Metal wire for fusion additive manufacturing using metal 3D printers, additive manufacturing products, and manufacturing methods for additive manufacturing products

Abstract

To provide a metal wire for welding additive manufacturing by a metal 3D printer, a lamination molding, and a manufacturing method of the lamination molding, which can suppress burnt cracks, by securing material homogeneity and wear resistance, in addition to holding high hardness and anticorrosion necessary as a laminate molding.SOLUTION: A metal wire for welding additive manufacturing by a metal 3D printer comprises, in mass%, C: more than 0.35% to 1.2% or less, Ni: 2.0% or less, Cr: 10 to 17%, Mo: 3.0% or less, Ti: 0.03 to 0.2%, Nb: 0.03 to 0.5%, V: 0.03 to 0.5%, and W: 0.03 to 0.5%, and has a carbonitride index D value defined by formula (1) of 100 or more. When the metal wire is deposited by MIG arc welding with the metal wire as a welding material and cooled at an average cooling rate of 1°C / s to 10°C / s from the end of welding to 500°C, an amount of retained austenite is 5% to 50%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to metal wire for additive manufacturing using metal 3D printers, additive manufactured products, and methods for manufacturing additive manufactured products, which maintain the high hardness and corrosion resistance required for additive manufactured products while ensuring material uniformity and wear resistance and suppressing cracking. [Background technology]

[0002] In recent years, metal 3D printers have been expected to be a revolutionary production technology, and various technologies have been proposed. The main technical methods proposed are those using metal powder and those using metal wire.

[0003] When using metal powder, for example, a manufacturing method has been disclosed in which SUS630 powder is irradiated with an electron beam, melted and solidified, and then layered in three dimensions (Patent Document 1). However, when using metal powder, the material is expensive, and the high porosity reduces the reliability of the parts. Furthermore, if the parts are simply layered, problems such as sensitization and material non-uniformity arise, necessitating a heat treatment process such as sintering. Dimensional variations also occur during sintering. Furthermore, when a binder is used, not only are debinding and sintering processes required, but sintering also causes large volume changes, which can easily result in errors in the dimensional accuracy of the parts.

[0004] On the other hand, when metal wire is used, for example, a method of forming a three-dimensional part by laminating weld beads formed by metal wire has been disclosed (Patent Document 2). Also, a manufacturing method has been disclosed in which stainless steel metal wire is welded and laminated using two deposition devices to reduce thermal deformation, stress, and internal cracks caused by high heat during deposition (Patent Document 3).

[0005] As such, it is difficult with conventional 3D additive technology to suppress all of the dimensional fluctuations, thermal deformation, internal cracks, voids, material uniformity, and metal structure stability of parts, and to obtain parts that are durable and reliable.Patent Document 4 discloses a manufacturing method for a 3D printer that uses metal wire welding and lamination to create 3D parts, in which the transformation temperature of the metal structure is controlled and the composition is adjusted so that a low-C, low-N martensitic structure always appears, and which uses stainless steel metal wire that has excellent heat resistance (thermal deformation resistance), material and metal structure uniformity, internal crack resistance, and internal void resistance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-186653 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-266174 [Patent Document 3] Japanese Patent Application Publication No. 2018-87379 [Patent Document 4] Japanese Patent Publication No. 2020-147785 Summary of the Invention [Problem to be solved by the invention]

[0007] There is a demand for additively manufactured products that are 3D formed by welding and layering metal wires and have high hardness, wear resistance, and corrosion resistance.One possible method is to use wire made of martensitic stainless steel as the welding material for additive manufacturing. Conventionally, medium- to high-carbon martensitic stainless steels (SUS440A, SUS440C, etc.) have had the problem that hardness and wear resistance decrease when a large amount of retained austenite is generated. When martensitic stainless steel wire is used to form an additively manufactured product through 3D welding and lamination, the hardness of the product can be uneven depending on the part, resulting in insufficient material uniformity. The additively manufactured product also has insufficient wear resistance. Furthermore, cracks can occur in the manufactured product. It is believed that a temperature difference occurs between the top and bottom of the additively manufactured product after cooling, causing cracks due to thermal stress. These are hereinafter referred to as "quench cracks." In order to solve the above-mentioned problems, an object of the present invention is to provide a martensitic stainless steel wire having excellent wear resistance by producing a shaped product at an appropriate temperature in continuous lamination, as well as a reliable part and a method for producing the same at low cost.

