JP2022102850A - SOLID WIRE FOR GAS SHIELD ARC WELDING USED FOR WELD OF LOW Si STEEL, JOINTING METHOD OF LOW Si STEEL, AND REPAIR METHOD OF LOW Si STEEL - Google Patents

Abstract

To provide a solid wire for gas shield arc welding which is excellent in work efficiency relative to a weld rod, and in which excessive deposition of a deposit or corrosion can be suppressed on zinc plating after performing weld to a low Si steel, and a jointing method of a low Si steel capable of forming deposit metal with preferable mechanical performances, and a repair method of the low Si steel.SOLUTION: There is provided a solid wire for gas shield arc welding which is used for at least one application out of, jointing of a low Si steel and repair of a defective part of the low Si steel. In the solid wire for gas shield arc welding, a steel component includes a steel wire which comprises, in mass% with respect to total mass of the wire: 0.02-0.15% of C; 0.15% or less of Si; 0.3-2.2% of Mn; 0.05-0.30% of Ti; 0.001-0.10% of Al; 0.015% or less of P; 0.030% or less of S; 0.0080% or less of N; and 0.0080% or less of O, with a balance formed of Fe and impurities. There is also provided a weld method using the same solid wire.SELECTED DRAWING: None

Description

The present disclosure relates to a solid wire for gas shielded arc welding used for joining or repairing a low Si steel material having a Si content of 0.05% by mass or less, a method for joining a low Si steel material, and a method for repairing a low Si steel material.

Gas shielded arc welding is widely used in various fields, for example, in the construction field, it is used for welding such as assembling and joining steel columns.
When gas shielded arc welding is performed on a steel member using a solid wire, oxygen contained in the oxidizing gas in the shield gas reacts with elements such as Si and Mn contained in the steel material and the wire to be contained in the weld metal. It is possible to reduce the amount of oxygen in the steel and secure tensile performance and impact performance.

Low Si-based welding materials are generally used to improve corrosion resistance to molten zinc, but it is difficult to reduce Si acting as a deoxidizer in gas shielded arc welding solid wires, and molten zinc. Poor corrosion resistance to. Therefore, the hot-dip galvanizing kettle and the members to be hot-dip galvanized after welding are not subjected to solid wire welding for gas shielded arc welding, but are welded by a welding rod. However, the welding rod has a problem that the working time becomes long because the welding is not completed with one welding rod.

To solve such a problem, the solid wire of Patent Document 1 reduces Si to 0.2 to 0.5% and obtains a deoxidizing effect by adding Al, but the Si content is not sufficiently examined. Moreover, the corrosion resistance in hot-dip zinc and the design property in hot-dip galvanizing have not been investigated.
Further, Patent Document 2 proposes a solid wire for pulse MAG welding in which the Si content is controlled to less than 0.10%. Patent Document 2 describes that such a solid wire can obtain a flat and wide bead shape with a small amount of spatter generated in welding of a thin steel plate and good compatibility with a welded member. ing.

Japanese Patent No. 5652574 Japanese Patent No. 5037369

When joining steel materials (referred to as "low Si steel materials" in the present disclosure) whose Si content is suppressed to 0.05% by mass or less for reasons such as low cost without the need for high strength, or when joining by welding, or When repairing a defective portion of a low Si steel material by overlaying it with a welding material, if the welding rod is used as the welding material, it is necessary to repeatedly replace the welding rod, resulting in poor work efficiency. Another problem is that the use of welding rods increases the amount of slag and waste.

On the other hand, it is possible to improve work efficiency by using solid wire, but in order to improve corrosion resistance, when zinc plating is applied to the low Si steel material after welding, a precipitate containing iron and zinc (Fe-) is applied to the welded portion. Zn intermetallic compound) may be excessively deposited and the appearance may be impaired. In this case, in a product whose design is required, it takes time and effort to grind the overprecipitated portion.
Further, in the case of a plating kettle manufactured by performing gas shield arc welding on a low Si steel material, in the zinc plating step of accommodating molten zinc in the plating kettle, deposits are excessively deposited on the welded portion of the plating kettle and at the same time. There is a problem that the thickness of the steel material in the welded part of the plating pot becomes thin (thickening).
Further, the same problem occurs not only when the low Si steel material is joined but also when the defective portion of the low Si steel material is repaired by gas shielded arc welding using a solid wire.

