JP4430387B2 - Cleaning agent before welding - Google Patents

Description

The present invention relates to a pre-weld cleaning agent, and more particularly to a pre-weld cleaning agent suitable for cleaning and removing organic substances adhering to the surface of an object to be welded in a pretreatment such as electron beam welding.

  For welding metal parts, various welding methods such as electron beam welding and laser welding are used. For example, in electron beam welding, welding is performed by irradiating a metal part with a high-speed electron beam in a vacuum chamber. At this time, if an organic substance such as processing oil or emulsified oil adheres to the surface of the metal part to be welded, the organic substance is gasified by heat during welding. Blow holes and spatter are generated by gas jetting from inside the molten metal. Thus, the organic matter adhering to the surface of the workpiece is a cause of poor welding. Therefore, it is necessary to clean the surface of the workpiece before welding.

Various cleaning agents have been proposed as cleaning agents used for cleaning the surface of the workpiece. For example, Patent Document 1 discloses a water-soluble detergent containing a surfactant having a predetermined structure and a polyalkylene polyamine dicyanammonium chloride that is a cationic oil-water separator. Patent Document 2 discloses a cleaning agent comprising at least morpholine, a polyoxyethylene polyoxypropylene block polymer, an aliphatic acid having 6 to 12 carbon atoms, a dicarboxylic acid having 6 to 18 carbon atoms, and water.
Japanese Patent No. 3361930 JP-A-8-34993

  The water-soluble cleaning agent disclosed in Patent Document 1 contains a cationic oil / water separating agent to improve the oil / water separating property of the cleaning liquid. In other words, the processing oil is removed from the surface of the object to be cleaned, and the emulsion in which the removed processing oil and the surfactant are combined is easily separated and removed from the cleaning liquid, and the reattachment of the emulsion to the object to be cleaned is suppressed. ing.

  However, since the cationic oil-water separator is easily adsorbed on the metal material that is the object to be cleaned, it tends to remain on the surface of the object to be cleaned after cleaning. The remaining cationic oil-water separating agent is gasified by heat during welding and causes blowholes and spatter. In addition, there is a risk that soot and spear remain after combustion, which may cause poor welding.

  If spatter occurs during electron beam welding, the sealing material in the vacuum chamber deteriorates and air leakage occurs. When the degree of vacuum decreases, there is a risk of causing arcing (abnormal discharge). In addition, if flaws or the like are generated during welding, the vacuum pump is contaminated and causes a malfunction.

Moreover, the cleaning agent disclosed in Patent Document 2 contains morpholine as an amine. Since the free amine is only morpholine, it has a bad odor and is not practical. Moreover, since the powdery dicarboxylic acid contained in the detergent has a weak binding force with morpholine, it returns to the original powder by drying after washing. For this reason, white spots remain on the surface of the object to be cleaned, causing poor welding.

  As described above, the components of the cleaning agent may cause poor welding or defects in the welding apparatus. Therefore, it is desirable that the cleaning agent used for cleaning before welding does not contain as much components as possible that may cause welding defects. In other words, it is desirable that the cleaning agent is composed of a component that is difficult to inhibit weldability.

  Further, metal soap often adheres to the surface of the object to be cleaned. Metal soap is a compound of metal ions and fatty acids. Metal soap is often contained in a processing oil used when cutting an object to be cleaned, and adheres to the surface of the object to be cleaned. Moreover, it may be produced | generated from the metal ion in water and the fatty acid in a cleaning agent. As a result of analysis of the gas component inside the blowhole generated by the inventor by the present inventor, it was found that about 90% is hydrogen. From this, it is considered that many blow holes are generated by gasifying the metal soap attached to the surface of the object to be cleaned during welding. Therefore, when metal soap adheres to the surface of the object to be cleaned, it is important to remove the metal soap. However, the conventional water-soluble cleaning agents including the cleaning agents disclosed in Patent Documents 1 and 2 cannot sufficiently remove the metal soap adhered to the surface of the object to be cleaned.