[0008] The present invention aims to provide a metal wire for additive manufacturing using a metal 3D printer, an additive manufactured product, and a method for manufacturing an additive manufactured product, which can ensure material uniformity and wear resistance and suppress cracking while maintaining the high hardness and corrosion resistance required for additive manufactured products. [Means for solving the problem]

[0009] That is, the gist of the present invention is as follows. [1] In mass%, It has a chemical composition comprising C: over 0.35% to 1.2% or less, Si: 3.0% or less, Mn: 3.0% or less, P: 0.1% or less, S: 0.4% or less, Ni: 2.0% or less, Cr: 10 to 17%, Mo: 3.0% or less, Al: 2.0% or less, N: 0.15% or less, O: 0.015% or less, Ti: 0.03 to 0.2%, Nb: 0.03 to 0.5%, V: 0.03 to 0.5%, W: 0.03 to 0.5%, the balance being Fe and unavoidable impurities; A metal wire for use in deposition additive manufacturing using a metal 3D printer, characterized in that the carbonitride index D value defined by the following formula (1) is 100 or more. Carbonitride index D=(500-400C-30Mn-15Ni-12Cr-8Mo)+(800Ti+700Nb+600V+500W)... (1) In formula (1), the element symbol indicates the content (mass %) of the element in the metal wire. [2] In place of a part of the Fe, further in mass% A group containing one or more of Cu: 5.0% or less, Co: 5.0% or less, and B: 1.0% or less; A group containing one or more of Sn: 0.5% or less, Sb: 0.5% or less, Au: 0.5% or less, and In: 0.5% or less; A group containing one or more of Mg: 0.02% or less, Ca: 0.02% or less, Hf: 0.02% or less, and REM: 0.02% or less; A group containing one or more of the following: Ta: 2.0% or less, Zr: 2.0% or less, Pb: 0.4% or less, Ag: 0.4% or less The metal wire for deposition additive manufacturing using a metal 3D printer according to [1] is characterized in that it contains an element included in one or more of the groups listed above.

[0010] [2A] A metal wire for deposition additive manufacturing using a metal 3D printer according to [1], characterized in that it contains, in mass %, one or more of Cu: 5.0% or less, Co: 5.0% or less, and B: 1.0% or less in place of a portion of the Fe. [2B] A metal wire for use in deposition additive manufacturing using a metal 3D printer according to [1] or [2A], characterized in that it contains, in mass %, one or more of Sn: 0.5% or less, Sb: 0.5% or less, Au: 0.5% or less, and In: 0.5% or less in place of a portion of the Fe. [2C] A metal wire for use in fusion deposition additive manufacturing using a metal 3D printer according to any one of [1], [2A] and [2B], characterized in that it further contains, in mass %, one or more of Mg: 0.02% or less, Ca: 0.02% or less, Hf: 0.02% or less, and REM: 0.02% or less in place of a portion of the Fe. [2D] A metal wire for use in deposition additive manufacturing using a metal 3D printer according to any one of [1], [2A], [2B] and [2C], characterized in that, in place of a portion of the Fe, it further contains, by mass%, one or more of Ta: 2.0% or less, Zr: 2.0% or less, Pb: 0.4% or less, and Ag: 0.4% or less.

