Solid wire, method for manufacturing laminate molding, and multilayer build-up welding method

Abstract

To provide a solid wire which can further improve slag peelability, and can improve characteristics of weld metal and workability.SOLUTION: A solid wire 21 has a wire core wire, and copper plating applied to the surface of the wire core wire. The wire core wire contains appropriate contents of C, Si, Mn and Ti, in which the contents of Al and S are equal to or less than predetermined amounts, and the balance of Fe and unavoidable impurities. When the contents of Mn, Si, Ti and Al in the wire core wire are, by mass%, represented by [Mn], [Si], [Ti] and [Al], Expression (1): [Al]<[Ti] is satisfied, a value α by Expression (2): α=[Mn]2 / [Si] is 1.8 or less, and a value β by Expression (3): β=[Si] / [Ti] is 5.0 or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a solid wire, a method for manufacturing a laminated object, and a multi-layer submerged welding method.

Background Art

[0002] In recent years, various steel materials have been developed to improve strength, toughness, etc. Gas shielded arc welding using a solid wire capable of high-efficiency welding is frequently used for welding members using these steel materials.

[0003] Gas shielded arc welding is a welding method in which an arc is generated and the wire is melted by the arc to form a weld metal. During this welding, an oxide (slag) adheres to the surface of the formed weld metal. In particular, when forming a weld metal by stacking multiple layers of beads, if the slag is left unattended, the slag will mix into the weld metal, and a weld metal with desired properties cannot be obtained. Also, when stacking multiple layers of beads by gas shielded arc welding, the arc may become unstable or the arc may be interrupted due to the slag formed on the surface.

[0004] By the way, the wire used for welding can also be applied to "additive manufacturing" technology, more specifically, wire and arc-based additive manufacturing (WAAM) technology. Therefore, also in such an additive manufacturing field, as in the case of welding, a decrease in metal properties due to slag mixing and a decrease in arc stability occur. The term "additive manufacturing" may be used in a broad sense as the term "laminated manufacturing" or "rapid prototyping". In this specification, the term "laminated manufacturing" is uniformly used.

[0005] As described above, during welding or during the manufacture of a laminated object, slag is generated on the surface of the weld metal, which may cause problems in the weld metal or reduce the weldability. Therefore, it is preferable that the slag can be easily removed. For this reason, various wires have been proposed for the purpose of improving the peelability of slag.

[0006] For example, Patent Document 1 discloses a carbon dioxide shielded arc welding steel wire in which the Mn content among the components of the steel wire material for welding is kept low, the Si content is increased, and the value of (Si content) / (Mn content) is 1.2 or more. Further, the wire described in Patent Document 1 contains REM (Rare Earth Metal), which has the effect of finely peeling slag, in the range of 0.015 to 0.100% by mass.

[0007] Also, Patent Document 2 describes that by appropriately adjusting the ratio of the contents of Si and Mn, which are elements that generate slag, the amount of slag generated can be reduced. In the wire for gas shielded arc welding described in Patent Document 2, the value of (Si content) / (Mn content) is 0.40 to 0.90. Further, Patent Document 3 describes that the slag peelability is remarkably improved by the accumulation of Bi at the bead interface. Therefore, the solid wire for gas shielded arc welding described in Patent Document 3 contains Bi in the range of 0.01 to 0.3% and limits (S content)+(Bi content) to 0.03 to 0.2%.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] The wires described in Patent Documents 1 and 3 contain alloy components such as expensive REM and harmful Bi. However, it is not desirable to intentionally contain such alloy components in the wire. In addition, the wire described in Patent Document 1 has a high Si content set, but extreme control to high Si leads to deterioration of the properties of the weld metal, so it is not preferable. Further, Patent Document 2 proposes that by controlling (Si content) / (Mn content), both improvement of slag detachability and reduction of slag amount can be achieved. However, the inventors of the present application further conducted studies for improving slag detachability and mechanical properties.

[0010] The present invention has been made in view of the above problems, and without adding special alloy components, by only controlling the components generally contained in the steel material, it is possible to further improve the slag detachability, and a solid wire capable of improving the properties and workability of the weld metal, and a method for manufacturing a laminated object and a multi-layer submerged arc welding method using the solid wire are provided.

Means for Solving the Problems

[0011] The above object of the present invention is achieved by the configuration of the following [1] related to the solid wire.

[0012] [1] A solid wire having a wire core wire and copper plating applied to the surface of the wire core wire, The wire core wire, with respect to the total mass of the wire core wire, C: 0.03% by mass or more and 0.15% by mass or less, Si: 0.2% by mass or more and 1.0% by mass or less, Mn: 0.5% by mass or more and 1.5% by mass or less, and Ti: 0.02% by mass or more and 0.1% by mass or less, contains Al: 0.05% by mass or less, S: 0.05% by mass or less, and The remainder consists of Fe and inevitable impurities, When the Mn content in the wire core is expressed as [Mn] in mass%, the Si content as [Si] in mass%, the Ti content as [Ti] in mass%, and the Al content as [Al] in mass%, it satisfies the following formula (1), the value α calculated by the following formula (2) is 1.8 or less, and, the value β calculated by the following formula (3) is 5.0 or more, which is a characteristic of the solid wire. [Al] < [Ti] ··· Formula (1) α = [Mn] 2 / [Si] ··· Formula (2) β = [Si] / [Ti] ··· Formula (3)

[0013] Also, a preferred embodiment of the present invention related to the solid wire relates to the following [2] to [4].

