Fe-based powder for additive manufacturing

Abstract

The present invention relates to an Fe-based powder for additive manufacturing comprising the following elements in wt% based on the weight of all the elements of the powder: i) C, in an amount ranging from 0.18 to 0.27, ii) Si, in an amount ranging from 0.02 to 0.50, iii) Mn, in an amount ranging from 0.1 to 0.8, iv) Cr, in an amount ranging from 1.2 to 4.0, v) Mo, in an amount ranging from 1.8 to 3.0, vi) V, in an amount ranging from 0.2 to 0.9, vii) Zr, in an amount ranging from 0.001 to 0.015, viii) N, in an amount of at most 0.06, where 0.18 lt; c + Nlt; 0.33, and wherein Mo / Cr > = 0.75, with the balance being Fe. The invention also relates to the use of the Fe-based powder for additive manufacturing, and to a method of producing an object by additive manufacturing, the method comprising constructing an object by repeatedly performing i) melting particles contained in the Fe-based powder as described herein, ii) solidifying the melt to form a constructed object, iii) tempering the constructed object.

Description

[0001] The present invention relates to an Fe-based powder for additive manufacturing, use of the Fe-based powder, and a method for producing an object by additive manufacturing using the Fe-based powder. Background Art

[0002] Additive manufacturing (AM) or three-dimensional (3D) printing is a promising manufacturing technology that can produce complex structures and bodies that cannot be easily achieved via conventional manufacturing processes.

[0003] In many additive manufacturing techniques, particularly laser powder bed fusion (L-PBF), powder is melted and subsequently 4 ~10 6 K / s cooling rate for rapid solidification.

[0004] There is a constant need in industry to find new materials for additive manufacturing.

[0005] AISI H13 is a Cr, Mo, V based hot working tool steel with a martensitic microstructure that must be used in the quenched and tempered condition. This steel exhibits a combination of high hardness and toughness after tempering above the secondary hardening peak (approximately 500°C), at which temperature the microstructure consists of tempered martensite and finely distributed secondary carbides.

[0006] This material is difficult to process by L-PBF additive manufacturing due to cracking, especially without plate preheating or L-PBF chamber heating. The cracking observed in AISI H13 processed by L-PBF without plate preheating or heated L-PBF chamber can be explained by two mechanisms related to the accumulation of large residual stresses in the hard fresh martensite that lead to brittle fracture: • The first and most important source of residual stress is the martensitic phase transformation occurring at about 200°C to 280°C, which results in a locally constrained volume expansion and a sharp increase in dislocation density.

[0007] • The second source of residual stress is the steep temperature gradient, which is characteristic of L-PBF processing, which leads to two different stress induction mechanisms: thermal gradient and volume shrinkage during non-equilibrium rapid solidification of the melt pool.

[0008] The crack sensitivity due to residual stress can be explained by the high hardness and limited ductility of the extremely supersaturated BCC (or BCT) martensite matrix. Dislocation interactions lead to the formation of immobile dislocations, crack nucleation (or crack propagation from pre-existing defects), and ultimately brittle fracture.

[0009] It is an object of the present invention to provide a new Fe-based powder which eliminates or at least alleviates the above-mentioned problems. In particular, the present invention aims to provide a powder for additive manufacturing which does not cause cracks or substantially does not cause cracks during laser-based 3D printing. Furthermore, the present invention provides a powder which requires heating or plate heating below 200°C during additive manufacturing processing. The present invention also imparts improved tempering resistance to the powder compared to low-carbon or medium-carbon hot-working tool steels previously used in additive manufacturing. Furthermore, the present invention aims to provide a powder having softer fresh (native) martensite with a higher martensite start temperature than previously known hot-working tool steel powders. Another object of the present invention is to provide an object or body processed by means of, for example, L-PBF, which has a lower cold crack sensitivity, a higher thermal conductivity and a lower solidification crack sensitivity. Summary of the Invention