The present invention has been made in view of such a situation, and it is an object of the present invention to provide a pre-welding cleaning agent that is unlikely to cause welding failure or failure of a welding apparatus even when used for cleaning before welding . In addition, it is an object of the present invention to provide a pre-welding cleaning agent that can also remove metal soap adhered to the surface of an object to be cleaned.

The pre-weld cleaning agent of the present invention is mainly composed of 1 to 40 wt% of alicyclic amine containing morpholine, 1 to 20 wt% of liquid fatty acid, 1 to 5 wt% of nonionic surfactant, and the remainder of water, and is in powder form It is characterized by not containing any dicarboxylic acid . The pre-welding cleaning agent of the present invention contains a nonionic surfactant as a cleaning component, and effectively removes organic substances on the surface of the object to be cleaned. Moreover, since it contains an alicyclic amine and a liquid fatty acid, it also has a rust preventive action on the surface of the object to be cleaned. That is, when washed with the pre-welding detergent of the present invention, a film made of a neutralized salt of an alicyclic amine and a liquid fatty acid is formed on the surface of the object to be cleaned. As a result, generation of rust on the surface of the object to be cleaned is effectively suppressed.

  This inventor investigated the presence or absence of flaming (soot, spear) production | generation at the time of welding, and combustibility about alicyclic amine and liquid fatty acid. As for the combustibility, iron was assumed as an example of a metal material to be cleaned, and it was examined whether or not it was easily gasified before the iron melted. If it is not gasified before melting of iron, it can be said that it is difficult to cause blowholes and spatter. The investigation results are shown in Tables 1 and 2 below in comparison with other compounds usually used in cleaning agents. Symbols indicating flammability in each table indicate that when the sample is ignited and the fire type is moved away, ◎: Continue to burn and burn to the end, ○: Continue to burn but have unburned, △: Fire after a while Excessive burn-out remaining, x: Indicates that the fire is extinguished immediately and there is much unburned residue. In addition, symbols indicating comprehensive judgment indicate ◎: suitable, ○: suitable, ×: inappropriate.

As shown in Table 1, in the alicyclic amine, there was no generation | occurrence | production of a spear and favorable combustibility compared with ethanolamine etc. Further, as shown in Table 2, even in the case of liquid fatty acids, generation of soot and spears was small and combustibility was good as compared with powdered dicarboxylic acids . That is, it can be said that even if the alicyclic amine and the liquid fatty acid remain on the surface of the object to be cleaned after cleaning, it is difficult to cause poor welding or the like. On the other hand, powdered dicarboxylic acid often burns and has poor flammability, and if it remains on the surface of the object to be cleaned, it causes a welding failure or the like.

Therefore, if cleaning is performed using the pre-welding cleaning agent of the present invention that contains an alicyclic amine and a liquid fatty acid and does not contain a powdered dicarboxylic acid , in the subsequent welding, welding defects or defects in the welding apparatus may occur. Can be reduced.

The pre-welding cleaning agent of the present invention preferably contains a chelating agent in addition to the main agent. As described above, metal soap is often attached to the surface of the object to be cleaned. By blending the chelating agent, the metal soap can be effectively removed as a complex compound. Therefore, if it wash | cleans using the cleaning agent before welding of this invention of the aspect containing a chelating agent, generation | occurrence | production of the welding defect and the malfunction of a welding apparatus can be reduced more.

The pre-welding cleaning agent of the present invention mainly comprises an alicyclic amine, a liquid fatty acid, and a nonionic surfactant, and does not contain a powdered dicarboxylic acid . Since the pre-weld cleaning agent of the present invention is composed of components that do not easily impair weldability, even when used for cleaning before welding, it is difficult to cause poor welding or problems with the welding apparatus. Moreover, the metal soap adhering to the to-be-washed | cleaned object surface can be effectively removed by mix | blending a chelating agent further. As a result, it is possible to further suppress the occurrence of defective welding and defects in the welding apparatus in the weld after cleaning.

