Metal powder for directed energy deposition and / or for laser or electron-beam powder bed fusion, and method for producing same

Abstract

The present invention relates to the use of non-spherical metal particles for additive manufacturing, in particular for laser deposition welding or for selective laser melting. In particular, the present invention relates to the use of metal particles having a sphericity in a range from ≥ 0.67 to ≤ 0.98 in methods for laser deposition welding or selective laser melting.

Description

[0001] Metal powder for directed energy deposition and / or for powder bed melting by laser or electron beam and process for its production

[0002] Description

[0003] The present invention relates to the use of non-spherical metal particles for additive manufacturing, in particular for directed energy deposition or for powder bed-based laser melting. In particular, the present invention relates to the use of metal particles with a sphericity in a range of > 0.67 to < 0.98 in directed energy deposition and / or powder bed-based laser melting processes. Furthermore, the present invention relates to a method for producing metal particles for use in additive manufacturing.

[0004] The present invention relates to the field of additive manufacturing. Additive manufacturing is a concept or approach in the manufacturing industry in which production is designed to be flexible and adaptable in order to respond quickly to changing requirements and conditions. In particular, the present invention relates to the field of laser metal deposition (LMD), directed energy deposition (DED), powder bed fusion (PBF), selective laser melting (SLM), selective laser sintering (SLS), and electron beam melting (EBM). In the traditional sense, manufacturing is often focused on a specific product line or process, and changes often require extensive adaptation and investment.However, additive manufacturing aims to overcome these limitations by integrating agility and adaptability into the production process.

[0005] A key aspect of additive manufacturing is the use of advanced production technologies such as Industry 4.0, the Internet of Things (IoT), artificial intelligence (AI), and machine learning. These technologies enable high levels of connectivity and interoperability of machines, systems, and systems in manufacturing. Real-time data monitoring and analysis enables production systems to quickly respond to changes, detect errors, and find optimal solutions.

[0006] Another important aspect of additive manufacturing is the use of flexible manufacturing systems, which allow for the production of different products in small batch sizes or even as single pieces. This is often referred to as "batch size 1" and requires production to be able to switch quickly from one product to another without long setup times or extensive manual intervention.

[0007] Additive manufacturing offers many advantages, such as shorter lead times, higher productivity, lower inventory costs, and adaptability to changing market demands. It enables companies to quickly respond to individual customer requests and offer customized products.

[0008] One manufacturing technique widely used in additive manufacturing is laser cladding. Laser cladding is a welding process that uses a laser beam to melt and weld material. It is a form of buildup welding in which additional material is selectively applied to a surface to repair, coat, or modify it. Laser cladding offers several advantages over other welding processes. Because the laser beam can be controlled very precisely, the process enables the welding of small areas and complex shapes. It creates a small heat-affected zone, resulting in minimal deformation of the workpiece. In addition, the laser enables high welding speeds and good control of welding parameters.

[0009] Laser cladding is used in various industries, such as automotive, aerospace, tool manufacturing, and medical technology. It is used to repair damaged or worn components, apply wear-resistant coatings, or produce customized components.

[0010] In laser cladding, a focused laser beam is directed at the workpiece. The laser beam heats the workpiece material and melts it locally. At the same time, a filler material in powder or wire form is introduced into the molten pool. This filler material bonds with the workpiece material, forming a weld or coating. The choice of filler material depends on factors such as the material to be welded, the desired weld quality, strength, corrosion resistance, and other properties. The most common filler materials for laser cladding are:

[0011] - Wire electrodes: Wire electrodes are a commonly used form of filler metal. They consist of an alloy that is to be welded to the base material. The wire is continuously fed during the welding process and melts together with the base material to form the weld. - Powder: Powdered filler metals are applied to the weld either manually or automatically. The powder can consist of a variety of materials, including metals, alloys, or ceramics. It melts in the molten metal pool and forms the weld.

[0012] - Powder wire combination: This method uses a combination of wire electrode and powder. The wire is introduced into the molten pool while powdered filler metal is added simultaneously. This combination allows for better control of weld properties and can meet specific requirements such as wear resistance, corrosion resistance, or coating properties.

