JP2782081B2 - Surface treatment agent for steel to be welded - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a surface treating agent for a steel material to be welded for the purpose of preventing the adhesion of spatter to the steel material to be welded.

<Conventional technology> Normally, spatter adhered to the base metal, etc. around the weld,
A grinder or a tool must be used to remove the tool. ing.

(1) Japanese Patent Publication No. 42-129: A paint-like spatter-adhesion inhibitor comprising a phenolic, alkyd, polyurethane, urea, or melamine synthetic resin and a solvent.

(2) Japanese Patent Publication No. 47-32573: A method of preventing adhesion of spatter, slag, flux and the like by applying a thermosetting resin around a welded portion.

(3) JP-B-51-29871 and JP-B-52-40295: Sputter adhesion preventives in which silicon carbide or an amphoteric compound or an acidic inorganic material is blended as a filler in a component of a paint.

(4) JP-A-52-44743: A spatter adhesion inhibitor obtained by adding a composite sintered powder of calcium oxide and ferric oxide to an alkyd resin.

(5) JP-B-48-24009, JP-B-48-24010, and JP-B-48-30337: A rust-preventive paint that does not hinder weldability by mixing a dehydrogenated rust-inhibiting pigment and a resin component in a solvent. .

(6) JP-B-54-1491, JP-B-43-2779,
JP-B-43-2780: A rust-preventive paint at the bevel to improve weldability by mixing a pigment containing a component to be a slag-making agent and a resin component in a solvent.

In each of the above inventions (1) to (6), a coating composition comprising an oily resin alone or an oily resin and an inorganic filler having heat resistance or a slag forming agent is applied to a welded portion and its periphery. Further, an extremely stable coating film is formed on the surface of the steel material to prevent the adhesion of welding spatter and to prevent rust at the groove.

However, the method using an oily resin as described above has drawbacks such as the danger of fire, toxicity, and deterioration of the working environment caused by the organic solvent vaporized at the time of application.

Recently, a nonflammable water-based treatment agent for improving the working environment and working safety, etc., and a surface treatment method for steel using the water-based treatment agent have been proposed in place of the solvent type described above. The following inventions have been proposed as such a water-based treating agent.

(7) JP-B-46-13810: A paste-like welding spatter adhesion inhibitor prepared by mixing a water-soluble phenol resin and a surfactant with chalky and talc.

(8) JP-B-52-23899: A sputter adhesion inhibitor obtained by mixing a surfactant, a rust inhibitor, a monohydric alcohol and water.

(9) JP-A-57-131270: Alkyd resin or acrylic resin having at least one free carboxylic acid group or sulfonic acid group, a compatibilizer and neutralizing the free carboxylic acid or sulfonic acid group Surface treatment agent for a steel material to be welded, comprising an aqueous solution containing ammonia or a lower amine as necessary.

<Problems to be Solved by the Invention> However, the heat-resistant temperature of the synthetic resin used in the surface treatment agents (1) to (9) is 300 ° C. or less, and cannot withstand higher temperatures.

Further, those using a pigment as a component of the surface treatment agent have poor storage stability and have problems such as precipitation of the pigment during storage of the surface treatment agent. When the surface treatment agent is a high-viscosity solution for preventing the precipitation of the pigment, the precipitation of the pigment in the solution can be delayed, but the coating and the handling become inconvenient.

In addition, when the surface treatment agent is removed from the base material after the end of welding, when a water-based surface treatment agent is used, the pigment as a constituent component is included in the wastewater as a suspended substance in the removal such as washing with water. There is a problem that it is impossible to discharge because of the pollution.

<Means for Solving the Problems> The present invention has been proposed in view of the above, an inorganic metal salt or an organic metal salt having a solubility of 5 or more and a melting point of 300 ° C. or more, a water-soluble binder, and a surfactant. And to a surface treatment agent for a steel material to be welded, which is dissolved in water.