Hereinafter, the pre-welding detergent of the present invention will be described in detail. In addition, the cleaning agent before welding of this invention is not limited to the following embodiment. The pre-welding cleaning agent of the present invention can be implemented in various forms that have been modified or improved by those skilled in the art without departing from the scope of the present invention.

The pre-welding cleaning agent of the present invention is composed mainly of an alicyclic amine, a liquid fatty acid, and a nonionic surfactant and does not contain a powdered dicarboxylic acid . The alicyclic amine is preferably water-soluble. The alicyclic amine contains morpholine and may contain other alicyclic amines. The type of other alicyclic amine is not particularly limited as long as it is water-soluble, and examples thereof include N-cyclohexyldiethanolamine and cyclohexylamine. These alicyclic amines may be used alone or in combination of two or more. Especially, the compound which contains an oxygen atom in a molecule | numerator is suitable since it is easy to gasify before iron melt | dissolves and combustibility is favorable. In particular, a compound containing an oxygen atom in the ring, such as morpholine, may be used. In this case, since morpholine exists as a neutralized salt with liquid fatty acid, there is no problem of odor described above.

The content rate of the alicyclic amine in the cleaning agent before welding of this invention is 1-40 wt%. From the viewpoint of effectively exhibiting the anticorrosive effect, the content of the alicyclic amine shall be the 1 wt% or more. In order to increase the rust prevention effect, the content of the alicyclic amine may be increased. However, considering practicality such as cost, the content of the alicyclic amine is set to 40 wt% or less . In particular, from the viewpoint of reducing welding defects and the like, it is desirable that the content be 25 wt% or less. More preferably, it is 10 wt% or less.

In addition, in this specification, the suitable content rate of each component is shown on the assumption that the cleaning agent before welding of the present invention is diluted with water to a concentration of 1% or more and 3% or less. Therefore, when the dilution rate at the time of use differs from the said range, what is necessary is just to adjust the content rate of each component suitably according to a dilution rate.

  The type of liquid fatty acid is not particularly limited. Examples thereof include caprylic acid having 9 or less carbon atoms and isononanoic acid. These liquid fatty acids may be used alone or in combination of two or more.

The content rate of the liquid fatty acid in the cleaning agent before welding of this invention shall be 1-20 wt%. From the viewpoint of effectively exhibiting the rust prevention effect, the content ratio of the liquid fatty acid is 1 wt% or more . On the other hand, in consideration of practicality such as cost, the content ratio of the liquid fatty acid is set to 20 wt% or less . In particular, from the viewpoint of reducing welding defects and the like, it is desirable that the content be 10 wt% or less. More preferably, it is 5 wt% or less.

  As the nonionic surfactant, a known activator may be used. Examples include higher alcohol ethoxylates, pluronic types, tetronic types, aliphatic amine ethoxylates, sorbitan fatty acid ester ethoxylates, fatty acid polyethers, secondary alcohol ethoxylates, and the like. One kind of these nonionic surfactants may be used alone, or two or more kinds may be mixed and used.

  The present inventor investigated the presence or absence of flaming (soot, spear) generation and flammability of various nonionic surfactants in the same manner as the cyclic amines described above. The survey results are shown in Table 3. In addition, the symbol in the comprehensive judgment in each table | surface shows (double-circle): suitable, (circle): suitable, (triangle | delta): Somewhat problematic.

  As shown in Table 3, the higher alcohol ethoxylate and the fatty acid polyether had almost no burnout and good combustibility. This shows that both are suitable from the viewpoint of weldability. In addition, the Pluronic type, Tetronic type, and secondary alcohol ethoxylate produced a small amount of spear, resulting in inferior combustibility compared with higher alcohol ethoxylate and fatty acid polyether. In addition, when a secondary alcohol ethoxylate is used, an emulsification characteristic will improve and chemical degreasing performance can be improved. For this reason, when performing ultrasonic cleaning or immersion cleaning with poor physical cleaning power other than spray cleaning, secondary alcohol ethoxylate may be used.