[0014] [2] The wire core further contains at least one selected from Mo, Ni, and Cr, with respect to the total mass of the wire core, Mo: 0.01 mass% or more and 0.50 mass% or less, Ni: 0.01 mass% or more and 1.2 mass% or less, Cr: 0.01 mass% or more and 1.0 mass% or less, which is a characteristic of the solid wire according to [1].

[0015] [3] The wire core further contains at least one selected from Cu and Zr, with respect to the total mass of the wire core, Cu: 0.01 mass% or more and 0.40 mass% or less, Zr: 0.02 mass% or more and 0.50 mass% or less, which is a characteristic of the solid wire according to [1] or [2].

[0016] [4] When the C content in the wire core is expressed as [C] in mass %, the Ni content as [Ni] in mass %, the Cr content as [Cr] in mass %, and the Mo content as [Mo] in mass % with respect to the total mass of the wire core, the value Ceq calculated by the following formula (4) is 0.4 or more and 0.6 or less. The solid wire according to any one of [1] to [3]. Ceq = [C] + [Mn] / 6 + [Si] / 24 + [Ni] / 40 + [Cr] / 5 + [Mo] / 4 ··· Formula (4)

[0017] The above object of the present invention is achieved by the configuration of the following [5] related to the method for manufacturing a laminated object.

[0018] [5] While supplying a shielding gas, repeating a step of melting the solid wire according to any one of [1] to [4] to form a welding bead, and having a lamination step of laminating a plurality of the welding beads. A method for manufacturing a laminated object.

[0019] A preferred embodiment of the present invention related to the method for manufacturing a laminated object relates to the following [6].

[0020] [6] The lamination step includes an n - layer bead forming step of forming a welding bead for the nth layer, and after the n - layer bead forming step, without removing the slag formed on the surface of the welding bead of the nth layer, an (n + 1) - layer bead forming step of forming a welding bead for the (n + 1)th layer. The method for manufacturing a laminated object according to [5].

[0021] The above object of the present invention is also achieved by the configuration of the following [7] related to the multi - layer build - up welding method.

[0022] [7] While supplying a shielding gas, repeating a step of melting the solid wire according to any one of [1] to [4] to form a weld metal, and having a multi - layer build - up welding step of laminating a plurality of the weld metals. A multi - layer build - up welding method.

[0023] Also, a preferred embodiment of the present invention relating to the multi-layer build-up welding method relates to the following [8].

[0024] [8] The multi-layer build-up welding process is as follows. An n-layer weld metal forming process for forming the weld metal of the nth layer, After the n-layer weld metal forming process, without removing the slag formed on the surface of the weld metal of the nth layer, an (n + 1)-layer weld metal forming process for forming the weld metal of the (n + 1)th layer, characterized in that it has, the multi-layer build-up welding method according to [7].

Effect of the Invention

[0025] According to the present invention, without adding special alloy components, only by controlling the components generally contained in the steel material, the slag detachability can be further improved, and the characteristics and workability of the weld metal can be improved. A solid wire, and a method for manufacturing a laminated structure and a multi-layer build-up welding method using the solid wire can be provided.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0027] As a result of intensive studies to solve the above problems, the inventors have found a component system that is easy to peel off for the slag layer. Specifically, regarding the component balance of SiO2 - TiO2 - MnO in the slag, a component range capable of improving slag peelability has been found, and a component range of the solid wire has been found such that the component balance of this slag falls within a desired range. The present invention has been made based on these findings.

[0028] Hereinafter, embodiments for carrying out the present invention will be described in detail. It should be noted that the present invention is not limited to the embodiments described below, and can be arbitrarily modified and implemented without departing from the gist of the present invention. Also, as described above, the solid wire according to the embodiment of the present invention is suitably used in gas shielded arc welding and additive manufacturing. Therefore, in this specification, the welding method and the additive manufacturing method can be mutually substituted. For example, terms such as "welding" can be appropriately substituted with terms such as "welding", "additive manufacturing", "additive manufacturing", and the term "weld metal" can be appropriately substituted with terms such as "welded metal", "laminate", "additively manufactured body", "additively manufactured object".

[0029] First, the solid wire according to this embodiment will be described.

[0030] 〔Solid wire〕 The solid wire according to this embodiment has a wire core wire and copper plating applied to the surface of this wire core wire. Regarding the components contained in the wire core wire of the solid wire according to this embodiment, the effects and reasons for numerical limitations will be described in detail. In the following description, unless otherwise specified, the content of each component in the wire core wire is defined as a value based on the content with respect to the total mass of the wire core wire. Hereinafter, the wire core wire may be simply referred to as the core wire.

[0031] (C: 0.03 mass% or more and 0.15 mass% or less) C is an element necessary to ensure the strength of the weld metal. If the C content in the core wire is less than 0.03% by mass, it becomes difficult to sufficiently ensure the strength of the weld metal. Therefore, the C content in the core wire is set to 0.03% by mass or more, preferably 0.04% by mass or more, based on the total mass of the core wire. On the other hand, if the C content in the core wire is too high, hot cracking of the weld metal is likely to occur. Therefore, the C content in the core wire is set to 0.15% by mass or less, preferably 0.1% by mass or less, and more preferably 0.09% by mass or less.

