JP7295418B2 - welding material - Google Patents

Description

The present disclosure relates to welding materials.

Low-alloy heat-resistant steel represented by 2.25% Cr-1% Mo is widely used for equipment used at high temperatures such as thermal power boilers.
In recent years, in thermal power generation, high temperature and high pressure steam conditions have been promoted in order to improve thermal efficiency, and there is a movement to raise the steam conditions in exhaust heat recovery boilers as well.
Low-alloy heat-resistant steel is also widely used for the piping material of heat recovery steam generators. Therefore, many proposals have been made for low-alloy heat-resistant steels that actively utilize W and V to increase creep strength.

For example, Patent Document 1 includes Cr: 2.0% to 8.0%, W: 0.1% to 2.5%, V: 0.05% to 0.50%, etc. in terms of weight %. Also disclosed is a low-alloy steel with improved creep properties and hydrogen corrosion resistance due to low S and low N.
Patent Document 2 contains Cr: 1.5% to 3.5%, W: 1% to 3%, V: 0.1% to 0.35%, etc., and Ti and N A low-alloy heat-resistant steel having excellent creep strength and toughness is disclosed in which the content is specified within a predetermined range.

On the other hand, these low-alloy heat-resistant steels are generally used after being welded. Therefore, many proposals have been made for welding consumables for low-alloy steels to be used for welding.
For example, Patent Document 3 discloses creep Welding materials used for TIG welding of heat-resistant steel with excellent strength have been proposed.
Patent Document 4 contains, in mass%, Cr: 0.5% to 3.5%, W: 0.01% to 2%, V: 0.005% to 0.4%, etc. Ti and N Disclosed is a welding material for use in welding W-containing, low-alloy heat-resistant steels in which σ satisfies a predetermined relationship.
In addition, Patent Document 5 includes Cr: 2% to 3%, V: 0.05% to 0.3%, Mo: more than 0.4% to 0.8%, etc., and the relationship between W and Mo and 0.7%≤Mo+0.5W≤1.2% and 0.4≤Mo/W≤1.8.

JP-A-63-18038 JP-A-4-268040 JP-A-5-269590 JP-A-2002-18593 Japanese Patent Application Laid-Open No. 2004-230410

By the way, unlike coal-fired power boilers, exhaust heat recovery boilers are rarely operated continuously, and it is common to repeat stoppage and operation according to the required amount of power generation. However, the trains are operated in such a way that they stop at night. Therefore, members such as piping used in the heat recovery boiler are repeatedly heated to a high temperature and cooled to a normal temperature.
In this way, when used in applications where heating to high temperatures and cooling are repeated, it has been found that the weld metal obtained using these welding consumables may not stably obtain sufficient toughness. . In particular, it has been found that when the welding material essentially contains Sn, which is effective in improving the corrosion resistance of the weld metal, there is a phenomenon that the toughness cannot be stably obtained.

The present disclosure has been made in view of the above-mentioned current situation, and is a welding that contains W and Sn, has a high back wave forming ability, and can obtain a weld metal that has excellent toughness even when heating to high temperatures and cooling are repeated. Intended to provide material.

The gist of the present disclosure for achieving the above object is as follows.
<1> C in mass%: 0.03% to 0.09%,
Si: 0.25% to 0.55%,
Mn: 0.30% to 1.00%,
P: 0.015% or less,
S: 0.0002% to 0.0050%,
Sn: 0.0005% to 0.0100%,
Ni: 0.20% to 1.00%,
Cr: 1.8% to 2.8%,
Mo: 0.05% to 0.35%,
W: 1.0% to 2.2%,
V: 0.15% to 0.28%,
Nb: 0.01% to 0.11%,
N: 0.001% to 0.012%,
Al: 0.020% or less, and O: 0.020% or less,
and the total amount of S and Sn satisfies the formula (1), and the balance is Fe and impurities.
0.0010≦[%S]+[%Sn]≦0.0120 (1)
In the formula (1), [%S] and [%Sn] mean mass % of S and Sn contained in the welding material, respectively.
<2> Instead of part of the Fe, in mass%,
Ta: 0.20% or less,
Ti: 0.20% or less,
Co: 0.50% or less,
Cu: 0.50% or less,
B: 0.005% or less,
Ca: 0.015% or less,
The welding material according to <1>, containing at least one element selected from the group consisting of Mg: 0.015% or less and REM: 0.05% or less.