[0013] Directed energy deposition (DED) is a 3D printing process that uses a focused energy source such as a plasma arc, laser, or electron beam to melt a material while simultaneously depositing it through a nozzle. Like other additive manufacturing processes, DED systems can be used to add material to existing parts, make repairs, or occasionally build new parts.

[0014] DED processes are also known by other names, including Laser Engineered Net Shaping (LENS), Direct Metal Deposition (DMD), Electron Beam Additive Manufacturing (EBAM), Directed Light Fabrication, and 3D Laser Cladding, depending on the exact application or method used.

[0015] In directed energy deposition, molten material is applied to a specific surface, where it solidifies and fuses the materials into a structure. Directed energy deposition machines typically use a nozzle mounted on a multi-axis arm that can move in multiple directions, allowing for variable deposition. The process is typically performed in a controlled chamber with reduced oxygen levels. Electron beam-based systems perform the process in a vacuum, while laser-based systems use a completely inert chamber for reactive metals. It is also possible to use a shielding gas to cover the part and prevent contamination during metal 3D printing.

[0016] DED uses a heat source to melt a powder or wire and apply it to the surface of an object. Powder offers greater deposition accuracy.

[0017] The material is deposited in layers and solidifies from the melt pool to create new features. The layers are typically 0.25 mm to 0.5 mm thick. Cooling times for the materials are very rapid, at approximately 1000–5000 °C per second. The cooling time affects the final grain structure, although overlaps in the material can cause remelting, creating a uniform but variable microstructure.

[0018] Almost any weldable metal can be additively manufactured using the DED process, including aluminum, Inconel, niobium, stainless steel, tantalum, titanium and titanium alloys, and tungsten.

[0019] The advantages of directed energy deposition include the ability to control grain structure, making it suitable for repairing high-quality functional parts. However, this requires a balance between accuracy and speed, as higher speeds result in lower accuracy and a less consistent microstructure. Furthermore, the properties of the metal powder used significantly influence the deposition result. Directed energy deposition (DED) materials are still relatively limited, and molten metallurgy processes are still being further researched. Like other additive manufacturing processes, one advantage of the DED process is the ability to produce relatively large parts with minimal tooling.

[0020] This process also enables the production of components with composition gradients or hybrid structures using several materials with different compositions.

[0021] Directed Energy Deposition can be used to manufacture components, but is also used for repairs or to add material to existing components.

[0022] The DED process can produce parts similar to those produced using conventional machining. This means that DED is only suitable for applications where conventional manufacturing is expensive or slow. This makes the process ideal for manufacturing workpieces from expensive or difficult-to-machine metals. DED is therefore suitable for the production of parts such as brackets, tanks, and fins for the aerospace industry. The production of near-net-shape parts is primarily used in the aerospace, defense, energy, and marine sectors. Although this process leads to improved product design, time savings, and cost reduction, it is not considered suitable for the mass production of small components in large quantities due to the fixed pricing structure and post-processing requirements.

[0023] Because the DED process can be used to print existing parts, it is ideal for adding additional functional features to existing parts.

[0024] Direct energy deposition is increasingly replacing traditional methods for repairing parts. Because it's an automated process, DED offers a high degree of control and repeatability, which is especially important for complex and precise parts. The process is already being used for applications such as repairing damaged turbine blades or propellers.

[0025] Another manufacturing technique widely used in additive manufacturing is selective laser melting. Selective laser melting (SLM) is an additive manufacturing process used to produce three-dimensional objects from metal powder. It belongs to the family of 3D printing processes and is based on the layer-by-layer deposition and fusion of metal powder particles using a high-power laser.

[0026] In selective laser melting, the metal powder to be processed is applied layer by layer to a build platform. The laser beam is then directed at specific areas of the powder layer, where it selectively melts and bonds the powder. Precise control of the laser allows complex geometric shapes to be created by applying and fusing material layer by layer.

[0027] An important aspect of selective laser melting is the ability to produce high-density, fully metallic components. The melting process enables good fusion between the particles and leads to a homogeneous material structure. This results in components with high mechanical strength and good density.