The present disclosure has been made in view of the above-mentioned circumstances, and has superior work efficiency as compared with the case of using a welding rod. When welding is performed on a low Si steel material and then zinc plating is applied to the low Si steel material. A solid wire for gas shielded arc welding that suppresses excessive precipitation and corrosion of precipitates in the weld when used as a zinc plating kettle, and a welded metal with good mechanical performance are formed using the solid wire. It is an object of the present invention to provide a method for joining a low-Si steel material and a method for repairing a low-Si steel material.

The above problem is solved by the following means.
<1> A solid wire for gas shielded arc welding used for at least one of the applications of joining a low Si steel material having a Si content of 0.05% by mass or less and repairing a defective portion of the low Si steel material.
The steel component is mass% of the total mass of the wire.
C: 0.02 to 0.15%,
Si: 0.15% or less,
Mn: 0.3-2.2%,
Ti: 0.05 to 0.30%,
Al: 0.001 to 0.10%,
P: 0.015% or less,
S: 0.030% or less,
N: 0.0080% or less, and O: 0.0080% or less,
A solid wire for gas shielded arc welding containing a steel wire containing Fe and impurities as a balance.
<2> By mass% with respect to the total mass of the wire
Sb: 0.10% or less Cu: 0.50% or less,
Cr: 1.5% or less,
Nb: 0.3% or less,
V: 0.3% or less,
Mo: 1.0% or less,
The solid wire for gas shielded arc welding according to <1>, further comprising one or more selected from the group consisting of Ni: 3.0% or less and B: 0.010% or less.
<3> The solid wire for gas shielded arc welding according to <2>, wherein a copper plating layer is formed on the surface of the steel wire, and at least a part of the Cu is contained as the copper plating layer.
<4> For a low Si steel material having a Si content of 0.05% by mass or less, the solid wire for gas shielded arc welding according to any one of <1> to <3>, Ar and 5 to 30 A method for joining a low Si steel material, which comprises a step of joining by gas shield welding using a shield gas containing CO ₂ by volume.
<5> The solid wire for gas shielded arc welding according to any one of <1> to <3> for a low Si steel material having a Si content of 0.05% by mass or less and having a defect. A method for repairing a low Si steel material, which comprises a step of overlaying and repairing the defect portion by gas shield welding using Ar and a shield gas containing 5 to 30% by volume of CO ₂ .

According to the present disclosure, the work efficiency is superior to that when a welding rod is used, and when a low Si steel material is welded and then the low Si steel material is zinc-plated or used as a zinc plating kettle, welding is performed. A solid wire for gas shielded arc welding that suppresses excessive precipitation and corrosion of precipitates in the part, and a method for joining low Si steel materials that can form a welded metal with good mechanical performance using the solid wire and low A method for repairing Si steel is provided.

It is a figure which shows the shape of the steel plate used for welding the groove groove in an Example. FIG. 3 is an enlarged front view showing a region indicated by X at the end of the steel plate shown in FIG. 1. It is a figure which shows the end part of the steel material after welding the groove groove of the steel material shown in FIG. 1 with a solid wire (A) and a welding rod (B), and before galvanizing. It is a figure which shows the end part of the steel material after welding the groove groove of the steel material shown in FIG. 1 with a solid wire (A) and a welding rod (B), and then galvanizing.