[0011] [3] A metal wire for deposition additive manufacturing by a metal 3D printer according to any one of [1] to [2D], characterized in that the metal wire is used as a welding material to be deposited by MIG arc welding, and when cooled at an average cooling rate of 1°C / s to 10°C / s from the end of welding to 500°C, the amount of retained austenite is 5% to 50%. [4] An additive manufacturing product characterized in that a plurality of layers having the component composition described in any one of [1] to [2D] are fabricated by additive manufacturing, and the amount of retained austenite is 5% to 50%. [5] A method for manufacturing an additive manufacturing product according to the fourth aspect, characterized in that the metal wire for additive manufacturing by a metal 3D printer according to any one of [1] to [2D] is used as a welding material for additive manufacturing by MIG arc welding, and then the metal wire is cooled from the end of welding to 500°C at an average cooling rate of 1°C / s to 10°C / s. [Effects of the Invention]

[0012] The present invention provides a metal wire for deposition additive manufacturing using a metal 3D printer, an additive manufactured product, and a method for manufacturing an additive manufactured product, which maintains the high hardness and corrosion resistance required for additive manufactured products while ensuring material uniformity and wear resistance and suppressing cracking. DETAILED DESCRIPTION OF THE INVENTION

[0013] Each requirement of the present invention will be explained below. In the following explanation, (%) means mass (%) unless otherwise specified.

[0014] The present invention is directed to an additively manufactured product that maintains the required high hardness and corrosion resistance, while ensuring material uniformity and wear resistance and suppressing quench cracks. Here, the required high hardness means that the additively manufactured product has an Hv of 700 or more. The material uniformity means that the difference between the maximum and minimum Hv values ​​is 80 or less when the Hv is measured at at least five points on the additively manufactured product. The additive manufacturing product can be produced by using the metal wire for additive manufacturing using the metal 3D printer of the present invention as a welding material and performing additive manufacturing using MIG arc welding with the metal 3D printer to produce a three-dimensional product.

[0015] The additive manufacturing product can achieve the above quality that the present invention aims for by containing the specified components specified below and having the amount of retained austenite in the steel of 5% to 50%.

[0016] First, the essential component composition of the metal wire and layered manufacturing product of the present invention will be described. C is contained in an amount of more than 0.35% to ensure the necessary hardness and the necessary amount of retained austenite. It is preferably 0.40% or more. On the other hand, if C exceeds 1.2%, it becomes difficult to ensure material uniformity and suppress cracking. It is preferably 0.80% or less.

[0017] Although Si is effective for deoxidation during welding, excessive addition can deteriorate material uniformity and promote the precipitation of intermetallic compounds during additive manufacturing, which can lead to cracking. Therefore, the Si content is limited to 3.0% or less. Preferably, it is 0.05% or more and 2.0% or less. Si need not be present.

[0018] Mn is effective for deoxidation during welding, but if added in excess, the austenite structure becomes stable, making it difficult to harden and preventing material uniformity. Therefore, the content is limited to 3.0% or less. Preferably, it is 0.05% or more and 2.0% or less. Mn does not have to be contained.

[0019] To ensure uniformity of the material, P is limited to 0.1% or less, preferably 0.05% or less. The lower the P content, the better, and no lower limit is set.

[0020] In order to ensure uniformity of the material, the upper limit of S is set to 0.4%, and preferably 0.0004 to 0.10%.

[0021] Ni may be added as needed to improve the toughness and corrosion resistance of the matrix, but if it exceeds 2.0%, austenite is generated and stable material uniformity cannot be obtained, so the upper limit is set to 2.0%, preferably 0.1 to 1.0%.

[0022] Cr is added in an amount of 10% or more to ensure uniformity of the material and corrosion resistance (durability). However, adding more than 17% conversely leads to non-uniformity of the material and metal structure. Therefore, the upper limit is set to 17%. The preferred range is 10.5 to 16.5%.

[0023] Mo is added to improve the corrosion resistance of the matrix, but if added in excess of 3.0%, the material and metal structure will become non-uniform. Therefore, the upper limit is set to 3.0%. The preferred range is 0.1 to 2.0%. Mo need not be added.

[0024] Al is effective for deoxidation during welding, but if added in excess, a martensite structure cannot be stably obtained, and the material uniformity deteriorates. Therefore, the upper limit is set to 2.0%. It is preferably 0.001 to 1.2%. Al does not necessarily have to be contained.