[0028] Selective laser melting is used in various industries, such as automotive, aerospace, medical, and tool manufacturing. It enables the production of complex components with high precision and offers considerable design freedom.

[0029] Selecting the right filler material is crucial for the quality and performance of the weld, as well as the results of selective laser melting. When using powder as a filler material for laser cladding, it must possess certain properties to ensure a successful welding process. These include:

[0030] - Particle size: The particle size of the powder plays a crucial role, as it influences its melting and application properties. The powder should have a defined and controlled particle size distribution. The particle size can vary depending on the application and the desired welding parameters. Generally, particle sizes in the range of a few micrometers to a few hundred micrometers are used.

[0031] Grain shape: The shape of the powder grains can also have an impact. Until now, it has been assumed that powders with a spherical or nearly spherical shape must be used, as they enable good flow and melt formation. Irregular or branched grain shapes are considered problematic, as they lead to problems during application and melting.

[0032] - Purity: The powder should be of high purity to avoid impurities that could impair weld quality and mechanical properties. Impurities such as oxides, carbides, or foreign particles should be minimized to ensure weld quality.

[0033] Chemical composition: The chemical composition of the powder must be compatible with the base material and the desired welding properties;

[0034] Weldability: The powder should exhibit good weldability, meaning it should melt easily and evenly and form a stable melt. Weldability can be influenced by the melting point, flowability, and other thermal properties of the powder. In powder bed melting (PBF), as in the SLM process, the material to be processed is applied in powder form in a thin layer to a base plate. The powdered material is completely remelted locally using a laser beam or electron beam and, after solidification, forms a solid layer of material. The base plate is then lowered by the amount of one layer thickness, and more powder is applied. This cycle is repeated until all layers have been remelted. The finished component is cleaned of excess powder, machined as needed, or used immediately.

[0035] The typical layer thicknesses for the component structure range between 15 and 500 pm for all materials. To avoid oxygen contamination of the material, the process takes place under a protective gas atmosphere of argon or nitrogen.

[0036] Components manufactured using selective laser melting (SLM) or powder bed melting (PBF) are characterized by high specific densities (> 99%). This ensures that the mechanical properties of the additively manufactured component largely correspond to those of the base material.

[0037] However, a component with selective densities can also be manufactured specifically, based on bionic principles or to ensure a partial Young's modulus. In lightweight construction in aerospace and body implants, such selective elasticities within a component are often desired and cannot be produced using conventional processes.

[0038] Compared to conventional processes (casting), SLM and PBF processes are characterized by the elimination of tools or molds (formless manufacturing), thus reducing time to market. Another advantage is the high degree of geometric freedom, which enables the production of component shapes that are impossible or only possible with great effort using mold-based processes. Furthermore, storage costs can be reduced, as specific components do not need to be stored but can be manufactured additively on demand.

[0039] Generally, the higher the laser or electron beam power, the greater the roughness of the component. Modern system technology can control density and surface quality according to the "shell-core principle." Segmented exposure specifically influences the outer areas of the component, overhangs, and high-density component areas. An optimized exposure strategy improves the quality level and simultaneously increases build speeds. The performance profile of a component can be significantly improved with the help of segmented exposure.

[0040] Against the background of the known prior art, the object of the present invention is to provide a metallic additive for laser cladding or directed energy deposition as well as a metallic powder for SLM and / or DBF processes, which has improved properties compared to the previously known powdered additives or powders and in particular leads to improved welding or melting results.

[0041] This object is achieved by using metal particles according to claim 1. Embodiments of the invention can be found in the dependent claims and the following description.