Hereinafter, embodiments that are an example of the present disclosure will be described.
In the present specification, the numerical range represented by using "-" is such a numerical value when "exceeding" or "less than" is not added to the numerical values described before and after "-". Means the range including as the lower limit value and the upper limit value. In addition, the numerical range when "greater than" or "less than" is added to the numerical values before and after "to" means a range in which these numerical values are not included as the lower limit value or the upper limit value.
In the numerical range described stepwise in the present specification, the upper limit of the numerical range described in one step may be replaced with the upper limit value of the numerical range described in another step, and in the examples. It may be replaced with the value shown. Further, the lower limit of the numerical range in one step may be replaced with the lower limit of the numerical range described in another step, or may be replaced with the value shown in the embodiment.
Regarding the content, "%" means "mass%" unless otherwise specified.
Further, when the content (%) is not limited to the lower limit value and only the upper limit value is limited to "~% or less", it means that the content can be contained within the range of more than 0% to the upper limit value.

The inventors of the present disclosure have diligently considered the application of solid wires that have not been used in the past in order to solve the above-mentioned problems. As a result, by adjusting the steel component of the solid wire, even if gas shielded arc welding is performed on the low Si steel material using the solid wire, excessive precipitation of precipitates is suppressed in the zinc plating after welding. It has been found that the deterioration of appearance and corrosion resistance is effectively suppressed.
Further, it has been found that the solid wire of the present disclosure does not have any problem even if it is copper-plated in the same manner as the conventional solid wire. Hereinafter, the reasons for limiting each component will be described.

In the solid wire for gas shielded arc welding in the present disclosure (sometimes referred to as "solid wire" or simply "wire" in the present disclosure), the steel portion as the base material is "steel" regardless of the presence or absence of copper plating. Called "line". That is, when not plated, the solid wire is composed of steel wire, and when copper plated, the solid wire is composed of the steel wire and the copper-plated layer.
Further, the “total wire mass” in the present disclosure means the total mass of the solid wire including the copper plating when copper plating is applied. Further, in the following, the chemical composition of the solid wire is expressed by mass% with respect to the total mass of the wire.

<Solid wire for gas shield arc welding>
The solid wire for gas shielded arc welding according to the present disclosure is used for at least one of the application of joining a low Si steel material having a Si content of 0.05% by mass or less and repairing a defective portion of the low Si steel material. , The steel component is mass% of the total weight of the wire,
C: 0.02 to 0.15%,
Si: 0.15% or less,
Mn: 0.3-2.2%,
Ti: 0.05 to 0.30%,
Al: 0.001 to 0.10%,
P: 0.015% or less,
S: 0.030% or less,
N: 0.0080% or less, and O: 0.0080% or less,
Includes steel wire with the balance consisting of Fe and impurities.

[C: 0.02 to 0.15%]
C has the effect of stabilizing the arc and atomizing the droplets, and if the C content is less than 0.02%, the droplets become large, the arc becomes unstable, and the amount of spatter generated increases. Further, if the C content is less than 0.02%, the strength of the weld metal cannot be sufficiently obtained, and the desired strength cannot be obtained. Therefore, the lower limit of the C content is 0.02%. On the other hand, if the C content exceeds 0.15%, the tensile strength of the weld metal becomes too high, the toughness decreases, and the crack resistance decreases. Therefore, the upper limit of the C content is 0.15%.

[Si: 0.15% or less]
In ordinary welding wires, Si is positively added as a deoxidizing element. In addition, the tensile strength of the weld metal is improved by promoting deoxidation of the molten metal during arc welding with Si. However, in order to improve corrosion resistance, it is desirable to reduce Si as much as possible. Therefore, the upper limit of the Si content is 0.15% or less. The Si content is preferably 0.10% or less.

[Mn: 0.3 to 2.2%]
Mn is also a deoxidizing element like Si, and is an element that promotes deoxidation of the molten pool during arc welding and improves the strength of the weld metal. If the Mn content is less than 0.3%, the tensile strength of the weld metal is insufficient, and pore defects occur due to insufficient deoxidation. Therefore, the Mn content is set to 0.3% or more.
On the other hand, when the Mn content exceeds 2.2%, the tensile strength of the weld metal becomes too high and the toughness decreases. Therefore, the upper limit of the Mn content is 2.2%.

