JP5377904B2 - Cold rolling oil for electrical steel sheet and cold rolling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cold rolling oil for steel plate and cold rolling method capable of suppressing an oil stain which may be caused during the rolling of an electrical steel plate. <P>SOLUTION: This cold rolling oil for steel plate includes: at least one or more type(s) of base oil selected from animal and plant oil-and-fat, mineral oils and synthetic esters; a nitrogen-containing water-soluble cyclic compound, preferably a water-soluble triazole compound; and an oil-soluble dicarboxylic acid or an oil-soluble dicarboxylic acid derivative. By using such a cold rolling oil for steel plate, an oil stain is suppressed. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a cold rolling oil and a cold rolling method having excellent oil stain resistance, which are used during cold rolling of a steel sheet containing Si, particularly an electromagnetic steel sheet.

  Cold rolling oil is used for cold rolling of steel sheets for the purpose of lubrication, but in order to prevent seizure due to heat generated during rolling, emulsion type rolling oil is generally used. . Therefore, cold rolling oil is required to have a high balance of various characteristics such as emulsification stability, lubrication stability, corrosion resistance and mill cleanliness, in addition to lubricity.

  In particular, in steel sheets containing Si, such as electromagnetic steel sheets, the embrittlement stability is likely to be impaired when iron powder is mixed in the emulsion because of high brittleness, and further, discoloration of the steel sheet surface after rolling, so-called Oil stains also tend to occur.

  If the emulsification stability is impaired, there may be a portion of insufficient lubrication and a portion of excessive lubrication during cold rolling, resulting in a poor shape of the steel sheet after cold rolling. Also, when oil stain occurs, a temperature difference from the surroundings occurs during subsequent annealing due to a change in the color tone of the steel sheet surface, resulting in a defective shape or remaining as a pattern on the steel sheet surface.

  In recent years, the required quality on the surface of rolled material has become more stringent, and there is a strong demand for rolling oil that does not generate shape defects and oil stains that lower the product value. Furthermore, in order to improve quality stability and yield, there is a strong demand for rolling oils that have better lubricity and emulsion stability than conventional ones.

  The emulsification stability is affected by the type and amount of rolling oil base oil and surfactant used, but is also greatly affected by the type and amount of various additives. In general, the emulsification stability tends to deteriorate due to an increase in oil-based additives, and it is necessary to appropriately examine it depending on the type of steel sheet to be rolled.

  By the way, oil stain is caused by iron oxide generation due to the reaction of iron and moisture on the surface of the steel sheet, and it is said that an emulsion is generated when the emulsion is caught in a coil due to poor drainage after rolling and held at a high temperature. Yes. In an ordinary steel plate, oil stain is noticeable at 90 to 100 ° C., but in an electromagnetic steel plate, oil stain is easily noticeable at 110 to 120 ° C. In order to suppress oil stain, an approach from the viewpoint of facilities such as enhancing air blow and improving drainage is important, but it is not sufficient.

  Oil stain is greatly influenced by the rolling oil used, and can be suppressed by adding to the rolling oil a substance that easily chemisorbs on the surface of the steel sheet (see, for example, Patent Documents 1 to 5). Thereby, it is thought that contact with moisture is suppressed by forming an adsorption film on the steel plate, and oil stain is suppressed.

  For example, Patent Document 1 discloses a cold rolled oil obtained by adding a specific oil-soluble metal compound in an amount of 0.1 to 10% by mass as a metal amount to a base oil.

  Patent Document 2 discloses a cold rolling oil composition characterized by containing a heterocyclic compound having nitrogen and / or sulfur as heteronodes.

  Further, in Patent Document 3, a base oil is mixed with one or more selected from a sulfosuccinic acid derivative, alkyl or alkenyl succinic acid and alkyl or alkenyl succinic acid ester. A hot rolling oil is disclosed.

  Patent Document 4 discloses a lubricating oil for hot rolling oil for aluminum plates containing a lubricating oil component, an oil-soluble compound having a triazole structure, and a water-soluble compound having a triazole structure.

  In Patent Document 5, at least one selected from a 1-hydroxybenzotriazole compound or a salt thereof, one selected from a phenoxyalkylcarboxylic acid compound or a salt thereof, at least one aliphatic dicarboxylic acid, and HLB of 11 to 11 The temper rolling agent which consists of at least 1 sort (s) of the nonionic surfactant which is 13 and was adjusted to pH 7-12 with the alkaline agent is disclosed.

