JP2004090044A - Coated electrode for low alloy steel welding having excellent resistance to sulfuric acid and hydrochloric acid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated electrode which is used for welding a low alloy steel by arc welding, has excellent resistance to sulfuric acid and hydrochloric acid, can yield a weld metal having excellent resistance to sulfuric acid and hydrochloric acid, and can keep satisfactory weldability. <P>SOLUTION: The coated electrode is obtained by coating coating material on a steel core wire and exhibits excellent resistance to sulfuric acid and hydrochloric acid. The coated electrode contains, by mass% of the total mass of electrode, 0.005 to 0.15 % C, 0.5 to 4 % Si, 0.2 to 2.4 % Mn, 0.1 to 1.2 % Cu, 0.1 to 0.6 % Ni, 0.02 to 0.25 % Sb, ≤0.03% P, ≤0.03% S and the balance Fe and inevitable impurities in either one of the steel core wire or the coating flux or both of those. <P>COPYRIGHT: (C)2004,JPO

Description

【００３３】
【表２】

【００３４】
【表３】

【００３５】
耐食性試験に使用した試験片は、図１に示すように作成した。すなわち、母材成分の影響を受けないように。軟鋼母材３上に交流溶接機を用い電流１７０Ａを使用し、９層で盛上げ部４を形成し、５層目からの溶着金属２を機械加工で試験片１（４ｍｍ×２５ｍｍ×２５ｍｍ）を各４個採取した。腐食試験は、４０℃の２０％硫酸で２４時間、及び８０℃の１０％塩酸で２４時間の浸食腐食試験を行い、各試験片４個の平均腐食減量を求め、共に２．５ｍｇ／（ｃｍ^２・ｈｒ）以下を良好、２．５〜１０ｍｇ／（ｃｍ^２・ｈｒ）をやや劣る、１１ｍｇ／（ｃｍ^２・ｈｒ）以上を劣る、とした。
【００３６】
溶接作業性の調査では、板厚１２ｍｍ、幅１００ｍｍ、長さ４５０ｍｍの軟鋼をＴ型に組み、交流溶接機を用い、水平隅肉では電流１７０Ａ、立向姿勢では１５０Ａを使用して溶接作業を行ない、アーク状態、スラグ状態、スパッタの多少、ビード形状などを調査した。その判定は、各姿勢の評価を総合判定し、良好を○印、やや劣るを△印、劣るを×とした。
【００３７】
その試験結果を表４に示す。
【００３８】
【表４】