According to the present disclosure, there is provided a welding material that contains W and Sn, has high back-bead forming ability, and provides a weld metal with excellent toughness even after repeated heating to high temperatures and cooling.

It is a schematic diagram showing the shape of the plate material subjected to groove processing in the example.

In order to solve the above-described problems, the present inventors have proposed welding containing 1.0% to 2.2% W, 0.0002% to 0.0050% S, and 0.0005% to 0.0100% Sn. A detailed investigation was carried out on the weld metal obtained using the material. As a result, the following knowledge was clarified.
(1) As a result of investigating the toughness of the weld metal subjected to repeated heating to high temperature and cooling to normal temperature, toughness decreased significantly as the total content of S and Sn increased.
(2) As a result of observing the fracture surface of the steel after the impact test, it was found that on the fracture surface, regions fractured at the former austenite grain boundaries were mixed, and the ratio increased as the total content of S and Sn increased. rice field. Moreover, S and Sn were detected from the fractured surface fractured at the former austenite grain boundary.

From the above results, the reason for the decrease in toughness was presumed as follows.
S and Sn contained in the welding material undergo solidification segregation and grain boundary segregation during the process of solidification and cooling of the weld metal. Furthermore, in the process of repeating heating to a high temperature and cooling during use, it segregates at grain boundaries and concentrates at prior austenite grain boundaries. Both S and Sn reduce the cohesive strength of grain boundaries, resulting in a reduction in toughness.
As a result of various studies, the inventors of the present invention have found that the necessary toughness can be obtained by controlling the total amount of S and Sn contained in steel to 0.0120% or less.
On the other hand, S and Sn increase the penetration depth during welding and improve the back wave formability. In addition, the inventors also found that in order to suppress weld defects and maintain soundness as a welded joint, it is necessary to control the total amount to 0.0010% or more.

The welding material according to the present disclosure has been completed based on the above findings.
That is, the welding material according to the present disclosure is, in mass %,
C: 0.03% to 0.09%,
Si: 0.25% to 0.55%,
Mn: 0.30% to 1.00%,
P: 0.015% or less,
S: 0.0002% to 0.0050%,
Sn: 0.0005% to 0.0100%,
Ni: 0.20% to 1.00%,
Cr: 1.8% to 2.8%,
Mo: 0.05% to 0.35%,
W: 1.0% to 2.2%,
V: 0.15% to 0.28%,
Nb: 0.01% to 0.11%,
N: 0.001% to 0.012%,
Al: 0.020% or less, and O: 0.020% or less,
and the total amount of S and Sn satisfies the formula (1), and the balance consists of Fe and impurities.
0.0010≦[%S]+[%Sn]≦0.0120 (1)
In the formula (1), [%S] and [%Sn] mean mass % of S and Sn contained in the welding material, respectively.

An embodiment that is an example of the present disclosure will be described.
In addition, in this disclosure, "%" display of the content of each element means "% by mass". In addition, in the present disclosure, unless otherwise specified, a numerical range represented using "to" means a range including the numerical values described before and after "to" as lower and upper limits. In addition, a numerical range when "more than" or "less than" is attached to a numerical value described before and after "to" means a range that does not include these numerical values as lower or upper limits.
In the numerical ranges described stepwise in the present disclosure, the upper or lower limit of one stepwise numerical range may be replaced with the upper or lower limit of another stepwise numerical range, and , may be replaced by the values shown in the examples.
In addition, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.

[composition]
The reasons for limiting the composition of the welding material in this embodiment are as follows.
C: 0.03% to 0.09%
It is effective in obtaining the bainite structure of the weld metal, forms carbides, and contributes to tensile strength and creep strength. In order to sufficiently obtain these effects, the content should be 0.03% or more. However, if it is excessively contained, the creep strength and toughness are lowered, so the content is made 0.09% or less. A preferred lower limit for the C content is 0.04%, and a preferred upper limit is 0.08%. A more preferable lower limit is 0.05%, and a more preferable upper limit is 0.07%.

Si: 0.25% to 0.55%
Si is contained as a deoxidizing agent during the production of welding consumables, and is an element effective in improving the steam oxidation resistance of weld metals. In order to fully obtain the effect, it is necessary to contain 0.25% or more. However, excessive content causes a decrease in ductility. Therefore, the Si content is set to 0.55% or less. A preferred lower limit for the Si content is 0.27%, and a preferred upper limit is 0.53%. A more preferable lower limit is 0.30%, and a more preferable upper limit is 0.50%.