[Ti: 0.05 to 0.30%]
Ti is a deoxidizing agent and is an element that improves the tensile strength of the weld metal. If the Ti content is less than 0.05%, the tensile strength becomes low, and pore defects occur due to insufficient deoxidation. On the other hand, if it exceeds 0.30%, the tensile strength becomes too high and the toughness decreases.

[Al: 0.001 to 0.10%]
Al is a deoxidizing element and improves the strength of the weld metal by promoting deoxidation of the molten metal during arc welding. Therefore, the lower limit of the Al content is 0.001%.
On the other hand, when Al is excessively contained, Al-based oxides are excessively generated, and the ductility of the weld metal is lowered. When the Al content exceeds 0.10%, the tensile strength of the weld metal becomes too high and the toughness decreases. Therefore, the upper limit of the Al content is set to 0.10%.

[P: 0.015% or less]
P is an element generally mixed as an impurity in steel, and P is one of the main elements that cause high-temperature cracking of a weld metal. It is desirable to suppress the P content as much as possible because it has the effect of corrosion resistance when the P content is kept low. If the P content exceeds 0.015%, the corrosion resistance is lowered and the weld metal is liable to crack at high temperature. Therefore, the upper limit of the P content is set to 0.015%.

[S: 0.030% or less]
Like P, S is also an element that is generally mixed as an impurity in steel, and is usually contained as an impurity in solid wire for arc welding. When S exceeds 0.030%, high temperature cracking of the weld metal is likely to occur. It also reduces toughness. Therefore, the upper limit of the S content is set to 0.030%.

[N: 0.0080% or less]
N is also an element that is generally mixed in steel as an impurity. Therefore, N is also contained as an impurity in the steel wire of the solid wire for arc welding according to the present disclosure. When the N content exceeds 0.0080%, the toughness of the weld metal is lowered, and pore defects are likely to occur. In addition, it will be present as inclusions of large nitrides in the steel, and will be present as inclusions in the weld metal as they are, and will easily become welding defects. Therefore, the N content is set to 0.0080% or less.

[O: 0.0080 or less]
O is also an element that is generally mixed in steel as an impurity. Therefore, O is also contained as an impurity in the steel wire of the solid wire for arc welding according to the present disclosure. When O exceeds 0.0080%, the toughness of the weld metal is lowered, and pore defects are likely to occur. In addition, it will be present as inclusions of large oxides in the steel, and will be present as inclusions in the weld metal as they are, and will easily become welding defects. Therefore, the O content is set to 0.0080% or less.

The solid wire according to the present disclosure may contain other elements in addition to the above elements. For example, Sb, Cu, Cr, Nb, V, Mo, Ni, and B contain one or more of Sb, Cu, Cr, Nb, V, Mo, Ni, and B because the same effect can be obtained even if they are contained in the steel wire of the solid wire according to the present disclosure. You may. Cu may be contained as copper plating formed on the surface of the steel wire. When each of these elements is contained in the solid wire, the content is as follows with respect to the total mass of the wire.

[Sb: 0.10% or less]
Sb may not be contained. When Sb is contained, similarly to S, by increasing the surface tension of the molten pool, it is possible to generate inward convection in the weld pool and collect the slag in the center of the weld bead. Therefore, it is possible to prevent slag from remaining on the toe of the weld bead, and the welding workability is improved.
On the other hand, if the Sb content is excessive, the toughness of the weld metal is lowered. Therefore, the upper limit of Sb is set to 0.10% or less.

[Cu: 0.50% or less]
Cu may not be contained. Cu may be contained in the steel wire, or may be contained as copper plating regardless of the presence or absence of Cu in the steel wire. In solid wire for arc welding, copper plating is often applied to stabilize the wire feedability and electrical conductivity. Further, even when copper plating is not performed, the steel wire may contain Cu to some extent.
On the other hand, when Cu is excessive, welding cracks are likely to occur. Therefore, the upper limit of the Cu content is 0.50% or less.