[0025] N is limited to 0.15% or less to ensure material uniformity. If N exceeds 0.15%, precipitation of carbonitride precipitates is promoted, resulting in variations in hardness and metal structure. N is preferably 0.05% or less. More preferably, N is 0.03% or less. The lower the N content, the better, and no lower limit is set.

[0026] O is contained in an amount of 0.015% or less to ensure adequate fluidity during welding. If added in excess of 0.015%, the material uniformity decreases, so the upper limit is set to 0.015%. The preferred range is 0.001 to 0.01%.

[0027] Ti:0.03~0.2%, Nb:0.03~0.5%, V:0.03~0.5%, W:0.03~0.5% The inclusion of Ti, Nb, V, and W can improve wear resistance by utilizing the hard carbides of these elements. Therefore, the content of each of Ti, Nb, V, and W is set to 0.03% or more. On the other hand, if the content of any of these elements is too high, the material uniformity decreases, so Ti is set to 0.2% or less, and Nb, V, and W are set to 0.5% or less.

[0028] The above formula (1) is the carbonitride index D, which indicates the degree of influence of the content of elements in steel on carbonitride formation. The part enclosed in left parentheses on the right side of formula (1) represents the Ms point, i.e., the temperature at which austenite begins to transform to martensite when cooled from a high temperature. The part enclosed in right parentheses on the right side of formula (1) represents the empirical value of the influence of each element on the carbonitride index D, based on data on the carbide formation energy associated with the inclusion of each element. By setting the carbonitride index D calculated by formula (1) to 100 or more, the amount of retained austenite in the steel of the additively manufactured product can be adjusted to be equal to or less than the upper limit of the preferred range of the present invention. Preferably, the carbonitride index D is 150 or more. If the carbonitride index D is less than 100, the amount of retained austenite will exceed the upper limit, due to the high C and Cr contents.

[0029] The metal wire and layered manufacturing product of the present invention comprise the remainder Fe and impurities. Furthermore, it is preferable that the metal wire and layered manufacturing product selectively contain the following components in place of a portion of the Fe.

[0030] Cu, Co, and B may be added as needed to improve the toughness of the matrix. However, if the Cu and Co contents exceed 5.0% each, and if the B content exceeds 1.0%, the material uniformity deteriorates. Therefore, the upper limits of Cu and Co are set to 5.0%, and the upper limit of B is set to 1.0%. Preferably, Cu is 4.0% or less, Co is 4.0% or less, and B is 0.3% or less.

[0031] Sn, Sb, Au, and In may be added as needed to improve the corrosion resistance of the matrix. However, if each of them is added in an amount exceeding 0.5%, the material uniformity deteriorates. Therefore, the upper limit is set to 0.5%. Preferably, it is 0.4% or less.

[0032] Mg, Ca, Hf, and REM are effective for deoxidation during welding, so they may be added as needed. However, excessive addition of these elements will deteriorate the uniformity of the material. Therefore, each of these elements is limited to 0.02% or less, and preferably 0.01% or less.

[0033] Ta and Zr may be added as needed to form fine precipitates in the matrix and improve heat resistance (thermal deformation resistance). Pb and Ag may also be added as needed to improve machinability after 3D printing. However, if the Ta and Zr contents exceed 2.0% each, and if the Pb and Ag contents exceed 0.4% each, the material uniformity deteriorates. Therefore, the upper limits for Ta and Zr are set to 2.0%, and for Pb and Ag to 0.4%. Preferably, Ta and Zr are 1.0% or less, and Pb and Ag are 0.3% or less.

[0034] The metal wire of the present invention has a chemical composition that includes Fe and impurities other than the elements described above. That is, the metal wire of the present invention is a stainless steel metal wire. Typical unavoidable impurities include Ge, Na, Be, F, Ga, etc., and these may be mixed in amounts of 0.01% or less as unavoidable impurities during the steel manufacturing process. Furthermore, although typical optional added elements are specified in [2] above, elements not listed in this specification may also be included within a range that does not impair the effects of the present invention.