That is, the surface treating agent of the present invention solves the above-mentioned conventional problems by using, as a pigment, an inorganic or organic metal salt which is water-soluble and has a high melting point.

The degree of water solubility of the above inorganic metal salt or organic metal salt is 5 or more, that is, 5 g or more per 100 g of water.
When a pigment having low water solubility, that is, a pigment having a solubility of less than 5, is used as a pigment in the surface treatment agent, it is difficult to remove metal salts in the surface treatment layer in the step of washing and removing the surface treatment layer after welding. Or the metal salt remains on the steel surface without being removed, and the paint adhesion is poor.
This causes problems such as peeling of the paint. Therefore, the higher the water solubility, that is, the higher the solubility, the better the purpose of removing by water washing.

The heat resistant temperature (melting point) of the above-mentioned inorganic metal salt or organic metal salt is 300 ° C. or more, preferably 400 ° C. or more. When a metal salt with a low melting point is used as a pigment, the metal salt in the surface treatment layer is melted by the welding heat, and when applied to an inclined steel material or upright surface, the molten metal salt flows into the groove. Produces welding defects. In addition, at locations where the metal salt has flowed off (the portions to which the surface treatment agent is applied), adhesion of spatter is insufficiently prevented.

Here, the explanation of the welding heat of the steel material at the time of welding described above is added.
It was found that the temperature rose to 300 ° C. or more at a temperature of 10 ° C. or more and at a distance of 10 mm or more from the bead portion, depending on the welding conditions.

Therefore, if the melting point of the inorganic metal salt or the organic metal salt used as a pigment is 300 ° C. or more, preferably 400 ° C. or more, the effect of preventing spatter adhesion does not decrease, and welding defects such as blow holes also occur. Absent.

In addition to the above conditions of water solubility and melting point, it is necessary to consider that there is no toxicity to the human body.

Examples of the inorganic metal salt having the above-mentioned properties include potassium nitrite, calcium nitrate, sodium carbonate, potassium carbonate, potassium sulfate, sodium sulfate, aluminum sulfate, calcium chloride, potassium chloride, sodium chloride, ferrous chloride, and silica. Sodium acid, sodium aluminum oxide, sodium metaborate and the like can be mentioned.

Examples of the organic metal salt include sodium oxalate, sodium benzoate, sodium acetate, iron acetate, potassium propionate and the like.

The mixing ratio of the above-mentioned inorganic metal salt or organic metal salt to the surface treating agent is 5% or more, preferably 10 to 50%. If the mixing ratio is less than 5%, the effect of preventing spatter adhesion is insufficient, and if the mixing ratio is more than 50%, problems such as generation of blowholes and pits during welding and lowering the strength of the weld metal by melting may occur. is there.

However, the surface treatment agent prepared by dissolving only the above-mentioned inorganic metal salt or organic metal salt in water has no film-forming property,
Further, since there is no wettability, the applied portion after the evaporation of water is only in a state where salt is wiped (a state in which metal salts are scattered), and has little effect on preventing adhesion of spatter.

Therefore, a water-soluble binder, for example, one or more of polyvinyl alcohol, carboxymethylcellulose, casein, soluble starch, polyacrylamide and the like is added to the surface treatment agent to impart film forming properties.

Further, a surfactant such as polyethylene glycol alkyl ether, polyethylene glycol alkyl allyl ether, polyethylene glycol fatty acid ester, HLB8 such as polyoxyethylene polyoxypropylene diether as a nonionic surfactant to increase the wettability of the surface treatment agent. The above, as anionic surfactants such as dialkyl sulfosuccinate, higher alcohol sulfate sodium salt, alkyl sulfate sodium salt, alkyl allyl sulfate sodium salt, polyoxyalkyl ether phosphate, etc.
Add seed or two or more.

As described above, the surface treating agent for the material to be welded according to the present invention is water-soluble and has a high melting point and is a solid inorganic metal salt or an organic metal salt. And a water-soluble binder.