[0010] The present invention relates to an Fe-based powder for additive manufacturing, comprising the following elements, calculated in wt%, based on the weight of all elements of the powder: i) C, the amount ranges from 0.18 to 0.27, ii) Si in an amount ranging from 0.02 to 0.50, iii) Mn in an amount ranging from 0.1 to 0.8, iv) Cr, in an amount ranging from 1.2 to 4.0, v) Mo, in an amount ranging from 1.8 to 3.0, vi) V, in the range of 0.20 to 0.90, vii) Zr in an amount ranging from 0.001 to 0.015, viii) N, in an amount of up to 0.06, Where C+N ranges from 0.18 to 0.33, and Among them Mo / Cr≥0.75, The balance is Fe.

[0011] This ensures that the as-built (i.e., directly after L-PBF processing) hardness does not exceed 500 ± 20 HV 10, which is to resist cold cracking. This is because a large C + N content will lead to an increase in the lattice tetragonality of the martensite, resulting in a hardness increase of more than 500 ± 20 HV 10. The significant volume expansion caused by the martensitic phase transformation translates into large residual stresses, which, combined with the lower impact toughness, will promote cold crack growth.

[0012] According to one embodiment, the relationship between the elements satisfies the following mathematical formula (i): 440>545 - 601.2(1-e (0.868C wt%)) -34.4 Mn wt% - 13.7 Si wt% -9.2 Cr wt% -17.3 Ni wt% - 15.4 Mo wt% + 10.8 V wt% + 11.0 Zr wt%>300 (i) In all embodiments of the present invention, the element contents are given in wt % based on the weight of all elements of the powder.

[0013] According to one embodiment, C ranges from 0.18 to 0.27, preferably from 0.18 to 0.25.

[0014] According to one embodiment, Si ranges from 0.05 to 0.35, preferably from 0.05 to 0.30, and most preferably from 0.05 to 0.1.

[0015] According to one embodiment, Mn ranges from 0.3 to 0.7, preferably from 0.3 to 0.5 or from 0.3 to 0.45, most preferably from 0.3 to 0.4.

[0016] According to one embodiment, Mo ranges from 2.0 to 2.8, preferably from 2.0 to 2.7 or from 2.0 to 2.5, and most preferably from 2.0 to 2.2.

[0017] According to one embodiment, Cr ranges from 1.9 to 3.2, preferably from 2.5 to 3.2 or from 2.5 to 3.1, and most preferably from 2.5 to 2.9.

[0018] According to one embodiment, V ranges from 0.50 to 0.90, preferably from 0.50 to 0.60.

[0019] According to one embodiment, Zr ranges from 0.001 to 0.002.

[0020] According to one embodiment, N is lower than 0.06.

[0021] According to one embodiment, C+N is between 0.18 and 0.33.

[0022] According to one embodiment, the ratio of Mo to Cr (Mo / Cr) is equal to or greater than 0.75.

[0023] As used herein, the term “Fe-based powder for additive manufacturing” refers to a ready-to-print Fe-based powder for additive manufacturing processes such as binder jetting, directed energy deposition, or powder bed fusion, such as laser beam powder bed fusion or electron beam powder bed fusion.

[0024] Mathematical formula (i) is a known relationship for predicting the martensitic transformation (Ms temperature) and was published in Advanced Engineering Materials in 2013. The constraints used in this formula (300°C to 440°C) ensure the formation of martensite with sufficient hardness to resist cold cracking and acceptable toughness during L-PBF processing, given the weight percentage combination of alloying elements specified in the present invention.

[0025] Increasing the carbon content above the present invention range lowers the martensite start temperature to an undesirable degree. Carbon contents below the present invention range promote the formation of ferrite or bainite even at high cooling rates, reducing martensite hardness and reducing secondary carbides, which is undesirable due to loss of hardness after quenching and tempering and loss of wear resistance of the additively manufactured object.

