JP2009113073A - Spatter adhesion inhibitor for metal welding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spatter adhesion inhibitor for metal welding, which is satisfactory in handling quality, and can be sufficiently inexpensively formed. <P>SOLUTION: The spatter adhesion inhibitor for metal welding is formed of a powder mixture composed of two or more kinds of compound including at least barium sulfate and calcium carbonate of ≤20 μm in average grain size. The powder mixture containing 4 to 95 wt.% barium sulfate, and 5 to 96 wt.% calcium carbonate is employed. Further, such an alkaline powder as to make the suspension to be obtained when water of the same weight as that of the above powder mixture is added to the powder mixture exhibit alkalinity of ≥10 in pH is incorporated into the powder mixture. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a spatter adhesion preventing agent that prevents spatter generated and scattered when welding metal from adhering to the periphery of a welded portion of a base metal.

  When metal is welded, particulate molten metal, generally called spatter, is generated and scattered around the welded portion. If this spatter adheres to the welded base metal, not only the appearance is impaired, but if it adheres to the bolt joint, a gap is created between the base metal and the splice to provide sufficient bolt tightening force. The serious problem of not being able to get it will also be caused. Further, when the base metal is applied after welding, there is a problem that the adhesion between the undercoat and the overcoat is impaired if the spatter remains attached.

For this reason, normally, in the finishing work after welding, it is called “scrap removal” to remove spatter. In order to simplify such scrap removal as much as possible, conventionally, as shown in Patent Documents 1 and 2, for example, a drug for preventing spatter adhesion to a base metal is also provided. This kind of spatter adhesion preventing agent for metal welding is applied by brushing or the like around the welded portion of the base metal prior to the welding operation. When it is dried, a thin film is formed on the surface of the base metal, and this film serves as a barrier against sputtering and prevents spatter adhesion.
Japanese Unexamined Patent Publication No. 7-088685 Japanese Patent Laid-Open No. 10-305390

  Since most conventional spatter adhesion preventive agents for metal welding are liquid, handling and packing are difficult, and handling such as liquid leakage is likely to occur during transportation. The problem of not being good is recognized. Further, such conventional liquid spatter adhesion preventive agent for metal welding is apt to be expensive because it uses a very special component.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a spatter adhesion preventing agent for metal welding that is easy to handle and can be formed at a sufficiently low cost.

One spatter adhesion preventive agent for metal welding according to the present invention is formed in a powder form,
It consists of two or more kinds of powder mixtures containing at least barium sulfate and calcium carbonate having an average particle size of 20 μm or less,
The powder mixture contains 4 to 95% by weight of barium sulfate and 5 to 96% by weight of calcium carbonate,
Furthermore, the powder mixture contains an alkaline agent powder that exhibits an alkalinity of pH 10 or more when the suspension obtained by adding the same weight of water is added.

  More specifically, as the above-mentioned alkaline agent powder, it is desirable that 0.05% by weight or more of calcium hydroxide, sodium carbonate, or both of them is contained with respect to the whole powder mixture.

  Moreover, in this powder-form spatter adhesion preventive agent for metal welding according to the present invention, it is desirable that the powder mixture contains 1 to 15% by weight of polyethylene glycol.

  The present invention also provides a liquid metal welding spatter adhesion inhibitor, which is obtained by mixing the above-described powder mixture metal spatter adhesion inhibitor with water. It will be. In this case, the powder mixture may be mixed with a liquid containing not only water but also other liquids.

  In the liquid spatter adhesion preventive agent for metal welding according to the present invention, the weight ratio of water to the powder mixture is preferably 1 to 2 times.

  When the spatter adhesion preventing agent for metal welding of the present invention comprising a powder mixture is added to water, a suspension containing at least barium sulfate and calcium carbonate (hereinafter simply referred to as “suspension”) can be formed. When this suspension is applied to the periphery of the welded portion of the base metal using a brush or the like, it is dried in a short time of about 1 hour after the application to form a thin powder film on the surface of the base metal. When this powder coating is formed, even if spatter is scattered when the base metal is subsequently welded, the powder coating acts as a barrier to prevent the spatter from adhering to the base metal. Is done. Therefore, the scrap removal work in the finishing process after the completion of welding becomes very easy. In addition, the powder coating itself is easy to remove, and the finishing work after completion of welding is facilitated from this point.