[0032] (Si: 0.2% by mass or more and 1.0% by mass or less) Si is an element having a deoxidizing effect. If the Si content in the core wire is less than 0.2% by mass, a sufficient deoxidizing effect cannot be obtained for the weld metal. Therefore, the Si content in the core wire is set to 0.2% by mass or more, preferably 0.4% by mass or more, and more preferably 0.5% by mass or more, based on the total mass of the core wire. On the other hand, if the Si content in the core wire exceeds 1.0% by mass, the toughness of the weld metal decreases. Therefore, the Si content in the core wire is set to 1.0% by mass or less, preferably 0.95% by mass or less, based on the total mass of the core wire.

[0033] (Mn: 0.5% by mass or more and 1.5% by mass or less) Mn, like the above Si, is an element having a deoxidizing effect and is an essential element for ensuring the strength and toughness of the weld metal. Also, Mn is an element that affects slag detachability. When the MnO content in the slag increases, the slag detachability decreases. Therefore, in this embodiment, the following formula (2): α = [Mn] 2By appropriately controlling the value α obtained by [Si], it is possible to improve the slag detachability. When the Mn content in the core wire is less than 0.5% by mass, the above effect cannot be sufficiently obtained. Therefore, the Mn content in the core wire is 0.5% by mass or more with respect to the total mass of the core wire, preferably 0.55% by mass or more, and more preferably 0.6% by mass or more. On the other hand, when the Mn content in the core wire exceeds 1.5% by mass, embrittlement of the weld metal occurs. Therefore, the Mn content in the core wire is 1.5% by mass or less with respect to the total mass of the core wire, preferably 1.2% by mass or less, and more preferably 1.1% by mass or less.

[0034] (Ti: 0.02% by mass or more and 0.1% by mass or less) Ti is an element necessary to improve weldability. Also, Ti is an essential element for adjusting the composition system to be easily detachable from the slag, and is an important component for obtaining the component range of SiO2 - TiO2 - MnO that can improve the slag detachability. For this reason, in this embodiment, while adjusting the Ti content in the core wire, for the purpose of improving the slag detachability, it is necessary to control the ratio with Si and further satisfy the formula (1) to be described later: [Al] < [Ti]. When the Ti content in the core wire is less than 0.02% by mass, the SiO2 - TiO2 - MnO composition of the slag cannot be made within the desired range, and the slag detachability decreases. Therefore, the Ti content in the core wire is 0.02% by mass or more with respect to the total mass of the core wire, preferably 0.03% by mass or more. On the other hand, when the Ti content in the core wire exceeds 0.1% by mass, the component balance of SiO2 - TiO2 - MnO in the slag deviates from the desired range, and the slag detachability deteriorates. Therefore, the Ti content in the core wire is 0.1% by mass or less with respect to the total mass of the core wire.

[0035] (Al: 0.05% by mass or less) Al is an element that inhibits the adjustment of the composition system to one that easily peels off slag. When the Al content in the core wire exceeds 0.05% by mass, the SiO2-TiO2-MnO composition that can improve slag detachability cannot be brought within the desired range, and the slag detachability decreases. To be within the component range, it is desirable for the Al content to be low, and it may not contain Al substantially in the core wire. Therefore, the Al content in the core wire is 0.05% by mass or less with respect to the total mass of the core wire, preferably 0.03% by mass or less, and more preferably 0.02% by mass or less.

[0036] ([Al]<[Ti]) As described above, Al is an element that easily forms slag. When the Al content in the core wire is equal to or higher than the Ti content in the core wire, the content of Al2O3 in the slag increases, and the desired SiO2-TiO2-MnO component range of the slag found by the present inventors cannot be realized. For this reason, the Al content in the core wire needs to be controlled to be lower than the Ti content. Therefore, when the Ti content in the core wire with respect to the total mass of the core wire is represented by [Ti] in % by mass, and the Al content in the core wire with respect to the total mass of the core wire is represented by [Al] in % by mass, it satisfies the following formula (1), and it is more preferable that 2×[Al]<[Ti]. [Al]<[Ti] ··· Formula (1)

[0037] <S: 0.05% by mass or less> S is an element that has the effect of reducing the viscosity of the molten metal and promoting the detachment of the droplets hanging at the tip of the solid wire. Also, S is an element that has the effect of smoothing the bead by reducing the viscosity of the molten metal. In the present embodiment where improving slag detachability is an issue, it is not necessary to contain S in the core wire. However, in order to promote the detachment of the droplets and obtain the effect of smoothing the bead, the S content in the core wire is preferably 0.005% by mass or more with respect to the total mass of the core wire. On the other hand, when the S content in the core wire exceeds 0.05% by mass, small spatter increases and the toughness of the weld metal decreases. Therefore, the S content in the core wire is 0.05% by mass or less with respect to the total mass of the core wire, and preferably 0.03% by mass or less.