[Cr: 1.5% or less]
Cr may not be contained. When Cr is contained, Cr enhances the hardenability of the welded portion to increase the strength, while when it is excessively contained, the ductility of the welded portion is lowered. Therefore, when Cr is contained, the content is 1.5% or less.

[Nb: 0.3% or less]
Nb may not be contained. When Nb is contained, Nb can enhance the hardenability of the welded portion and increase the strength of the weld metal. However, if it is contained in an excessive amount, the toughness of the welded portion is lowered. Therefore, when Nb is contained, it should be 0.3% or less.

[V: 0.3% or less]
V may not be contained. When V is contained, V may be contained in order to enhance the hardenability of the welded portion and improve the tensile strength, but if it is excessively contained, the toughness of the welded portion is lowered. Therefore, the upper limit of the V content is 0.3% or less.

[Mo: 1.0% or less]
Mo may not be contained. When Mo is contained, Mo may be contained in order to enhance the hardenability of the welded portion and improve the tensile strength, but when it is excessively contained, the tensile strength of the welded portion becomes too high. And the toughness decreases. Therefore, the upper limit of the Mo content is 1.0% or less.

[Ni: 3.0% or less]
Ni may not be contained. When Ni is contained, Ni may be contained in order to improve the tensile strength and elongation of the welded portion, but if it is excessively contained, welding cracks are likely to occur. Therefore, the upper limit of the Ni content is 3.0% or less. It is preferably 2.5% or less.

[B: 0.010% or less]
B may not be contained. When B is contained, B has an effect of improving the structure of the weld metal and improving the toughness by a synergistic effect with Ti, but when it is excessively contained, welding cracks of the weld metal occur. Therefore, the upper limit of the B content is 0.010%. It is preferably 0.005% or less.

[Remaining: Fe and impurities]
The rest of the components described above consist of Fe and impurities. Impurities refer to components contained in raw materials and components mixed in during the manufacturing process, not components intentionally contained in steel wire. The total amount of impurities contained in the steel wire is 2% or less, more preferably 1% or less.

(Copper plating)
The solid wire according to the present disclosure may further include copper plating formed on the surface of the steel wire. By applying copper plating, wire feeding and electrical conductivity can be stabilized.
In the case of a solid wire having copper plating formed on the surface of the steel wire, the amount of copper plating adhered is not particularly limited, but the total amount of copper plating and the amount of Cu contained in the steel wire with respect to the total weight of the wire, that is, the solid wire If the Cu content as a whole is too high, welding cracks will occur. From this point of view, the content of Cu contained in the copper plating is preferably 0.5% or less in mass% with respect to the total mass of the wire.

As described above, the solid wire according to the present disclosure may contain Cu in the steel wire, and may contain, for example, 0.1% or less of Cu with respect to the total mass of the wire. Therefore, in the case of a solid wire plated with copper, the total content of Cu in the solid wire according to the present disclosure is preferably 0.1 to 0.5%.

(Wire diameter)
The diameter of the solid wire according to the present disclosure is not particularly limited, but is, for example, 0.8 to 2.4 mm.

<Gas shield arc welding>
Next, a method of performing gas shield welding on a low Si steel material using the solid wire for gas shield arc welding according to the present disclosure will be described.
The solid wire for gas shielded arc welding according to the present disclosure includes a method of joining a low Si steel material using a low Si steel material having a Si content of 0.05% by mass or less and a Si content of 0.05% by mass or less. It can be suitably used in a method of repairing a low Si steel material by overlaying the defective portion of the low Si steel material.