[0026] Therefore, the carbon content according to the present invention increases the martensitic transformation temperature and the subsequent volume expansion at higher temperatures with a smaller amplitude, resulting in lower residual stresses that can be borne by the softer and tougher fresh martensite without cracking. In addition, since the hardness of the hypoeutectoid Fe-C quenched martensite is proportional to the carbon content and the cooling rate (v'), the carbon content of the Fe-based powder according to the present invention results in a softer martensite with a lower overall hardness compared to, for example, AISI H13, which has a complementary effect in improving resistance to brittle fracture caused by internal residual stresses.

[0027] Silicon acts as a deoxidizer. Its absence significantly reduces oxidation resistance and machinability. Silicon contents below the inventive range make machining of the manufactured object difficult, while silicon contents above the inventive range promote segregation during solidification and reduce the toughness of the final additively manufactured object. Silicon also contributes to secondary carbide formation by hindering cementite precipitation at lower temperatures.

[0028] Furthermore, the silicon range of the present invention enhances the thermal conductivity of the resulting additively manufactured objects, reduces hot tearing susceptibility, and delays the secondary hardening peak that occurs at higher temperatures during the tempering phase. This ultimately leads to enhanced resistance to thermal softening and improved resistance to thermal fatigue cracking in objects additively manufactured from Fe-based powders.

[0029] Manganese improves the hardenability and machinability of additively manufactured objects. It also binds sulfur, which may be present as an impurity, and prevents red brittleness. Manganese levels above the inventive range lower the martensite start temperature and stabilize austenite, which is undesirable.

[0030] Molybdenum contributes significantly to hardenability. It also leads to the formation of secondary Mo-rich carbides (which are smaller in diameter than Cr carbides), which are more resistant to coarsening than Cr-rich carbides. Molybdenum contents above the inventive range significantly reduce the martensite start temperature and promote the precipitation of Mo-rich carbides during austenitizing heat treatment, which is undesirable.

[0031] In terms of oxidation resistance, the chromium content within the range of the present invention is sufficient. In order to provide hardenability in a large section of the manufactured body, it is necessary to combine the minimum amount of Cr according to the present invention with Mo. A Cr content above the range of the present invention and above 75% of the Mo wt% will increase the activity of chromium, resulting in the formation of secondary Cr that is easily coarsened. 23 C6 and Cr7C3 carbides, which are undesirable and detrimental to tempering resistance. In addition, Cr contents above the range of the present invention reduce the martensite start temperature.

[0032] Vanadium partially forms V(C,N) at high temperatures (e.g., 950-1100°C), which inhibits excessive grain growth during austenitization. Residual V during austenitization, or partial dissolution of V(C,N), forms extremely fine and stable V(C,N) secondary carbide precipitates during tempering, which maintains the hardness of the Fe-based powder at a high level.

[0033] The combination of vanadium content with C and N content within the scope of the present invention reduces the driving force for high temperature V (C, N) formation, thereby ensuring the formation of sufficient vol% of fine secondary V (C, N) carbides ( Figure 4 (TEM image in [1]). This contrasts with AISI H13, which retains most of the carbon and vanadium within the austenite matrix during austenitization. Furthermore, due to the extremely fine microstructure after L-PBF treatment, no primary / proeutectoid vanadium (C, N) is required to control prior austenite grain growth during austenitization. Therefore, the vanadium content range of the present invention accommodates this while also providing sufficient amounts of extremely fine and stable secondary vanadium (C, N) to form during tempering at approximately 500°C to 680°C.

[0034] Zr forms ZrC in the presence of carbon and ZrO2 in the presence of oxygen in the metal melt during solidification and can act as an inoculant to reduce grain size when manufactured as Fe-based powders. Zr is known to act as a sulfur scavenger and improve grain boundary strength. The presence of Zr should be strictly controlled to less than 0.015 wt.% to avoid excessive primary carbide formation and stabilization of ferrite.

[0035] According to one embodiment, the Fe-based powder comprises, in wt%, Co: up to 0.1, Ni: up to 0.1, Al: up to 0.1, Ti: up to 0.1, Nb: up to 0.01, W: up to 0.01, Hf: up to 0.005, Ta: up to 0.005, Pb: up to 0.0005, Sn: up to 0.003, O: up to 0.1, The balance is Fe and possibly other impurities, which may include S, P and Cu.