[0038] (α = [Mn] 2 / [Si]: 1.8 or less) By appropriately controlling the relationship between the Mn content and the Si content in the solid wire, the ratio of MnO to SiO2 in the slag layer can be adjusted to a desired range. That is, when the Mn content in the core wire with respect to the total mass of the core wire is represented by [Mn] in % by mass, and the Si content in the core wire with respect to the total mass of the core wire is represented by [Si] in % by mass, when the value α calculated by the following formula (2) exceeds 1.8, the ratio of MnO to SiO2 in the slag layer deviates from the desired range and the slag detachability decreases. Therefore, the value α calculated by the following formula (2) is 1.8 or less, preferably does not exceed 1.5, and more preferably is 1.3 or less. α = [Mn] 2 / [Si] ··· Formula (2)

[0039] (β = [Si] / [Ti]: 5.0 or more) By appropriately controlling the relationship between the Si content and the Ti content in the solid wire, the ratio of SiO2 to TiOx in the slag layer can be adjusted to a desired range. That is, when the Si content in the cored wire is represented as [Si] in mass% with respect to the total mass of the cored wire, and the Ti content in the cored wire is represented as [Ti] in mass% with respect to the total mass of the cored wire, if the value β calculated by the following formula (3) is less than 5.0, the proportion of TiOx increases. As a result, the SiO2-TiO2-MnO composition of the slag with high peelability cannot be made within the desired range, the component balance is disrupted, and the slag peelability deteriorates. Therefore, the value β calculated by the following formula (3) should be 5.0 or more, preferably 6.0 or more, and more preferably 10 or more. β = [Si] / [Ti] ··· Formula (3)

[0040] Since Mo, Ni, and Cr are important elements for adjusting Ceq described later, the solid wire according to the present embodiment preferably contains at least one selected from Mo, Ni, and Cr in the cored wire within the range shown below.

[0041] (Mo: 0.01 mass% or more and 0.50 mass% or less) Mo is an important element for adjusting Ceq and has the effect of improving hardenability and forming carbides to improve the strength of the weld metal. In the present embodiment where improving slag peelability is an issue, it is not always necessary to contain Mo in the cored wire. However, in order to obtain the effect of improving the strength of the weld metal, the Mo content in the cored wire is preferably 0.01 mass% or more, more preferably 0.2 mass% or more, and even more preferably 0.25 mass% or more with respect to the total mass of the cored wire. On the other hand, when the Mo content in the cored wire is 0.50 mass% or less, it is possible to prevent the toughness of the weld metal from deteriorating. Therefore, when Mo is contained in the cored wire, the Mo content in the cored wire is 0.50 mass% or less, preferably 0.40 mass% or less, and more preferably 0.30 mass% or less with respect to the total mass of the cored wire.

[0042] (Ni: 0.01% by mass or more and 1.2% by mass or less) Ni, like Mo, is an important element for adjusting Ceq, an element that improves hardenability, an element necessary for enhancing the strength of the weld metal, and an element that dissolves in the matrix to improve toughness. In the present embodiment where improving slag detachability is an issue, it is not necessarily required to contain Ni in the core wire. However, in order to obtain the effect of enhancing the strength of the weld metal, the Ni content in the core wire is preferably 0.01% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.5% by mass or more with respect to the total mass of the core wire. On the other hand, in order to suppress an increase in the raw material cost of the solid wire, the Ni content in the core wire is preferably 1.2% by mass or less, more preferably 0.8% by mass or less with respect to the total mass of the core wire.

[0043] (Cr: 0.01% by mass or more and 1.0% by mass or less) Cr, like Mo and Ni, is an important element for adjusting Ceq, an element that improves hardenability, and an element necessary for enhancing the strength of the weld metal. In the present embodiment where improving slag detachability is an issue, it is not necessarily required to contain Cr in the core wire. However, in order to obtain the effect of enhancing the strength of the weld metal, the Cr content in the core wire is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.40% by mass or more, and particularly preferably 0.44% by mass or more with respect to the total mass of the core wire. On the other hand, even if the core wire contains more than 1.0% by mass of Cr, the effect of enhancing the strength of the weld metal saturates. Therefore, the Cr content in the core wire is preferably 1.0% by mass or less, more preferably 0.9% by mass or less, even more preferably 0.8% by mass or less with respect to the total mass of the core wire. Further, the Cr content in the core wire is more preferably 0.7% by mass or less, even more preferably 0.6% by mass or less, and particularly preferably 0.5% by mass or less with respect to the total mass of the core wire.

[0044] In order to further adjust Ceq to a more preferable range, it is preferable to contain Mo in the core wire and at least one selected from Ni and Cr in the core wire. The preferable content of Mo, Ni, and Cr in this case is the same as the above range. When Mo is contained in the core wire and Ni or Cr is contained, as long as Ni and Cr are within the range of their respective contents, either only one of them may be contained in the core wire, or both of them may be contained in the core wire.

[0045] (Cu: 0.01 mass% or more and 0.40 mass% or less) (Zr: 0.02 mass% or more and 0.50 mass% or less) Cu is an element that improves hardenability and is necessary for enhancing the strength of the weld metal. Also, Zr is an element that acts as a deoxidizer and has the effect of increasing the strength of the weld metal. In the solid wire according to this embodiment, it is preferable to contain at least one selected from Cu and Zr in the core wire.

