JPH05200582A - Welding wire for fire resistant steel with excellent weatherability - Google Patents

Abstract

PURPOSE:To inexpensively provide the welding wire for the fire resistant steel with excellent weatherability that the fire resistant character is excellent, the local corrosion can be prevented for using at the seaside and the welding part of excellent weatherability can be obtained. CONSTITUTION:The content of C, Si, Mn, Ti, N is restricted as the component in the wire, the welding metal strength of 600 deg. is surely kept by combinatedly adding the specially very small amount of V and the suitable amount of Mo, further, one kind or two kinds of B or Al is contained and Cr is not contained on the viewpoint of the local corrosion, the suitable amount of Cu, Ni, is respectively contained as the remarkably useful element for the weatherability, the index that the weatherability and the fire resistant character are obtained at the same time without damaging the welding workability is defined and the sum of this characteristic index is made to 0.30-0.60%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding wire used for various structures in the fields of construction, civil engineering, marine structures, etc., and can prevent local corrosion especially when used on a beach. The present invention relates to a welding wire for refractory steel having excellent weather resistance.

[0002]

2. Description of the Related Art As is well known, general structural rolled steel (JIS G 3101), welded structural rolled steel (JIS G 3106), welded as building materials for various structures in the fields of construction, civil engineering and marine structures. Structural weather resistant hot rolled steel (JIS G 3114), high weather resistant rolled steel (JIS G 3125), general structural carbon steel pipe (JIS G 3444), general structural square steel pipe (JI)
SG 4366) and the like are widely used. These welding materials include solid wires for mild steel and high-strength steel MAG welding (JIS Z 3312), carbon dioxide arc welding solid wires for weathering steel (JIS Z 331).
5) and TIG welding steel rods and wires (JIS Z 3316) of mild steel and low alloy steel are widely used. For example, JP 61-242785 A and JP 62
No. 267096 discloses a wire component for improving droplet transferability, and Japanese Patent Application Laid-Open Nos. 59-61592, 61-159296 and 1-170598 disclose reduction in spatter. Japanese Unexamined Patent Publication No. 61-195793 discloses a wire component for improving the slag removability, and Japanese Unexamined Patent Publication No. 62-158595 discloses a wire component for improving the wire feeding property. Has been done.

By the way, a welded portion constructed by using the above-mentioned steel material and the above-mentioned welding material in a building such as a building, an office, a residence, etc., which is closely related to daily life, among various kinds of building, secures safety in a fire. For this reason, it is obliged to apply a sufficient fireproof coating, and various building-related laws stipulate that the temperature of steel and welds should not exceed 350 ° C during a fire.

That is, the steel material and the welded portion have a proof stress of about 60 to 70 at room temperature at about 350 ° C. when used in a building.
%, Which may cause the collapse of the building, so it must be used in such a situation. For example, spread slag wool, rock wool, glass wool, etc. as a base material on the surface of the steel material and the welded portion, and a felt, and a method of covering with fireproof mortar and on the heat insulating material layer, A fireproof coating such as a method of protecting with a metal thin plate, that is, an aluminum or stainless steel thin plate is carefully applied to prevent thermal damage in the case of a fire. Therefore, it is inevitable that the refractory coating construction cost will be higher than the welding material price itself, and the construction cost will increase significantly. Therefore, when the conventional welding wire is used for the structure as described above, the price is low, but the high temperature characteristics are low, so the original welding material characteristics cannot be exhibited, and it is possible to use it without coating or light coating. First, it must have an expensive fireproof coating. For this reason, there is a problem that the construction cost becomes high and the space used for the building becomes narrow, so that the economic efficiency is lowered. Also,
Mag-weld solid wire (JIS Z 3317) for heat-resistant steel represented by molybdenum steel, chrome molybdenum steel and stainless steel, and JP-A-57-1008.
According to the wire for heat-resistant steel disclosed in Japanese Patent Publication No. 92 and Japanese Patent Application Laid-Open No. 58-100994, the high temperature characteristics are good, but it is very economical to use in addition to the welding construction technology. Have difficulty. Furthermore, with the recent rise in the height of buildings, the design technology has been improved and its reliability has led to a review of the fireproof design, and the new fireproof design method for buildings in 1987 has been stipulated. .. As a result, the above-mentioned 350 ° C
The high-temperature strength of steel and welds and the load actually applied to the building make it possible to determine the ability of the refractory coating without depending on the temperature limitation of the steel, and in some cases it is possible to use steel without coating. became.

