and b) after integrated HIP and curing according to the present invention. [Figure 8] a) SEM images of material 350 after conventional HIP and curing (WD=4.6mm, EHT=10.00kV, magnification 10.00KX), and b) after integrated HIP and curing according to the present invention (WD=4.5mm, EHT=10.00kV, magnification 10.00KX). Larger gray areas are of the (Cr,V)C carbide type, and smaller, rounder, whiter particles are of the V,N enriched carbide / nitride type. [Figure 9] a) SEM image of material 350 with marked carbide edges after conventional HIP and curing, and b) after integrated HIP and curing according to the present invention. [Figure 10] A schematic diagram showing the effect of the present invention (dotted line) on the carbide area distribution compared to conventional HIP and hardening (solid line). [Figure 11] A schematic diagram of the method according to the present invention. [Figure 12] A graph showing the decrease in d90 and d10 values ​​of the carbide area distribution, in percentage terms, when using the present invention. [Figure 13] A graph showing the carbide area distribution for samples prepared using conventional HIP and heat treatment, and for samples prepared using the present invention (URQ). The graph shows the difference in d90 and d10 values ​​for white and gray carbides, and the average value of the above difference. [Figure 14] Graphs showing the carbide area distribution for samples prepared using conventional HIP and heat treatment, and for samples prepared using the present invention (URQ). Max represents the maximum carbide area, and SD represents the standard deviation. [Modes for carrying out the invention]

[0020] In this application, the terms 3D printing or 3D printing or freeform or additive manufacturing refer to the same thing and are used synonymously.

[0021] In this application, the term "carbide size" refers to the widest portion of the cross-sectional area of ​​a carbide or carbide cluster.

[0022] In this application, the term "carbide area" refers to the cross-sectional area of ​​the carbide.

[0023] In this application, the term "carbide cluster area" refers to the cross-sectional area of ​​a carbide cluster. A carbide cluster is a group of individual carbides arranged close together to function as one large carbide.

[0024] In this application, the term "average carbide area" refers to the average cross-sectional area of ​​the carbide.

[0025] In this application, the term "average carbide cluster area" refers to the average cross-sectional area of ​​carbide clusters.

[0026] In this application, the term "maximum carbide area" refers to the maximum 10% of the carbide area. ,child This indicates that the area is greater than or equal to a certain value.

[0027] In this application, the term "maximum carbide size" means that 10% of the carbide, preferably 5%, and more preferably 1%, of the carbide have a maximum size equal to or greater than this size.

[0028] 3D printing products The object of the present invention is to provide a three-dimensional (3D) printed material formed from or containing an iron-based alloy having high hardness and good high temperature properties. The alloy comprises a metal matrix and carbide particles incorporated within the metal matrix. The alloy is iron (balanced Fe)-based and contains carbon and chromium, and may further contain tungsten, cobalt, vanadium, molybdenum, and carbon. Preferably, the alloy has a very low oxygen content, preferably 100 ppm or less by weight, more preferably less than 50 ppm by weight.

[0029] The alloy of the present invention comprises carbon, chromium, and (balanced) iron, as well as at least two of tungsten, cobalt, molybdenum, and vanadium. In a preferred embodiment, the alloy comprises tungsten, molybdenum, and vanadium. In another preferred embodiment, the alloy comprises tungsten, cobalt, molybdenum, and vanadium.

[0030] The chromium (Cr) content is 2.0% or more and 22% or less by weight. In one preferred embodiment, the above content is 3 to 10%, preferably 3.5 to 4.5% by weight. In another preferred embodiment, the chromium content is 18 to 22% by weight, more preferably about 20% by weight.

[0031] The tungsten (W) content is 2% by weight and 13% by weight. In a preferred embodiment, the tungsten content is 4% to 12% by weight. In a preferred embodiment, the above content is preferably 6% to 11% by weight.

[0032] The cobalt (Co) content is 9% by weight or more and 18% by weight or less. In one embodiment, the above content is preferably 10 to 17% by weight.

[0033] The vanadium (V) content is 3% by weight and 8% by weight. In one embodiment, the above content is preferably 4% to 7% by weight.

[0034] The molybdenum (Mo) content is 1% by weight and 10% by weight. In one embodiment, the above content is preferably 2-8% by weight, more preferably 5-7% by weight.

[0035] The carbon (C) content is 1.0% or more and 5.0% or less by weight. In one embodiment, the above content is preferably 1.4% or more and 3.0% or less by weight, more preferably 2.20 to 2.60% by weight, and more preferably 2.30 to 2.50% by weight.

[0036] Aside from unavoidable impurities, the remainder of the alloy is iron, or Fe balance. The amount of iron in the balance depends on the amounts of the other components. Typically, the amount of iron is 50-70% by weight, preferably 60-65% by weight. The oxygen content in the 3D printed product should be as low as possible. In this invention, the oxygen content is preferably 30 ppm or less, or 20 ppm or less.

[0037] The alloy may further contain unavoidable amounts of impurities of several other elements, or trace amounts of impurities. These elements may be, but are not limited to, niobium, nickel, manganese, silicon, boron, tantalum, or combinations thereof. The total amount of the aforementioned several other elements or impurities is preferably less than 1% by weight, less than 0.5% by weight, or less than 0.05% by weight.

[0038] In a preferred embodiment, the alloy is Carbon: 1.0% by weight and 5.0% by weight; Chromium: 2.0% by weight and 22.0% by weight; Iron: Balance; Includes, The above alloy is Tungsten: 2% by weight and 13% by weight; Cobalt: 7% by weight and 18% by weight; Molybdenum: 1% by weight and 10% by weight; Vanadium: 3% by weight and 8% by weight; It further contains at least two of the elements; The above alloy contains unavoidable trace amounts of impurities.

[0039] One advantage of the present invention is that it does not require the use of any organic binders or adhesives, and therefore the 3D printed product typically has a combined content of iron, vanadium, molybdenum, carbon, tungsten, chromium, and cobalt of 95% or more by weight. In one embodiment of the present invention, the combined content of iron, vanadium, molybdenum, carbon, tungsten, chromium, and cobalt is 97% or more by weight. Preferably, the combined content of iron, vanadium, molybdenum, carbon, tungsten, chromium, and cobalt is 98% or more by weight. More preferably, the combined content of iron, vanadium, molybdenum, carbon, tungsten, chromium, and cobalt is 99% or more by weight. Most preferably, the combined content of iron, vanadium, molybdenum, carbon, tungsten, chromium, and cobalt is 99.9% or more by weight. In one embodiment of the present invention, the amount of organic compounds in the 3D printed product is 0.1% or less by weight. Preferably, the amount of organic compounds in the 3D printed product is 0.05% by weight or less. In one embodiment of the present invention, the product is essentially free of any organic compounds. Carbon in the product is mainly present in the form of carbides such as tungsten and chromium carbides, although elemental carbon and elemental tungsten may also be present in the matrix.

