JPH02263596A - Coated electrode - Google Patents

Abstract

PURPOSE:To improve welding efficiency without using particularly a high current by coating the coated electrode with a coating material having a specific chemical compsn. CONSTITUTION:The coated electrode is formed by coating the circumference of a carbon steel core rod which is limited in chemical compsn., by weight %, to 0.035 to 0.10% Si, <=0.003% Al, <=0.008% N, and 0.001 to 0.0095% O, with the coating material for non- and low-hydrogen type electrodes consisting of 10 to 32% TiO2, 8 to 30% SiO2, 0.5 to 8% Al2O3, 2 to 16% Mn, 3 to 25% metal carbonate, <=8% org. matter, 1 to 37% iron in the iron alloy as Fe, and the balance the oxide, metals and unavoidable impurities, exclusive of the above- mentioned elements. Namely, the welding speed of the electrode is increased and the working efficiency is greatly improved by increasing the Si of the core wire to be used, lowering the ratio of the Al as far as possible and limiting N and O to limit the coating material.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a coated arc welding rod used for welding in all sectors such as shipbuilding, construction, and bridge construction. This invention relates to coated arc welding rods for obtaining metals.

(Conventional technology) Even in the welding industry where automation and semi-automation are progressing, there is still strong demand for welding rods due to their ease of use, but they have the disadvantage of slow welding speed compared to automatic welding methods. ing. A variety of studies are being carried out in the industry in a desire to eliminate these drawbacks as much as possible.

For example, "Welding arc phenomenon" (Sanpo, July 1960)
Page 314 (first published on May 15th) describes the relationship between melting rate and core #i species, but the melting rate is greatly influenced by the coating material, and no means to significantly improve the melting rate are described. do not have.

Furthermore, Japanese Patent Publication No. 60-39479 discloses that the molar ratio of water glass in a high cellulose welding rod can be limited to prevent burnout and improve welding efficiency.
According to what the inventors have confirmed with non-low hydrogen welding rods, fillet welding rods, and low hydrogen welding rods, using water glass with a Hatake molar ratio provides better coverage than using low molar ratio water glass. This is an unfavorable result because the surface dries quickly, which impedes productivity.

Furthermore, Japanese Patent Publication No. 62-16754 discloses that the O% Al and N content of the core wire is limited to improve stick burn resistance, and the welding properties are improved by using a current 20 to 30 times higher than that of conventional welding rods. Methods to improve efficiency have been shown, but with non-low hydrogen welding rods and low hydrogen welding rods, using too high a current in vertical welding causes dripping of molten metal, and self-fusion # It has been pointed out that C Seri has shortcomings such as 7-ng cut being more likely to occur, which has become a problem.

(Problems to be Solved by the Invention) As mentioned above, although coated arc welding rods are easier to use than automatic welding methods, they have a problem with welding speed, so the industry aims to improve welding efficiency. Therefore, there was a strong demand for the development of a coated arc welding rod that would eliminate this drawback.

The present invention improves the welding speed, which is a problem with conventional welding rods, and
In particular, a coated arc welding rod with improved welding efficiency without using high current is provided.

(Means for solving problems) The present invention is the following coated arc welding rod.

(1) Si: 0.035-0.10%, Al: 0
, 003% or less, N: 0.008% or less, 0: 0.001-0.0095%, Tio2: 10-32%, SiO2: 8-30%, Al2O: 0.5 to 8%, Mn: 2 to 16%, metal carbonate: 3 to 25%, amount of organic matter 8% or less, iron content in iron alloy as Fe: 1 to 37%, balance other than above. A coated arc welding rod characterized in that it is coated with a non-low hydrogen welding rod coating consisting of oxides, metals, and inevitable impurities.

(2) Si: 0.035-0.10%, At: 0
, 003% or less, N: 0.008% or less, 0: 0.001~0.0095% around the carbon steel core wire, TiO2: 10% or less, Sin: 15~35%, A1 O,: 0.5 to 8%, Mn: 2 to 16%, Metal carbonate: 9% or less, Organic matter: 8% or less, Iron content in iron alloy: 38 to 55%, remainder oxidation other than the above. 1. A coated arc welding rod characterized in that it is coated with a fillet welding rod coating agent consisting of materials, metals, and unavoidable impurities.