Under these circumstances, a welding wire having a fireproof property has been studied for the first time, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2-52196.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have conducted various studies on important properties that welding materials for various building materials should hold, and as a result, have more economical efficiency, fire resistance and weather resistance. It was also concluded that a welding wire that can obtain an excellent weld is needed. As a currently considered welding wire for refractory steel, there is currently no welding wire to which the above weather resistance is added.

On the other hand, the currently used welding materials for weathering steel have the original weathering resistance and the ones on the assumption that a welded portion is obtained by sacrificing the weathering resistance to some extent, and coating is applied thereto. There are two types, one is based on the assumption that the welded part is used naked or subjected to rust stabilization treatment, but in order to give the welded part the original weather resistance performance, it is a weather resistance contributing element. It is generally practiced to use a welding wire containing all of Cu, Cr and Ni. But,
As a result of various studies by the present inventors only on the weather resistance,
Certainly, there was no problem with the conventional way of thinking about the weathering performance in the inland area, but it was found that there is a problem in using it at the beach area, especially from the viewpoint of local corrosion. However, there is currently no welding wire that can solve this problem and can obtain a conventional weld metal having excellent weather resistance.

Under these circumstances, the inventors of the present invention set out to develop a welding wire that is extremely difficult as described above, and as a result of various investigations, as a result, for the first time, it was found that the welding wire was excellent in economic efficiency and excellent in weather resistance. Has invented an epoch-making welding wire capable of simultaneously obtaining a weld metal having a good refractory property. The object of the present invention will be described in detail. As described above, it is possible to prevent local corrosion when used on the beach, has excellent weather resistance, and has a fire resistance property that can be supplied to the market at an economical price, particularly at 600 ° C. Excellent in high temperature characteristics,
Another object of the present invention is to provide a gas shielded arc welding wire having excellent impact toughness and excellent workability.

[0009]

The present invention overcomes the above-mentioned problems and achieves the object, and its concrete means are as follows. (1) By weight ratio, C: 0.01 to 0.12%, Si:
0.40 to 1.00%, Mn: 1.00 to 2.20%,
Cu: 0.25 to 0.65%, Ni: 0.10 to 0.5
0%, Mo: 0.05 to 0.60%, Ti: 0.05 to
0.35%, V: 0.004-0.10%, N: 0.0
Contains 100% or less, (C + Si / 24 + Mn / 6 +
Cu / 35 + Ni / 40 + V / 14 + Mo / 4) is 0.
A welding wire for refractory steel excellent in weather resistance, characterized in that it is 30 to 0.60%, and the balance is composed of iron and unavoidable impurities.

(2) C: 0.01-0.1 by weight ratio
2%, Si: 0.40 to 1.00%, Mn: 1.00
2.20%, Cu: 0.25 to 0.65%, Ni: 0.
10 to 0.50%, Mo: 0.05 to 0.60%, T
i: 0.05 to 0.35%, V: 0.004 to 0.10.
%, N: 0.0100% or less, (C + Si / 2
4 + Mn / 6 + Cu / 35 + Ni / 40 + V / 14 + M
o / 4) is 0.30 to 0.60%, and further B:
A welding wire for refractory steel excellent in weather resistance, characterized by containing one or two of 0.002 to 0.0070% and Al: 0.020% or less, and the balance being iron and unavoidable impurities.

[0011]

First of all, as a result of research on the weld metal strength in the case of fire, the maximum attainable temperature in the case of fire is 1000.
Since it is ℃, it is necessary to add a large amount of expensive alloying elements to the well-known welding wire in order to provide the corresponding portion with a proof stress of 70% or more at room temperature, and it can be used from the economical aspect. I confirmed that I could not.

Then, as a result of further research, 600
We have found that the welded part with a high temperature proof stress at 70 ° C of 70% or more at room temperature is the most economical, can reduce the amount of expensive additive elements, and can thin the fireproof coating of the welded part. We have found a welding wire component system with excellent fire resistance that can be used without coating when the fire load is small.
Furthermore, with the aim of further economic effect to this welding wire, it has an unprecedented characteristic, that is, it has the epoch-making performance addition that local corrosion can be prevented even when it is used on the beach and the conventional weather resistance can be obtained. Has invented a welding wire that has

The fire resistance characteristic of the present invention is that a small amount of V
60 by adding a small amount of B and adding a small amount of V and adding a suitable amount of Mo
The point is that the weld metal strength of 0 ° C can be secured. Regarding the weather resistance, Cu and N, which are extremely effective elements for the weather resistance according to the conventional knowledge as described above, are used.
i and Cr are not contained in appropriate amounts respectively, but from the viewpoint of local corrosion prevention for use on the beach, by adding Cu and Ni in appropriate amounts without adding Cr,
Local corrosion can be prevented and the conventional weather resistance can be obtained.