【００３９】
溶接棒Ｎｏ．１〜Ｎｏ．１７は、本発明例であり、特に、溶接棒Ｎｏ．１〜Ｎｏ．１５は、各要件が全て適正であるので耐硫酸及び耐塩酸での腐食減量が少なく良好な結果であり、溶接作業性も満足できるものであった。これらにくらべてＮｏ．１６、１７は、溶接金属の十分良好な耐食性が得られたものの、Ｎｏ．１６では、炭酸石灰の添加量が多いため良好なアーク状態が得られず溶接作業性がやや悪くなり、Ｎｏ．１７では、炭酸石灰が少ないのでアーク力が弱く溶接作業性がやや劣化した。
【００４０】
溶接棒Ｎｏ．１８〜Ｎｏ．２６は、比較例であり、Ｎｏ．１８とＮｏ．１９は、Ｓｂの平均粒径が適正でない場合であり、Ｎｏ．１８は、Ｓｂの平均粒径が小さいのでスラグの粘性が低下し立向姿勢で溶接金属が垂れ易くなり凸ビードとなり、Ｃｕが少ないので腐食し易くなった。また、Ｎｏ．１９は、Ｓｂの平均粒径が大き過ぎることとＮｉが添加されないので耐食性がやや悪くなった。
【００４１】
Ｎｏ．２０は、蛍石が多いのでスラグ剥離性が悪く、溶接棒全体のＣが多いので耐食性の劣化を招いた。
【００４２】
Ｎｏ．２１は、Ｓｉが少ないので溶接作業性が悪く、Ｓが多すぎるので硫酸での耐食性が悪くなった。また、Ｃｕが多すぎるので、耐割れ性が劣化した。
【００４３】
Ｎｏ．２２、Ｎｏ．２４〜Ｎｏ．２７は、溶接棒全体のＳｂが不足または添加されないため、耐硫酸性と耐塩酸性が悪い例である。Ｎｏ．２２は、Ｍｎが多いのでスラグの粘性が低下し立向姿勢でビードが垂れ易くなり溶接作業性の劣化を招いた。
【００４４】
Ｎｏ．２５とＮｏ．２６は、従来の溶接棒であるがＮｉも添加されないので腐食され易くなった。
【００４５】
Ｎｏ．２３は、蛍石が少なくＳｉが多いのでアーク力が強くなりスパッタの飛散が増加し、Ｐが過剰に多いので耐硫酸性と耐塩酸性が悪くなった。
【００４６】
【発明の効果】
本発明は、以上詳述したように、極めて優れた耐硫酸性と耐塩酸性を有した溶接棒を容易にかつ安価に提供することが可能で、その産業上の価値は極めて高い。
【図面の簡単な説明】
【図１】（Ａ）腐食試験片の採取要領を説明する図。（Ｂ）（Ａ）のａ−ａ´断面図。
【符号の説明】
１…溶着金属の腐食試験片
２…溶着金属
３…母材
４…盛上げ（９層）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sulfuric acid-resistant dew-point corrosion-resistant low-alloy steel exhibiting excellent corrosion resistance in an atmosphere such as a flue of a coal-fired boiler or a refuse incineration facility where low-temperature corrosion is caused by sulfuric acid and hydrochloric acid like a chimney, that is, in a concentrated sulfuric acid and hydrochloric acid environment. And a welding rod for arc welding. Also, the present invention relates to a welding rod used for arc welding of steel having excellent acid resistance for use in a steel plating pickling tank containing a single or mixed pickling solution such as hydrochloric acid and sulfuric acid.
[0002]
[Prior art]
Generally, when a welded structure is used in a corrosive environment, if there is a difference in the corrosion resistance between the welded portion and the base material, the one having poor corrosion resistance is selectively corroded, and the life of the structure is significantly shortened. Further, when the welded portion is selectively corroded, stress concentration occurs in the corroded hole, and in extreme cases, there is a possibility that the structure is destroyed. As described above, in the use of a welded structure, in the case of an application where corrosion deterioration cannot be ignored, it is necessary to sufficiently secure not only the base material but also the corrosion resistance of the welded portion.
[0003]
In flue gas facilities such as stacks and chimneys such as coal-fired thermal power and refuse incineration facilities, sulfuric acid dew point corrosion and hydrochloric acid dew point corrosion occur due to sulfur trioxide and hydrogen chloride in exhaust gas.
[0004]
Existing welding rods for corrosion-resistant steel are systems containing Cu alone or containing Cu-Cr, which have sufficiently excellent corrosion resistance in a sulfuric acid dew point corrosion environment generated in a plant flue gas exhaust system of a heavy oil boiler. However, in a coal-fired boiler, refuse incineration or refuse gasification and melting facility, sulfuric acid dew-point corrosion and hydrochloric acid dew-point corrosion occur at the same time.
[0005]
Further, as an example of improving corrosion resistance, it has been proposed to include Cu and Sb in a weld metal (see, for example, Japanese Patent Publication No. 43-1380). It was not satisfactory.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems of the prior art, and provides a weld metal having excellent sulfuric acid resistance and hydrochloric acid resistance, and a low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance capable of securing good welding workability. It is an object of the present invention to provide a coated arc welding rod for arc welding.
[0007]
[Means for Solving the Problems]
The present inventors have studied in detail the metallurgical factors affecting the sulfuric acid dew point corrosion resistance and the hydrochloric acid dew point corrosion resistance of the weld metal, and identified the composition of the entire welding rod formed by coating a steel core wire with a coating agent. By doing so, it has been found that a weld metal having excellent corrosion resistance can be obtained. That is, first, P and S, which are impurities of the welding rod, are limited, and (1) By using a specific C-Si-Cu-Ni-Sb system, a sulfuric acid resistant and hydrochloric acid resistant weld metal can be obtained. Can be (2) Sulfuric acid resistance and hydrochloric acid resistance are further improved by defining S in the component system of (1). (3) When Mo is added in the component system (1) or (2), the hydrochloric acid resistance can be remarkably improved. (4) When Cr is added to the component system (3), the high-concentration sulfuric acid resistance in an oxidizing atmosphere can be improved. (5) By defining the content of the metal carbonate, metal fluoride and metal oxide in the coating material in the component system of (2) or (3), good welding workability can be secured. (6) In the component system according to any one of the above (1) to (5), Sb is contained in the coating agent, and by limiting the average particle size of the Sb, excellent corrosion resistance is ensured while ensuring good welding. Is obtained. The present invention has been completed based on these findings, and the gist thereof is as follows.
(1) In a coated arc welding rod obtained by coating and coating a steel core wire, in one or both of the steel core wire and the coating agent, the mass% with respect to the total mass of the welding rod is
C: 0.005 to 0.15%,
Si: 0.5-4%,
Mn: 0.2-2.4%,
Cu: 0.1 to 1.2%,
Ni: 0.1 to 0.6%,
Sb: 0.02 to 0.25
Containing
Further, P: 0.03% or less,
S: A coated arc welding rod for low alloy steel welding excellent in sulfuric acid resistance and hydrochloric acid resistance, characterized in that the content is limited to 0.03% or less and the balance is Fe and inevitable impurities.