Mn: 0.30% to 1.00%
Like Si, Mn is contained as a deoxidizing agent during the production of welding consumables, but it is also effective in obtaining the bainite structure of the weld metal. In order to sufficiently obtain the effect, it is necessary to contain 0.30% or more. However, an excessive content causes creep embrittlement, so the content is made 1.00% or less. A preferred lower limit for the Mn content is 0.35% and a preferred upper limit is 0.95%. A more preferable lower limit is 0.40%, and a more preferable upper limit is 0.90%.

P: 0.015% or less P, when contained excessively, lowers the creep ductility of the weld metal and increases the susceptibility to solidification cracking during welding. Therefore, the P content should be 0.015% or less. The P content is preferably 0.013% or less, more preferably 0.012% or less. It should be noted that the lower the P content is, the better. Therefore, the preferable lower limit of the P content is 0.0005%, and the more preferable lower limit is 0.001%.

S: 0.0002 to 0.0050%
If S is contained excessively, it segregates at the grain boundaries during the formation of the weld metal and in the process of repeated heating and cooling during use, thereby lowering the toughness of the weld metal. In addition, it reduces the creep ductility of the weld metal. Therefore, the S content should be 0.0050% or less. On the other hand, S affects the temperature dependence of the surface tension of the molten metal, and has the effect of increasing the penetration depth. Therefore, it is made 0.0002% or more. A preferred range for the S content is 0.0005% to 0.0045%, and a more preferred range is 0.0008% to 0.0040%. Also, the content of S must satisfy the relationship with Sn, which will be described later.

Sn: 0.0005% to 0.0100%
Sn concentrates under the scale on the surface of the weld metal and is effective in improving corrosion resistance, especially in an environment where heating and cooling are repeated and condensed water easily adheres to the surface, such as in an exhaust heat recovery boiler. Furthermore, it evaporates from the molten pool and forms an arc current path, thereby increasing the penetration depth. In order to obtain these effects, Sn must be contained in an amount of 0.0005% or more. On the other hand, if Sn is contained excessively, it segregates at the grain boundaries during the formation of the weld metal and the repeated heating and cooling during use, resulting in a decrease in the toughness of the weld metal. Therefore, the Sn content should be 0.010% or less. A preferred range of the Sn content is 0.0008% to 0.0080%, and a more preferred range is 0.0010% to 0.0060%. Also, the Sn content must satisfy the relationship with S, which will be described later.

Ni: 0.20% to 1.00%
Ni is an effective element for obtaining the bainite structure of the weld metal and contributes to the improvement of toughness. In order to sufficiently obtain the effect, it is necessary to contain 0.20% or more. However, it is an expensive element, and excessive content causes an increase in cost, so 1.00% is made the upper limit. A preferred lower limit of the Ni content is 0.25%, and a preferred upper limit is 0.95%. A more preferable lower limit is 0.30%, and a more preferable upper limit is 0.90%.

Cr: 1.8% to 2.8%
Cr is an effective element for ensuring high-temperature steam oxidation resistance and corrosion resistance of the weld metal. In addition, it precipitates as carbide and contributes to the improvement of creep strength. In order to sufficiently obtain these effects, it is necessary to contain 1.8% or more. However, if it is excessively contained, the stability of the carbide is lowered and the creep strength is rather lowered, so the content is made 2.8% or less. A preferred lower limit to the Cr content is 2.0%, and a preferred upper limit is 2.6%. A more preferable lower limit is 2.2%, and a more preferable upper limit is 2.4%.

Mo: 0.05% to 0.35%
Mo dissolves in the matrix and contributes to securing creep strength at high temperatures. In order to sufficiently obtain this effect, the content should be 0.05% or more. However, even if it is contained excessively, the effect is saturated and it is an expensive element, which increases the material cost. A preferred lower limit to the Mo content is 0.08% and a preferred upper limit is 0.30%. A more preferable lower limit is 0.10%, and a more preferable upper limit is 0.25%.