Further, the features of the welding wire of the present invention are that it is not necessary to simply add the above-mentioned components, but the welding workability is not impaired, and the fire resistance performance at 600 ° C., the impact toughness at room temperature and the weather resistance are ensured. (C + Si / 24 + Mn / 6 + Cu / 35 +)
Ni / 40 + V / 14 + Mo / 4) is 0.30 to 0.
It is in the range of 60%.

Therefore, first, taking into consideration the behavior of the temperature of the welded portion during a fire, the amount of V added and the fire resistance strength at 600 ° C. were calculated. It was found that the impact toughness of the steel deteriorates.
Therefore, in order to secure fire resistance and improve impact toughness,
By adding a proper amount of Mo to a small amount of V, a remarkable improvement effect was recognized. Further, it has been found that the addition of a small amount of B is effective in order to obtain a further improvement effect.

The effective addition amount of each is as follows. If the amount of V added is less than 0.004%, the effect cannot be obtained, and if it exceeds 0.1%, the effect of improving the fire resistance is saturated and the impact toughness is reduced. Mo addition amount is 0.05%
If it is less than 0.1%, the effect cannot be obtained, so the lower limit of the amount of Mo added is set to 0.05%. Further, if it exceeds 0.60%, the effect commensurate with the addition is not recognized, so the upper limit of the addition amount is set to 0.6.
0%

If the amount of B added is less than 0.002%, the effect of improving impact toughness cannot be obtained, so the lower limit was made 0.002%. On the other hand, if it exceeds 0.0070%, the crystal grains of the weld metal are coarsened, which leads to a decrease in impact toughness and hot cracking tends to occur, so the upper limit is made 0.0070%. In addition, it is known in the conventional heat-resistant steels to use Mo to increase the high temperature strength, but as described above, as a welding wire for weather resistant fire-resistant steels used for construction, a slight amount of V and a proper amount are used. Welding wires to which Mo is added in combination are not known.

As described above, if the fire resistance performance can be obtained by the combined addition of V and Mo or the addition of B, the welded portion is not further provided with a fireproof coating to prevent local corrosion on the beach and If weather resistance can be added that allows the parts to be used without being exposed, the space available for buildings can be expanded, construction costs can be significantly reduced, and economic efficiency can be greatly improved.

Regarding the weather resistance, from the viewpoint of preventing local corrosion, Cr, which has been an element effective in weather resistance, has been used.
As a result of investigating the relationship with the local corrosion, as shown in FIG. 1, it was found that as the Cr addition amount increased, the corrosion plate thickness reduction amount increased almost uniquely. Incidentally, for reference, those without addition of Cu and Ni are also shown, but it can be seen that the corrosion is slightly reduced by the addition of Cr, but the corrosion amount is significantly increased as compared with the addition of Cu and Ni in appropriate amounts. .. Therefore, in order to obtain the conventional weather resistance without adding Cr, which is different from the conventional knowledge, Cu and Ni
Respectively 0.25 to 0.65%, 0.10 to 0.50
Inventing an epoch-making wire which, when contained in an amount of 0.1%, can prevent local corrosion even under severe exposure conditions such as beaches, is extremely hard to rust, and can prevent the progress of corrosion. Therefore, if the Cu and Ni contents are high values exceeding the above range, the weldability is significantly deteriorated and the toughness is deteriorated. Therefore, it is necessary to set the upper limits of the Cu and Ni contents to 0.65% and 0.50%, respectively. is there. In addition, the lower limits are 0.25% and 0.1, respectively, as the minimum amount for obtaining weather resistance.
It is necessary to contain 0%.

The Cu amount includes the Cu amount when Cu plating is applied to the wire surface. In the wire of the present invention, Cu is added to the wire core itself, and Cu plating is performed from the viewpoint of rust resistance / feedability and electric conductivity of the wire, and the total amount of both is the Cu amount. Furthermore, the welding wire of the present invention does not have to be added with the above-mentioned components only, and at the same time, the fire resistance performance at 600 ° C., the impact toughness assurance at room temperature and the weather resistance can be obtained without impairing the welding workability. (C + Si / 24 + Mn / 6 + Cu / 35 +, defined as an index
It is an essential requirement that the sum of Ni / 40 + V / 14 + Mo / 4) (hereinafter abbreviated as characteristic index) is in the range of 0.30 to 0.60%.