[0035] Next, the amount of retained austenite in the steel of the additively manufactured product will be described. The additively manufactured product of the present invention contains the predetermined components specified above, and the amount of retained austenite in the steel is specified to be 5% to 50%. Because retained austenite is soft and tough, the generation of 5% or more retained austenite has the effect of stress relief against quench cracking in the hard martensite phase. On the other hand, because retained austenite has lower strength than martensite, if the amount of retained austenite exceeds 50%, the hardness and wear resistance of the additively manufactured product will decrease. Furthermore, the amount of retained austenite in the steel is preferably 15% to 40%.

[0036] That is, the layered manufacturing product of the present invention is formed by layered manufacturing of a plurality of layers having the component composition of the present invention, and is characterized in that the amount of retained austenite is 5% to 50%.

[0037] The method for producing an AM product of the present invention is characterized in that a metal wire for AM with a metal 3D printer having the composition of the present invention is used as a welding material, and AM is performed by MIG arc welding, followed by cooling at an average cooling rate of 1°C / s to 10°C / s from the end of welding to 500°C. By using a metal wire having the composition of the present invention and adjusting the average cooling rate from the end of welding after AM to 500°C, the Cr carbide precipitation temperature range, within a range of 1°C / s to 10°C / s, the amount of retained austenite can be adjusted to 5% to 50%. The slower the cooling rate after AM, the more likely the amount of retained austenite can be reduced. Therefore, when a metal wire having a predetermined composition within the composition range of the present invention is used and cooled at an average cooling rate within a range of 1°C / s to 10°C / s, if the amount of retained austenite is too small, the average cooling rate can be increased, and if the amount of retained austenite is too large, the average cooling rate can be decreased, resulting in the amount of retained austenite falling within the range of the present invention. The average cooling rate is set to a range of 1°C / s to 10°C / s because slow cooling (gradual cooling) below 1°C / s causes the austenite phase after molding to change to the ferrite phase, resulting in a decrease in hardness, and a rate above 10°C / s causes thermal stress due to the temperature difference in the molded product and tensile stress due to martensitic transformation, resulting in quench cracks.

[0038] Regarding the metal wire for additive manufacturing using a metal 3D printer according to the present invention, when used as a welding material for additive manufacturing using a metal 3D printer, the above-mentioned preferable amount of retained austenite can be achieved by MIG arc welding. This can be confirmed by the fact that when the metal wire is used as a welding material for additive manufacturing using a metal 3D printer, the amount of retained austenite is 5% to 50% when the metal wire is MIG arc welded and cooled at an average cooling rate of 1°C / s to 10°C / s from the end of welding to the Cr carbide precipitation temperature range of 500°C. When the average cooling rate is cooled at a predetermined cooling rate within the range of 1°C / s to 10°C / s, if the amount of retained austenite is too low, the average cooling rate is increased, and if the amount of retained austenite is too high, the average cooling rate is decreased. As a result, if the amount of retained austenite falls within the range of the present invention, it can be confirmed that the present invention applies; if not, it does not apply.

[0039] The metal wire of the present invention is used for additive manufacturing using a metal 3D printer. That is, the metal wire is used as a material when a metal 3D printer builds up weld beads of the metal wire to build up a three-dimensional part.

[0040] According to the present invention as described above, it is possible to provide a metal wire for deposition additive manufacturing using a metal 3D printer, an additive manufactured product, and a method for manufacturing an additive manufactured product, which can maintain the high hardness and corrosion resistance required for additive manufactured products, while ensuring material uniformity and wear resistance and suppressing quench cracking. [Example]

[0041] Example 1 Steels having the chemical compositions shown in Tables 1 to 3 were melted in a 45 kg vacuum melting furnace and processed into steel bars with a diameter of 11 mm by hot forging and hot extrusion. These were then repeatedly drawn and annealed to produce metal wires with a diameter of 1.2 mm. In Tables 2 and 3 and Tables 5 and 6 described below, values ​​outside the ranges of the present invention are underlined.