[0042] To achieve the object, the invention proposes the use of metal particles for additive manufacturing, in particular for laser cladding or for selective laser melting, wherein the metal particles have a sphericity of < 0.98, preferably < 0.95, more preferably < 0.94, in particular < 0.93 and > 0.67, preferably > 0.67, preferably > 0.70, in particular > 0.90. Surprisingly, it has been found that non-spherical particles can contribute to an improvement in the welding result or melting results. Within the scope of the invention, it has been shown in particular that the use of irregular, non-spherical particles, so-called grit, surprisingly leads to improved welding results in laser cladding. In particular, this was shown in the investigation of the tensile strength of standardized tensile specimens.Surprisingly, it has also been shown that these high tensile strengths can be achieved without any further pretreatment of the welding substrate—that is, the substrate to which material is applied by laser cladding—such as the conventional heat pretreatment. In addition to manufacturing advantages, this also offers economic benefits, as less energy is required in the process.

[0043] The sphericity parameter SPHT indicates the roundness of the particles, which is determined from the particle circumference U and the particle area. Perfect circles or spheres have a sphericity equal to 1. For all other shapes, the sphericity is < 1. The following applies: where P is the measured circumference or the circumference of a particle projection and A is the measured area covered by a particle projection

[0044] According to one embodiment of the invention, it can be provided that the metal particles have an average particle diameter in a range of < 145 pm, preferably < 135 pm, more preferably < 130 pm, in particular < 125 pm and > 15 pm, preferably > 30 pm, preferably > 40 pm, in particular > 45 pm. It has been shown that excellent welding results can be achieved with such a selected particle size. The particle size can be determined, for example, by scanning each particle in all spatial directions. For each scanning direction, the maximum chord is determined, which is defined as the maximum distance between two edge points perpendicular to the scanning direction. The x c min - Particle size is determined from the narrowest measured chord. The mean particle diameter can be calculated as a weighted value Mv according to xi, r = L xq r (x) Ax.

[0045] According to a further embodiment of the invention, it can be provided that the metal particles have a hardness of > 200 HV, preferably > 400 HV, more preferably > 625 HV, more preferably > 650 HV, in particular > 675 HV and < 800 HV, preferably < 750 HV.

[0046] According to a further preferred embodiment of the invention, it can be provided that the metal particles have an iron content in a range of > 60.0 wt.%, preferably > 61.0 wt.%, in particular > 61.4 wt.% and < 98.95 wt.%, preferably < 98.5 wt.%, in particular < 98 wt.%.

[0047] According to a further preferred embodiment of the invention, it can be provided that the metal particles have a carbon content in a range of > 0.0 wt.%, preferably > 0.3 wt.%, in particular > 0.8 wt.% and < 2.6 wt.%, preferably < 2.3 wt.%, in particular < 2.0 wt.%.

[0048] According to a further preferred embodiment of the invention, it can be provided that the metal particles have a silicon content in a range of > 0.2 wt.%, preferably > 0.3 wt.%, in particular > 0.4 wt.% and < 3.5 wt.%, preferably < 3 wt.%, in particular < 2.6 wt.%.

[0049] According to a further preferred embodiment of the invention, it can be provided that the metal particles have a manganese content in a range of > 0.25 wt.%, preferably > 0.3 wt.%, in particular > 0.35 wt.% and < 2 wt.%, preferably < 1.8 wt.%, in particular < 1.3 wt.%. According to a further preferred embodiment of the invention, it can be provided that the metal particles have a chromium content in a range of > 15.0 wt.%, preferably > 20.0 wt.%, in particular > 23.0 wt.% and < 32.0 wt.%, preferably < 31.0 wt.%, in particular < 30.0 wt.%.

[0050] According to a further preferred embodiment of the invention, it can be provided that the metal particles have a martensite structure.

[0051] According to a preferred embodiment of the invention, it can be provided that the metal particles have a bulk density according to DIN ISO 697 of < 3.6 g / cm 3 , preferably < 3.5 g / cm 3 , especially < 3.2 g / cm 3 , such as 3.08 g / cm 3 , 3.06 g / cm 3 or 3.01 g / cm 3 have.

[0052] According to a preferred embodiment of the invention, it can be provided that the metal particles have a flow rate according to DIN EN ISO 4490 at an outlet opening of 2.5 mm of > 21 s, preferably > 23 s, in particular > 26 s such as 27.7 s, 27.8 s, 27.9 s, or 28 s, and at an outlet opening of 5.0 mm of > 4.5 s, preferably > 5 s, in particular > 5.5 s, such as 6.5 s, 6.6 s or 6.7 s.