  And since this metal spatter anti-adhesive agent consists of a powder mixture, unlike liquid ones, packing and packing for transportation is easy, and problems such as liquid leakage occur during transportation. It is excellent in handleability. Thus, the spatter adhesion preventing agent for metal welding that has been transported to the welding site with good handleability can be used by simply mixing it with water at the welding site.

  In addition, since barium sulfate and calcium carbonate are currently available at a relatively low cost, this spatter adhesion inhibitor for metal welding can be produced at a lower cost than conventional products.

  In addition, those powders and those having an average particle diameter of 20 μm or less are used as powders such as polyethylene glycol that are selectively added as appropriate. This is because not only the brush coatability is deteriorated, but also the powder film after the suspension is dried becomes considerably thick and the workability is impaired.

  Further, since the spatter adhesion preventing agent for metal welding contains barium sulfate and calcium carbonate, the suspension becomes a slurred slurry mainly due to the action of barium sulfate. Such a suspension is less likely to sag when brushed, and is unlikely to flow into the welded portion, so that the workability is very good.

  On the other hand, the powder of barium sulfate alone is likely to cause iron rust on the base metal. However, in the spatter adhesion preventive agent for metal welding of the present invention, the calcium carbonate and alkaline agent added together with this barium sulfate. The effect of suppressing the occurrence of iron rust can be obtained.

  Moreover, when said alkaline agent powder is contained in a powder mixture, the effect that the external appearance of a powder mixture will become favorable is also acquired.

  The reason why the lower limit of barium sulfate is set to 4% by weight in the spatter adhesion preventive agent for metal welding of the present invention is that the viscosity of the suspension is lowered and the effect of suppressing sagging is impaired if the amount is less than that. is there. Moreover, the reason why the upper limit value of barium sulfate is 95% by weight is that if it is more than that, iron rust tends to occur in the base metal.

  On the other hand, in the spatter adhesion preventing agent for metal welding of the present invention, the lower limit of calcium carbonate is set to 5% by weight. If the amount is less than that, not only iron rust is generated but also the amount of expensive barium sulfate used is increased. This is because the production cost of the spatter adhesion preventing agent becomes very high because it increases relatively. In addition, the upper limit of calcium carbonate is 96% by weight. If it is more than that, the viscosity of the suspension is lowered, the effect of suppressing dripping is impaired, and the suspension is left for a long period of time. This is because sometimes it becomes a solid and hardens at the bottom of the container, making it difficult to reuse.

  In addition, in the spatter adhesion preventive agent for metal welding according to the present invention, when the powder mixture contains polyethylene glycol, the powder film obtained by drying the suspension has a coating property (that is, a mere powder). In addition to being an aggregate, it is imparted with a film property that is somewhat rigid, and since the freezing point of the suspension is lowered, the effect of facilitating use in the cold can be obtained.

  Thus, when adding polyethyleneglycol, the lower limit is made into 1 weight% because each effect mentioned above will fade if it is less than that. Further, the upper limit of 15% by weight is that if the amount is too large, the viscosity of the suspension becomes too high to be difficult to use, the powder film becomes extremely thick and difficult to use, This is to avoid that the powder film is close to the coating film itself rather than a collection of powders, resulting in poor removability in the finishing operation.

  Note that the liquid metal welding spatter adhesion preventive agent according to the present invention is basically formed by adding the metal welding spatter adhesion preventive agent of the present invention made of a powder mixture to water, that is, the above suspension. Since it is the liquid itself, the above-described effects are exhibited in the same manner.

  Hereinafter, embodiments of the present invention will be described in detail.

  Several types of spatter adhesion preventing agents for metal welding according to the present invention and spatter adhesion preventive agents for comparative evaluation outside the present invention were prepared, and their properties and effects were examined. The results will be described below.