[0046] If the Cu content in the core wire is 0.01 mass% or more, the effect of improving the strength of the weld metal can be obtained. Therefore, the Cu content in the core wire is preferably 0.01 mass% or more, more preferably 0.10 mass% or more, and even more preferably 0.20 mass% or more with respect to the total mass of the core wire. On the other hand, when the Cu content in the core wire is 0.40 mass% or less, precipitation of fine Cu particles in the matrix can be prevented, and a decrease in the toughness of the weld metal can be suppressed. Therefore, the Cu content in the core wire is preferably 0.40 mass% or less with respect to the total mass of the core wire.

[0047] Note that since the solid wire according to this embodiment is copper-plated on its surface, the Cu content derived from the copper plating can be 0.1 mass% or more and 0.3 mass% or less with respect to the total mass of the wire.

[0048] If the Zr content in the core wire is 0.02% by mass or more, the strength of the weld metal can be increased and a deoxidizing effect can be obtained. Therefore, the Zr content in the core wire is preferably 0.02% by mass or more, more preferably 0.06% by mass or more, based on the total mass of the core wire. On the other hand, if the Zr content in the core wire becomes too high, it affects the slag composition. Therefore, the Zr content in the core wire is preferably 0.50% by mass or less, more preferably 0.10% by mass or less, based on the total mass of the core wire.

[0049] In addition, as long as Cu and Zr are within their respective ranges, either only one of them or both of them may be contained in the core wire.

[0050] (Ceq = [C] + [Mn] / 6 + [Si] / 24 + [Ni] / 40 + [Cr] / 5 + [Mo] / 4: 0.4 or more and 0.6 or less) The carbon equivalent (Ceq: carbon equivalent) is an index indicating the strength characteristics of the weld metal. For example, an equation for Ceq is known according to JIS. When the C content in the wire core wire based on the total mass of the core wire is expressed as [C] in mass%, the Mn content as [Mn] in mass%, the Si content as [Si] in mass%, the Ni content as [Ni] in mass%, the Cr content as [Cr] in mass%, and the Mo content as [Mo] in mass%, the higher the Ceq calculated by the following formula (4), the higher the strength of the obtained weld metal.

[0051] From the viewpoint of ensuring the balance between the strength and toughness of the weld metal, the Ceq calculated by the following formula (4) is preferably 0.4 or more. On the other hand, if Ceq is 0.6 or less, a decrease in the toughness of the weld metal can be suppressed. Therefore, the value of Ceq calculated by the following formula (4) is preferably 0.6 or less.

[0052] Ceq = [C] + [Mn] / 6 + [Si] / 24 + [Ni] / 40 + [Cr] / 5 + [Mo] / 4 ··· Formula (4)

[0053] <Remainder: Fe and unavoidable impurities> In the solid wire according to this embodiment, the remainder of the components in the core wire is Fe and inevitable impurities. Representative elements as inevitable impurities in the core wire include, for example, O and N. These inevitable impurities are inevitably mixed in at the stage of melting the steel material or manufacturing the steel wire rod. The O content in the core wire is acceptable if it is 0.030 mass% or less with respect to the total mass of the core wire, preferably 0.020 mass% or less, and more preferably 0.0080 mass% or less. Also, the N content in the core wire is acceptable if it is 0.020 mass% or less with respect to the total mass of the core wire. Note that since O has the effect of making the droplet diameter finer during welding, O may be contained in the core wire. In this case, the O content in the core wire may be 0.0010 mass% or more.

[0054] Note that in the solid wire according to this embodiment, the effect of improving peelability, which is one of the problems of the present invention, can be obtained without containing Bi and Te in the core wire. Therefore, there is no need to add Bi and Te to the core wire, and when they are not usually added, the contents of Bi and Te are considered not to exceed 0.005 ppm each with respect to the total mass of the core wire. Also, since Bi and Te are heavy metals, it is more preferable that they do not exceed 0.001 ppm each with respect to the total mass of the core wire. In this embodiment, REM components such as Ce also do not need to be contained in the core wire. Also, since REM components such as Ce are components that can affect the slag composition, even when contained in the core wire as impurities, it is preferable that they do not exceed 0.01 mass% with respect to the total mass of the core wire, and more preferably do not exceed 0.005 mass%.

[0055] 〔Manufacturing method of solid wire〕 As a method for manufacturing the solid wire according to the present embodiment, it is not particularly limited as long as molten steel having the above-described composition is used, and a general method for manufacturing a solid wire for welding can be applied. For example, molten steel having the above composition is melted in a conventional melting furnace such as an electric furnace or a vacuum melting furnace, and a casting process is performed to obtain an ingot by casting using a mold having a predetermined shape. Next, a heating process of heating the obtained ingot to a predetermined temperature is performed. Thereafter, a hot rolling process is performed in which the heated ingot is hot-rolled to obtain a steel material (bar shape) having a predetermined shape. Thereafter, a cold rolling process or a wire drawing process in which the obtained steel material (bar shape) is subjected to cold rolling (cold wire drawing) one or more times is performed to produce a core wire having a desired dimension. In addition, an annealing process of annealing at a temperature of 1000 to 1200 ° C. is performed as necessary. Thereafter, a plating layer forming process of applying Cu plating to the surface of the core wire is performed. Thereby, the solid wire according to the present embodiment can be manufactured.