(2) In mass% based on the total mass of the welding rod, in one or both of the steel core wire and the coating agent,
S: 0.005 to 0.02%
The coated arc welding rod for welding low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance according to (1), characterized by containing (1).
(3) In one or both of the steel core wire and the coating agent, in mass% based on the total mass of the welding rod,
Mo: 0.01 to 0.6%
The coated arc welding rod for welding low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance according to (1) or (2), characterized by containing:
(4) In mass% based on the total mass of the welding rod, one or both of the steel core wire and the coating agent,
Cr: 0.1 to 1.7%
The coated arc welding rod for welding low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance according to any one of (1) to (3), characterized by containing:
(5) In the coating agent in mass% based on the total mass of the coating agent,
Metal carbonate: 35-55%,
Metal fluoride: 13 to 30%,
Metal oxide: 0.5 to 15%
The coated arc welding rod for welding low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance according to any one of (1) to (4), characterized by containing:
(6) The low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance according to any one of (1) to (5), wherein the average particle size of Sb in the coating agent is 45 to 150 μm. Covered arc welding rod for welding.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The coated arc welding rod of the present invention is obtained by coating a steel core wire with a coating agent.Each element for obtaining a weld metal having required characteristics is obtained from any of a steel core wire and a coating agent. It may be added. Accordingly, in the following description, unless otherwise specified, each component element may be contained as a whole of the welding rod in one or both of the steel core wire and the coating agent.
[0009]
First, the regulation of the contents of C, Si, Mn, P, S, Cu, Ni, and Sb with respect to the total mass of the welding rod will be described.
In the present invention, C does not include the metal carbonate in the coating agent or the C content of CO or CO ₂ of organic matter, and C in the coating material, for example, SiC, Fe—Mn, and Fe—Si, and C in the steel core wire. C is added to secure the strength of the weld metal, but if the total amount exceeds 0.15%, the crack resistance and sulfuric acid resistance of the weld metal decrease. From the viewpoints of sulfuric acid resistance and hydrochloric acid resistance, the content of C is preferably as small as possible. However, if it is less than 0.005%, the arc force is weak, the penetration is insufficient, and the welding workability deteriorates. And When it is necessary to consider the balance between the sulfuric acid resistance and the hydrochloric acid resistance, the content is most preferably 0.05% or less.
[0010]
When Si is contained in an amount of 0.5% or more, it coexists with Cu and improves the sulfuric acid resistance and hydrochloric acid resistance of the weld metal particularly in a sulfuric acid concentration region of about 40%. However, if it exceeds 4%, no improvement in corrosion resistance is observed, the toughness of the weld metal is significantly reduced, the arc force becomes excessively strong, and the welding workability is degraded, so the upper limit was made 4%. When more emphasis is placed on welding workability and toughness of a weld metal, 0.5 to 2% is preferable. When Si is added from the coating agent, Fe-Si is used.
[0011]
Mn is added to the entire welding rod in an amount of 0.2% or more to deoxidize the weld metal and adjust the strength. However, if it exceeds 2.4%, the viscosity of the slag is reduced, and the bead in the vertical position is liable to drop. Since the workability deteriorates, the limited range is 0.2 to 2.4%. When Mn is added from a coating agent, metal Mn or Fe-Mn is used.
[0012]
P is an impurity element and significantly impairs the sulfuric acid resistance and hydrochloric acid resistance of the weld metal, so the range is set to 0.03% or less. More preferably, when the content is 0.01% or less, the sulfuric acid resistance and the hydrochloric acid resistance are remarkably improved, and the content is most preferably 0.005% or less.
[0013]
S is an impurity element and needs to be limited to ensure sufficient sulfuric acid resistance and hydrochloric acid resistance of the weld metal. If it exceeds 0.03%, the sulfuric acid resistance is significantly reduced, so the upper limit was made 0.03%.
[0014]
In a Cu-Mo-Sb-based welding rod, when S is contained in an amount of 0.005% or more, the sulfuric acid corrosion resistance of the weld metal and the hydrochloric acid resistance are significantly improved. However, if the content exceeds 0.02%, the effect is saturated, and the mechanical properties (lamellar tear resistance and the like) and the hot workability are reduced. It is preferably set to 02%.
[0015]
In order to secure the sulfuric acid resistance and the hydrochloric acid resistance of the weld metal, Cu must be added in an amount of 0.1% or more. Even if added in excess of 1.2%, the corrosion resistance is almost saturated and the crack resistance of the weld metal is degraded, so the range of 0.1 to 1.2% was made the limited range. Preferably, addition of 0.25 to 0.75% is most excellent. When adding Cu from the coating agent, metal Cu is used.
[0016]
Ni is an essential element added in an amount of 0.1% or more for the purpose of improving the hydrochloric acid resistance of the weld metal and preventing surface cracks at the time of solidification of the weld metal caused by addition of Cu or Sb. However, since the effects are saturated even if they are added, the range is limited to 0.1 to 0.6%. The range of 0.1% to Cu% × 0.5 is preferable. When Ni is added from the coating agent, Fe—Ni or metallic Ni is used.