[0053] Both the flow rate and the bulk density provide an indication of the particle's deviation from the ideal sphere. Surprisingly, it has been shown that, contrary to expectations, the particles in their fractured form, and thus deviating from the ideal spherical shape, exhibit good conveyability and are advantageously suited for use in additive manufacturing.

[0054] According to a further preferred embodiment of the invention, the particles exhibit a removal rate, measured according to ASTM G75, of > 40 mg, preferably > 42 mg, in particular > 45 mg. The removal rate from a standard test specimen is given in mg. An ST52 test specimen was considered, with a test duration of 2 hours and a load of 22.24 N at a speed of 20 m / min, and with the use of 150 g of H2O VE and 150 g of metal particles (particles to be tested). Surprisingly, it has been shown that the metal particles to be used according to the invention, despite their high abrasiveness, can be advantageously used for additive manufacturing.

[0055] With regard to the method for producing metal particles for use in additive manufacturing, the object of the invention is achieved by a method comprising the steps:

[0056] - Melting a starting metal mixture to obtain an alloy with an iron content in a range of > 60.0 wt.%, preferably > 61.0 wt.%, in particular > 61.4 wt.% and < 98.95 wt.%, preferably < 98.5 wt.%, in particular < 98 wt.%, a carbon content in a range of > 0.0 wt.%, preferably > 0.3 wt.%, in particular > 0.8 wt.% and < 2.6 wt.%, preferably < 2.3 wt.%, in particular < 2.0 wt.%, a silicon content in a range of > 0.2 wt.%, preferably > 0.3 wt.%, in particular > 0.4 wt.% and < 3.5 wt.%, preferably < 3 wt.%, in particular < 2.6 wt.%, and a manganese content in a range of > 0.25 wt.%, preferably > 0.3 wt.%, in particular > 0.35 wt.% and < 2 wt.%, preferably < 1.8 wt.%, in particular < 1.3 wt.%, optionally a chromium content in a range of > 23.0 wt.%, preferably > 24.0 wt.%, in particular > 25.0 wt.% and < 32.0 wt.%, preferably < 31.0 wt.%, in particular < 30.0 wt.-%;.

[0057] - Granulation of the melt by water atomization to obtain granulated particles of defined size;

[0058] - optional austenitization of the granulated particles by heating and quenching the particles;

[0059] - optional tempering of the austenitized particles; and

[0060] - breaking the particles to an average particle diameter in a range of < 145 pm, preferably < 135 pm, more preferably < 130 pm, in particular < 125 pm and > 15 pm, preferably > 30 pm, preferably > 40 pm, in particular > 45 pm. According to a preferred embodiment of the method, the granulated particles are austenitized at a temperature in a range of > 800 ° C and < 1050 ° C, preferably > 850 ° C and < 950 ° C. In particular, it can be provided that the particles are heated to the stated temperature for a period of > 600 s and < 1800 s, preferably > 900 s and < 1200 s and are then quenched in a water bath.

[0061] According to a further embodiment of the method, it can be provided that the austenitized particles are tempered at a temperature in a range of > 450°C and < 650°C, preferably > 500°C and < 600°C. The tempering can preferably be carried out for a time of > 600 s and < 7200 s, preferably > 900 s and < 3600 s.

[0062] The breaking of the particles to a particle size in the specified range can be carried out in one stage or in several stages by means of cascading breaking stages with an increasingly finer degree of breaking.