[0040] The multiphase alloy mainly comprises a matrix of iron, carbon, and chromium, but may also include cobalt, tungsten, and / or molybdenum. Carbides of chromium, vanadium, molybdenum, and tungsten, i.e., CrC type, VC and WC, or W / Mo6C, are present in the matrix. Depending on the alloy composition, the carbides of the present invention may mainly be W / Mo6C and VC, and the total amount of the above carbides is 20 - 30% by volume, preferably 22 - 28% by volume. The carbides of the 3D printed product are uniformly distributed (well dispersed), and the size distribution can be found in Table 3, is schematically shown in FIG. 10, and is narrow as shown in FIGS. 12 - 14. The matrix may further contain vanadium or nitrogen-enriched carbides / nitrides. The maximum carbide size of the 3D printed and hardened product is 10 μm or less. In one embodiment, the maximum carbide size is 8 μm or less, 5 μm or less, preferably 3 μm or less. The average carbide size is usually 5 μm or less, or 3 μm or less, or 1 μm or less. The average carbide area is preferably 5 μm 2 or less, more preferably 2 μm 2 or less, even more preferably 1 μm 2 or less. In one embodiment, the average carbide area is 0.025 μm 2 or more, but preferably 0.25 μm 2 or more. This indicates that a narrow carbide size distribution is found in the products of the present invention. The maximum carbide area is preferably 10 μm 2 or less, preferably 8 μm 2 or less, or 5 μm 2 or less, or 4 μm 2 or less. The small carbide size, carbide area, and maximum carbide area of the products according to the present invention are, in part, the result of the method according to the present invention. The carbide area distribution preferably has a d90 value of 2.20 μm 2 or less, preferably 2.0 μm 2 or less, more preferably 1.8 μm 2 or less, more preferably 1.6 μm 2 or less. In one embodiment, the difference between the d90 and d10 values is 1.90 μm 2The following, preferably 1.70 μm 2 The following, and more preferably 1.50 μm 2 The following applies:

[0041] Metallic compounds containing carbides can result in the formation of clusters, strings, dendritic or reticular structures by the carbides, which make the material more brittle. Typically, in these types of alloys, especially those with high chromium and carbon content, chromium is present (Cr7C3 and Cr 23 C6, however, forms carbides (such as other stoichiometric types). These carbides typically grow rapidly during the solidification stage, resulting in large, long stringers with dimensions of 100–1000 μm. These large carbides reduce the macroscopic fracture toughness and fatigue resistance in the material. Therefore, one of the advantages of the present invention is that the 3D product generally contains carbides or carbide particles that are smaller and better dispersed in the matrix than those found in the prior art. This is a result of the method according to the present invention.

[0042] One advantage of the present invention is the realization of improved mechanical properties of 3D printed products. The hardness of the cured product (austenitized at 1180°C, then tempered three times at 560°C for 1 hour (h), and then air-cooled at temperatures less than 25° between temperature stages) can be at least 1050 HV2 kg (HV2), such as at least 1075 HV2 kg, or at least 1100 HV2 kg, or at least 1125 HV2 kg. In some embodiments, the hardness is 1075-1175 HV2 kg or 1100-1150 HV2 kg. The hardness is determined using a 2 kg Vickers indentation (HV2).

[0043] While not bound by theory, the mechanical properties of the present invention are considered to be a result of the product's microstructure. 3D printed products essentially lack a dendritic structure of carbides. The carbides present are small in size and, as can be seen in the diagram, are uniformly distributed within the matrix. There are no or very few carbides with a size of 15 μm or larger, which are typically found in alloys of 3D printed and cured products. Instead, the average size of the carbides is 10 μm or less, or even 5 μm or less.

[0044] The present invention not only facilitates the production of products and components having improved mechanical properties, but also enables the production of products having highly or complex three-dimensional shapes and forms. Products may have multiple cavities, multiple channels, or multiple holes, and products may have multiple curved parts or multiple helical forms. These shapes or forms are produced without any removal of the alloy other than any optional post-processing. Multiple cavities, multiple holes, or multiple channels may be curved; that is, their surfaces may be curved, helical, or helical, etc. In some embodiments, products include cavities that are sealed, or have openings whose diameter or width is less than the diameter or width of the cavity below. Products may be cutting tools such as milling cutters, shaper cutters, power skiving cutters, drills, milling tools, etc., forming tools such as extrusion heads, wire drawing dies, hot rolling rolls, etc., or wear components such as pump or valve components, sliding or rolling bearing rings, etc.

[0045] method This method is schematically shown in Figure 11. The present invention also relates to a method for producing 3D printed products from alloy powder, comprising an integrated HIP and hardening process. The alloy is an iron-based alloy (Fe balance) further comprising carbon and an unavoidable amount of impurities. The alloy may further comprise at least one of chromium, tungsten, cobalt, vanadium, and molybdenum. In one preferred embodiment, the iron-based alloy comprises carbon, chromium, vanadium, and molybdenum. In another preferred embodiment, the iron-based alloy comprises carbon, tungsten, chromium, cobalt, vanadium, and molybdenum. In yet another preferred embodiment, the iron-based alloy comprises carbon, tungsten, chromium, vanadium, and molybdenum.

[0046] In yet another preferred embodiment, the alloy is as defined above. The alloy is iron-based (Fe-balanced), comprising carbon and chromium, and may further comprise tungsten, cobalt, vanadium, molybdenum, and carbon. In one embodiment, the alloy is iron-based (Fe-balanced), comprising carbon and chromium, and further comprises at least two of the multiple elements tungsten, cobalt, vanadium, and molybdenum. Preferably, the alloy has a very low oxygen content, preferably 100 ppm or less by weight, more preferably less than 50 ppm by weight.

[0047] The carbon content of the iron-based alloy may be 0.2% or more and 5% or less by weight. In one embodiment, the carbon content is 2.20% or more and 2.60% or less by weight. In a preferred embodiment, the above content is 2.30 to 2.50% by weight. In one embodiment, the carbon (C) content is 1.0% or more and 5.0% or less by weight. In one embodiment, the above content is preferably 1.4% or more and 3.0% or less, more preferably 2.20 to 2.60% by weight, and more preferably 2.30 to 2.50% by weight.