[0042] [Table 1]

[0043] [Table 2]

[0044] [Table 3]

[0045] The prototype metal wire was then repeatedly welded in a spiral pattern using a robotic MIG arc welder. Three-dimensional modeling was performed by stacking layers in a direction perpendicular to the welding direction, producing a hollow rectangular prism. Arc welding conditions included a shielding gas of Ar + 3% oxygen, a welding current of 200 A, an arc voltage of 30 V, and a welding speed of 200 cm / min. After the fusion additive manufacturing process, the specimen was cooled at an average cooling rate of 2.8 °C / s from the end of welding to 500 °C. The amount of retained austenite was evaluated. If the amount of retained austenite was outside the range of 5% to 50%, the average cooling rate was increased if the amount of retained austenite was too low, or decreased if the amount of retained austenite was too high, within the range of 1 °C / s to 10 °C / s from the end of welding to 500 °C. As a result, the amount of retained austenite was adjusted to fall within the range of the present invention. Some comparative examples could not be adjusted to fall within the range of the present invention. The average cooling rate was measured using an infrared thermograph (thermal imaging camera) by measuring the cooling time from the temperature of the molded product after welding to the Cr carbide precipitation temperature range of 500°C.

[0046] The square pillars were then inspected for hardness, material uniformity, wear resistance, and the presence or absence of quench cracks. Tables 4 and 5 show the inspection results.

[0047] [Table 4]

[0048] [Table 5]

[0049] The amount of retained austenite was measured using a saturation magnetization measuring device, using a test piece measuring φ5 mm × 20 mm prepared from a square pillar by electrical discharge machining. The central hardness was measured using a Vickers hardness tester by embedding a cross section cut out from a square pillar perpendicular to the lamination direction in resin and polishing it, and then measuring the HV hardness (load 10 kg) at the center in the lamination direction. To check material uniformity, a cross section cut from a square pillar perpendicular to the lamination direction was embedded in resin and polished, and the HV hardness (1 kg load) was measured at five points on the bottom surface of the additive manufacturing product: at 1 / 4, 1 / 2, and 3 / 4 heights, and on the top surface. The difference between the maximum and minimum HV values ​​at the five points was taken as the hardness variation ΔHV, with a ◎ if ΔHV was 40 or less, a ○ if over 40 and up to 80, and an × if over 80.

[0050] Abrasion resistance was evaluated using a pin-on-disk friction and wear tester, with test pieces (pins) measuring φ5mm x 10mm cut out from the square pillar. The disk, which served as the opposing abrasive material, was made of emery paper (#800) with hard SiC particles attached. The abrasive grain hardness was equivalent to approximately 3200HV. The test piece was fixed to a sample holder, and the surface of the test piece was pressed against the rotating opposing abrasive material with a test load of 20N, while the abrasion test was carried out at a sliding speed of 0.66m / s for 30 seconds. The volume of material lost due to abrasion was calculated from the difference in sample thickness before and after the test, and this was defined as the abrasion loss V (mm 3 ) and the specific wear rate C (mm 2 / N) is calculated as 5.0×10 -8 mm 2 If it is less than / N, it is OK, 5.0 × 10 -8 mm 2 If it exceeded / N, it was marked as ×. Specific wear amount C = wear loss V / (test load W × friction distance L) ... (2)

[0051] The evaluation of cracking was carried out by visually inspecting the outer and inner surfaces of the additive manufacturing product, and a rating of ◯ was given if there were no cracks, and × if there were cracks.

[0052] For additive manufacturing products using the metal wire of the present invention, the amount of retained austenite was within the preferred range of the present invention, and while maintaining the required high hardness, material uniformity and wear resistance were ensured, and cracking was suppressed.

[0053] On the other hand, it is clear that the comparative steels a to ak do not satisfy the ranges specified in the present invention and do not satisfy the required properties. In the comparative steels a, n, and aj, the carbonitride index D value is below the lower limit and the amount of retained austenite exceeds the upper limit, so that the hardness is reduced and the material uniformity and wear resistance are poor. Comparative steel r has a low Cr content, so it is difficult to harden (prone to uneven hardening), and the uniformity of hardness is poor.