JP 2000-104089 A Japanese Patent Laid-Open No. 3-81397 JP 61-163998 A JP 2004-263087 A JP 2001-288492 A

  By the way, the emulsion has a form in which the oil phase is dispersed in the water phase, and both the oil phase and the water phase are mixed even in a sealed state in the coil. For this reason, the inventors of the present application require an action from both the oil phase and the aqueous phase in order to produce a uniform adsorption film with few defects on the surface of the steel sheet. It was conceived that oil stain can be more effectively suppressed by using the agent together.

  As disclosed in the above Patent Documents 1 to 5, so far, it has been dealt with by adding a specific compound as an oil stain suppression means, but both are added alone, and compounds of different systems are used in combination. It has not been. For this reason, there is a problem that the oil stain resistance is not sufficient in a place where the oil phase and the aqueous phase coexist.

  For example, in Patent Document 1, since there is no oil stain suppression action from the aqueous phase side, local discoloration is a concern.

  Also, in Patent Document 2, since it is used alone, there is a concern that oil stain is likely to occur at a local defect portion.

  Moreover, in patent document 3, the use as an emulsion is not assumed. Moreover, even if it uses as an emulsion, the water-soluble additive is not used, but there is a concern that the oil stain inhibiting action is insufficient from the aqueous phase side. In addition, the target material is for aluminum or aluminum alloy, and oil stain resistance with respect to an electromagnetic steel sheet in which oil stain is likely to occur is not considered.

  In Patent Document 4, an oil-soluble compound and a water-soluble compound are used in combination to impart iron corrosion resistance to ancillary equipment. Evaluating. Oil stain is a discoloration that occurs when the emulsion is hermetically held in a steel sheet coil at a high temperature, but this situation is not expected, and oil stain occurs under severe conditions such as high temperature sealing. It is insufficient in terms of oil stain resistance with respect to easy electrical steel sheets.

  Further, Patent Document 5 effectively prevents the occurrence of gum-up, but does not assume a situation where the emulsion is in a high-temperature sealed state, and is resistant to oil stains on electrical steel sheets that are prone to oil stains. Sex is not considered.

  Therefore, the present invention has been made in view of such a problem, and an object of the present invention is to provide an electromagnetic wave excellent in oil stain resistance that can suppress oil stains that can occur when rolling an electromagnetic steel sheet. It is providing the cold rolling oil for steel plates, and the cold rolling method.

  As a result of intensive studies to solve the problems of the prior art, the present inventors have found that the above problems can be solved by simultaneously using a specific water-soluble compound and an oil-soluble compound as described above. The present invention has been completed. That is, this invention consists of the following structures.

(1) containing at least one base oil selected from animal and vegetable oils and fats, mineral oils and synthetic esters, a nitrogen-containing water-soluble cyclic compound, and an oil-soluble aliphatic dicarboxylic acid or oil-soluble aliphatic dicarboxylic acid derivative; The nitrogen-containing water-soluble cyclic compound is at least one water-soluble triazole compound selected from benzotriazole, tolyltriazole, carboxybenzotriazole, and 1-hydroxybenzotriazole, and contains the water-soluble triazole compound with respect to the base oil The oil-soluble aliphatic dicarboxylic acid or oil-soluble aliphatic dicarboxylic acid derivative is alkylated, alkenylated or anhydrous with respect to malonic acid, succinic acid or glutaric acid. One of the oil-soluble ones Other is 2 or more, the content of the oil-soluble aliphatic dicarboxylic acids or oil-soluble aliphatic dicarboxylic acid derivative with respect to the base oil is characterized by a 3.1 to 10.0 wt%, the electromagnetic Cold rolling oil for steel plate.
( 2 ) A cold rolling method characterized by using an emulsion obtained by diluting the cold rolling oil for electrical steel sheets according to (1) to 0.2 to 20% by volume in a rolling manner in a rolling mill.

As described above, according to the present invention, it is possible to provide cold rolled oil for electrical steel sheets having excellent oil stain resistance. Moreover, the surface quality of the excellent rolling material can be obtained by the cold rolling method to which the cold rolling oil for electrical steel sheets of the present invention is applied.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  The present invention is for solving the problems of the prior art, and is excellent in emulsifiability and emulsification stability as well as lubricity, and has excellent oil stain resistance. A rolling method is provided, which is suitable for a steel sheet containing Si, particularly an electromagnetic steel sheet.