[0017]
Sb is an element that coexists with Cu to further improve the sulfuric acid resistance and hydrochloric acid resistance of the weld metal. If it is less than 0.02%, good corrosion resistance cannot be obtained, and if it exceeds 0.25%, the arc state is degraded and the viscosity of the slag is too low, so that the weld metal is liable to hang in a standing posture and exhibit a convex bead.
[0018]
When Sb is added from the coating agent, metal Sb is used, but the average particle size is also important. If it is less than 45 μm, the viscosity of the slag decreases, and particularly, it becomes easy to become a convex bead in the vertical position. If it exceeds, segregation in the coating agent becomes a problem, and the amount of Sb in the weld metal is not stabilized, and the corrosion resistance is hindered. Therefore, in order to obtain better welding workability and better corrosion resistance, it is preferable to limit the average particle size of Sb in the coating agent to the range of 45 to 150 μm.
[0019]
Mo is an element that, when added together with Cu, in an amount of 0.01% or more based on the total mass of the welding rod, significantly improves the hydrochloric acid resistance of the weld metal, and is added as necessary. The effect is further enhanced by the complex addition with Cu-Sb. If the content exceeds 0.6%, the sulfuric acid resistance and the hydrochloric acid resistance decrease, so the content was limited to 0.01 to 0.6% based on the total weight of the welding rod. When Mo is added from the coating agent, metal Mo or Fe-Mo is used.
[0020]
Cr is 0.1% or more based on the total mass of the welding rod, if necessary, in order to ensure corrosion resistance in an oxidizing sulfuric acid dew-point corrosion environment that occurs especially in plants with a high sulfur oxide content in exhaust gas. If it is added in excess of 1.7%, the corrosion resistance is adversely affected.
[0021]
On the other hand, when Cr is added in an amount of 0.1% or more, it is an element that inhibits hydrochloric acid resistance. If the environment is not an oxidizing sulfuric acid dew-point corrosion environment, Cr is not added, that is, less than 0.1%. When Cr is added from the coating agent, metallic Cr or Fe-Cr is used.
[0022]
Although not a limitation of the present invention, elements of Al, Ti, Nb, V, Ta, W, Sn, REM, and Ca may be added to the entire welding rod as needed.
[0023]
Sn does not inhibit sulfuric acid dew point corrosion resistance and hydrochloric acid dew point corrosion resistance even if added or contained as an unavoidable impurity. However, if it exceeds 0.05%, the toughness of the welded joint is significantly reduced. , 0.05% or less.
[0024]
The steel core wire used in the present invention has a C content of 0.08% or less, a Si content of 0.03% or less, a Mn of 0.20 to 0.60%, and a P in order to obtain good welding performance and corrosion resistance. Is preferably 0.035% or less, and S is preferably 0.040% or less.
[0025]
Next, the reasons for limiting the amounts of metal carbonate, metal fluoride and metal oxide in the coating agent will be described. Metal carbonates are lime carbonate, barium carbonate, magnesium carbonate, etc., and are the main raw materials used to generate CO ₂ gas during welding to cut off nitrogen, oxygen and hydrogen from the atmosphere to obtain a healthy weld metal. It is. If it is less than 35%, its function cannot be exhibited, and if it exceeds 55%, the arc state and bead shape are deteriorated, and welding workability is deteriorated.
[0026]
Therefore, the content of the metal carbonate in the coating agent is preferably set to 35 to 55%.
[0027]
Metal fluorides are fluorite, cryolite, barium fluoride, etc., which secure good fluidity of slag and are added as a main component together with metal carbonate. If less than 13%, the function is not satisfied, and 30% is not fulfilled. If it exceeds, the slag removability deteriorates and the bead shape also deteriorates. Therefore, the content of the metal fluoride in the coating agent is preferably 13 to 30%.
[0028]
The metal oxide is SiO ₂ , TiO ₂ , Na ₂ O, K ₂ O, Al ₂ O _3, etc. In order to maintain the arc state and the slag state at the time of welding well, one or two metal oxides are contained in the coating agent. It is preferred to add in a combination of more than one species. If their total content is less than 0.5%, the arc stability and the slag state cannot be maintained satisfactorily. On the other hand, if they exceed 15%, the oxygen in the molten metal increases and the toughness decreases.
[0029]
Therefore, the content of the metal fluoride in the coating agent is preferably 0.5 to 15%.
[0030]
The welding rod of the present invention melts a steel having a required composition, and then rolls it while hot or cold to form a steel core wire having a required diameter by processing such as drawing, and then coating the coating with a coating agent. It can be dried to obtain a coated arc welding rod.
[0031]
【Example】
The present invention will be described in more detail by way of examples. A steel core wire (diameter: 4.0 mm, length: 400 mm) having the composition shown in Table 1 was coated with a coating agent having the composition shown in Table 2 and dried, and 26 types of compositions shown in Table 3 (continued in Table 2) were obtained. We created a welding rod. Using this welding rod, multi-layer welding was performed under the following test conditions, a test piece was sampled, and a corrosion resistance test of sulfuric acid and hydrochloric acid of the deposited metal and a welding workability investigation were performed, and a comprehensive judgment was made.
[0032]
[Table 1]