W: 1.0% to 2.2%
W forms a solid solution in the matrix or precipitates as a carbide, and contributes to ensuring the tensile strength and creep strength of the weld metal at high temperatures. In order to sufficiently obtain this effect, the content should be 1.0% or more. However, even if it is contained excessively, the effect is saturated and it is an expensive element, which increases the material cost. A preferred lower limit for the W content is 1.2%, and a preferred upper limit is 2.0%. A more preferred lower limit is 1.4% and a preferred upper limit is 1.8%.

V: 0.15% to 0.28%
V precipitates in grains as fine carbonitrides and contributes to the improvement of the creep strength of the weld metal. In order to fully obtain the effect, it is necessary to contain 0.15% or more. However, if the content becomes excessive, a large amount of coarse precipitates occur, which rather leads to a decrease in creep strength and creep ductility, so the content is made 0.28% or less. A preferred lower limit for the V content is 0.17%, and a preferred upper limit is 0.26%. A more preferable lower limit is 0.18%, and a more preferable upper limit is 0.24%.

Nb: 0.01% to 0.11%
Like V, Nb precipitates in grains as fine carbonitrides and contributes to the improvement of the creep strength of the weld metal. In order to sufficiently obtain the effect, it is necessary to contain 0.01% or more. However, if it is contained excessively, it precipitates in large amounts and coarsely, rather causing a decrease in creep strength and creep ductility, so the content is made 0.11% or less. A preferable lower limit of the Nb content is 0.02% and a preferable upper limit is 0.10%. A more preferable lower limit is 0.03%, and a more preferable upper limit is 0.08%.

N: 0.001% to 0.012%
N combines with V and Nb during use at high temperatures and precipitates in grains as fine carbonitrides, contributing to the improvement of the creep strength of the weld metal. In order to obtain this effect, it is necessary to contain 0.001% or more. However, if it is contained excessively, it causes coarsening of carbonitrides, which rather causes deterioration of creep ductility. A preferred lower limit of the N content is 0.002% and a preferred upper limit is 0.010%. A more preferable lower limit is 0.003%, and a more preferable upper limit is 0.008%.

Al: 0.020% or less Al is contained as a deoxidizing agent during the production of welding materials. Moreover, it is not preferable from the viewpoint of creep strength. Therefore, the content of Al is set to 0.020% or less. It is preferably 0.018% or less, more preferably 0.015% or less. It should be noted that there is no particular need to set a lower limit, but an extreme reduction increases the manufacturing cost of the welding material. Therefore, it is preferable to make it 0.001% or more.

O: 0.020% or less O exists as an impurity, but when it is contained in a large amount, it reduces the workability of the welding material during production. Therefore, the O content is set to 0.020% or less. It is preferably 0.015% or less, more preferably 0.010% or less. It should be noted that the lower limit does not have to be set, that is, the content may be 0%, but extreme reduction increases the manufacturing cost of the welding material. Therefore, it is preferable to make it 0.001% or more.

Total content of S and Sn: 0.0010% to 0.0120%
(0.0010≦[%S]+[%Sn]≦0.0120)
As described above, S and Sn improve the back wave forming ability. In order to obtain this effect, the total content of S and Sn should be 0.0010% or more. However, if S and Sn are excessive, as described above, the toughness is lowered, so the total content of S and Sn should be 0.0120% or less. A preferred lower limit for the total content of S and Sn is 0.0012%, and a preferred upper limit is 0.0100%. A more preferable lower limit is 0.0015%, and a more preferable upper limit is 0.0080%.

Furthermore, the welding material according to the present disclosure contains Ta: 0.20% or less, Ti: 0.20% or less, Co: 0.50% or less, Cu: 0.50% or less, At least one element selected from the group consisting of B: 0.005% or less, Ca: 0.015% or less, Mg: 0.015% or less, and REM: 0.05% or less may be contained. The reason for the limitation will be described below.

Ta: 0.20% or less Like Nb and V, Ta precipitates in grains as fine carbonitrides and contributes to the improvement of the creep strength of the weld metal. However, if Ta is contained excessively, it precipitates in large amounts and coarsely, rather causing a decrease in creep strength and creep ductility, so the content is made 0.20% or less. A preferred upper limit is 0.18%, more preferably 0.15% or less. The preferable lower limit when Ta is contained is 0.01%, and the more preferable lower limit is 0.02%.