  The steel plate used in the present invention is suitably one containing Si, and a steel plate generally called an electromagnetic steel plate is used. The addition amount of Si is, for example, preferably 0.6% by mass or more and less than 7.0% by mass, more preferably 0.8% by mass to 3.5% by mass, and further preferably 2.0% by mass to 3%. The range is 25 mass%. As other additive elements, for example, Al or Mn may be contained. The Al content is preferably 0.1% by mass or more and less than 3.0% by mass, for example, and the Mn content is preferably 0.01% by mass or more and less than 1.0% by mass, for example. In addition, the content of the typical element is, for example, suitably 0.01% by mass or less, more preferably 0.002% by mass or less.

  The base oil contained in the cold rolled oil used in the present invention is selected from animal and vegetable oils, mineral oils and synthetic esters, and those conventionally used for cold rolled oil can be used. Specifically, as animal and vegetable oils and fats, for example, beef tallow, palm oil, palm kernel oil, rapeseed oil, coconut oil and the like can be mentioned, and as mineral oils, for example, machine oil, spindle oil, turbine oil and the like can be mentioned. be able to. Synthetic esters include, for example, monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, octyl alcohol, lauryl alcohol, isobutyl alcohol, 2-ethylhexyl alcohol, or ethylene glycol, propylene glycol, butylene glycol. , Neopentyl glycol, hexylene glycol, glycerin, polyglycerin, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol and other polyhydric alcohols, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, etc. Monovalent fatty acids or acrylic acid, methacrylic acid, succinic acid, alkenyl succinic acid having 12 carbon atoms, dimer acid having 36 carbon atoms, And polyvalent fatty acids such mer acid, synthetic ester can be used. As the base oil used in the present invention, one or more selected from these groups can be used.

  The nitrogen-containing water-soluble cyclic compound contained in the cold-rolled oil used in the present invention, preferably a water-soluble triazole compound, forms an adsorbed film on the steel sheet surface from the aqueous phase, and causes moisture that causes oil stain generation. There is an effect of reducing contact with the steel plate. Examples of the water-soluble triazole compound include 1,2,3-triazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, and benzoate. Examples include triazole, tolyltriazole, carboxybenzotriazole, 1-hydroxybenzotriazole and the like. These compounds may be used alone or in combination of two or more.

  The content of the nitrogen-containing water-soluble cyclic compound, preferably the water-soluble triazole compound, relative to the base oil is preferably, for example, 0.1 to 5.0% by mass, more preferably 0.3 to 3.0. It is mass%, More preferably, it is 0.5-2.0 mass%. If it is less than 0.1% by mass, the effect on oil stain resistance is insufficient. On the other hand, if it exceeds 5.0 mass%, the effect is saturated and it is not economical.

  The oil-soluble dicarboxylic acid or oil-soluble dicarboxylic acid derivative contained in the cold-rolled oil used in the present invention generates an adsorption film on the steel sheet surface from the oil phase, and contact between the water and the steel sheet that causes oil stain generation There is an effect of reducing.

  Oil-soluble polybasic acids or oil-soluble polybasic acid derivatives are, for example, alkylated, alkenylated, and anhydrous for malonic acid, succinic acid, glutaric acid, adipic acid, vimelic acid, suberic acid, azelaic acid, and sebacic acid. Or at least one of the above to make it oil-soluble. These compounds may be used alone or in combination of two or more.

  The content of the oil-soluble dicarboxylic acid or the oil-soluble dicarboxylic acid derivative with respect to the base oil is, for example, preferably 0.1 to 10.0% by mass, more preferably 0.3 to 7.0% by mass. More preferably, it is 0.5 to 5.0% by mass. If it is less than 0.1% by mass, the effect on oil stain resistance is insufficient, such being undesirable. On the other hand, if it exceeds 10.0% by mass, the effect is saturated and it is not economical.

  Nitrogen-containing water-soluble cyclic compound, preferably water-soluble triazole compound and oil-soluble dicarboxylic acid or oil-soluble dicarboxylic acid derivative, in combination, both in the aqueous phase and oil phase Due to the combined effect, a dense adsorption film with few defects is formed on the surface of the steel sheet. As a result, oil stain resistance is dramatically improved.

