JPS6356395A - Agent for preventing generation of blowhole and pit for arc welding - Google Patents

Abstract

PURPOSE:To improve welding quality by combining a viscosity decreasing agent contg. Te, Se, etc., and flux contg. metal fluoride, etc., and further, supplying the viscosity decreasing agent and flux at a specific ratio per unit length of a weld line. CONSTITUTION:The viscosity decreasing agent is formed of 1 kinds selected from simple substances Te, Se, REM and Sb or the oxide thereof and furthermore, the flux is formed of at least 21 kinds among TiO2, SiO2, Al2O3, MgO, etc., or CaCO3, MgCO3, etc., and CaF2, MgF2, etc. and is combined with the viscosity decreasing agent. The compounding ratio is further so set that 0.05-10g viscosity decreasing agent and 0.025-5g flux per m of the length of the weld line can be simultaneously supplied. The viscosity of a molten pool is decreased and the flux is converted to slag by the above-mentioned method, by which the generation of blowholes and pits is prevented. The welding quality is, therefore, improved.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention Industrial Application Field The present invention relates to a composition for preventing the occurrence of blowholes and pits, which are serious defects in arc welding.

Conventional technology and its problems When performing arc welding using solid wire or flux-cored wire, if the weld area is coated with brimer paint or has a galvanized layer, this may vaporize during welding. This has become a bigger problem than before, as it tends to cause blowholes and pits.

When these blowholes and pits occur, the strength of the joint decreases and rework is required, but this requires a large amount of man-hours to scrape off the defective location, repair weld, and further adjust the bead shape. be.

One way to solve this problem is to burn off the primer and galvanized layer on the weld line using a gas burner, etc. before welding, but this still requires a large amount of man-hours, and the primer and galvanized layer on the weld line other than the weld line is burnt off. This can also damage the layer, impairing its antirust ability and appearance.

Another method is to perform preliminary welding to decompose the primer and galvanized layer of the welded area using an arc, and then perform final welding, but this also increases the number of man-hours.
There is too much surplus, it takes time to set welding conditions,
It has the following problems.

Furthermore, there is a method of using a stripping agent to remove the primer or galvanizing before welding, but it is necessary to wipe off or wash the reaction residue after applying the stripping agent and allowing it to react, and in addition, the stripping agent Because they contain large amounts of organic solvents, acids, and alkalis, they tend to impair the working environment and safety.

By the way, JP-A-61-30286 discloses a composition for preventing blowholes, which contains TiO, ferrotitanium, ferromanganese, ferrosilicon, iron, illuminite, aluminum, 5iO1,
This is a method in which powders such as mica, talc, and potassium feldspar are spread, and these powders create an agitation effect in the weld pool during welding, causing the gas that causes blowholes to float to the surface along with the slag. However, since the method disclosed in this publication causes stirring, it has major drawbacks in that the bead shape becomes dirty and spatter increases.

The present invention was made with the aim of solving the above-mentioned drawbacks of the conventional technology, and even if there is a primer coating or galvanized layer on the welded part, it can prevent the occurrence of blowholes and pits with a simple operation. The present invention aims to provide an agent for preventing the occurrence of blowholes and pits in arc welding, which can improve the efficiency of welding work.

Structure of the Invention The structure of the present invention is to apply at least one viscosity reducing agent selected from Te, Se, REM, and Sb alone or their oxides along the welding line at a rate of O', 05 to 05 per meter.
10g and further TiO2,5iO1, A I, 0°,
Metal oxides such as MgO, Ca C03, M g C0
A flux containing at least one kind of metal carbonate such as No. 3 metal carbonate, metal fluoride such as CaF2, MgF, etc. is contained along the welding line in an amount of 0.025 to 5 g per 1 m so that it can be supplied at the same time. The subject matter is an agent for preventing the occurrence of blowholes and pits in arc welding, which is characterized by the following.

Measures to solve the problem Consider supplying a substance to the welding line prior to or during welding that reduces the viscosity of the weld pool and makes it easier for vaporized gas to be discharged. They found that Te, Se, REM, and Sb alone or their oxides are effective as the viscosity-lowering agent, and furthermore, other defects that are likely to occur due to viscosity reduction can be prevented by adding flux.