Next, the above V, Mo,
The reason for limiting the components other than B, Cu, and Ni will be described in detail. C is an element effective in increasing the room temperature strength and the fire resistance strength, and if less than 0.01%, it is difficult to secure the strength, so the lower limit is made 0.01%. Further, if it exceeds 0.12%, the sensitivity to hot cracking increases and the toughness deteriorates, so the upper limit is made 0.12%.

Si is an indispensable element as a main deoxidizing material. If it is less than 0.40%, deoxidizing is insufficient and welding defects such as blowholes are generated in the weld metal.
40%. Further, if it exceeds 1.00%, it causes the solid solution hardening of ferrite and lowers the toughness, so the upper limit is made 1.00%. Mn is a deoxidizing agent similar to Si and is an essential element for securing strength and toughness, and it is necessary to contain 1.00% as a minimum capable of securing strength and toughness, and the lower limit is 1 0.00%. On the other hand, 2.
If it exceeds 20%, the hot cracking susceptibility is increased and the toughness is deteriorated, so the upper limit is made 2.20%.

Ti forms a Ti oxide, refines the microstructure of the weld metal, and is effective in improving toughness.
If less than 05%, this effect cannot be expected, so the lower limit is 0.0
5% Further, if it exceeds 0.35%, the toughness is significantly impaired, so the upper limit is made 0.35%. N is generally contained in the wire as an unavoidable impurity,
If the amount of N is large, toughness is reduced and welding defects such as blowholes are generated in the weld metal, so the upper limit is made 0.0100%.

Since Al is an element generally contained in melting the wire, the lower limit of Al is not limited in the present invention. However, if the amount of Al increases, the cleanliness of the welded part deteriorates and the impact toughness of the welded part deteriorates, so the upper limit was made 0.020%. The wire of the present invention contains P and S as unavoidable impurities. Since the effects of P and S on high temperature strength are small, the amount thereof is not particularly limited, but generally segregates at the grain boundaries and oxidizes the grain boundaries, which causes a decrease in toughness. Is improved. Desirable amounts of P and S are each 0.020% or less.

[0025]

【Example】

(Example 1) Table 1 shows the chemical composition of the refractory steel sheet having excellent weather resistance used in the test, and Table 2 shows the chemical composition of the welding wire for refractory steel having excellent weather resistance used in the test. Table 2 with a plate thickness of 25 mm
After processing the fire-resistant steel plate having excellent weather resistance shown in Fig. 2 into the groove shape (T = 25 mm, D = 12 mm, φ = 45 °) shown in Fig. 2, the wire shown in Table 2 was used, and the welding conditions shown in Table 3 were used. Welded joints were manufactured in.

After the welding is completed, JIS is applied from the center of the plate thickness of the test material.
G 3111 A-1 tensile test piece and the same No. 4 Charpy test piece and high temperature tensile test piece are JIS G 0567.
A 10φ test piece was sampled and a mechanical test was performed. The test results are shown in Table 4. Wire symbols 1 to 10 are wires according to the present invention, which have excellent welding workability, excellent high-temperature strength, good impact toughness, a small amount of corrosion reduction in the welded portion, and sufficient weather resistance. On the other hand, wire symbols 11 to 2
3 is a wire outside the scope of the present invention, which is provided for comparison.

The wire symbol 11 is a wire for general 490 N / mm ² class high-strength steel currently used in the market and has good welding workability, but does not consider fire resistance characteristics. Therefore, the high temperature strength of 600 ° C. is low, the wire of the present invention cannot be used for the target structure, and the corrosion resistance is 10 times larger than that of the wire of the present invention because the weather resistance is only Cu plating of the wire. There is.

In the wire symbol 12, Ti is 0.02%, which is lower than that of the present invention, and the characteristic index is 0.67, which exceeds the range of the present invention.
It is 5%, which is a conventional wire for weather resistant fire resistant steel that does not consider local corrosion. Welding workability with this wire is slightly spattered, but arc stability is good, room temperature strength is extremely high at 841 N / mm ² , some hot cracks occur in the welded part, and corrosion amount is also It is about twice as much as the wire of the present invention. From this, in order to weld with peace of mind, even if each additive component to the wire is within the range of the present invention, the characteristic index is 0.30 within the range of the present invention.
Controlling the content to 0.60% is an important factor that balances the strength and toughness of the welded metal portion without impairing the welding workability, can prevent local corrosion, and can simultaneously obtain weather resistance and fire resistance. I understand.