[0056] 〔Method for manufacturing a laminated object〕 The method for manufacturing a laminated object according to the present embodiment uses the solid wire according to the present embodiment, and while supplying a shielding gas, a step of melting the solid wire by an arc to form a weld bead is repeated, and a lamination step of laminating a plurality of the weld beads is included. Hereinafter, with reference to the drawings, the method for manufacturing a laminated object according to the present embodiment will be specifically described.

[0057] FIG. 1 is a schematic cross-sectional view showing a method for manufacturing a laminated object according to an embodiment of the present invention. As shown in FIG. 1, while supplying a shielding gas 23 from the inside of a gas nozzle 22, a solid wire 21 held by a chip (not shown) is melted by an arc to produce, for example, a first layer 1 of a weld bead in 3 passes. Thereafter, the above steps are similarly repeated to produce a second layer 2, and the lamination step of further laminating weld beads is repeated to obtain a laminate 20. When repeating the lamination step, the solid wire 21 is moved so that the direction of the solid wire 21 during the production of the second layer 2 is opposite to the direction of the solid wire 21 during the production of the first layer 1. That is, the weld beads are laminated so that the traveling direction of the solid wire 21 is reversed for each layer. Then, when the laminate 20 reaches a desired size and shape, the arc is stopped, and the slag on the surface is removed to manufacture a laminated object 30.

[0058] In this embodiment, after the formation of each layer, the step of removing the slag formed on the surface thereof can be omitted. That is, the above lamination step preferably includes an n-layer bead forming step of forming a weld bead of the nth layer and an (n + 1)-layer bead forming step of forming a weld bead of the (n + 1)th layer without removing the slag formed on the surface of the weld bead of the nth layer after the n-layer bead forming step. However, n is an integer of 1 or more and (the total number of target layers - 1) or less.

[0059] 〔Multi-layer overlay welding method〕 The multi-layer overlay welding method according to this embodiment uses the solid wire according to the above embodiment, and while supplying a shielding gas, repeatedly performs a step of melting the solid wire by an arc to form a weld metal, and has a multi-layer overlay welding step of laminating a plurality of the weld metals. Regarding a specific multi-layer overlay welding method, it can be described by referring to the method for manufacturing the laminated object above and replacing the weld bead with the weld metal, the laminate with the multi-layer overlay weld metal, and the laminated object with the multi-layer overlay weld structure.

[0060] Therefore, in this embodiment, after the formation of each layer, the step of removing the slag formed on its surface can be omitted. That is, the multi-layer build-up welding process preferably includes an n-layer weld metal forming process for forming the weld metal of the nth layer, and, after the n-layer weld metal forming process, an (n + 1)-layer weld metal forming process for forming the weld metal of the (n + 1)th layer without removing the slag formed on the surface of the weld metal of the nth layer. Here, n is an integer of 1 or more and (the total number of target layers - 1) or less.

[0061] As described above, the solid wire according to this embodiment has excellent slag detachability. Therefore, when a laminated object or a multi-layer build-up welded structure is manufactured using the solid wire according to this embodiment, the slag is easily detached even during the lamination process or multi-layer build-up welding. For example, it is possible to prevent the slag from remaining in the laminated object 30. As a result, the occurrence of defects in the laminated object 30 or the multi-layer build-up weld metal can be suppressed. Further, as described above, since the solid wire according to this embodiment has excellent slag detachability, it is not necessary to remove the slag layer by layer. Thus, since the slag removal process during the lamination process or the multi-layer build-up welding process can be partially or entirely omitted, the manufacturing process of the laminated object and the multi-layer build-up welding can be simplified.

[0062] In the method for manufacturing a laminated object and the multi-layer build-up welding method according to this embodiment, the type of shielding gas used is not particularly limited. For example, an Ar-CO2 mixed gas can be used as the shielding gas.

Examples

[0063] Hereinafter, the effects of the present invention will be specifically described with reference to the present invention examples and comparative examples, but the present invention is not limited thereto.

[0064] [Manufacture of Solid Wire] A solid wire having a diameter of 1.2 mm was produced by preparing a core wire such that the content components in the core wire had various contents and applying copper plating to the surface thereof.

[0065] [Manufacturing of a laminated object] A laminated object was manufactured using a laminated manufacturing system equipped with a welding robot, a welding power source, and a control device. Specifically, a welding torch was provided at the tip of the tool of the welding robot, and a solid wire was held by this welding torch. While controlling the moving direction of the solid wire by the control device, a weld bead was formed. FIG. 2 is a top view showing the manufacturing method of the laminated object, and FIG. 3 is a cross-sectional view showing the obtained laminated object. As shown in FIGS. 1 and 2, first, while supplying shielding gas, the solid wire was melted by an arc to form a rectangular wall portion 41 with a weld bead. Next, a fillet filling portion 42 was formed with a weld bead at the peripheral portion in the region inside the wall portion 41. Then, a central filling portion 43 was formed so that three (3 passes) weld beads 11a, 11b, and 11c were arranged in parallel in the longitudinal direction in the rectangular region where the fillet filling portion 42 was not formed, and the first layer 1 was formed.