(3) Si: 0,035-0.10%, Al: 0
．． 003% or less, N: 0,008% or less, o: o, oot ~ 0.0095%. 1.0: 6% or less, Si: 3-15%, Mn: 8% or less, Metal carbonate: 21-56%, Metal fluoride: 2-23%, Organic matter: 2% or less, In iron alloy A coated arc welding rod characterized in that it is coated with a low-hydrogen coating for welding rods, the iron content being Fe: 5 to 50%, the balance being oxides other than those mentioned above, metals, and unavoidable impurities.

Note that the carbon steel core wire in the present invention refers to Si, A1, N
, chemical components other than O comply with JIS G3523.

(Function) In view of the above-mentioned situation, the present inventors have been conducting intensive research on improving the welding speed of coated arc welding rods, mainly from the perspective of the core wire. As a result, the Si of the core wire used was
By increasing the amount of Al compared to that shown in Publication No. 2-16754, keeping the amount of Al as low as possible, limiting N and ○, and limiting the coating material, the welding speed of the welding rod is increased and work efficiency is increased. The present invention was made based on the knowledge that the welding rod is significantly improved over conventional welding rods.

The present invention will be explained in detail below.

The welding rod of the present invention is based on the following test results.

That is, in the steelmaking process, C0.05 to 0.09%,
As shown in Table 1, Mn0.51-0.65% contains Si,
Carbon steel core wires were prepared using various combinations of Al, N, and O, and the following welding rods 1 to 2 were prepared.

■Diameter 4Is length 450ml11 drawn, cut core wire with TiO219.8%, 5I0219.1%, A I
20.3.2%, Mn8.2%, CaCOdo, 5%,
4.1% organic matter, FC20.3% in iron alloy, 6.4% iron oxide as FeO, 1.1% Mn oxide as MnO, N 1120 as other components,
A coating agent for non-low hydrogen welding rods consisting of 7.3% of K to, M go, etc. was coated on each of the above carbon steel core wires so that the coating rate was about 29%, and the coating was applied at a maximum temperature of 170°C.
A welding rod was prepared by drying at ℃.

■Tio, 8.1%, Sio, 25.9% on the core wire drawn and cut to a diameter of 5 mm and a length of 700a+m
, A I20 *3.9%, Mn7.3%, CaCO3
2.3%, organic matter 0.4%, iron content in the iron alloy as Fe 46.3%, other components as Na20-K
A coating agent for fillet welding rods consisting of 5.8%, such as -01M no. A welding rod was prepared using the following steps.

■Diameter 4mm%, length 400mm drawn, cut core wire Tio 23.2%, Si○27.9%, A1□0
．． 0.4%, Si6.5%, Mn2.3%, CaCO
340.5%, BaC0°3.1%, CaF 214,
2%, organic matter 0.2%, iron content in iron alloy 1
4.6%, other components include Na2Q, K,
A low-hydrogen welding rod coating agent consisting of 7.1% O, etc. is applied to each carbon steel core wire to a coating rate of approximately 30%, and then dried at a maximum temperature of 400°C to produce a welding rod. did.

Using each of the obtained test welding rods, JIS2318
Based on the welding rate measurement method for 2-coated 7-layer welding rods, the first
Steel plate 1 ((A) 100a+m, (
B) 450a+m and (c) 12.7a+n) were welded using an AC welder at 180A for the non-low hydrogen welding rod, 210A for the fillet welding rod, and 180A for the low hydrogen welding rod, and welded the bead. 2 was prepared and the welding speed was measured.

The results are shown in Figures 2 to 4, and it was confirmed that the amount of Si in particular had the greatest effect on improving the welding speed. In other words, by adding an appropriate amount of Si to the core wire, the specific resistance of the core wire increases and the core wire temperature rises during welding, which increases the melting speed of the core wire and therefore the melting speed of the welding rod itself. 6 If A1, N, and O are within the specified range, the amount of Si will be 0.035%.
If it is less than 0.10%, the welding speed will not be sufficiently improved, and if it exceeds 0.10%, the specific resistance of the core wire will be excessive, the core wire will overheat during welding, and the coating material will change in quality. This phenomenon occurs and it becomes impossible to obtain sound weld metal.