That is, in the method for joining the low Si steel material according to the present disclosure, the solid wire for gas shielded arc welding according to the present disclosure, Ar and 5 to 30 are used for the low Si steel material having a Si content of 0.05% by mass or less. It is a method including a step of performing joining by gas shield welding using a shield gas containing CO ₂ by volume.
Further, in the method for repairing a low Si steel material according to the present disclosure, a solid wire for gas shielded arc welding according to the present disclosure, Ar and It is a method including a step of overlaying the defective portion by gas shield welding using a shield gas containing 5 to 30% by mass of CO ₂ .

The low Si steel material used in the method for joining the low Si steel material or the method for repairing the low Si steel material according to the present disclosure is not particularly limited in other components and structures as long as the Si content is 0.05% by mass or less, and after welding. It may be selected according to the intended use.
Further, as the shield gas, a gas containing Ar and 5 to 30% by volume of CO ₂ is used, and the total of Ar and CO ₂ is preferably 100%, but less than 5% by volume other than Ar and CO ₂ . It is permissible to contain gas.

The welded metal portion formed by the method for joining the low Si steel material according to the present disclosure and the welded metal portion formed by the method for repairing the low Si steel material are, for example, the tensile strength obtained by the tensile test specified in JIS Z3111: 2005. The strength is 430 MPa or more, and the Charpy absorption energy obtained in the impact test is 47 J or more.
In addition, the corrosion resistance after hot-dip galvanizing after welding also shows excellent corrosion resistance because the chemical composition of the weld metal is appropriately adjusted. Since excessive precipitates are suppressed in the joint portion or the overlay portion in the zinc plating, it is possible to produce a product having an excellent appearance (design).

Next, the solid wire for gas shielded arc welding according to the present disclosure will be specifically described with reference to Examples and Comparative Examples, but the solid wire for gas shielded arc welding according to the present disclosure is limited to the following examples. It's not a thing.

<Manufacturing of solid wire>
The raw material steel was vacuum melted, forged, rolled, wire drawn, annealed, copper-plated on the wire surface as needed, and then finished and drawn to a product diameter of 1.2 mm to form a 20 kg spool. .. The chemical composition of these solid wires is shown in Table 1. Each mass% of the chemical composition of the total mass of the solid wire and the amount of copper plating adhered in Table 1 means mass% with respect to the total mass of the wire. Values outside the scope of this disclosure are underlined. In addition, the indication of-in the table indicates that the element was not intentionally added.

<Gas shield arc welding test>
Welding test pieces were prepared by performing gas shielded arc welding using each of the prototype solid wires having a diameter of 1.2 mm. The types of steel and gas shown in Table 2 were used.
In the welding test, a steel sheet having a tensile strength of 400 MPa class and having groove grooves shown in FIGS. 1 and 2 formed on the steel sheet having the chemical components shown in Table 3 was used. The unit of dimensions in the figure is "mm".
The mechanical performance of the weld metal of the solid wire was evaluated according to JIS Z3312: 2009, and the welding conditions were as shown in Table 5.

(Tensile test of weld metal)
The tensile test of the weld metal was performed by a weld metal performance test in accordance with JIS Z3111: 2005.
According to JIS Z3312: 2009, the tensile property symbol 43 of the weld metal, which is a standard for welding wires, it was judged that the strength was good (passed) when the tensile strength (TS) was 430 MPa or more and 600 MPa or less.

(Corrosion test: Confirmation of corrosion resistance of weld metal)
The corrosion resistance (corrosion rate) of the weld metal immersed in the hot-dip zinc of the hot-dip galvanizing kettle operating at 430 to 450 ° C. (average 440 ° C.) for 72 hours was evaluated. A case of 1.30 mg / cm ² / hr or less was judged to be acceptable.

(Impact test of weld metal)
The impact test of the weld metal was performed by a weld metal performance test in accordance with JIS Z3111: 2005.
Welding wire standard JIS Z3312: 2009 Impact characteristics of weld metal According to the temperature symbol 0, the impact performance is good (passed) when the Charpy absorption energy at the impact test temperature of 0 ° C is 47J. It was judged.