The wire symbol 13 increases C to 0.15%, which exceeds the range of the present invention, for the purpose of improving strength, and Ni and C are added.
It is a wire that does not include u and does not consider weather resistance. Although the strength certainly shows a high value, some high temperature cracks have occurred in the welded portion, and the corrosion amount of the welded portion is also greater than that of the wire of the present invention because weather resistance performance is not considered, either, It is more than other comparison wires.

The wire symbol 14 mainly exceeds Ni in the range of 2.6 for the purpose of improving toughness and enhancing weatherability.
This is a wire in which 0% is added and Ti is not added. Surely, since a large amount of Ni, which affects the weather resistance, is added, the amount of corrosion is smaller than other comparative wires, and although it is a reference value, the toughness tends to be improved.
Since the amount was 0.39%, which is less than the range of the present invention, spatter was generated frequently and welding workability was remarkably poor, and minute blowholes were generated in the welded part due to insufficient deoxidation.

The wire symbol 15 is intended to improve the high temperature strength by adding Mo alone instead of adding no V, and at the same time, for imparting weather resistance, Cu and Ni are 0.20% and less than the range of the present invention, respectively. This wire contains 0.08% of Cr and 0.30% of Cr which exceeds the range of the present invention.
The toughness is almost a good value due to the addition of B, but the high temperature strength cannot be obtained by adding Mo alone, and the corrosion amount of the welded portion is as large as 0.112 mm.

Wire symbols 16 and 18 are inland weather resistant fire resistant steel wires to which Cr is added, which does not take local corrosion into consideration. In this wire, although each additive component is within the scope of the present invention, since Cr is added as described above,
Although the strength and toughness of the welded portion are good, the amount of corrosion is about 2-3 times as large as that of the wire of the present invention. Wire symbol 1
No. 7 is a wire in which C and Si are mainly increased to 0.14% and 1.12%, which exceed the range of the present invention, for the purpose of improving strength. However, although the strength is about the same as that of the wire symbol 11, there is a large defect that the toughness is greatly reduced and further hot cracking occurs in the welded portion. Further, since the weather resistance and the fire resistance are not taken into consideration, the high temperature strength is low and the corrosion amount is large like the wire symbol 11.

The wire symbol 19 has a content of Mo of 0.44% within the range of the present invention and has a C content of C in consideration of weather resistance in order to secure high temperature strength by adding Mo alone without adding V.
It is a wire containing a small amount of u. The high temperature strength is much lower than that of the wire of the present invention, the fire resistance is not secured, and Ni, which is an element for obtaining weather resistance, is not added,
Since Cu is also less than the range of the present invention, the corrosion amount of the welded portion is considerably large.

In the wire symbol 20, 0.15% of V exceeding the range of the present invention is added in consideration of the balance of strength and toughness,
This is a wire in which Si is 0.37%, which is less than the range of the present invention, Mn is also close to the lower limit of the range of the present invention, and 0.26% of Cr is added for the purpose of improving the conventional weather resistance. The room temperature strength is almost satisfactory, but since the amount of Si is less than the range of the present invention, minute blow holes are generated due to insufficient deoxidation during welding, and in addition, spatter frequently occurs and welding workability is also increased. Remarkably bad, and further, a V amount exceeding the range of the present invention caused some high temperature cracks in the initial layer. In addition, the amount of corrosion of the welded portion is increased due to the addition of Cr.

The wire symbol 21 is a wire for 0.5% Mo steel which is a heat-resistant steel currently used in the market.
2.44% in which n, B, and N each exceed the range of the present invention,
0.0079%, 0.0134%, characteristic index 0.6
It is 39%, which exceeds the range of the present invention, and the weather resistance is not considered at all. Although the welding workability is good, the strength is only slightly improved, the initial high temperature strength is not satisfied, and the weather resistance is not taken into consideration. Therefore, the corrosion amount is very large and is about 10 times that of the wire of the present invention. There is.

The wire symbol 22 is a wire for heat-resistant steel which is the same as the above-mentioned wire symbol 19, and is 1.25% Cr-0.5% Mo.
It is a wire for steel. The welded portion formed by this wire is premised on heat treatment after welding, and has high strength and low toughness when used as it is. Moreover, since this kind of wire has a special purpose, the wire unit price is very high, and it is impossible to supply the wire at an economical price. Furthermore, the amount of corrosion is also large from the viewpoint of weather resistance.