[0048] The chromium content may be 2% by weight or more and 30% by weight or less. In one embodiment, the chromium (Cr) content is 2.0% by weight or more and 22% by weight or less. In a preferred embodiment, the above content is 3.8 to 4.4% by weight, preferably 3.9 to 4.3% by weight. In a preferred embodiment, the above content is 3 to 10% by weight, preferably 3.5 to 4.5% by weight. In another preferred embodiment, the chromium content is 18 to 22% by weight, more preferably about 20% by weight.

[0049] The tungsten (W) content may be 2% by weight or more and 25% by weight or less. In a preferred embodiment, the content is 5% by weight or more and 13% by weight or less. In a preferred embodiment, the tungsten content is 4% by weight or less and 12% by weight or less. In a more preferred embodiment, the content is 6% by weight or less and 11% by weight or less. In one embodiment, the tungsten (W) content is 2% by weight or more and 13% by weight or less. In a preferred embodiment, the content is preferably 6% by weight or less and 11% by weight or less.

[0050] The cobalt (Co) content can be 5% by weight or more and 25% by weight or less. In one embodiment, the content is 9% by weight or more and 18% by weight or less. In a more preferred embodiment, the content is 10 to 17% by weight. In one embodiment, the cobalt (Co) content is 7% by weight or more and 18% by weight or less. In a preferred embodiment, the content is 9% by weight or more and 18% by weight or less. In one embodiment, the content is preferably 10 to 17% by weight.

[0051] The vanadium(V) content may be 2% by weight or more and 15% by weight or less. In a preferred embodiment, the content is 5% by weight or more and 8% by weight or less. In a more preferred embodiment, the content is 6-7% by weight. In one embodiment, the vanadium(V) content is 3% by weight or more and 8% by weight or less. In one embodiment, the content is preferably 4% by weight or more and 7% by weight or less.

[0052] The molybdenum (Mo) content may be 2% by weight or more and 20% by weight or less. In a preferred embodiment, the content is 3% by weight or more and 10% by weight or less. In a more preferred embodiment, the content is 4% by weight or more and more preferably 5% by weight or more and more preferably 5% by weight or more. In one embodiment, the molybdenum (Mo) content is 1% by weight or more and 10% by weight or less. In one embodiment, the content is preferably 2% by weight or more and more preferably 5% by weight or more.

[0053] Aside from unavoidable impurities, the remainder of the alloy is iron, or Fe balance. The amount of iron in the balance depends on the amounts of the other components. Typically, the amount of iron is 50-70% by weight, preferably 60-65% by weight. The oxygen content in 3D printed products should be as low as possible. In this invention, the oxygen content is preferably 30 ppm or less, or 20 ppm or less.

[0054] The alloy may further contain unavoidable amounts of impurities of several other elements, or trace amounts of impurities. These elements may be, but are not limited to, niobium, nickel, manganese, silicon, boron, tantalum, or combinations thereof. The total amount of the above several other elements or impurities is preferably less than 1% by weight, less than 0.5% by weight, or less than 0.05% by weight.

[0055] In a preferred embodiment, the alloy is Carbon: 1.0% by weight and 5.0% by weight; Chromium: 2.0% by weight and 22.0% by weight; Iron: Balance; Includes, The above alloy is Tungsten: 2% by weight and 13% by weight; Cobalt: 7% by weight and 18% by weight; Molybdenum: 1% by weight and 10% by weight; Vanadium: 3% by weight and 8% by weight; It further contains at least two of the elements; The above alloy contains unavoidable trace amounts of impurities.

[0056] The oxygen content in 3D printed products should be as low as possible. Preferably, the oxygen content should be 30 ppm or less, or 20 ppm or less.

[0057] 3D printing Next, refer to Figure 11. The method uses a free-form apparatus (3D printer) having a chamber in which the powder is placed. The free-form method comprises the steps of obtaining an iron-based alloy powder (step 10) and 3D printing the powder (step 12). This is done by forming a layer of alloy powder in a low-oxygen environment within the chamber, as defined below. The 3D printing method may be carried out as described in International Publication 2018 / 169477, incorporated herein by reference, or based on the method described in International Publication 2018 / 169477. One preferred free-form apparatus is an electron beam apparatus (EBM) by Arcam, such as the ARCAM A2X. The alloy contains, in the above amounts, carbon, tungsten, molybdenum, chromium, vanadium, and cobalt, and the choice of alloy depends on the desired properties of the final product. The oxygen and other impurity content in the reactor should be as low as possible, such as 10 ppm or less (corresponding to gas purity grade 5) or 1 ppm or less (corresponding to gas purity grade 6), and the environment in the reactor may contain inert gases such as argon or helium. The vacuum pressure in the reactor should be 1.5 × 10⁻⁶ -3 mBar or less, preferably 1.5 × 10⁻⁶ -4 It may be less than mBar. In one embodiment, the initial pressure in the reactor is about 1.10 × 10⁻⁶ mBar. -5 mBar(1.10×10 -3 (Pa), and then the pressure is 1.5 × 10 -3 mBar or less, or preferably 1.5 × 10⁻⁶ -4To increase the energy level to below mBar, an inert gas such as helium or argon is added. The powder is then locally melted by exposing it to an energy beam for a period of time sufficient to melt it. The energy beam can be a laser beam or an electron beam. The beam is swept across the powder in any pattern. The duration of the sweep can range from a few milliseconds to a few minutes, depending on the alloy and the size of the particles in the powder. The molten powder can then be solidified, at least partially, into a multilayer metal alloy. Another layer of powder can then be added on top of the solidified alloy.

[0058] To avoid crack formation in the product and to improve its properties, the product is maintained at an elevated temperature (first elevated temperature) during printing or formation of the 3D printed product. Crack formation may occur at lower temperatures due to a combination of increased internal stress and increased material brittleness. The increase in internal stress is brought about by volume changes in phase transitions and, furthermore, by normal thermal expansion. The elevated temperature to avoid crack formation may be 300°C or higher, 400°C or higher, 500°C or higher, 550°C or higher, 600°C or higher, 700°C or higher, 800°C or higher, or 900°C or higher, but is usually 1100°C or lower. For example, the base plate or workbench on which the product is based may be equipped with a heating device. Thus, the 3D printed product may exhibit a temperature gradient within it during its construction. The heating of the product should be controlled so that the temperature of the constructed product during the construction process is preferably 600°C or higher, 700°C or higher, or 750°C or higher, but usually 900°C or lower, 850°C or lower, or 800°C or lower. In one embodiment, the temperature is 720°C to 790°C, such as 780°C. The temperature should, of course, be low enough for the molten powder layer to solidify at least partially before a new powder layer is added. This not only makes the method less expensive but also allows for a more positive effect on the microstructure.