(Plating test)
The welding test piece was immersed in hot-dip zinc at 450 ° C. for 3 minutes, and the plating state was evaluated according to the following criteria. A passes, B effectively passes, and C fails. 3 shows the end of the welding test piece before plating, and FIG. 4 shows the end of the welding test piece after plating. In each drawing, A is Example 1 and B is JIS Z 3211: 2008. It is a welding rod of E4319 U.
A: The welded part is the same as the base material, and it is unknown.
B: The color tone of the welded part and the base material are different, but there is no step.
C: A step can be seen between the welded portion and the base metal.

Table 2 shows the materials used for each test and the evaluation results.

In the comparative example, the steel component of the solid wire was out of the range specified in this disclosure, and one or more evaluation items were rejected.

(Confirmation of welding defects)
For the evaluation of welding defects, after welding the groove groove in FIG. 1, visually confirm the presence or absence of pore defects such as pits on the bead surface, and cut the welding test piece to a width of 10 mm and blow holes in the vertical cross section. The presence or absence of pore defects was visually confirmed and evaluated. If even one pore defect appeared, it was considered as defective.

(Comparative test of welding work efficiency and plating test)
Using the solid wire and the welding rod of Example 1, the groove grooves 12A and 12B of the steel material 10 (test material) having the shapes shown in FIGS. 1 and 2, respectively, under the conditions shown in Tables 4 and 5 below. We compared the work efficiency of welding and performed a plating test.
As shown in Table 4, when the solid wire of Example 1 was used, the welding time was less than half that of the case where the welding rod was used. Further, since the welding rod of Comparative Example B had a high P, the corrosion test result and the plating test result were poor.

(Comparative test when applied to high Si steel materials)
Using the solid wire of Example 1, gas shielded arc welding was performed on the steel materials 1 and 2 in Table 3 under the conditions shown in Table 5, and then a plating test was performed. In welding, a seal gas containing Ar and 20% by volume CO ₂ was used.
As shown in Table 6, when welding was performed on the steel material 2 having a Si content of more than 0.05% by mass, the thickness of the steel material of the steel material 2 became thin, so that the appearance evaluation was poor as C.

10 Steel material (test material)
12A, 12B Groove groove

Claims (5)

A solid wire for gas shielded arc welding used for at least one of the applications of joining low Si steel materials having a Si content of 0.05% by mass or less and repairing defects in the low Si steel materials.
The steel component is mass% of the total mass of the wire.
C: 0.02 to 0.15%,
Si: 0.15% or less,
Mn: 0.3-2.2%,
Ti: 0.05 to 0.30%,
Al: 0.001 to 0.10%,
P: 0.015% or less,
S: 0.030% or less,
N: 0.0080% or less, and O: 0.0080% or less,
A solid wire for gas shielded arc welding containing a steel wire containing Fe and impurities as a balance. By mass% of the total mass of the wire
Sb: 0.10% or less Cu: 0.50% or less,
Cr: 1.5% or less,
Nb: 0.3% or less,
V: 0.3% or less,
Mo: 1.0% or less,
The solid wire for gas shielded arc welding according to claim 1 or 2, further comprising one or more selected from the group consisting of Ni: 3.0% or less and B: 0.010% or less. The solid wire for gas shielded arc welding according to claim 2, wherein a copper plating layer is formed on the surface of the steel wire, and at least a part of the Cu is contained as the copper plating layer. The solid wire for gas shielded arc welding according to any one of claims 1 to 3 and Ar and 5 to 30% by volume with respect to a low Si steel material having a Si content of 0.05% by mass or less. A method for joining a low Si steel material, which comprises a step of joining by gas shield welding using a shield gas containing CO ₂ . The solid wire for gas shielded arc welding according to any one of claims 1 to 3, and Ar and 5 are used for a low Si steel material having a Si content of 0.05% by mass or less and having a defect. A method for repairing a low Si steel material, which comprises a step of overlaying and repairing the defective portion by gas shield welding using a shield gas containing ~ 30% by mass of CO ₂ .

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