《Welding conditions》
As the welding wire, a wire having a diameter of 1.4 mm classified into YGW11 of JIS Z 3312 (the chemical component by the mill sheet is shown in Table 1 below) was used. Welding was performed in a downward posture using a carbon dioxide semi-automatic arc welder. The welding conditions were measured with an ammeter and a voltmeter attached to the welding machine, the current was set to 280 A, and the arc voltage was set to 33V. SS400 steel having a thickness of 9 mm was used as the test steel described below.

<< Evaluation Items and Evaluation Method >>
The spatter adhesion preventive agent for metal welding of the present invention consisting of a powder mixture and the powder mixture of the present invention for comparison with the present invention were mixed with tap water and used. And in order to examine the properties of the suspension at that time, the state when the suspension was applied to the test steel, the spatter adhesion state after welding, etc., the following items (a) to (e) Examined.

(a) Various powder suspensions were prepared by changing the average particle size of the powder mixture, the state of the dry powder film after brushing, and the composition and particle size of the powder, and each suspension was inclined at 45 °. The same area of the test steel material was applied using the same paint brush, and the state and appearance of the powder film after the coating film was dried were examined.

(b) The composition of the powder mixture and the viscosity of the suspension The composition of the powder and the particle size are changed to prepare a plurality of types of suspensions. Each suspension is kept at 20 ° C., and manufactured by BROOKFIELD. The viscosity was measured with a digital viscometer (DV-II +).

(c) Composition of powder mixture and state of powder coating after brushing A plurality of types of suspensions were prepared by changing the average particle size and composition of main components of barium sulfate and calcium carbonate. A fixed amount was applied to the same area of the test steel material tilted to the same area using the same paint brush, and the dried powder film was converted to the film thickness by the weight method for comparison.

(d) Application of various suspensions and spatter after welding We prepared multiple types of suspensions by changing the composition and particle size of the powder, and welded each suspension at the factory site. This was applied to a 10 × 30 cm area around the head using a brush having a width of 50 mm and dried. Thereafter, the actual product was welded, the number of spatters remaining after the powder film was washed and removed, and the spatter adhesion preventing effect was evaluated.

(e) Powder mixture composition and ease of scrap removal, etc. Prepare multiple types of suspensions by changing the powder composition and particle size, and use each suspension for actual welding at the factory site did. Thereafter, the dried powder film was evaluated for (1) easy removal with a brush and (2) easy removal with water.

(f) Composition of barium sulfate and calcium carbonate and various operational characteristics Various characteristics of the suspension obtained by adding and mixing barium sulfate and calcium carbonate with various mixing ratios (application workability) The iron rust of the powder film, the state of the suspension) were investigated and evaluated. The state of the suspension was examined from the viewpoint of whether or not it was appropriate for reuse. In this case, the average particle diameter of barium sulfate and calcium carbonate is 15 μm.

(g) Barium sulfate, calcium carbonate, alkaline agent composition and powder coating iron rust generating barium sulfate and calcium carbonate were mixed at various mixing ratios, and calcium hydroxide or sodium carbonate was added as an alkaline agent. Thus, a powder mixture was obtained. Then, the pH of the suspension obtained by adding water to the powder mixture and the iron rust generation property of the powder film formed by applying the suspension to a welded product and drying were investigated. evaluated. In this case, the average particle diameter of barium sulfate and calcium carbonate is 15 μm.

"Evaluation results"
Table 2 below shows the evaluation results regarding the item (a). In this table, the samples marked “invention” in the “No.” column are those according to the present invention, and other samples are those outside the present invention (the same applies hereinafter).

  As shown in Table 2, the suspension containing the powder having an average particle diameter exceeding 20 μm has problems such as being difficult to mix, adhering to the brush in large quantities, and having a thick powder film. The product has no such defects.

Next, Table 3 below shows the evaluation results regarding the item (b).