[0059] In one embodiment, 3D printing is performed. A. A step of forming a layer of iron-based alloy powder on a base plate in a chamber, wherein the iron-based alloy further contains carbon and an unavoidable amount of impurities, and the powder forms a layer of iron-based alloy powder containing substantially spherical particles and / or substantially spherical particles; B. A step of locally melting the powder by exposing it to an energy beam for a period of time sufficient to form a molten pool; C. A step of solidifying the molten powder into a multiphase alloy in a molten pool; D. A step of optionally creating a further layer of powder on the previous layer by repeating steps i to iii, wherein step ii includes placing powder on the previous layer; Includes, The product being constructed is heated and maintained at the temperature that was raised during the process.

[0060] The advantages of using EBM compared to lasers are that it allows for the creation of thicker powder layers and the use of powders with larger particles. Carbide growth occurs during the solidification of the molten material, and the growth time should be limited to limit the size of the carbides. Solidification time is mainly influenced by the thermal diffusion rate, the heat of solidification, and the thermal diffusion distance. The solidification rate in conventional casting methods can be improved by cooling the molten material using either a preferred method such as casting in a strongly cooled refractory mold or casting the details. Furthermore, while the cooling rate in existing conventional cladding techniques is still high, it is not high enough to hinder carbide growth or to obtain a completely dense material.

[0061] Novel integrated HIP and curing The resulting 3D printed product is then processed in an integrated HIP and curing process. This can preferably be done using a Quintus machine equipped with Uniform Rapid Heating (URQ®). In this integrated process, the 3D printed product is placed in a suitable oven or furnace (step 14). The print is heated to a first temperature of at least 850°C and the pressure is increased to a first pressure of at least 80 MPa. The product is maintained at this temperature and pressure for a first holding time (step 16), after which the temperature is further increased to a second temperature of at least 950°C. At the second temperature, the product is maintained for a second holding time (step 18), after which it is rapidly heat-treated (cooled) to a third temperature and the pressure is further reduced to a third pressure (step 20). Heat treatment can be carried out using any preferred means, such as a gas, including an inert gas. To obtain better mechanical properties and microstructure, quenching is carried out at a high cooling rate of at least 10°C / s, more preferably 20°C / s, more preferably 30°C / s, more preferably at least 40°C / s, and more preferably up to 50°C / s. The product is maintained at a third temperature and pressure for a third holding time. After quenching and pressure reduction, a temperature cycle (tempering) is performed in which the temperature is increased to a fourth temperature and the pressure is increased to a fourth pressure. The product is maintained at a fourth temperature and pressure for a fourth holding time, after which the temperature may be reduced to a fifth temperature. The pressure may be further reduced to a fifth pressure. The temperature cycle may be repeated at least once, preferably twice.

[0062] In one embodiment, the first temperature is at least 1000°C, preferably 1200°C or less, preferably in the range of 1100°C to 1200°C, and more preferably in the range of 1120°C to 1150°C.

[0063] In one embodiment, the second temperature is at least 1050°C, preferably in the range of 1100°C to 1200°C, and more preferably in the range of 1180°C to 1200°C. The second temperature is higher than the first temperature.

[0064] In one embodiment, the third temperature is 75°C or lower. In the quenching step (step 20), the temperature is rapidly cooled from the second temperature to a third temperature of 50°C or lower in one embodiment, and the third pressure is preferably 65 MPa or lower.

[0065] In one embodiment, the first pressure is less than 210 MPa, and preferably in the range of 90 to 120 MPa.

[0066] In one embodiment, the second pressure is at least 80 MPa, preferably at least 90 MPa, or preferably at least 100 MPa, preferably less than 210 MPa, and more preferably less than 150 MPa. In a preferred embodiment, the first and second pressures are the same, i.e., the pressure is not changed in step 18.

[0067] In one embodiment, the third pressure is in the range of 30 to 70 MPa, preferably 55 to 65 MPa.

[0068] In one embodiment, the fourth pressure is at least 70 MPa, preferably in the range of 70 to 80 MPa, and more preferably about 75 MPa.

[0069] In one embodiment, the fourth temperature is in the range of 500 to 600°C, preferably 550 to 580°C, and more preferably about 560°C.

[0070] In one embodiment, the fifth temperature is 50°C or lower, and preferably in the range of 20 to 25°C.

[0071] The holding time depends on the alloy composition and thickness of the product. In a preferred embodiment, each holding time is sufficient for the product to reach the set or target temperature or the furnace temperature. In a preferred embodiment, the first holding time is in the range of 1 to 4 hours, preferably 3 hours. In a preferred embodiment, the second holding time is in the range of 10 to 60 minutes, preferably 30 minutes. In a preferred embodiment, the third holding time is in the range of 1 second to 1 hour, or 30 seconds to 30 minutes. In another embodiment, the fourth holding time is in the range of 30 minutes to 3 hours, preferably 1 hour.

[0072] As seen in the examples, products obtained according to or by the method of the present invention unexpectedly possess high hardness and, in many cases, retain their original brittleness. This is unexpected compared to conventional hardening processes, as alloys treated by conventional hardening methods are already hardened to their "complete hardening temperature" according to conventional knowledge. That this effect can be achieved for different types of steel is further evident when examining and comparing the results from PM-HSS materials (M42, materials 150, 280, and 290) as well as highly alloyed martensitic stainless steel (material 350).

[0073] While not bound by theory, integrated HIP and heat treatment are thought to reduce the amount of large carbides. This is shown, for example, in Figure 12, where the reduction in the d90 value is greater than the reduction in the d10 value. Figures 12-14 show products in which this method has a narrower carbide area distribution, and the amount of large carbides is greater than that of small carbides. More than the amount Prioritize reduction done This clearly demonstrates the resulting product. Since the white carbide is, for example, the carbide of W, the effect of the reduction in area distribution on the white carbide, as seen in Figure 13, is even more interesting.

[0074] All embodiments disclosed herein should be understood as some exemplary examples of the present invention. It will be understood that various modifications, combinations, and changes can be made to embodiments and aspects without departing from the scope of the invention. In particular, different partial solutions in different embodiments can be combined in other configurations where technically possible. [Examples]

[0075] Example 1 The Quintus QIH 21 URQ machine was used to compare separate HIP and hardening, as well as integrated HIP and hardening, for 3D-printed high-alloy materials having the compositions shown in Table 1. Four 3D-printed Fe alloys, namely three types of high-speed steel and one type of martensitic stainless steel, were compared. 3D printing was basically carried out as described in International Publication 2018 / 169477, incorporated herein by reference. All four materials were first solidified by conventional methods, hardened by conventional methods, and tempered by HIP. Then, samples from exactly the same 3D-printed batch were treated with a novel integrated HIP, hardening, and tempering process, using the same conventional hardening and tempering times and temperature settings. See Table 1.