[0036] According to one embodiment, the Fe-based powder contains one or more of the elements Co, Ni, Al, Ti, Nb, W, Hf, Ta, Pb, Sn, O, S, P and Cu in a total amount of at most 0.6 wt%, or at most 0.3 wt%, or at most 0.1 wt%.

[0037] According to one embodiment, the elements contained in the Fe-based powder are present as an alloy, ie, the chemical composition is substantially uniform in each particle of the powder. Thus, each particle of the powder may contain substantially the same element ratios as described herein.

[0038] According to one embodiment, at least 90 vol% of the particles of the powder have a particle size as measured by laser diffraction according to ISO 13320 below 110 μm, or below 100 μm, or below 53 μm, or below 45 μm, for example below 38 μm, or below 32 μm, or below 25 μm, or below 16 μm.

[0039] According to one embodiment, at least 10 vol% of the particles of the powder have a particle size higher than 5 μm.

[0040] According to one embodiment, the density of the extracted Fe-based powder ranges from about 7 to about 9 g / cm³, preferably from 7.5 to 8.5 g / cm³.

[0041] According to one embodiment, the Fe-based powder is lath martensite and does not contain other types of martensite, such as butterfly martensite or lenticular martensite or a mixture thereof.

[0042] The present invention also relates to a method for producing an Fe-based powder as disclosed herein, comprising the steps of: i) providing a steel melt having an elemental composition such that, after subsequent atomization, an Fe-based powder as disclosed herein is obtained; ii) providing Fe-based powder by atomizing a steel melt; iii) optionally extracting an Fe-based powder fraction from the atomized powder, wherein preferably at least 90 vol% of the powder has particles with a particle size < 110 μm or any other upper limit as described herein, and preferably with a particle size > 5 μm.

[0043] According to one embodiment, the steel melt is converted into an Fe-based powder using an atomization technique (e.g., a gas atomization technique) in which a stream of steel melt flowing through a nozzle is broken up into droplets by impacting the steel melt with a high-pressure inert gas stream (e.g., nitrogen or argon), wherein the particles thus produced are collected in a protective atmosphere. The pressure of the gas stream is preferably above 30 bar. Higher or lower pressures may be used depending on the exact desired properties of the powder. The droplets are then cooled in a conventional atomization tower to form solid particles. The cooling rate will affect the properties of the powder, but typically a rate of 10 2 to 10 7 K / s. Subsequently, the desired fraction of particles is preferably extracted using a sieving operation comprising the conventional steps of passing the powder through a sieve and / or a suitable air classification device (e.g., the ATP Turboflex air classifier from Hosokawa Micron Ltd.). Alternative air classification or powder separation equipment may also be used.

[0044] The present invention also relates to the use of an Fe-based powder as defined herein for additive manufacturing, for example for the manufacture or repair of tool holders, injection molding tools or molds, extrusion molds, hot stamping molds, forging molds, etc. Fe-based powders have proven to be very promising powders for various additive manufacturing processes, such as laser powder bed fusion (L-PBF), electron powder bed fusion (E-PBF), direct energy deposition (DED), and binder jetting, in particular for L-PBF. Although L-PBF is described in detail herein as a suitable additive manufacturing process, any other process is equally suitable for additive manufacturing.

[0045] The invention also relates to a method for producing an object by additive manufacturing, said method comprising building the object by repeatedly performing the following operations: i) melting the particles contained in the Fe-based powder as described herein; ii) solidifying the melt; iii) Tempering the constructed object.

[0046] According to one embodiment, tempering of the constructed object may be performed without any prior heat treatment such as homogenization or austenitization.

[0047] According to one embodiment, a preliminary heat treatment, such as homogenization or austenitization, is performed before tempering of the constructed object.

[0048] According to one embodiment, the melting and solidification steps are performed iteratively or repeatedly, as is conventional in the field of additive manufacturing, to produce an object of a desired shape.