When A1 exceeds 0.003%, spatter increases, the arc becomes unstable, and the welding speed decreases. N is 0.0
If it exceeds 0.8%, the toughness of the weld metal will be reduced and blowholes will be more likely to occur. Furthermore, 0 is 0.001%
If it is less than 0.0095%, the pitting resistance will be poor, and if it exceeds 0.0095%, blowholes in the horizontal fillet bead will increase and spatter will increase, reducing the welding speed. The contents of Si, AlN, and 0 were determined as described above.

In addition, in order to investigate the relationship between the core wire composition and coating material in more detail, we investigated the proportions of non-low hydrogen welding rods, fillet welding rods, and low hydrogen welding rods by varying the ratio. Low hydrogen welding rods include TiO210~32Kudzu, S
i O28-30%, A Lo 0.5-8%, M
n2 to 16%, metal carbonate 3 to 25%, organic matter 8% or less, iron content in the iron alloy as Fe within the range of 1 to 37%, fillet welding rod TiozlO% or less, Si○215-3
5%, Al□0.0.5-8%, Mn2-16%, metal carbonate 9% or less, organic matter 8% or less, iron content in iron alloy F
e is within the range of 38 to 55%, and T for low hydrogen welding rods.
i O*, 10% or less, Si025-19%, A L
o, 6% or less, 5i3-15%, Mn 8% or less,
If the metal carbonate is 21-56%, the metal fluoride is 2-23%, the organic matter is 2% or less, and the iron content in the iron alloy is within the range of 5-50% as Fe, the welding speed of any welding rod can be improved. I confirmed that I would get it.

The coating material used in the coating composition includes TiO□ sources such as rutile, synthetic rutile, and illuminite; SiO2 sources such as silica sand, talc, and sodium silicate; and A1□O1 sources such as mica, potassium feldspar, and alumina. Metal carbonates include lime carbonate, dolomite, and magnesium carbonate; metal fluorides include fluorite and cryolite; Mn sources include Fe-Mn and metal manganese; organic substances include cellulose, starch, dexF phosphorus, and alginate. As iron content in iron alloys, iron powder, Fe-Mn, F
Fe Si as a Si source, such as e Si, 51-
There are Mn, etc.

The coated arc welding rod of the present invention is manufactured using a conventional extrusion type coating machine using the core wire and coating material as described above so as to have a coverage of 25 to 50%.

(Example) Table 2 shows the chemical composition of the carbon steel core wires used in the welding rods of the present invention and comparison welding rods, and Table 3 shows the chemical compositions of the carbon steel core wires used in the welding rods of the present invention and comparison welding rods, and Table 3 shows the chemical compositions of the core wires used in combination with the above-mentioned core wires and non-low hydrogen welding rod coating materials. The welding workability and welding speed of the welding rods are the same in Table 4 (an example of a fillet welding rod is shown in Table 5).
The table also shows examples of low hydrogen welding rods.

The welding rods shown in Table 6 were used, and the welding workability was determined by using a normally used steel plate with a thickness of 12.71 mm. Non-low hydrogen and low hydrogen welding rods were mainly used for horizontal fillet, downward, The fillet welding rod was evaluated in each vertical position, in the horizontal fillet position, and in the downward fillet position, and a good one was marked with an ○ mark, and a poor one was marked with an X mark. In addition, the welding speed was measured by welding according to JIS Z3182 according to the procedure shown in Figure 1 at the current shown in Table 6, and was 28 g/win or more for non-low hydrogen welding rods and 46 g/win for fillet welding rods. More than i+in, 26g with low hydrogen welding rod
/win or more was marked as good O, and those that did not meet these standards were marked as poor.

The non-low hydrogen based welding rods H1 to H5 of the examples exhibited good welding workability and good welding speed.