  On the other hand, with the aliphatic amine ethoxylate and sorbitan fatty acid ester ethoxylate, a slight amount of burnt residue remained, and the flammability was not good. For this reason, there was a slight problem in terms of weldability. From the above, it can be said that the nonionic surfactant preferably includes at least one selected from higher alcohol ethoxylates, fatty acid polyethers, and secondary alcohol ethoxylates.

The content ratio of the nonionic surfactant in the pre-welding detergent of the present invention is 1 to 5 wt%. From the viewpoint of exhibiting the cleaning effect of the practical, the content of the nonionic surfactant shall be the 1 wt% or more. On the other hand, if practicality such as cost is taken into consideration, the content ratio of the nonionic surfactant is set to 5 wt% or less in the case of spray cleaning or the like with excellent physical cleaning power . In particular, about 3 wt% is preferable.

The pre-welding cleaning agent of the present invention preferably contains a chelating agent in addition to the main agent. In this case, the metal soap adhering to the surface of the object to be cleaned can be effectively removed. The kind of chelating agent to be used is not particularly limited. For example, EDTA (ethylenediaminetetraacetic acid) inorganic neutralized salt, EDTA organic neutralized salt, DTPA (diethylenetriaminepentaacetic acid) inorganic neutralized salt, DTPA organic neutralized salt, polycarboxylic acid inorganic neutralized salt, polycarboxylic acid organic neutralized salt Examples include salts. One kind of these chelating agents may be used alone, or two or more kinds may be mixed and used. Among these, the EDTA organic neutralized salt and the DTPA organic neutralized salt are preferable because they are less combustible than other materials and have good combustibility.

The content ratio of the chelating agent in the pre-welding detergent of the present invention is not particularly limited. From the viewpoint of effectively exhibiting the effect of removing the metal soap, the content of the chelating agent is preferably 1 wt% or more. On the other hand, in view of practicality such as cost, it is desirable that the content of the chelating agent is 20 wt% or less. In particular, from the viewpoint of reducing welding defects and the like, it is desirable that the content be 10 wt% or less. More preferably, it is 5 wt% or less.

Moreover, the cleaning agent before welding of this invention can contain various additives other than the above as needed. For example, an antifoaming agent etc. can be included. Here, examples of the antifoaming agent include a silicon-based antifoaming agent and an alcohol-based antifoaming agent. However, the flammability of the silicon-based antifoaming agent is poor, and many burnouts remain during welding. Therefore, in consideration of weldability, it is desirable to use an alcohol-based antifoaming agent that does not leave flaming and has good flammability. When adding an antifoamer, the content rate is not specifically limited. In order to exhibit the defoaming effect, 1 wt% or less is sufficient. About 0.5 wt% is preferable.

The pre-welding cleaning agent of the present invention is prepared by mixing the predetermined component and water as a solvent. And it dilutes with water as needed and uses it. The dilution rate can be appropriately set as long as a desired effect is obtained. For example, the pre-weld cleaning agent of the present invention may be used after diluting with water to a concentration of 1% or more and 3% or less. The pre-welding cleaner of the present invention can be used in various cleaning methods such as spray cleaning, ultrasonic cleaning, and immersion cleaning. Further, the pre-weld cleaning agent of the present invention is suitable for pre-cleaning of various weldings such as electron beam welding and laser welding.