[0049] According to one embodiment, austenitization is performed at, for example, 950-1100°C.

[0050] According to one embodiment, the additively manufactured objects produced from Fe-based powders are austenitized (e.g., 1020°C for 20 minutes), gas quenched, and tempered (hereinafter QT), which can be performed in a manner similar to wrought materials (e.g., AISI H13). In addition, objects made from Fe-based powders can be directly tempered (hereinafter DT) from the as-built state.

[0051] According to one embodiment, homogenization or annealing of the as-built object is not always necessary, since the as-built object resulting from the building process has a microstructure that is primarily martensite with only small amounts of retained austenite, ie, is substantially free of undesirable precipitates.

[0052] According to one embodiment, tempering is performed at a temperature in the range of 200-700°C, preferably twice, each lasting for a period of 1 to 3 hours, for example, 2 hours each. Tempering at too high a temperature may result in a decrease in hardness due to the recovery of dislocations and the coarsening of carbides.

[0053] According to one embodiment, tempering is performed at a temperature in the range of 500-650° C., preferably twice, each time preferably for 2 hours. Tempering can increase the hardness of the object to above 520 HV5, for example about 540 HV5.

[0054] According to one embodiment, tempering is performed such that any heat treatment of the constructed object is performed at a temperature below 700°C, preferably below 650°C.

[0055] According to one embodiment, the melt is heated to 10 4 ~10 6 K / s cooling rate solidification. 4 ~10 6 Solidification at a cooling rate of K / s can be called rapid solidification.

[0056] According to one embodiment, a method of producing an object by additive manufacturing comprises building the object by repeatedly performing the following operations: i) depositing an Fe-based powder as described herein; ii) applying a binder to form a bonded Fe-based powder, iii) Curing and debonding of the adhesive and subsequently: iv) Sintering bonded Fe-based powders.

[0057] v) austenitizing the sintered Fe-based powder and subsequently quenching, and vi) Tempering the constructed object.

[0058] When performing this embodiment, the additive manufacturing process is preferably binder jetting.

[0059] Example 1 An Fe-based metal melt was provided by induction melting in an open furnace, and the metal melt was then subjected to gas atomization treatment under a nitrogen atmosphere to provide an Fe-based powder (Example Composition 1) containing the following elements (balance being Fe): Example Composition 1 C: 0.27 wt% Si: 0.08 wt% Mn: 0.40 wt% Cr: 1.90 wt% Mo: 2.20 wt% V: 0.50 wt% Zr: 0.001 wt% N: 0.020 wt% Compared to AISI H13 powder, the equilibrium solidification temperature range of this Fe-based powder is reduced. As can be noted from Table 1, this reduction ranges from 18 to 43°C for Example Composition 1 and Simulated Compositions 2-4. The martensite start temperature of Compositions 1-4 according to the present invention ranges from 325 to 400°C, which is at least approximately 75°C higher than that of AISI H13 powder, as determined from computational modeling (simulations) and experimental results, as also shown in Table 2. The experimental martensite start temperature (Ms) of Example Composition 1 and AISI H13 samples was measured using the dilatometric method (DIL 805) by heating cylindrical objects (4 mm diameter, 10 mm length) to 1020°C at 10 K / min using induction heating and holding the temperature at 1020°C for 20 minutes, followed by quenching using an inert gas flow at 40 K / s. The recorded expansion (length change) was used to experimentally determine the start temperature of the martensitic transformation (i.e., the Ms temperature). Modeling (simulation) was also performed using the commercial thermodynamic software Thermo-Calc to obtain the modeled martensite temperatures (Ms) of Compositions 1 to 4 and AISI H13 steel. Since the calculated Ms temperatures obtained from the modeling were almost at the same level as the experimental Ms temperatures in Table 1, all modeling results were considered valid.