[0066] After that, as shown in FIG. 3, in the same manner, the wall portion 41, the fillet filling portion 42, and the central filling portion 43 were repeatedly formed. After forming the second layer 2 to the eleventh layer 11, the lamination was completed, and a laminated object 50 was obtained. Note that the inter-pass temperature was not controlled, and the solid wire was continuously moved so that the traveling direction of the solid wire for forming the weld beads 11a, 11b, and 11c was reversed for each layer. In this way, two laminated objects were manufactured from one solid wire by the same method and subjected to the evaluation test shown below.

[0067] The welding conditions when forming the wall portion 41, the fillet filling portion 42, and the central filling portion 43 are shown below. Wall portion 41, fillet filling portion 42: Welding amount per unit time: 1.38 (kg / hr), Heat input per unit length: 4.55 (kJ / cm) Central filling portion 43: Welding amount per unit time: 5.03 (kg / hr), Heat input per unit length: 21.11 (kJ / cm) Type and flow rate of shielding gas: 80 vol% Ar - 20 vol% CO2 gas, 20 liters / min

[0068] [Evaluation of Additive Manufactured Object and Method for Manufacturing Additive Manufactured Object] [Evaluation of Peelability] The slag peelability was evaluated by visually observing the appearance of the slag formed on the surface of the obtained additive manufactured object 50. As the evaluation criteria for slag peelability, those in which natural slag peeling occurred were rated as ○ (good), those in which the slag could not be removed without applying a strong impact with a chipper or hammer were rated as × (bad), and those in which the slag peeled off by applying a light impact were rated as △ (acceptable). Furthermore, those in which large peeling pieces exceeding half of the width of the welding beads 11a, 11b, and 11c in the central filling portion 43 were observed during natural peeling were rated as ◎ (excellent).

[0069] [Evaluation of Arc Starting Performance] During the manufacturing process of the above additive manufactured object, for a total of 88 passes from the first pass of the fillet filling portion 42 of the first layer to the third pass of the central filling portion 43 of the eleventh layer, the number of times an error occurred due to poor arc generation or the like during arc starting was measured. As the evaluation criteria for arc starting performance, those in which the number of error occurrences was 5 or less were rated as ◎ (excellent), those in which the number of error occurrences was 6 or more and 10 or less were rated as ○ (good), those in which the number of error occurrences was 11 or more and 20 or less were rated as △ (acceptable), and those in which the number of error occurrences was 21 or more were rated as × (bad).

[0070] [Strength of Weld Metal] From one of the two manufactured laminated objects, an A2 test piece for tensile testing was sampled in accordance with JIS Z3111, and a tensile test of the weld metal was carried out in accordance with JIS Z2241 to measure the tensile strength. FIG. 4 is a perspective view showing the position for sampling a test piece for tensile testing from the laminated object, and FIG. 5 is a top view thereof. As shown in FIG. 4, the laminated object 50 has a length of one side in a plan view of 100 mm, a length of the other side of 60 mm or 100 mm, and a height of about 45 mm. This laminated object 50 was horizontally cut at a height of 13 mm from the bottom surface and horizontally cut at a height of 13 mm from the upper surface, and divided into a lower layer portion 51, a middle layer portion 52, and an upper layer portion 53. Then, three test pieces were sampled from the middle layer portion 52 so as to be parallel to the direction in which the weld bead extends, and subjected to a tensile test.

[0071] <Toughness of Weld Metal> From the other of the two manufactured laminated objects, a notched standard test piece (10 mm × 10 mm × 55 mm) for tensile testing was sampled in accordance with the Charpy impact test method for metallic materials described in JIS Z2242:2018. Then, in accordance with JIS Z2242, the Charpy absorbed energy (vE0) at 0°C was measured to evaluate the toughness of the weld metal. The sampling position of the notched standard test piece for tensile testing was the same as the positions shown in FIGS. 4 and 5.

[0072] As the evaluation criteria for the toughness of the weld metal, those with a Charpy absorbed energy (vE0) of 120 J or more were judged to be excellent, those with a value of 47 J or more and less than 120 J were judged to be good, and those with a value less than 47 J were judged to be poor.

[0073] The content of the components in the core wire of each solid wire used and the values calculated by formulas (1) to (4) are shown in Table 1 below. Also, the evaluation results of each evaluation test are shown in Table 2 below. In Table 1 below, formulas (1) to (4) are as follows. [Al] < [Ti] ··· Formula (1) α = [Mn] 2 / [Si] ··· Formula (2) β = [Si] / [Ti] ··· Equation (3) Ceq = [C] + [Mn] / 6 + [Si] / 24 + [Ni] / 40 + [Cr] / 5 + [Mo] / 4 ··· Equation (4)

[0074] In the column of the content of each component described in Table 1 below, "-" indicates that the element is not added, and even if it is unavoidably contained, it is 0.01% by mass or less with respect to the total mass of the core wire. Also, in the column of the evaluation results described in Table 2 below, "-" indicates that it has not been measured.