  As shown in Table 3, by adding water to the mixed powder of barium sulfate and calcium carbonate, the sagging flow can be prevented, and a viscosity range with good workability (this is generally 800 to 3000 cP [centipoise], that is, 0.8 to It is considered that a suspension contained in 3.0 Pa · s [Pascal · second] is obtained.

Next, Table 4 below shows the evaluation results regarding the item (c).

  As shown in Table 4, for suspensions containing only barium sulfate or calcium carbonate, the powder film becomes thicker, it tends to flow when brushing, and the powder is hard to use because it settles at the bottom. However, the product of the present invention does not recognize such a problem. It was also confirmed that the inclusion of polyethylene glycol lowered the freezing point of the suspension and lowered the freezing temperature.

Next, Table 5 below shows the evaluation results regarding the item (d).

  As shown in Table 5, the suspension containing only barium sulfate has a remarkable effect of preventing spatter adhesion, but has a problem that the powder film becomes thick and difficult to use. Moreover, about the suspension containing only calcium carbonate, the malfunction that a spatter adhesion prevention effect is low and it flows easily at the time of brush coating is recognized. On the other hand, it was confirmed that the product of the present invention has a good effect of preventing spatter adhesion while being difficult to flow.

Next, Table 6 below shows the evaluation results regarding the item (e).

  As shown in Table 6, according to the spatter adhesion preventive agent for metal welding of the present invention, the scum removal workability is clearly improved as compared with those outside the present invention.

Next, Table 7 below shows the evaluation results regarding the item (f).

  As shown in Table 7, when the barium sulfate content is 3% by weight, the suspension does not become a slurry and tends to flow when applied. There was a problem that it was hard to reuse because it hardened on the bottom of the container. It can be inferred that this defect occurs in the same manner even in the case of less than 3% by weight from the property of barium sulfate.

  On the other hand, when the amount of barium sulfate is 96% by weight, iron rust is likely to occur in the powder film, which is not preferable in appearance. This defect is considered to occur similarly when barium sulfate exceeds 96% by weight.

  On the other hand, in the spatter adhesion preventive agent for metal welding of the present invention, the above-mentioned problems were not recognized.

Next, Table 8 below shows the evaluation results regarding the item (g). In addition, the iron rust generation | occurrence | production and external appearance observation result shown in this Table 8 are a thing at the time of leaving for 1 day, 5 days, and 10 days, after apply | coating suspension to the plane of a welding actual product. The results are also indicated by abbreviations, which means that “◎ ·· 0 to 9 spots rust occurred”, “O ·· 10 to 20 spots rust occurred on a 100 mm × 100 mm sample surface. ”,“ Δ ·· Many spots rusted ”and“ × ·· Rusted all over ”.

  As shown in Table 8, when the alkaline agent contained in the powder mixture was less than 0.05% by weight, iron rust was significantly generated in the powder film, and defects in appearance were observed.

  On the other hand, when the alkaline agent contained in the powder mixture is 0.05% by weight or more (pH 10.1 or more), the generation of iron rust in the powder film is small, and the effect of suppressing iron rust is remarkable.

Claims (5)

It consists of two or more kinds of powder mixtures containing at least barium sulfate and calcium carbonate having an average particle size of 20 μm or less,
The powder mixture contains 4 to 95% by weight of barium sulfate and 5 to 96% by weight of calcium carbonate,
Further, the powder mixture contains an alkaline agent powder that makes the suspension obtained when the same amount of water is added hydrolyzed so as to exhibit an alkalinity of pH 10 or higher. .   The spatter adhesion preventive agent for metal welding according to claim 1, wherein the powder mixture contains 0.05% by weight or more of calcium hydroxide and / or sodium carbonate as the alkaline agent powder.   The spatter adhesion preventive agent for metal welding according to claim 1 or 2, wherein the powder mixture contains 1 to 15% by weight of polyethylene glycol.   A metal spatter adhesion preventive agent for metal welding comprising a powder mixture according to any one of claims 1 to 3 mixed with water.   The spatter adhesion preventive agent for metal welding according to claim 4, wherein the weight ratio of water to the powder mixture is 1 to 2 times.