[0063] The invention is further explained below using examples:

[0064] Example 1 :

[0065] A metal powder with a grain distribution between >45 pm and <125 pm and a sphericity of 0.95 was applied to a S235 steel substrate using a Trumpf disk laser deposition system with a power of 1500 W under argon with a gas flow of 101 / min and a material flow of 18 g / min. The composition of the metal powder consisted of approximately 0.924 wt% silicon, approximately 0.856 wt% carbon, approximately 0.893 wt% manganese, 0.311 wt% chromium, 0.163 wt% copper, 0.105 wt% nickel, 0.032 wt% molybdenum, 0.042 wt% aluminum, 0.012 wt% lead, 0.006 wt% arsenic, 0.002 wt% calcium, 0.022 wt% tin, 0.003 wt% titanium, 0.015 wt% tungsten, 0.013 wt% vanadium, 0.007 wt% zinc, 0.0001 wt% boron, 0.0035 wt% bismuth, 0.009 wt% cobalt, 0.003 niobium, 0.009 wt% phosphorus, 0.012 % wt. sulfur, balance iron and a bulk density of >7.0 g / cm 3 a hardness of 675 HV. The particles had a bulk density according to DIN ISO 697 of < 3.1 g / cm3 and a flow rate according to DIN EN ISO 4490 at a discharge width of 2.5 mm of 27.8 s. The particles exhibited a removal rate according to ASTM G75 of > 45 mg. The resulting weld achieved a tensile strength R p o,2 of an average of 785 MPa.

[0066] Example 2:

[0067] A metal powder with a grain size distribution between >45 pm and <125 pm and a sphericity of 0.96 was melted using an EOS M 290 selective laser melting system with an nLight AFX 1000 fiber laser with a maximum power of 1200 W, a wavelength of 1070 nm (+ / - 10 nm), and a focus diameter of 85 pm, an effective power of 333 W, and a layer thickness of 40 pm. The metal powder was preheated to 160°C. The build rate was approximately 4 mm. 3 / s, which corresponds to an hourly output of approximately 115g / h. The composition of the metal powder consisted of approximately 0.924 wt% silicon, approximately 0.856 wt% carbon, approximately 0.893 wt% manganese, 0.311 wt% chromium, 0.163 wt% copper, 0.105 wt% nickel, 0.032 wt% molybdenum, 0.042 wt% aluminum, 0.012 wt% lead, 0.006 wt% arsenic, 0.002 wt% calcium, 0.022 wt% tin, 0.003 wt% titanium, 0.015 wt% tungsten, 0.013 wt% vanadium, 0.007 wt% zinc, 0.0001 wt% boron, 0.0035 wt% bismuth, 0.009 wt% cobalt, 0.003 niobium, 0.009 wt% phosphorus, 0.012 wt% sulfur, Rest iron and had a bulk density of >7.0 g / cm 3 a hardness of 675 HV. The particles had a bulk density according to DIN ISO 697 of < 3.15 g / cm 3 and a flow rate of 35.5 s according to DIN EN ISO 4490 at a discharge width of 2.5 mm. The particles exhibited a removal rate of > 45 mg according to ASTM G75. The resulting component was consistently homogeneous and free of cavities.

Claims

Patent claims 1. Use of metal particles for additive manufacturing, in particular for laser deposition welding or for selective laser melting, wherein the metal particles have a sphericity of < 0.98, preferably < 0.95, more preferably < 0.94, in particular < 0.93 and > 0.67, preferably > 0.67, preferably > 0.70, in particular > 0.

9.

2. Use of metal particles according to claim 1, wherein the metal particles have an average particle diameter of < 145 pm, preferably < 135 pm, more preferably < 130 pm, in particular < 125 pm and > 15 pm, preferably > 30 pm, preferably > 40 pm, in particular > 45 pm.

3. Use of metal particles according to one of the preceding claims, wherein the metal particles have a hardness of > 200 HV, preferably > 400 HV, more preferably > 625 HV, more preferably > 650 HV, in particular > 675 HV and < 800 HV, preferably < 750 HV.

4. Use of metal particles according to one of the preceding claims, wherein the metal particles have an iron content in a range of > 60.0 wt.%, preferably > 61.0 wt.%, in particular > 61.4 wt.% and < 98.95 wt.%, preferably < 98.5 wt.%, in particular < 98 wt.%.

5. Use of metal particles according to one of the preceding claims, wherein the metal particles have a carbon content in a range of > 0.0 wt.%, preferably > 0.3 wt.%, in particular > 0.8 wt.% and < 2.6 wt.%, preferably < 2.3 wt.%, in particular < 2.0 wt.%.