[0075]

Table 1

[0076]

Table 2

[0077] As shown in Table 1 and Table 2 above, in Invention Examples No. 1 to 8, the contents of C, Si, Mn, Ti, Al, and S contained in the core wire are within the ranges defined in the present invention, satisfy Equation (1), and the values α obtained by Equation (2) and the value β obtained by Equation (3) are also within the ranges defined in the present invention. Therefore, in any of the peelability and arc startability tests, the evaluation was Δ (acceptable) or higher. Also, in Invention Examples No. 3, 4, and 6 to 8, since the value Ceq obtained by Equation (4) is within the preferable range defined in the present invention, a result with an excellent balance between strength and toughness was obtained.

[0078] On the other hand, in Comparative Example No. 1, since the value α calculated by Formula (2) is outside the range defined in the present invention, the slag detachability decreased and the arc starting property also became poor. In Comparative Example No. 2, since the Ti content in the core wire and the values α and β calculated by Formulas (2) and (3) are outside the ranges defined in the present invention, the slag detachability decreased and the arc starting property also became poor. In Comparative Example No. 3, since the Si content, Ti content in the core wire and the value α calculated by Formula (2) are outside the ranges defined in the present invention, the desired deoxidation effect could not be obtained, and the slag detachability became worse. Since the values α and β calculated are outside the ranges defined in the present invention, the slag detachability decreased and the arc starting property also became poor.

[0079] In Comparative Example No. 4, since the Si content, Mn content, Ti content in the core wire and the value β calculated by Formula (3) are outside the ranges defined in the present invention, the slag detachability decreased. In Comparative Example No. 5, since the Al content in the core wire is outside the range defined in the present invention and the relationship between the Ti content and the Al content does not satisfy Formula (1), the arc starting property decreased.

Explanation of Reference Numerals

[0080] 1 First layer 2 Second layer 11 Eleventh layer 11a, 11b, 11c Weld bead 21 Solid wire 30, 50 Laminated object 41 Wall part 42 Fillet filling part 43 Central filling part 60, 65 Weld metal 61, 66 Slag layer 62 Layer 63 Upper layer 64 Granular body

Claims

1. A solid wire having a wire core and a copper plating applied to the surface of the wire core, wherein the wire core contains, based on the total mass of the wire core, C: 0.03% by mass or more and 0.15% by mass or less, Si: 0.2% by mass or more and 1.0% by mass or less, Mn: 0.5% by mass or more and 1.5% by mass or less, and Ti: 0.02% by mass or more and 0.1% by mass or less, Al: 0.05% by mass or less, S: 0.05% by mass or less, the balance being composed of Fe and inevitable impurities, when the Mn content in the wire core is represented as [Mn] in % by mass, the Si content as [Si] in % by mass, the Ti content as [Ti] in % by mass, and the Al content as [Al] in % by mass, the following formula (1) is satisfied, the value α calculated by the following formula (2) is 1.8 or less, and the value β calculated by the following formula (3) is 5.0 or more, a solid wire characterized by that. [Al] < [Ti]... Formula (1) α = [Mn] ２ / [Si] ··· Formula (2) β = [Si] / [Ti]... Formula (3)

2. the wire core further contains at least one selected from Mo, Ni, and Cr, based on the total mass of the wire core, Mo: 0.01% by mass or more and 0.50% by mass or less, Ni: 0.01% by mass or more and 1.2% by mass or less, Cr: 0.01% by mass or more and 1.0% by mass or less, the solid wire according to claim 1, characterized by that.

3. the wire core further contains at least one selected from Cu and Zr, based on the total mass of the wire core, Cu: 0.01% by mass or more and 0.40% by mass or less, Zr: 0.02% by mass or more and 0.50% by mass or less, the solid wire according to claim 2, characterized by that.

4. when the C content in the wire core is represented as [C] in % by mass, the Ni content as [Ni] in % by mass, the Cr content as [Cr] in % by mass, and the Mo content as [Mo] in % by mass, based on the total mass of the wire core, the value Ceq calculated by the following formula (4) is 0.4 or more and 0.6 or less, the solid wire according to any one of claims 1 to 3, characterized by that. Ceq = [C] + [Mn] / 6 + [Si] / 24 + [Ni] / 40 + [Cr] / 5 + [Mo] / 4... Formula (4)

5. A method for manufacturing a laminated object, comprising repeating a step of melting the solid wire according to any one of claims 1 to 3 while supplying shielding gas to form a welding bead, and having a laminating step of laminating a plurality of said welding beads.

6. The laminating step includes an n-layer bead forming step of forming a welding bead for the nth layer, and after the n-layer bead forming step, an (n + 1)-layer bead forming step of forming a welding bead for the (n + 1)th layer without removing the slag formed on the surface of the welding bead for the nth layer, The method for manufacturing a laminated object according to claim 5, characterized by comprising:

7. A multi-layer overlay welding method, comprising repeating a step of melting the solid wire according to any one of claims 1 to 3 while supplying shielding gas to form a weld metal, and having a multi-layer overlay welding step of laminating a plurality of said weld metals.

8. The multi-layer overlay welding step includes an n-layer weld metal forming step of forming a weld metal for the nth layer, and after the n-layer weld metal forming step, an (n + 1)-layer weld metal forming step of forming a weld metal for the (n + 1)th layer without removing the slag formed on the surface of the weld metal for the nth layer, The multi-layer overlay welding method according to claim 7, characterized by comprising:

Images