[0076] [Table 1]

[0077] Conventional HIP parameters involved heating to 1120-1150°C for 3 hours at a HIP pressure of 100 MPa, followed by cooling to room temperature, and then pressure release.

[0078] The test detail was heated to 1180°C for approximately 30 minutes, followed by rapid quenching at a cooling rate higher than 7°C / s in the 970°C-800°C range, and then cooled in air to 25-50°C, thus undergoing conventional hardening in a conventional vacuum furnace. The test detail was then tempered three times by heating it to 560°C for a holding time of 1 hour (h), and then cooling to 25°C between three temperature cycles.

[0079] Conventional HIP parameters, as well as curing and tempering, are all standard procedures performed by large-scale suppliers.

[0080] The novel integrated HIP, hardening, and tempering process according to the present invention uses the following parameters: first, the detail or product is heated to 1120-1150°C while the pressure is increased to a maximum of 100 MPa. At this stage, a holding time of 3 hours (h) is maintained, and then the temperature is increased to 1180°C with a new holding time of 30 minutes. From this stage, rapid temperature quenching is performed to 20°C (the pressure is also reduced to 60 MPa). Then, the temperature is increased three times to 560°C (followed by an increased pressure of 75 MPa), which constitutes the tempering cycle. The holding time at 560°C is 1 hour (h) each time, and the temperature between temperature cycles is 20°C.

[0081] The material samples were then compared in terms of hardness and microstructure. Hardness measurements were performed using a 2 kg Vickers indenter on ground and polished samples, following a standard material analysis method involving finish grinding with SiC P4000, in accordance with SS-EN ISO 6507. At this stage, hardness was measured at several points on multiple pieces that yielded the same results.

[0082] After cutting the sample from the processed material piece, the sample was further processed to facilitate carbide measurement. This preparation involved further polishing with a 1 μm diamond for 5 minutes, followed by a Struers OP-S solution (40 μm SiO2 at pH 9.8), a well-known method for facilitating carbide structure analysis.

[0083] result The hardness of all samples is shown in Table 2. Generally, the hardness after integrated HIP, hardening, and tempering is unexpectedly higher than that of conventional HIP and heat treatment processes. For material 150, it is 12% higher; for material 280, it is 11.8% higher; for material 290, it is 5% higher; and for material 350, it is 12% higher.

[0084] [Table 2]

[0085] The wear resistance of 280 materials subjected to conventional HIP and heat treatment methods was analyzed for the same grade of materials subjected to a novel integrated HIP and heat treatment method.

[0086] The test used to analyze wear resistance was a commercially available dimple grinder (Gatan) with a grinding wheel rotating on a horizontal axis, pressed against a sample rotating on a vertical axis. Diamond slurry with an average particle size of 2.5 μm was introduced into the contact before each run. A fixed load of 20 g was applied to the grinding wheel when it came into contact with the sample. Each test had a duration of 500 wheel rotations, resulting in a total sliding distance of approximately 31 m. For statistical purposes, the test was repeated three times for each sample.

[0087] Three cubes of test material were prepared, each having a test surface of approximately 6 × 6 mm, ground and polished to a surface roughness of Ra ~ 3 μm. The abrasion rate was determined by measuring the volume of material removed (abraded) using white light optical profilometry.

[0088] As a result, despite being cured at the same maximum temperature of 1180°C, they exhibited a 7.5% lower wear rate for the integrated HIP and heat-treated grades (see Figure 1).

[0089] Calculation of carbides In carbide size analysis, a comprehensive microstructure analysis is performed, and the corresponding representative microstructures are shown here.

[0090] The most important microstructural changes are the decrease in carbide (and / or carbide cluster) area and the narrowing of the carbide area distribution, as shown in Table 3. The maximum carbide / cluster is much smaller, and at the same time, the average carbide area shows a general trend of being larger. This suggests that the carbide area distribution is very narrow. This indicates that the toughness of the alloy is improved or at least not decreased, because the toughness of these kinds of high-hardness and high-alloy materials is determined by the "largest imperfections" in the material. These imperfections are usually some kind of impurities, oxides, large carbides or carbide clusters, but can also be grinding errors, i.e., white layers due to grinding at too high a temperature. Furthermore, the material becomes more uniform and isotropic with a narrower carbide distribution.

[0091] The microstructure was analyzed using a scanning electron microscope (SEM), as shown in the figures. The SEM was a Zeiss Ultra 55 FEG-SEM using secondary electron imaging mode. The primary electron energy (EHT, ultra-high tension voltage) was 3, 5, and 10 keV, and the aperture used was 30 (standard) or 60 μm. The microstructure of the material showed unexpectedly high carbide content and very fine carbides (Figures 2, 4, 6, and 8).

[0092] Carbides were calculated by utilizing the microstructure shown in Figure 2, for example, marking the boundaries of individual carbides or carbide clusters, and using suitable software.

[0093] The results can be seen in Figures 3, 5, 7, and 9. The calculation results for carbide area and ratio are shown in Table 3.

[0094] [Table 3]

[0095] Example 2 A series of tests were conducted on samples to examine how this method affects toughness (impact resistance) compared to conventional HIP and heat treatment.

[0096] Toughness measurements were performed by 3D printing 10 Charpy toughness rods in both the horizontal and vertical directions. After different heat treatments were tested, the rods were ground to the final test rod measurements, i.e., L×W×H = 7×10×55, + / - 0.025 mm. Surface roughness was set by the final surface grinding step, grit 4000. No notches were used on the test rods. Toughness was then measured at room temperature using a 300 J Charpy tester with an egg radius of 2 mm. Toughness results are presented in units of joules as the average value of 10 samples.

[0097] [Table 4]

[0098] As mentioned above, the hardness of the samples increased considerably when the samples were prepared using the integrated HIP and heat treatment according to the present invention. Unexpectedly, the toughness of the samples remained somewhat the same, and an increase in hardness is usually accompanied by a decrease in toughness. Figures 12-14 show the effect on the carbide area distribution for these samples, where white and gray carbides represent how they appear in SEM, with white carbides usually formed from heavy metal elements such as W, and gray carbides usually formed from lighter metallic elements such as Cr or V in quantifiable amounts of several different types. Carbide area analysis was performed as described above. Two products for each alloy were printed, one in a horizontally oriented position and the other in a vertically oriented position, and the values ​​shown are the average of the two products.