6. Use of metal particles according to one of the preceding claims, wherein the metal particles have a silicon content in a range of > 0.2 wt.%, preferably > 0.3 wt.%, in particular > 0.4 wt.% and < 3.5 wt.%, preferably < 3 wt.%, in particular < 2.6 wt.%.

7. Use of metal particles according to one of the preceding claims, wherein the metal particles have a manganese content in a range of > 0.25 wt.%, preferably > 0.3 wt.%, in particular > 0.35 wt.% and < 2 wt.%, preferably < 1.8 wt.%, in particular < 1.3 wt.%.

8. Use of metal particles according to one of the preceding claims, wherein the metal particles have a chromium content in a range of > 23.0 wt.%, preferably > 24.0 wt.%, in particular > 25.0 wt.% and < 32.0 wt.%, preferably < 31.0 wt.%, in particular < 30.0 wt.%.

9. Use of metal powder particles according to one of the preceding claims, wherein they have a bulk density according to DIN ISO 697 of < 3.6 g / cm 3 , preferably < 3.5 g / cm 3 , especially < 3.2 g / cm 3 , such as 3.08 g / cm 3 , 3.06 g / cm 3 or 3.01 g / cm 3 have.

10. Use of metal powder particles according to one of the preceding claims, wherein these have a flow rate according to DIN EN ISO 4490 at an outlet opening of 2.5 mm of > 21 s, preferably > 23 s, in particular > 26 s such as 27.7 s, 27.8 s, 27.9 s or 28 s, and at an outlet opening of 5.0 mm of > 4.5 s, preferably > 5 s, in particular > 5.5 s, such as 6.5 s, 6.6 s or 6.7 s.

11. Use of metal powder particles according to one of the preceding claims, wherein they have a removal, measured according to ASTM G75, of > 40 mg, preferably > 42 mg, in particular > 45 mg.

12. Method for producing metal particles for use in additive manufacturing, the object of the invention is achieved by a method comprising the steps: - Melting a starting metal mixture to obtain an alloy with an iron content in a range of > 60.0 wt.%, preferably > 61.0 wt.%, in particular > 61.4 wt.% and < 98.95 wt.%, preferably < 98.5 wt.%, in particular < 98 wt.%, a carbon content in a range of > 0.0 wt.%, preferably > 0.3 wt.%, in particular > 0.8 wt.% and < 2.6 wt.%, preferably < 2.3 wt.%, in particular < 2.0 wt.%, a silicon content in a range of > 0.2 wt.%, preferably > 0.3 wt.%, in particular > 0.4 wt.% and < 3.5 wt.%, preferably < 3 wt.%, in particular < 2.6 wt.%, and a manganese content in a range of > 0.25 wt.%, preferably > 0.3 wt.%, in particular > 0.35 wt.% and < 2 wt.%, preferably < 1.8 % by weight, in particular < 1.3 % by weight, optionally a chromium content in a range of > 23.0 % by weight, preferably > 24.0 % by weight, in particular > 25.0 % by weight and < 32.0 % by weight, preferably < 31.0 % by weight, in particular < 30.0 % by weight; - Granulation of the melt by water atomization to obtain granulated particles of defined size; - optional austenitization of the granulated particles by heating and quenching the particles; - optional tempering of the austenitized particles; and - Breaking the particles to an average particle diameter in a range of < 145pm, preferably < 135pm, more preferably < 130pm, in particular < 125pm and > 15pm, preferably > 30pm, preferably > 40pm, in particular > 45pm.

13. The method according to claim 12, wherein the granulated particles are melted at a temperature in a range of > 800°C and < 1050°C, preferably > 850°C and < 950°C austenitized, preferably for a time of > 600 s and < 1800 s, more preferably > 900 s and < 1200 s.

14. The method according to any one of claims 12 or 13, wherein the austenitized particles are tempered at a temperature in a range of > 450°C and < 650°C, preferably > 500°C and < 600°C, preferably for a time of > 600 s and < 7200 s, more preferably > 900 s and < 3600 s.

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