Therefore, the surface treating agent of the present invention has an excellent effect of preventing the adhesion of spatter on the material to be welded, and is particularly excellent in heat resistance, so that it can be compared with the conventional surface treating agent even in the material to be welded at a high temperature. This shows a remarkable effect of preventing spatter adhesion.

In addition, since each component constituting the surface treatment agent of the present invention is water-soluble, it can be very easily removed by washing with water after welding, and the possibility of remaining on the steel material is extremely low.
There is no problem with the flushed water.

<Example> Example 1 sodium sulfate 15% carboxymethylcellulose 0.3% polyethylene glycol alkyl ether 3% anticorrosive 0.1% rust inhibitor 0.1% water 81.5% Example 2 sodium oxalate 10% polyacrylamide 2% polyethylene glycol fatty acid ester 5% Preservative 0.1% Water 82.9% Example 3 Sodium Metaborate 20% Polyvinyl Alcohol 10% Alkyl Sulfate Sodium Salt 1% Antiseptic 0.1% Preservative 0.1% Water 68.8% Comparative Example 1 Sodium Sulfate 30% Antiseptic 0.1% Water 69.9% Comparative example 2 Water-based alkyd resin 10% Corrosion inhibitor 0.1% Preservative 0.1% Water 89.8%
× 300mm, 500 × 200mm, each joined to the T type,
Fillet welding was performed on both sides of the joint.

Welding conditions: carbon dioxide gas 25 l / min, welding wire 1.6 mm
φ, welding current 370 to 380 A, welding voltage 36 to 37 V, 4 layers. The test temperature was preheated to 23 ° C, 200 ° C, and 400 ° C before the start of welding.

The evaluation was represented by the number of spatters attached to the test piece, and is shown in Table 1. In addition, untreated samples were evaluated as blanks, and are shown in Table 1.

As is clear from Table 1 described above, Examples 1 to 3 satisfying the constitution of the present invention exhibited an excellent effect of preventing spatter adhesion at each test temperature, and did not show any welding defects such as blow holes.

On the other hand, Comparative Example 1 was not able to sufficiently cover the base material because it was composed of only the inorganic metal salt, and was unable to prevent the adhesion of spatter.

Comparative Example 2 forms a film of a synthetic resin containing no pigment, and has an effect of preventing spatter adhesion at low temperatures of 23 ° C. and 200 ° C., but at a high temperature (400 ° C.) Since the film cannot withstand heat, the effect of preventing the adhesion of spatter is significantly reduced.

<Effect of the Invention> As described above, the surface treatment agent for the steel material to be welded of the present invention is obtained by using an inorganic metal salt or an organic metal salt which is water-soluble, has a high melting point and is a solid in a normal state as a pigment. It has an excellent effect of preventing spatter from adhering to the material to be welded.

Therefore, the surface treating agent of the present invention is particularly excellent in heat resistance, and exhibits a remarkable effect of preventing adhesion of spatter even in a high-temperature welded material as compared with the conventional surface treating agent.

That is, for example, even when applied to an inclined high-temperature workpiece and a vertical surface, spatter can be prevented from being attached without causing sagging even at a high temperature of 300 to 400 ° C. or more.

In addition, since each component constituting the surface treatment agent of the present invention is water-soluble, it can be very easily removed by washing with water after welding, and the possibility of remaining in the steel material is extremely low.

Furthermore, since each component constituting the surface treating agent of the present invention, particularly, a metal salt, has high solubility in water, there is no problem in the drainage after washing with water.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23K 9/235 B23K 35/36 C10M 173/02 B23K 7/10 B23K 9/32

Claims (1)

(57) [Claims] 1. A surface treating agent for a steel material to be welded, wherein an inorganic metal salt or an organic metal salt having a solubility of 5 or more and a melting point of 300 ° C. or more, a water-soluble binder and a surfactant are dissolved in water.