[0099] As shown in Figure 12, both the d90 and d10 values ​​are lower when using this method compared to conventional HIP and heat treatment. Furthermore, Figure 12 shows that the decrease in the d90 value is greater than the decrease in the d10 value, indicating that this method has a more significant effect on the reduction of large carbides than on small carbides.

[0100] Figure 13 shows that the carbide area analysis is narrower for samples prepared using this method (URQ) compared to those prepared using conventional HIP and heat treatment. Furthermore, the carbide area distribution of the white and gray carbides is also more similar.

[0101] Figure 14 shows that preparing samples using the present invention (URQ) results in smaller carbides (mean), smaller maximum carbides (maximum), and a narrower distribution (SD, standard deviation).

[0102] Example 3 Here, printing tests of alloy M42 were compared between two heat treatment methods: a conventional 3-hour (h) HIP and hardening process in separate vacuum furnaces at 1180°C, followed by 3 × 560°C tempering, and an integrated HIP and heat treatment according to the present invention, using the same temperature and time settings as the conventional method but with different pressures.

[0103] The powder used was a gas atomized with a size fraction of 53-150 μm, having a composition in weight percent that conformed to the specifications. TIFF0007849860000005.tif1864

[0104] M42 is an ultra-high Mo steel, typically a conventional non-PM high-speed steel material, conforming to standards HS2-9-1-8, AISIS M42, or EN 1.3247.

[0105] Integrated HIP and heat treatment are performed under the following conditions, as described above: HIP at 1120°C and 1000 Bar for 3 hours (h) The temperature was increased to 1180℃. Heat treatment / hardening Tempering at 560°C with approximately 500 bar for 3 x 1 hour (h) It took place in [location].

[0106] Conventional HIP and heat treatment methods: In a separate HIP furnace, it was subjected to HIP at 1120-1150°C and 1000 bar for 3 hours (h). Cooled to room temperature, Transported to the hardening company, It hardens at 1180℃, It was tempered at 560°C for 3 x 1 hour (h).

[0107] According to the material specifications for this material (as a conventional rod), it can be hardened from 61 HRC to 68 HRC (Rockwell), the latter achieved in 3 × 1 hour (h) at a curing temperature of 1190°C + 560°C. When cured at 1180°C, the hardness is approximately 67.6 HRC. Austenitization occurs at 1050-1090°C (Erasteel material specification data).

[0108] Hardness and toughness are determined as described above.

[0109] result While conventionally hardened samples had a hardness of 945+ / -68 HV2kg, samples obtained by integrated HIP and heat treatment had a hardness of 1020+ / -69 HV2kg.

[0110] [Table 5]

[0111] This means that the hardness increases by 8% using this method.

[0112] The toughness of samples treated with integrated HIP and heat treatment was 13–21% lower than that of samples treated with conventional methods. While not bound by theory, this is thought to be a result of the lower carbon content, which means that the effects of integrated HIP and heat treatment were not fully realized in this case.