[0033]
[Table 2]

[0034]
[Table 3]

[0035]
The test piece used for the corrosion resistance test was prepared as shown in FIG. That is, it is not affected by the base metal component. Using a current of 170 A using an alternating current welding machine on a mild steel base material 3, a raised portion 4 is formed in nine layers, and a welded metal 2 from the fifth layer is machined into a test piece 1 (4 mm × 25 mm × 25 mm). Four of each were collected. In the corrosion test, an erosion corrosion test was performed for 24 hours with 20% sulfuric acid at 40 ° C. and for 24 hours with 10% hydrochloric acid at 80 ° C., and the average corrosion weight loss of four test pieces was determined. ² · hr) or less was good, 2.5 to 10 mg / (cm ² · hr) was slightly poor, and 11 mg / (cm ² · hr) or more was poor.
[0036]
In the study of welding workability, mild steel with a thickness of 12 mm, a width of 100 mm, and a length of 450 mm was assembled in a T-shape, using an AC welding machine, and using a current of 170 A in the horizontal fillet and 150 A in the vertical position. Then, the arc state, the slag state, the degree of spatter, and the bead shape were examined. For the determination, the evaluation of each posture was comprehensively determined, and a good mark was indicated by a circle, a slightly poor mark was indicated by a mark, and a poor mark was indicated by a cross.
[0037]
Table 4 shows the test results.
[0038]
[Table 4]