For H6 and H7, the relationship between the main component T i O2 and the welding rate was investigated. All welding rods showed good values for the welding speed, but H6 had too much T i O2, so H7
There was a problem with welding workability because the amount was too small. In H8, broholes increased because the N content in the core was too high. In H9, the N content in the core wire was high and the 0 content was too low, so defects such as blowholes and pits were likely to occur. For 810% H1l, the Si content in the core wire was too high, so although the welding speed improved, there was a tendency for burnout, and the welding workability was marked with an X mark. In H12, sputter loss increased because the Al content in the core wire was too high. H
In No. 13, the welding speed was not improved because the Si content in the core wire was too low.

Dull fill welding rods> The welding rods S1 to 85 of Examples had good welding workability and good values for welding speed.

In S6 and S7, the relationship between the main component 5if2 and the welding speed was investigated. All welding rods showed good values for the welding speed, but workability in fillet welding deteriorated because S6 had too little SiO2 and S7 had too much. S8 has a high N content in the core.

Since S9 was low, blowholes were generated, and because S9 was too high, spatter increased and the welding speed deteriorated. In S10, since the Al content in the core wire was too high, sputter loss was large and the welding speed was deteriorated. Since S11 had too high a Si content, the welding speed was good, but burnt spots occurred. The welding speed was not improved in S12 because the Al content was too high, and in S13 the Si content was too low.

Low Hydrogen Welding Rods> The welding rods L1 to L5 of Examples had good welding workability and good welding speeds.

For H6 and H7, the relationship between the metal carbonate, which is the main component, and the welding rate was investigated. Both welding rods improved the welding speed, but the welding workability was poor because H6 had less metal carbonate and H7 had too much.

In H8, because the N content in the core wire was too high, the toughness of the weld metal deteriorated and blowholes occurred. Since 0 was too high for H9, and A1 was high for Llo, there was a lot of sputter loss, and the welding speed was reduced.

Since Lll has a high Si content in the core wire, a phenomenon of bar burning was observed. L12 has a high Al content, so there is a lot of sputter loss, and H13
The welding speed was not improved due to the low Si content.

It is a figure which shows the relationship between A1, N, O, and a welding speed.

1... Steel plate, 2... Bead.

Claims (3)

[Claims] (1) Si: 0.035 to 0.10% (weight%, same below), Al: 0.003% or less, N: 0.008% or less, O: 0.001 to 0.0095%. Around the carbon steel core wire, TiO_2: 10-32%, SiO_2: 8-30%, Al_2O_3: 0.5-8%, Mn: 2-16%, metal carbonate: 3-25%, organic matter: 8 % or less, based on the iron content in the iron alloy: 1 to 37%, the balance being coated with a non-low hydrogen welding rod coating material consisting of oxides, metals, and unavoidable impurities other than those mentioned above. Welding rods. (2) Si: 0.035 to 0.10% (weight%, same below), Al: 0.003% or less, N: 0.008% or less, O: 0.001 to 0.0095%. Around the carbon steel core wire: TiO_2: 10% or less, SiO_2: 15-35%, Al_2O_3: 0.5-8%, Mn: 2-16%, metal carbonate: 9% or less, organic matter: 8% or less A coated arc welding rod characterized in that it is coated with a coating for a fillet welding rod consisting of an iron content in an iron alloy of 38 to 55% as Fe, and the remainder consisting of oxides, metals, and unavoidable impurities other than those mentioned above. (3) Si: 0.035-0.10% (wt%, same below), Al: 0.003% or less, N: 0.008% or less, O: 0.001-0.0095%. Around the carbon steel core wire: TiO_2: 10% or less, SiO_2: 5-19%, Al_2O_3: 6% or less, Si: 3-15%, Mn: 8% or less, metal carbonate: 21-56%, metal Fluoride: 2 to 23%, organic matter: 2% or less, iron content in the iron alloy as Fe: 5 to 50%, the balance consisting of oxides, metals, and unavoidable impurities other than those mentioned above.Low hydrogen-based coating material for welding rods. A coated arc welding rod characterized by being coated with.