[0113] (1) A 3D printed product formed of an iron-based alloy comprising a metal matrix and carbide particles incorporated into the metal matrix; The aforementioned alloy is Carbon: 1.0% by weight and 5.0% by weight; Chromium: 2.0% by weight and 22.0% by weight; Iron: Balance; Includes, The aforementioned alloy is Tungsten: 2% by weight and 13% by weight; Cobalt: 7% by weight and 18% by weight; Molybdenum: 1% by weight and 10% by weight; Vanadium: 3% by weight and 8% by weight; It further contains at least two of the elements; The aforementioned alloy contains unavoidable trace amounts of impurities; The maximum carbide area is 8 μm 2 It is less than 2 μm², and the average carbide area is 2 μm². 2 Less than; and / or The area distribution of carbides is 1.90 μm 2 The difference between the d90 and d10 values ​​is as follows: and / or The carbide area distribution is 2.20 μm 2 The following d90 values ​​are found: 3D printed products. (2) The carbon content is 1.4% or more and 3.0% or less by weight. The 3D printed products described in (1) above. (3) The alloy is Tungsten: 2% by weight and 13% by weight; Molybdenum: 1% by weight and 10% by weight; Vanadium: 3% by weight and 8% by weight; Optionally, Cobalt: 9% by weight and 18% by weight Further including, 3D printed products as described in (1) or (2) above. (4) The alloy is Carbon: 1.0% by weight and 3.0% by weight; Chromium: 2.0% by weight and 22.0% by weight; Molybdenum: 1% by weight and 10% by weight; Vanadium: 3% by weight and 8% by weight; Iron: Balance; Includes, The aforementioned alloy contains unavoidable trace amounts of impurities. 3D printed products as described in (1) or (2) above. (5) The alloy is Carbon: 2.20% by weight and 2.60% by weight; Tungsten: 5% by weight and 13% by weight; Chromium: 3.5% by weight and 4.5% by weight; Cobalt: 9% by weight and 18% by weight; Molybdenum: 3% by weight and 10% by weight; Vanadium: 5% by weight and 8% by weight; Iron: Balance; Inevitable trace amounts of impurities including, 3D printed products as described in (1) or (2) above. (6) The average carbide area is 1 μm 2 Less than, The 3D printed products described in (1) above. (7) The iron-based alloy Carbon: 2.25% by weight and 2.40% by weight; Tungsten: 6% by weight and 8% by weight; Chromium: 3.5% by weight and 4.5% by weight; Cobalt: 9% by weight and 12% by weight; Molybdenum: 5% by weight and 8% by weight; Vanadium: 5% by weight and 8% by weight; Iron: Balance; The 3D printed products described in (1) above, including the above. (8) The iron-based alloy Carbon: 1.2% by weight and 1.8% by weight; Chromium: 3.5% by weight and 4.5% by weight; Tungsten: 2.0% by weight and 4.0% by weight; Vanadium: 3% by weight and 5% by weight; Molybdenum: 1% by weight and 4% by weight; Iron: Balance; Inevitable trace amounts of impurities including, The 3D printed products described in (1) above. (9) The iron-based alloy Carbon: 1.5% or more and 2.3% or less by weight; Chromium: 17% or more and 22.0% or less by weight; Vanadium: 3% by weight and 5% by weight; Molybdenum: 1% by weight and 3% by weight; Iron: Balance; Inevitable trace amounts of impurities including, The 3D printed products described in (1) above. (10) The iron-based alloy Carbon: 1.0% or more and 1.20% or less by weight; Chromium: 2.0% by weight and 5.0% by weight; Molybdenum: 7% by weight and 10% by weight; Cobalt: 7% by weight and 9% by weight; Includes; The aforementioned alloy Tungsten: 1.0% by weight and 3.0% by weight; Vanadium: 1.0% by weight and 3.0% by weight; Iron: Balance; Inevitable trace amounts of impurities Further including, The 3D printed products described in (1) above. (11) The maximum carbide area is 4 μm 2 The following is preferred: 3 μm 2 The following are 3D printed products as described in any of (1) to (10) above. (12) The 3D printed product according to any one of (1) to (7) above, wherein the product has a hardness of at least 1050 HV 2 kg, preferably at least 1100 HV 2 kg. (13) A method for manufacturing a 3D printed product, a. Providing a powder of an iron-based alloy, wherein the iron-based alloy further contains carbon and an unavoidable amount of impurities; b. A step of 3D printing a product from an iron-based alloy in a free-form apparatus having a chamber, wherein the 3D printing is performed in a vacuum; c. The product obtained in step b, i. The step of placing the product inside the furnace; ii. Heating the product to a first temperature of at least 850°C, increasing the pressure inside the furnace to a first pressure of at least 80 MPa, and holding the product at the first temperature and first pressure for a first holding time; iii. Heating the product to a second temperature of at least 950°C, and holding the product at the second temperature and a second pressure for a second holding time; iv. The steps of quenching the product to a third temperature, reducing the pressure inside the furnace to a third pressure, and holding the product at the third temperature and third pressure for a third holding time; v. A step of performing a temperature cycle by heating the product to a fourth temperature, increasing the pressure in the furnace to a fourth pressure, holding the product at the fourth temperature and pressure for a fourth holding time, and then decreasing the temperature of the product to a fifth temperature. Steps processed by including, How to create 3D printed products. (14) The vacuum pressure is 1.5 × 10 -3 mBar or less, preferably 1.5 × 10⁻⁶ -4 The method according to (13) above, wherein the energy is less than or equal to mBar, and the energy beam is preferably an electron beam. (15) The method according to (13) or (14) above, wherein the first temperature is at least 1000°C, preferably 1400°C or less, preferably in the range of 1100 to 1200°C, and more preferably in the range of 1120 to 1150°C; and the second temperature is higher than the first temperature. (16) The second temperature is at least 1050°C, preferably in the range of 1100 to 1200°C, and more preferably in the range of 1180 to 1200°C; The second temperature is higher than the first temperature. The method described in any of (13) to (15) above. (17) The method according to any one of (13) to (16) above, wherein the third temperature is 50°C or less, and the third pressure is preferably 65 MPa or less. (18) The method according to any one of (13) to (17) above, wherein the first pressure is at least 90 MPa or less, preferably at least 100 MPa, preferably less than 210 MPa, and more preferably less than 150 MPa. (19) The method according to any one of (13) to (18) above, wherein the fourth temperature is in the range of 500 to 600°C, preferably 550 to 580°C, and more preferably about 560°C. (20) The method described in (18) above, wherein the first pressure is in the range of 90 to 120 MPa. (21) The method according to any of (13) to (20) above, wherein the third pressure is in the range of 55 to 65 MPa. (22) The method according to any one of (13) to (21) above, wherein the fourth pressure is at least 70 MPa, preferably in the range of 70 to 80 MPa, and more preferably about 75 MPa. (23) The method according to any one of (13) to (22) above, wherein the fifth temperature is 50°C or less, and preferably in the range of 20 to 25°C. (24) The method according to any one of (13) to (23) above, wherein the first holding time is in the range of 1 to 4 hours, preferably 3 hours. (25) The method according to any one of (13) to (24) above, wherein the second holding time is in the range of 10 to 60 minutes, preferably 30 minutes. (26) The method according to any one of (13) to (25) above, wherein the third holding time is in the range of 1 second to 30 minutes. (27) The method according to any one of (13) to (26) above, wherein the fourth holding time is in the range of 30 minutes to 3 hours, preferably 1 hour. (28) The method according to any one of (13) to (27) above, wherein the alloy further comprises at least one of chromium, tungsten, cobalt, vanadium, and molybdenum. (29) The alloy is Carbon: 1.0% by weight and 5.0% by weight; Chromium: 2.0% by weight and 22.0% by weight; Iron: Balance; Includes, The aforementioned alloy is Tungsten: 2% by weight and 13% by weight; Cobalt: 7% by weight and 18% by weight; Molybdenum: 1% by weight and 10% by weight; Vanadium: 3% by weight and 8% by weight; It further contains at least two of the elements; The aforementioned alloy contains unavoidable trace amounts of impurities. The method described in (13) above. (30) The method according to any one of (13) to (27) above, wherein the step of quenching the product is carried out at a cooling rate of at least 10°C / s, preferably at least 20°C / s, preferably at least 30°C / s, or at least 40°C / s. (31) The method described in (13) above, wherein the 3D printing is A. A step of forming a layer of iron-based alloy powder on a base plate in the chamber, wherein the iron-based alloy further contains carbon and an unavoidable amount of impurities, and the powder forms a layer of iron-based alloy powder containing substantially spherical particles and / or substantially spherical particles; B. A step of locally melting the powder by exposing it to an energy beam for a period of time sufficient to form a molten pool; C. The step of solidifying the molten powder into a multiphase alloy in the molten pool; D. A step of optionally creating a further layer of powder on the previous layer by repeating steps i to iii, wherein step ii includes placing the powder on the previous layer; Includes, The product being constructed is heated and maintained at the temperature that rose during the method. The method described in (13) above. (32) The method according to (13) above, wherein step v, which is a step of performing a temperature cycle, is repeated at least once, preferably twice. (33) The method according to any one of (13) to (32) above, wherein the second pressure is at least 80 MPa, preferably at least 90 MPa, or preferably at least 100 MPa, preferably less than 210 MPa, and more preferably less than 150 MPa. (34) Products obtained by any of the methods described in (13) to (33) above. (35) The product obtained is the product according to (34) above, having a hardness (HV2kg) at least 5%, preferably 7%, and more preferably 10% higher than the corresponding 3D printed product processed using conventional HIP and heat treatment. (36) The product according to (34) or (35) above, preferably with a holding time of 3 hours, wherein the first temperature is 1120 to 1150°C and the first pressure is about 100 MPa. (37) The hardness of the product described in (35) above is measured using a 2 kg Vickers indenter on a sample that has been ground and polished by a standard material analysis method of finish grinding with SiC P4000 in accordance with SS-EN ISO 6507. (38) The product is a milling cutter, shaper cutter, power skiving cutter, drill, milling tool, extrusion head, wire drawing die, hot rolling roll, or sliding or rolling bearing ring, as described in any of (1) to (12) or (34) to (37) above.