[0054] Comparative steels c, o, and s had low C contents, which reduced the base material hardness and resulted in poor wear resistance. Another factor contributing to the poor wear resistance of comparative steel s was that the amounts of Ti, Nb, V, and W, which are hard carbide-forming elements effective for improving wear resistance, were below the lower limits. Furthermore, comparative steels c, o, and s had low amounts of retained austenite, which resulted in little stress relaxation due to the retained austenite, resulting in quench cracking. The comparative steels i, ai, aj, and ak had reduced wear resistance because their contents of Ti, Nb, V, and W, which are hard carbide-forming elements effective for wear resistance, were below the lower limits.

[0055] In the comparative steels c, f, and s, there was almost no untransformed austenite, and quench cracking occurred. This quench cracking is thought to be caused by large strains due to the volume expansion during martensitic transformation.

[0056] Example 2 Additive manufacturing products were produced using Steel B of the present invention shown in Table 1 of Example 1, with the average cooling rate from the end of welding to 500°C set to five conditions shown in Table 6 below, and the other conditions being the same as those of Example 1. The amount of retained austenite for each was evaluated and is shown in Table 6. As is clear from Table 6, a relationship can be seen in which the amount of retained austenite decreases as the cooling rate slows.

[0057] [Table 6]

Claims

1. In mass%, It has a chemical composition including C: more than 0.35% to 1.2% or less, Si: 3.0% or less, Mn: 3.0% or less, P: 0.1% or less, S: 0.4% or less, Ni: 2.0% or less, Cr: 10 to 17%, Mo: 3.0% or less, Al: 2.0% or less, N: 0.15% or less, O: 0.015% or less, Ti: 0.03 to 0.2%, Nb: 0.03 to 0.5%, V: 0.03 to 0.5%, W: 0.03 to 0.5%, with the balance being Fe and unavoidable impurities; A metal wire for deposition additive manufacturing using a metal 3D printer, characterized in that the carbonitride index D value defined by the following formula (1) is 100 or more. Carbonitride index D=(500-400C-30Mn-15Ni-12Cr-8Mo)+(800Ti+700Nb+600V+500W)... (1) In formula (1), the element symbol represents the content (mass %) of the element in the metal wire.

2. In place of a part of the Fe, further in mass% a group containing one or more of Cu: 5.0% or less, Co: 5.0% or less, and B: 1.0% or less; a group containing one or more of Sn: 0.5% or less, Sb: 0.5% or less, Au: 0.5% or less, and In: 0.5% or less; a group containing one or more of Mg: 0.02% or less, Ca: 0.02% or less, Hf: 0.02% or less, and REM: 0.02% or less; A group containing one or more of Ta: 2.0% or less, Zr: 2.0% or less, Pb: 0.4% or less, and Ag: 0.4% or less The metal wire for deposition additive manufacturing using a metal 3D printer according to claim 1, characterized in that it contains an element included in one or more of the groups listed above.

3. 3. The metal wire for deposition additive manufacturing using a metal 3D printer according to claim 1 or 2, wherein the metal wire is deposited by MIG arc welding as a welding material, and when cooled at an average cooling rate of 1°C / s to 10°C / s from the end of welding to 500°C, the amount of retained austenite is 5% to 50%.

4. 3. An additively manufactured product, which is formed by deposition layer manufacturing of a plurality of layers having the component composition according to claim 1 or claim 2, and which has an amount of retained austenite of 5% to 50%.

5. The method for producing an additive manufacturing product according to claim 4, characterized in that the metal wire for additive manufacturing by a metal 3D printer according to claim 1 or claim 2 is used as a welding material for additive manufacturing by MIG arc welding, and then cooling is performed at an average cooling rate of 1 ° C. / s to 10 ° C. / s from the end of welding to 500 ° C.

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