[0060] Table 1 continued

[0061] When the Fe-based powder contains a low nitrogen level of less than 0.05 wt% based on the weight of all elements of the Fe-based powder, the amount of V (C, N) does not show a significant reduction compared to commercial AISI H13 powder at austenitizing temperatures of 1000-1100°C (the conventional austenitizing temperature of AISI H13) based on the reduced V and C content and activity as determined by Thermo-Calc software (see Table 2). The simulation thus performed yields an austenite with an amount of C and V in solid solution comparable to that of the AISI H13 material. After quenching and tempering, fine and stable secondary V (C, N) precipitates are obtained from the supersaturated quenched martensite.

[0062] Table 2

[0063] In another simulation of Example Composition 1 in which nitrogen was absent, the amounts of V and C remaining in solid solution generally increased (as shown in Table 3) compared to the amounts in Table 2, because the absence of nitrogen reduces the thermodynamic stability of VC carbides in the austenitizing temperature range.

[0064] Table 3

[0065] Objects additively manufactured from Fe-based powders (e.g., a 40 mm diameter and 20 mm wide drawing die and disc-shaped specimens) showed no crack formation in the built panels at room temperature or when preheated up to 170°C. Many commercial L-PBF machines can achieve this temperature range without excessive preheating.

[0066] V(C,N) particles Figure 1a and 1b The additively manufactured object (obtained from Example Composition 1) has finer austenite grains in the austenitized state (1020° C., 20 minutes) and does not contain Figure 1c Coarse V(C,N) grains of wrought AISI H13.

[0067] hardness Objects additively manufactured from Example Composition 1 were austenitized in a vacuum furnace (TAV Minijet) (1020°C, 20 minutes), gas quenched to room temperature, and tempered like wrought material (hereinafter QT), as well as directly tempered in the as-built state (hereinafter DT). Figure 2The tempering curve of the Fe-based powder (invention) shows that in the temperature range of 500-650°C, the Fe-based powder of the invention can also achieve a hardness level of HRC44 to HRC50 of AISI H13 steel.

[0068] Yield strength and toughness Tensile load and Charpy V-notch impact toughness were tested on objects additively manufactured from Example Composition 1. The tensile elongation exceeded 15% and the impact toughness exceeded 30 J, indicating that crack-free components were achieved.

[0069] Tensile testing was performed at room temperature on cylindrical specimens (45 mm height and 6 mm diameter) machined vertically to dimensions consistent with ASTM E8 / E8M-22. Instrumented Charpy V-notch (CVN) testing was performed according to ASTM E23-18. For this purpose, specimens measuring 55 × 12 × 12 mm³ were printed and machined to standard dimensions. Testing was performed on vertically built specimens, with the notch plane perpendicular to the build direction.

[0070] Table 4

[0071] Tempering resistance test A tempering resistance test at 650° C. was conducted by keeping an object printed using Example Composition 1 and AISI H13 steel in a chamber-shaped furnace at 650° C. for a predetermined time.

[0072] The objects of Example Composition 1 show enhanced tempering resistance compared to wrought AISI H13 in the QT condition (tempered at 610°C, initial hardness 47 HRC). In the DT condition (tempered at 630°C, initial hardness 47 HRC), the objects of Example Composition 1 outperform wrought AISI H13 in terms of hardness improvement. Figure 3 The result is as follows. Figure 3 As shown in .

[0073] Thermal fatigue (TF) test Thermal fatigue (TF) testing is performed using the following general procedure with commonly available equipment: The angular velocity of the ω The sample (disk) on the rotating axis was inductively heated up to 630 °C and then passed through a water jet (flow rate = 1.5 cm³ s) impacting the disk surface. -1) were rapidly cooled to 60°C. To ensure the minimum temperature was reached during each TF cycle, the sample was immersed in a water tank before induction heating began. The maximum target temperature was measured immediately after induction using an infrared pyrometer. The emissivity was set to 0.8, corresponding to the emissivity of iron oxide measured in previous studies. The test was periodically interrupted to evaluate TF cracking and surface microhardness distribution.