The viscosity reducing agent in the present invention may be a single substance of Te, Se, REM (rare earth metal), or Sb, or an oxide thereof, and these may be used alone or in combination as appropriate. It is something.

Further, the flux in the present invention includes sintered flux,
TiO2,5 used as raw material for molten flux
i02, A 1103, metal oxides such as MgO, Ca
Metal carbonates such as C03, M g CO, GaFl, M
Any ordinary welding flux raw material such as metal fluoride such as gFl may be used as appropriate.

Next, the blending ratio of the viscosity reducing agent and the flux in the present invention is not particularly limited, but it is desirable to mix 20 to 80 parts by weight of flux to 100 parts by weight of the viscosity reducing agent. .

When the inhibitor of the present invention is supplied onto the weld line, the blending ratio is 0.05 to 10 g of the viscosity reducing agent per 1 m of the weld line.
This was determined from data showing that supplying flux in a range of 0.025 to 5 g per 1 m of welding line yields suitable results.

In other words, if the amount of the viscosity reducing agent is less than 0.05 g per meter of welding line, it will not be effective, and if it exceeds 10 g, the bead shape will deteriorate and undercuts and overlaps will easily occur, causing practical problems. Also, if the amount of flux is less than 0.025 g per 1 m of welding line, it will not be effective, and 5
If the amount exceeds g, a hard slag will be formed and it will be difficult to remove the slag after welding.

In order to apply the inhibitor of the present invention onto the weld line in such a supply amount within such a range, it is preferable to mix the flux with the viscosity reducing agent in the ratio described above.

The inhibitor of the present invention has the above-mentioned viscosity reducing agent and flux as active ingredients, but in order to supply this onto the weld line, appropriate additives such as water, solvent, adhesive, dispersant, etc. may be added as necessary. Of course, the inhibitor of the present invention may be added to the weld line by spraying it as a powder prior to welding, spraying a suspended substance with a spray gun, etc. Furthermore, as a means of supplying it during welding, it can be added as a component of the welding wire, applied to the surface of the wire as a component of a coating material, or filled inside the wire. It is okay to do so.

The welding method to which the present inhibitor is applied is not particularly limited as long as it is an arc welding method, and for example, it can be suitably used in submerged arc welding, gas shielded arc welding, or manual welding. It is something.

Effects The present invention has the above structure. By supplying the inhibitor of the present invention to the welded part, the following effects prevent blowholes and pits from occurring, improve the appearance of the bead, and prevent undercuts. This has the effect of not causing overlap or overlap.

In general, the cause of blowholes and pits in arc welding is that the brimer and galvanized layer decompose due to the arc heat at the overlapped fillet weld surface, producing gases that diffuse into the weld metal and solidify the weld. If this gas is completely trapped, it will become a blowhole, and if the discharged part is not filled with solidified metal, it will become a pit.

However, when the inhibitor of the present invention is supplied to this weld zone, the active ingredients viscosity reducing agent, namely Te, S
E, REM, and Sb alone or their oxides are mixed into the weld pool to significantly lower the viscosity of the weld pool and lower the surface tension, thereby significantly improving the fluidity of the weld.

As a result, the gas generated by the decomposition of the primer and galvanization due to the arc heat floats up in the molten steel and is easily discharged, and by the time the weld solidifies, most of the generated gas evaporates, creating a blowhole inside the weld. This makes it possible to prevent the occurrence of pits.

Note that this effect is due to T, which is the active ingredient in the present invention.
e, Se, REM, Sb alone or obtained from their oxides, but "other compounds"
In other words, tellurides, selenides, rare earth compounds, as well as hydroxides, halides, organometallic compounds, etc. of the above metals are decomposed by the high temperature of the arc heat and act as simple substances of the above metals. Although the same effects as single metals can be expected, the reason why the present invention intentionally excludes these "other compounds" is that these "other compounds" are safer than the viscosity reducing agent as the active ingredient of the present invention. This is because it was judged to be inferior in economic efficiency and workability.

Next, to explain the action of flux, which is another active ingredient of the present invention, the welded part whose fluidity has been improved by the viscosity reducing agent described above will have undercuts and overlaps in fillet welding because the surface tension is reduced. Since defects such as these tend to occur easily, flux is blended for the purpose of preventing this.