Claims

1. A 3D printed product formed of an iron-based alloy comprising a metal matrix and carbide particles incorporated into the metal matrix; The aforementioned alloy is (i) Carbon: 1.0% by weight and 5.0% by weight; (ii) Chromium: 2.0% by weight and 22.0% by weight; (iii) at least two selected from tungsten: 2 to 13% by weight, cobalt: 7 to 18% by weight, molybdenum: 1 to 10% by weight, and vanadium: 3 to 8% by weight; (iv) Inevitable trace amounts of impurities; and (v) Iron: Remaining portion Combination The maximum carbide area is 8 μm 2 It is less than 2 μm², and the average carbide area is 2 μm². 2 Less than; and The area distribution of carbides is 1.90 μm. 2 The following has the difference between the d90 value and the d10 value: 3D printed products.

2. The carbon content is 1.4% or more and 3.0% or less by weight. The 3D printed product according to claim 1.

3. The 3D printed product according to claim 1 or 2, wherein (iii) comprises tungsten: 2 to 13% by weight, molybdenum: 1 to 10% by weight, vanadium: 3 to 8% by weight, and optionally cobalt: 9 to 18% by weight.

4. The aforementioned alloy, Carbon: 1.0% by weight and 3.0% by weight; Chromium: 2.0% by weight and 22.0% by weight; Molybdenum: 1% by weight and 10% by weight; Vanadium: 3% by weight and 8% by weight; Inevitable trace amounts of impurities; and Iron: Consists of the remainder, The 3D printed product according to claim 1.

5. The aforementioned alloy, Carbon: 2.20% by weight and 2.60% by weight; Tungsten: 5% by weight and 13% by weight; Chromium: 3.5% by weight and 4.5% by weight; Cobalt: 9% by weight and 18% by weight; Molybdenum: 3% by weight and 10% by weight; Vanadium: 5% by weight and 8% by weight; Inevitable trace amounts of impurities; and Iron: Consists of the remainder, A 3D printed product according to claim 1 or 2.

6. The aforementioned alloy, Carbon: 2.25% by weight and 2.40% by weight; Tungsten: 6% by weight and 8% by weight; Chromium: 3.5% by weight and 4.5% by weight; Cobalt: 9% by weight and 12% by weight; Molybdenum: 5% by weight and 8% by weight; Vanadium: 5% by weight and 8% by weight; Inevitable trace amounts of impurities; and Iron: Consists of the remainder, A 3D printed product according to claim 1 or 2.

7. The aforementioned alloy, Carbon: 1.2% or more and 1.8% or less by weight; Chromium: 3.5% by weight and 4.5% by weight; Tungsten: 2.0% by weight and 4.0% by weight; Vanadium: 3% by weight and 5% by weight; Molybdenum: 1% by weight and 4% by weight; Inevitable trace amounts of impurities; and Iron: Consists of the remainder, The 3D printed product according to claim 1.

8. The aforementioned alloy, Carbon: 1.5% by weight and 2.3% by weight; Chromium: 17% by weight and 22.0% by weight; Vanadium: 3% by weight and 5% by weight; Molybdenum: 1% by weight and 3% by weight; Inevitable trace amounts of impurities; and Iron: Consists of the remainder, A 3D printed product according to claim 1 or 2.

9. The average carbide area is 1 μm 2 Less than, The 3D printed product according to claim 1.

10. The maximum carbide area is 4 μm 2 The following is: A 3D printed product according to any one of claims 1 to 8.

11. The aforementioned product has a hardness of at least 1050 HV 2 kg, The aforementioned hardness is measured using a 2 kg Vickers indenter on a sample that has been ground and polished, according to a standard material analysis method for finish grinding with SiC P4000 in accordance with SS-EN ISO 6507. A 3D printed product according to any one of claims 1 to 9.

12. A method for manufacturing 3D printed products, a. A step of providing an iron-based alloy powder, The aforementioned iron-based alloy, (i) Carbon: 1.0% by weight and 5.0% by weight; (ii) Chromium: 2.0% by weight and 22.0% by weight; (iii) at least two selected from tungsten: 2 to 13% by weight, cobalt: 7 to 18% by weight, molybdenum: 1 to 10% by weight, and vanadium: 3 to 8% by weight; (iv) Inevitable trace amounts of impurities; and (v) Iron: Remaining portion A step of providing a powder of an iron-based alloy consisting of the following: b. A step of 3D printing a product from an iron-based alloy in a free-form apparatus having a chamber, wherein the 3D printing is performed in a vacuum; c. The product obtained in step b is i. The step of placing the product inside the furnace; ii. Heating the product to a first temperature of at least 850°C, increasing the pressure inside the furnace to a first pressure of at least 80 MPa, and holding the product at the first temperature and first pressure for a first holding time; iii. Heating the product to a second temperature of at least 950°C, and holding the product at the second temperature and a second pressure, wherein the second pressure is at least 80 MPa, for a second holding time; iv. The steps of quenching the product to a third temperature of 50°C or less, reducing the pressure inside the furnace to a third pressure of 65 MPa or less, and holding the product at the third temperature and pressure for a third holding time; v. A step of performing a temperature cycle by heating the product to a fourth temperature of 500 to 600°C, increasing the pressure inside the furnace to a fourth pressure of at least 70 MPa, holding the product at the fourth temperature and pressure for a fourth holding time, and then decreasing the temperature of the product to a fifth temperature of 50°C or less. Steps processed by Includes, The maximum carbide area is 8 μm 2 It is less than 2 μm², and the average carbide area is 2 μm². 2 It is less than, and The area distribution of carbides is 1.90 μm. 2 A method for producing a 3D printed product having the following difference between the d90 value and the d10 value.

13. The first temperature is at least 1000°C; The second temperature is higher than the first temperature. The method according to claim 12.

14. The method according to claim 12 or 13, wherein the first pressure is at least 90 MPa.

15. The method according to any one of claims 12 to 14, wherein the first holding time is in the range of 1 to 4 hours.

16. The method according to any one of claims 12 to 15, wherein the step of quenching the product is carried out at a cooling rate of at least 10°C / s.

17. Step v, which is a step in which a temperature cycle is performed, is repeated at least once. The method according to claim 12.

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