[0074] Compared to wrought AISI H13 with similar starting hardness, the inventive samples showed improved thermal fatigue average crack depth, maximum crack depth (the primary damage mechanism for dies and tools), and resistance to thermomechanical softening (hardness reduction) after DT (direct tempering) and QT (quenching and tempering). The inventive samples also showed an increase in average surface crack length (expressed as average crack length in Table 5) compared to wrought AISI H13. Combining average crack depth and surface crack length indicates that the TF damage in the inventive samples was confined to the surface, which was less severe than in the case of wrought AISI H13, which showed more through-cracks and increased surface softening.

[0075] Table 5

[0076] * 1500 cycles of quenching from 630℃ to 60℃ using circulating water Thermal conductivity The thermal conductivity coefficients of AISI H13 steel and the invented additively manufactured samples were determined by the following relationship (ii), where α represents the thermal diffusivity and C P represents the specific heat of the sample, ρ Representative density: The thermal diffusivity (α) values ​​were determined conventionally using the non-destructive, non-contact laser flash technique (Netzsch LFA 467 HyperFlash) at 25°C for four samples of each analyzed material, each with a diameter of 12.7 mm and a thickness of 2 mm. The thermal diffusivity was determined as the time required to reach 50% of the maximum temperature increase. To increase statistical confidence, the thermal conductivity determination was performed four times.

[0077] Specific heat ( C P ) values ​​were calculated using the conventional ratio method with the aid of differential scanning calorimetry (Netzsch DSC 204 Phoenix) using a sapphire reference sample. As can be noticed, an increased thermal conductivity is obtained for the inventive samples compared to the wrought AISI H13 steel.

[0078] Table 6

Claims

1. An Fe-based powder for additive manufacturing, the Fe-based powder for additive manufacturing containing the following elements in wt% based on the weight of all elements of the powder: i) C, with an amount ranging from 0.18 to 0.27, ii) Si, with an amount ranging from 0.02 to 0.50, iii) Mn, with an amount ranging from 0.1 to 0.8, iv) Cr, with an amount ranging from 1.2 to 4.0, v) Mo, with an amount ranging from 1.8 to 3.0, vi) V, with an amount ranging from 0.2 to 0.9, vii) Zr, with an amount ranging from 0.001 to 0.015, viii) N, with an amount of at most 0.06, where 0.18 < C + N < 0.33, and where Mo / Cr ≥ 0.75, the balance being Fe.

2. The Fe-based powder according to claim 1, wherein 440 > 545 - 601.2 (I-e (0.868C wt%) ) - 34.4Mn wt% - 13.7 Si wt% - 9.2 Cr wt% - 17.3 Ni wt% - 15.4 Mo wt% + 10.8 V wt% +11.0 Zr wt% > 300.

3. The Fe-based powder according to claim 1 or 2, wherein C ranges from 0.18 to 0.

25.

4. The Fe-based powder according to any one of claims 1 to 3, wherein Si ranges from 0.05 to 0.

1.

5. The Fe-based powder according to any one of claims 1 to 4, wherein Mn ranges from 0.3 to 0.

5.

6. The Fe-based powder according to any one of claims 1 to 5, wherein Mo ranges from 2.0 to 2.

7.

7. The Fe-based powder according to any one of claims 1 to 6, wherein Cr ranges from 2.5 to 3.

2.

8. The Fe-based powder according to any one of claims 1 to 7, wherein V ranges from 0.50 to 0.

60.

9. The Fe-based powder according to any one of claims 1 to 8, wherein Zr ranges from 0.001 to 0.

002.

10. The Fe-based powder according to any one of claims 1 to 9, wherein at least 90 vol% of the particles of the powder have a particle size lower than 110 μm.

11. The Fe-based powder according to any one of claims 1 to 10, wherein at least 90 vol% of the particles of the powder have a particle size higher than 5 μm.

12. Use of the Fe-based powder according to any one of claims 1 to 11 for additive manufacturing.

13. A method for producing an object by additive manufacturing, the method comprising constructing the object by repeatedly performing the following operations: i) melting the particles contained in the Fe-based powder according to any one of claims 1 to 11, ii) solidifying the melt to form the constructed object, iii) tempering the constructed object.

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