The wire symbol 23 is a wire in which Mo is increased to 0.74%, which exceeds the range of the present invention, and the characteristic index also slightly exceeds the range of the present invention, in order to secure the improvement in high temperature strength by adding Mo alone. Is. As a result, even if the characteristic index slightly exceeds the range of the present invention, the strength is considerably lower than that of the wire of the present invention, and it is not possible to sufficiently secure the fire resistance characteristics by adding Mo alone, and Ni that is an element for obtaining weather resistance performance is Without additives,
Since Cu is also far below the range of the present invention, the corrosion amount of the welded portion is also large. From this, it is understood that it is not only necessary to add various components but also that the characteristic index is within the range of the present invention.

As is clear from the above, the wire according to the present invention is excellent in welding workability, excellent in high temperature strength, good in impact toughness, can prevent local corrosion, and has conventional weatherability. While the welds that have enough can be obtained, the welds with the comparative wires have all the strengths that are too high or too low, or have defects such as a large amount of corrosion loss due to toughness deterioration and insufficient weather resistance, The comparative wire is unsuitable as a wire for refractory steel having excellent weather resistance. (Example 2) From the wires in Table 2, wire symbols 4, 1
Wires 0, 14, and 20 were selected, and welded joints were produced under the welding conditions shown in Table 5. After the completion of welding, various test pieces were sampled and mechanically tested in the same manner as in Example 1. The test results are shown in Table 6.

Since the wire symbols 14 and 20 have Si contents below the range of the present invention, blowholes were generated due to insufficient deoxidation in Example 1, but in this Example, the shield gas composition was Ar-20% CO 2. _{Since No. 2} is used, such a welding defect does not occur, but the yield of the weld metal such as Si and Mn is increased, and the strength is improved. But,
In the comparative example, since Cr is fundamentally added, the corrosion weight loss is large, and it is very difficult to simultaneously obtain the conventional weather resistance and fire resistance at the same time as local corrosion prevention at the beach where the wire of the present invention is intended. ..

Thus, the wire symbol 4 according to the present invention,
If it is 10, even if the shield gas composition is changed to an Ar—CO ₂ mixed gas and used, the welded joint having excellent fire resistance and excellent weather resistance can be obtained without affecting the performance.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

[0045]

[Table 5]

[0046]

[Table 6]

[0047]

As described above, according to the wire of the present invention, not only excellent high temperature strength and good impact toughness but also local corrosion on the beach are particularly excellent and sufficient conventional weather resistance is also provided. It is possible to obtain a welded portion or a welded joint having an epoch-making performance. Furthermore, the welding workability at the time of welding is good, and the cost for fireproofing the welded portion can be significantly reduced. Moreover, the wire of the present invention can be provided to the market at a low price, and the use of the wire of the present invention has a great effect that the construction is easy, the construction period can be shortened, and the construction cost is low as a whole. ..

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a Cr addition amount in a wire and a corrosion plate thickness reduction amount.

FIG. 2 is a front sectional view showing a groove shape used in Examples 1 and 2.

Claims (2)

[Claims] 1. By weight ratio, C: 0.01 to 0.12% Si: 0.40 to 1.00% Mn: 1.00 to 2.20% Cu: 0.25 to 0.65% Ni : 0.10 to 0.50% Mo: 0.05 to 0.60% Ti: 0.05 to 0.35% V: 0.004 to 0.10% N: 0.0100% or less is contained, (C + Si / 24 + Mn / 6 + Cu / 35 + Ni / 40
+ V / 14 + Mo / 4) is 0.30 to 0.60%, and the balance is composed of iron and unavoidable impurities. A welding wire for refractory steel excellent in weather resistance. 2. By weight ratio, C: 0.01 to 0.12% Si: 0.40 to 1.00% Mn: 1.00 to 2.20% Cu: 0.25 to 0.65% Ni : 0.10 to 0.50% Mo: 0.05 to 0.60% Ti: 0.05 to 0.35% V: 0.004 to 0.10% N: 0.0100% or less is contained, (C + Si / 24 + Mn / 6 + Cu / 35 + Ni / 40
+ V / 14 + Mo / 4) is 0.30 to 0.60%, and further, B: 0.002 to 0.0070%, Al: 0.020% or less, and one or two types are contained, and the balance is Welding wire for refractory steel with excellent weather resistance, which is composed of iron and inevitable impurities.