Ti: 0.20%
Like V and Nb, Ti precipitates in grains as fine carbonitrides and contributes to the improvement of the creep strength of the weld metal. However, if Ti is contained excessively, it precipitates in large amounts and coarsely, rather causing a decrease in creep strength and creep ductility, so Ti is made 0.20% or less. A preferred upper limit is 0.18%, more preferably 0.15% or less. In addition, the preferable lower limit when Ti is contained is 0.01%, and the more preferable lower limit is 0.02%.

Co: 0.50% or less Like Ni, Co is an element effective in obtaining a bainite structure of the weld metal and also contributes to improvement in toughness, so it may be contained as necessary. However, Co is an expensive element, and excessive content causes an increase in the cost of the welding material, so 0.50% is made the upper limit. A preferred upper limit is 0.45%, more preferably 0.40% or less. When Co is contained, the preferable lower limit is 0.01%, and the more preferable lower limit is 0.02%.

Cu: 0.50% or less Cu, like Ni and Co, is an element effective in obtaining the bainite structure of the weld metal and also contributes to the improvement of toughness, so it may be contained as necessary. . However, Cu is an expensive element, and excessive content causes an increase in the cost of the welding material, so the upper limit is 0.50%. A preferred upper limit is 0.45%, more preferably 0.40% or less. In addition, when Cu is contained, the preferable lower limit is 0.01%, and the more preferable lower limit is 0.02%.

B: 0.005% or less B has the effect of forming a solid solution in carbide and dispersing it finely, and contributes to the improvement of the high-temperature strength of the weld metal. However, an excessive B content increases the susceptibility to solidification cracking during welding, so the upper limit is 0.005%. A preferred upper limit is 0.0045%, more preferably 0.004% or less. The preferred lower limit for B content is 0.0005%, and the more preferred lower limit is 0.001%.

Ca: 0.015% or less Ca has the effect of improving the hot workability during the production of the welding material, so it may be contained as necessary. However, if added in excess, it binds with oxygen, resulting in a marked decrease in detergency and rather deterioration in hot workability. It is preferably 0.012% or less, more preferably 0.010% or less. When Ca is contained, the preferable lower limit is 0.0005%, and the more preferable lower limit is 0.001%.

Mg: 0.015% or less Mg, like Ca, has the effect of improving the hot workability during the production of the welding material, so it may be contained as necessary. However, excessive addition combines with oxygen, significantly lowering cleanliness and deteriorating hot workability, so the content should be 0.015% or less. It is preferably 0.012% or less, more preferably 0.010% or less. The preferred lower limit for Mg content is 0.0005%, and the more preferred lower limit is 0.001%.

REM: 0.05% or less Like Ca and Mg, REM (rare earth element) may be contained as necessary in order to improve hot workability during manufacturing of the welding material. However, when REM is excessively contained, it binds with oxygen and significantly lowers the cleanliness of the alloy, which in turn lowers the hot workability. Therefore, the upper limit is set to 0.05%. It is preferably 0.04% or less, more preferably 0.03% or less. When REM is contained, the preferred lower limit is 0.001%, and the more preferred lower limit is 0.005%.
"REM" is a generic term for a total of 17 elements including Sc, Y and lanthanoids, and the content of REM refers to the total content of one or more elements in REM. Also, REM is generally contained in the misch metal. For this reason, for example, a misch metal may be added to the alloy so that the content of REM is within the above range.

[Use]
As described above, the objects to be welded using the welding material according to the present disclosure are not limited.
Examples of equipment used at high temperatures include piping for waste heat recovery boilers; piping for boilers such as coal-fired power plants, oil-fired power plants, waste incineration power plants and biomass power plants; cracking tube; and the like.
Here, "use at high temperature" in the present embodiment includes, for example, a mode of use in an environment of 350° C. or higher and 700° C. or lower (further 400° C. or higher and 650° C. or lower).

EXAMPLES Hereinafter, the welding material according to the present disclosure will be described more specifically by way of examples. In addition, the welding material according to the present disclosure is not limited to these examples.

A plate is obtained by sequentially performing each process of hot forging, hot rolling, heat treatment and machining on an ingot cast by melting materials A to H having the chemical compositions shown in Table 1 in a laboratory. A plate (base material) with a thickness of 15 mm, a width of 50 mm, and a length of 100 mm and a plate (a material for welding material) with a thickness of 4 mm, a width of 200 mm, and a length of 500 mm were prepared. Furthermore, a cut filler (welding material) of 2 mm square and 500 mm long was produced by machining using this 4 mm thick plate (material for welding material).