In other words, by adding flux, this flux turns into slag due to arc heat, forming a slag layer, which promotes the forming effect, improves the bead appearance, and prevents undercuts and overlaps. . In addition, this slag layer exerts a heat-retaining effect by slowing down the solidification of the welded area as much as possible, completely evaporating the generated gas, and suppressing the rapid solidification of the welded area, resulting in a low viscosity shape. This will prevent disturbances.

Example 1 An inhibitor of the present invention having the following composition was prepared.

Te (l OO meshunder) Part 8 5i02 (
colloidal silica) (F) 2 parts calcium fluoride (F
) 2 parts Solvent (trichloroethane) 88 parts Note that (F) indicates a flux.

These were kneaded with a stirrer to make a paste-like suspension, and the following welding tests were conducted.

The above suspension was applied to both sides of the weld line of a T-shaped fillet welded test piece of a 12 mm thick zinc-rich primer coated steel plate (film thickness 20 microns) to give various Te amounts as shown in the upper row of Table 1. Then, horizontal fillet welding was performed.

The welding conditions are 250A, 28V, DC reverse polarity, welding speed 60cm/min, carbon dioxide flow rate 20cm/min, 1.2m.
The test was carried out using a solid wire (Y GWll) with a diameter of m.

The results are shown in Table 1.

Table 1 Note that the above evaluation was performed on the second bead side, where O indicates good bead appearance, Δ indicates somewhat poor bead appearance, and × indicates poor bead appearance.

Example 2 Se, Ce, Sb, T in place of Te in Example 1
e01.5e02, monazite (C:eO45%, La0
24% content), s b, and o were applied on the weld line with varying amounts of adhesion in the same manner as in Example 1, and then
Horizontal fillet welding was performed under the same conditions as in Example 1.

The results are shown in Table 2 (a), (b), and (c). (Evaluations are the same as in Example 1) Table 2 (a) Table 2 (b) Table 2 (c) Example 3 A suspension of the inhibitor of the present invention having the following composition was prepared.

TeO□ powder 2 parts sb powder 2 parts flux
2 parts Solvent (trichloroethane) 994 parts Total 1000 parts The components of the above flux are as follows.

Flux composition: Sin, 30 parts Tie, 10 parts AI, 0310 parts GaC0, 320 parts Mg0 20 parts This suspension was applied to both sides of the weld line of a T-type fillet weld test piece of a 4 mm thick galvanized steel plate (film thickness 10 microns). After applying and drying the flux repeatedly with a spray gun so that the amount of flux applied is as shown in the second row of Table 3,
Performed horizontal fillet welding.

The welding conditions are 220A, 25V, DC reverse polarity, welding speed 80cm/min, carbon dioxide flow rate 15mm/min, 1.0
The test was conducted using am diameter solid wire (Y GW12).

The results are shown in Table 3. (Evaluation was performed on the second bead side, and regarding the bead appearance and slag removability, O was good, Δ
indicates slightly bad, and X indicates poor. ) Table 3 However, regarding the bead appearance, △ marked with ★ indicates that it was slightly wavy, and △ marked with ※ indicates that there were irregularities. Regarding slag removability, - indicates that there is no slag, and △ indicates that the slab is thick and difficult to peel off.

C. Effects of the Invention The present invention is as described above, and as clearly seen in the examples, by supplying an appropriate amount of the inhibitor of the present invention onto the weld line, the occurrence of blowholes and pits can be completely prevented. In addition, the bead appearance is good and no other welding defects occur.

In this way, the inhibitor of the present invention is supplied to the welded part before or during welding when steel materials having a primer coating or galvanized layer are arc welded,
It is possible to prevent welding defects such as blowholes and pits with a simple operation, and therefore it can also improve the efficiency of welding operations, which has extremely significant effects.

Claims (1)

[Claims] 1. At least one viscosity reducing agent selected from Te, Se, REM, and Sb alone or their oxides is applied along the welding line in an amount of 0.05 to 10 g per meter, and Ti
Metal oxides such as O_2, SiO_2, Al_2O_3, MgO, metal carbonates such as CaCO_3, MgCO_3,
Apply flux containing at least one metal fluoride such as CaF_2 and MgF_2 for 1 m along the welding line.
An agent for preventing the occurrence of blowholes and pits in arc welding, characterized in that the agent contains 0.025 to 5 g per liter so that they can be supplied simultaneously.