[0039]
Welding rod No. 1 to No. No. 17 is an example of the present invention. 1 to No. In No. 15, all the requirements were appropriate, and the corrosion loss in sulfuric acid resistance and hydrochloric acid resistance was small and good results were obtained, and the welding workability was also satisfactory. No. compared to these. Nos. 16 and 17 showed that the weld metal had sufficiently good corrosion resistance. In No. 16, since a large amount of carbonated lime was added, a good arc state was not obtained, and the welding workability was slightly deteriorated. In No. 17, since the amount of carbonated lime was small, the arc force was weak and the welding workability was slightly deteriorated.
[0040]
Welding rod No. 18-No. No. 26 is a comparative example. 18 and no. No. 19 is a case where the average particle size of Sb is not appropriate. In No. 18, because the average particle size of Sb was small, the viscosity of the slag was reduced, the weld metal was easily drooped in a vertical position, and became a convex bead. No. In No. 19, the average particle size of Sb was too large and Ni was not added, so that the corrosion resistance was slightly deteriorated.
[0041]
No. In No. 20, the slag peeling property was poor due to the large amount of fluorite, and the corrosion resistance was degraded due to the large C in the entire welding rod.
[0042]
No. In No. 21, the welding workability was poor because of a small amount of Si, and the corrosion resistance with sulfuric acid was poor because of too much S. In addition, since there was too much Cu, the crack resistance was deteriorated.
[0043]
No. 22, no. 24-No. No. 27 is an example in which sulfuric acid resistance and hydrochloric acid resistance are poor because Sb of the entire welding rod is insufficient or not added. No. Sample No. 22 had a large Mn content, so that the viscosity of the slag was lowered, and the beads were easily drooped in the upright posture, resulting in deterioration in welding workability.
[0044]
No. 25 and no. 26 is a conventional welding rod, but was not easily added because Ni was not added.
[0045]
No. In No. 23, the amount of fluorite was small and the amount of Si was large, so that the arc force was increased and the scattering of spatter was increased, and the sulfur content and hydrochloric acid resistance were deteriorated due to excessive P.
[0046]
【The invention's effect】
INDUSTRIAL APPLICABILITY As described in detail above, the present invention can easily and inexpensively provide a welding rod having extremely excellent sulfuric acid resistance and hydrochloric acid resistance, and its industrial value is extremely high.
[Brief description of the drawings]
FIG. 1A is a diagram illustrating a procedure for collecting a corrosion test piece. (B) Aa 'sectional drawing of (A).
[Explanation of symbols]
1: Corrosion test piece of deposited metal 2: Deposited metal 3: Base metal 4: Raised (9 layers)

Claims (6)

In a coated arc welding rod obtained by coating a steel core wire with a coating agent, in one or both of the steel core wire and the coating agent, by mass% based on the total weight of the welding rod,
C: 0.005 to 0.15%,
Si: 0.5-4%,
Mn: 0.2-2.4%,
Cu: 0.1 to 1.2%,
Ni: 0.1 to 0.6%,
Sb: 0.02 to 0.25
Containing
And P: 0.03% or less,
S: A coated arc welding rod for welding low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance, which is limited to 0.03% or less, with the balance being Fe and inevitable impurities. In mass% based on the total weight of the welding rod, in one or both of the steel core wire and the coating material,
S: 0.005 to 0.02%
The coated arc welding rod for welding low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance according to claim 1, characterized by comprising: In% by mass based on the total mass of the welding rod, in one or both of the steel core wire and the coating material,
Mo: 0.01 to 0.6%
The coated arc welding rod for welding low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance according to claim 1 or 2, characterized by comprising: In% by mass based on the total mass of the welding rod, in one or both of the steel core wire and the coating material,
Cr: 0.1 to 1.7%
The coated arc welding rod for welding low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance according to any one of claims 1 to 3, characterized by comprising: In% by mass based on the total mass of the coating agent,
Metal carbonate: 35-55%,
Metal fluoride: 13 to 30%,
Metal oxide: 0.5 to 15%
The coated arc welding rod for welding low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance according to any one of claims 1 to 4, characterized in that: The coated arc for welding low alloy steel excellent in sulfuric acid resistance and hydrochloric acid resistance according to any one of claims 1 to 5, wherein the average particle size of Sb in the coating agent is 45 to 150 µm. Welding rods.

Images