[Back wave forming ability]
After performing the groove processing shown in FIG. First layer welding was carried out one by one.
Among the obtained welded joints, those in which a back bead is formed over the entire length of the weld line in both joints are considered to have a "pass" back wave formation ability, and among them, those with a back bead width of 2 mm or more over the entire length. "Pass/Excellent", and those with even a portion less than 2 mm were rated as "Pass/Acceptable". On the other hand, if there was even a part of the two joints where the back bead was not formed, it was determined as "failed".
After that, the cut filler having the same sign as the base material was used as the filler material, and subsequent lamination welding was performed in the groove by manual TIG welding. During welding, the heat input was set at 9 to 15 kJ/cm, and two welded joints were produced for each code. After that, a post-weld heat treatment was performed at 715° C. for 0.5 hours to obtain a welded joint for testing. Since the base material and the cut filler wire have the same composition, it is obvious that the chemical composition in Table 1 is synonymous with the chemical composition of the weld metal.

[Charpy impact test/toughness]
For one of the test welded joints of each code, the heating and cooling cycle of "room temperature→550° C.×108 hours→room temperature" was repeated five times. Then, three notched 2 mm V-notch full-size Charpy impact test pieces were sampled from the thickness direction central part of each of the welded joints that were heat-treated after welding and that were repeatedly heated and cooled, and subjected to the Charpy impact test. The Charpy impact test was performed in accordance with JIS-Z2242 (2005). The test was carried out at 20 ° C., and the average value of the absorbed energy of the three test pieces was 27 J or more. The test pieces were evaluated as “pass/excellent”, and the others as “pass/acceptable”.

[Creep rupture test]
In addition, for the codes that passed the Charpy impact test, a round bar creep test piece was taken from the test welded joint material as it was after the heat treatment after welding, and a creep rupture test was performed. A creep rupture test was conducted under the conditions of 550° C.×196 MPa, where the target rupture time of the base metal was 1000 hours, as an evaluation for long-term use. The creep rupture test was conducted in accordance with JIS-Z2271 (2010). Then, those whose rupture time exceeded the target rupture time were evaluated as "accepted", and those whose rupture time was shorter than that were evaluated as "failed".

From Table 2, it can be seen that the weld metal that satisfies the conditions specified in the present disclosure can obtain good toughness even after repeated heating to high temperatures and cooling, and also has the target creep strength.
On the other hand, for F1 and G1, the total amount of S and Sn exceeded the upper limit. I was not satisfied with the toughness to be applied.
In addition, in H1, the total amount of S and Sn was less than the lower limit, so a back bead was not formed over the entire length during the first layer welding, and the back wave forming ability was poor.
Thus, only when the requirements of the present disclosure are satisfied, the welding consumable has a sufficient ability to form Uranami, and the weld metal obtained using it has excellent toughness even after repeated heating and cooling, and the target It can be seen that it has a high temperature strength of

ADVANTAGE OF THE INVENTION According to this disclosure, it is possible to provide a welding material that contains W and Sn, has a high back wave formability, and provides a weld metal that has excellent toughness even after repeated heating to high temperatures and cooling.

Claims (2)

C in mass %: 0.03% to 0.09%,
Si: 0.25% to 0.55%,
Mn: 0.30% to 1.00%,
P: 0.015% or less,
S: 0.0002% to 0.0050%,
Sn: 0.0005% to 0.0100%,
Ni: 0.20% to 1.00%,
Cr: 1.8% to 2.8%,
Mo: 0.05% to 0.35%,
W: 1.0% to 2.2%,
V: 0.15% to 0.28%,
Nb: 0.01% to 0.11%,
N: 0.001% to 0.012%,
Al: 0.020% or less, and O: 0.020% or less,
and the total amount of S and Sn satisfies the formula (1), and the balance is Fe and impurities.
0.0010≦[%S]+[%Sn]≦0.0120 (1)
In the formula (1), [%S] and [%Sn] mean mass % of S and Sn contained in the welding material, respectively. Instead of part of the Fe, in mass %,
Ta: 0.20% or less,
Ti: 0.20% or less,
Co: 0.50% or less,
Cu: 0.50% or less,
B: 0.005% or less,
Ca: 0.015% or less,
The welding material according to claim 1, containing at least one element selected from the group consisting of Mg: 0.015% or less and REM: 0.05% or less.

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