  When the cold rolling oil of the present invention is used as an emulsion, it is dispersed in water using an optimal emulsifier. Usable emulsifiers include, for example, anionic surfactants, nonionic surfactants, and cationic surfactants, and nonionic surfactants are particularly preferable. The content of the emulsifier is, for example, preferably 0.1 to 10.0% by mass, more preferably 0.2 to 7.0% by mass with respect to the base oil.

  When using the cold-rolled oil of the present invention as an emulsion, it is usually preferable to dilute a water-diluted emulsion of 0.2 to 20 vol% with water as a coolant. The water used for dilution may be deionized water, tap water, or industrial water, and there is no particular limitation on the emulsion preparation method.

  If the cold rolling oil of the present invention is within the range in which the effects of the present invention are not impaired, various additives such as various oiliness improvers, extreme pressure additives, and antioxidants may be added as necessary. it can.

  In the present invention, the mechanism for improving the oil stain resistance of an electromagnetic steel sheet containing Si is not clear in detail, but in the case of an electromagnetic steel sheet, an oxide film formed on a new surface generated during rolling is Si or Al. It is considered that these alloy components exhibit properties different from those of ordinary steel sheets. Therefore, general additives and antioxidants cannot suppress the generation of oil stains, and by adding a specific amount of the specific substance disclosed in the present application, a stable oxide film is formed to prevent the generation of oil stains. It is thought to prevent.

  The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[Test method for emulsification and emulsion stability]
(1) Preparation of Test Emulsion Test rolling oils (Examples 1 to 10, Comparative Examples 1 to 8) shown in the compositions of Tables 1 and 2 were prepared and subjected to emulsion bathing under the following conditions.

Rolling oil concentration: 3 vol%
Bathing volume: 1L
Water used: Deionized water Bath temperature: 60 ° C
Stirring conditions: Homomixer 7000 rpm x 30 min
Iron powder contamination: 0 ppm (new oil) or 1000 ppm based on the emulsion

(2) Evaluation standard of emulsification property and emulsification stability The emulsification property was evaluated by the average particle size of the emulsion immediately after stirring, and the emulsification stability was evaluated by the rate of change of the average particle size when iron powder was added. In measuring the average particle size, a particle size distribution measuring device (Multisizer 3, manufactured by Beckman Coulter, Inc.) was used.

<Emulsification evaluation criteria>
○: 8 μm or less △: 8-12 μm
×: 12 μm or more

<Emulsification stability evaluation criteria>
Evaluation was based on the change rate of the average particle size when adding new oil and iron powder. The change rate of the average particle diameter was calculated based on the following formula. The evaluation criteria are as follows.

Rate of change = (average particle size when iron powder is added-average particle size of new oil) / average particle size of new oil

Evaluation Criteria for Emulsification Stability ◎: Less than 0.1 ○: 0.1-0.2
Δ: 0.2 to 0.4
Δ to ×: 0.4 to 0.6
×: 0.6 or more

[Lubricity test method]
Rolling lubrication tests were performed on the test rolling oils (Examples 1 to 10, Comparative Examples 1 to 8) shown in the compositions of Tables 1 and 2 using a high-speed strip rolling tester under the following conditions, and comparative evaluations were performed using rolling loads. . It can be said that the rolling lubricity is better as the rolling load is lower.

Test piece: Electrical steel sheet (1.2 mm × 30 mm × 500 mm) containing 3.0 mass% Si and 0.3 mass% Al
Roll: 500 mmφ (Emery paper # 80 polishing, surface roughness Ra 0.3 μm)
Rolling speed: 500 m / min
Rolling rate: 30%
Rolling oil concentration: 3 vol%
Bathing volume: 10L
Bath temperature: 50 ° C
Spray amount: 1L / min is supplied to the upper and lower rolls with a baseless pump

<Rolling lubricity evaluation criteria>
The rolling lubricity was evaluated from the rolling load. The evaluation criteria are as follows.

Evaluation criteria for rolling lubricity ◎: Rolling load is less than 350 N ○: Rolling load is 350 N or more and less than 370 N Δ: Rolling load is 370 N or more and less than 400 N ×: Rolling load is 400 N or more

[Oil stain resistance test method]
(1) Preparation of Test Emulsion Test rolling oils (Examples 1 to 10, Comparative Examples 1 to 8) shown in the compositions of Tables 1 and 2 were prepared and subjected to emulsion bathing under the following conditions.