Hereinafter, the suitable aspect of the cleaning agent before welding of this invention is shown.
(1) Alicyclic amine: 1 wt% to 5 wt% Liquid fatty acid: 1 wt% to 5 wt% Nonionic surfactant: 1 wt% to 5 wt% Chelating agent: 1 wt% to 5 wt% Antifoam: 1 wt% Hereinafter, water: remainder In this embodiment, the metal soap adhering to the surface of the object to be cleaned can be effectively removed, and it is possible to suppress the occurrence of poor welding and defects in the welding apparatus even in welding after cleaning.
(2) Alicyclic amine: 10 wt% to 20 wt% Liquid fatty acid: 3 wt% to 5 wt% Nonionic surfactant: 3 wt% to 5 wt% Chelating agent: 1 wt% to 5 wt% Antifoam: 1 wt% Hereinafter, water: balance This embodiment is suitable when the content of alicyclic amine is high and it is desirable to further suppress the occurrence of rust in the cleaned parts.
(3) Alicyclic amine: 1 wt% or more and 5 wt% or less Liquid fatty acid: 1 wt% or more and 5 wt% or less Nonionic surfactant (secondary alcohol ethoxylate)
: 10 wt% or more and 15 wt% or less Chelating agent: 1 wt% or more and 5 wt% or less Antifoaming agent: 1 wt% or less Water: Remaining In this aspect, the secondary alcohol ethoxylate which is excellent in an emulsification characteristic is used as a nonionic surfactant. Therefore, it is suitable when performing ultrasonic cleaning and immersion cleaning with poor physical cleaning power.

Based on the said embodiment, the cleaning agent before welding of this invention was prepared. Using the prepared pre-weld cleaning agent, pre- cleaning of electron beam welding was performed, and the occurrence of welding defects and defects in the welding apparatus in subsequent welding was investigated. Hereinafter, it demonstrates in order.

(1) was prepared before welding detergent composition and content of the following preparation of pre-weld cleaning agent.
N-cyclohexyldiethanolamine: 2.5 wt%
Morpholine: 2.5 wt%
Caprylic acid: 3wt%
Higher alcohol ethoxylate: 3wt%
EDTA organic neutralized salt: 3wt%
Alcohol-based antifoaming agent: 0.5 wt%
Water: remainder (2) Cleaning The pre-welding cleaning agent was diluted with water to a concentration of about 1% to obtain a diluted cleaning agent. Using this diluted cleaning agent, the iron differential case was cleaned with a spray cleaning device. The cleaning conditions were a diluted cleaning agent temperature of 60 to 80 ° C., a spray pressure of 0.3 MPa, and a cleaning time of 25 seconds.

(3) Evaluation of weldability The differential case after the cleaning was electron beam welded, and the occurrence rate of defective welds due to the occurrence of blowholes and the failure frequency of the welding apparatus were investigated. As a result, the incidence of defective welds was reduced by half compared to the case of cleaning with a conventional cleaning agent (trade name “Chemite Light CP-60MK (T)”, manufactured by Shimada Kasei Co., Ltd.). Moreover, the failure frequency of the welding apparatus was reduced by 60% or more.

From the above, it has been confirmed that by using the pre-weld cleaning agent of the present invention for cleaning, it is possible to reduce the occurrence of welding defects and defects in the welding apparatus in subsequent welding.

Claims (5)

It is characterized by containing 1 to 40 wt% of alicyclic amine containing morpholine, 1 to 20 wt% of liquid fatty acid, 1 to 5 wt% of nonionic surfactant, and the remainder of water, and no powdered dicarboxylic acid. And pre-weld cleaning agent.   The said nonionic surfactant is a cleaning agent before welding of Claim 1 containing 1 or more types chosen from a higher alcohol ethoxylate, fatty-acid polyether, and secondary alcohol ethoxylate.   Furthermore, the cleaning agent before welding of Claim 1 or Claim 2 containing 1-20 wt% chelating agent.   The said chelating agent is a cleaning agent before welding of Claim 3 containing at least 1 type of EDTA organic neutralization salt and DTPA organic neutralization salt.   Furthermore, the cleaning agent before welding of any one of Claim 1 thru | or 4 containing 1 wt% or less of alcohol type antifoaming agents.