Rolling oil concentration: 3 vol%
Bathing volume: 1L
Water used: Deionized water Bath temperature: 60 ° C
Stirring conditions: Homomixer 7000 rpm x 30 min

(2) Preparation of test plate Solvent (diethyl ether) having a size of 0.8 mm × 30 mm × 100 mm Degreased electrical steel sheet containing 3.0 mass% Si, 0.3 mass% Al was used as the above test emulsion. Then, 1 ml of the emulsion was dropped on the steel plate and rolled under the following conditions. The rolled steel plate was used as a test plate for oil stain resistance test.

Roll: 100 mmφ bright roll Rolling speed: 10 m / min
Reduction ratio: 5-pass rolling, total reduction ratio 50%

(3) Preparation of sample for oil stain resistance test and acceleration of oil stain The rolled test piece is cut into 30 mm × 100 mm, and 0.3 ml of the emulsion is dropped on the surface to make four sheets. Next, the four stacked test pieces are double-wound with aluminum foil, and the four corners are sandwiched with double clips. This was left for 16 hours in an environment of 110 ° C.

(4) Oil stain resistance evaluation criteria The steel plate surface after the above test was wiped with a solvent (diethyl ether), and the oil stain on the test piece was visually evaluated based on the following evaluation criteria.

A: Almost no oil stain is seen.
○: Slight oil stain is observed.
Δ: Oil stain is slightly noticeable.
Δ to X: Oil stain is conspicuous.
X: Oil stain is conspicuous.

  Tables 1 and 2 show the test results of Examples 1 to 10 and Comparative Examples 1 to 8 of the present invention. Table 1 shows the results of the examples, and Table 2 shows the results of the comparative examples.

  The components shown in Table 1 and Table 2 were as follows. In addition, the unit of content of each component in Table 1 and Table 2 is mass%.

Base oil 1: Trimethylolpropane trioleate Base oil 2: Triacylglycerol Water-soluble additive 1: Benzotriazole Water-soluble additive 2: Tolyltriazole Water-soluble additive 3: Carboxybenzotriazole Water-soluble additive 4: 1-H mud carboxymethyl benzotriazole oil soluble additive 1: alkenylsuccinic acid oil-soluble additive 2: alkenyl succinic anhydride oil soluble additive 3: alkenyl malonic acids oil soluble additive 4: alkenyl glutaric acid dihexyl sodium oil soluble additive 5: Tin octylate oil-soluble additive 6: Sodium dihexyl sulfosuccinate Oil-soluble additive 7: 1- [N, N-bis (2-ethylhexyl) aminomethyl] benzotriazole

  In Examples 1 to 10 to which the cold rolling oil of the present invention was applied, oil stain resistance was good. On the other hand, in Comparative Example 1 (without additives), Comparative Examples 2 and 4 (only water-soluble additives), and Comparative Examples 3 and 5 (only oil-soluble additives), sufficient oil stain resistance was not obtained. . In Comparative Examples 6 and 7 (using oil-soluble additives other than the present invention), it is difficult to achieve both emulsion stability and oil stain resistance. In Comparative Example 8 (combined use of water-soluble and oil-soluble triazole compounds) However, the oil stain resistance was insufficient.

  As described above, the cold rolling oil of the present invention has not only lubricity but also good emulsifiability and emulsion stability, and has particularly excellent oil stain resistance. Excellent surface quality of the rolled material can be obtained by a cold rolling method to which rolling oil is applied.

As mentioned above, although preferred embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

Claims (2)

At least one base oil selected from animal and vegetable oils, mineral oils and synthetic esters;
A nitrogen-containing water-soluble cyclic compound;
An oil-soluble aliphatic dicarboxylic acid or an oil-soluble aliphatic dicarboxylic acid derivative;
Containing
The nitrogen-containing water-soluble cyclic compound is at least one water-soluble triazole compound selected from benzotriazole, tolyltriazole, carboxybenzotriazole and 1-hydroxybenzotriazole;
The content of the water-soluble triazole compound with respect to the base oil is 0.1 to 5.0% by mass,
The oil-soluble aliphatic dicarboxylic acid or the oil-soluble aliphatic dicarboxylic acid derivative is one of those which are made oil-soluble by performing at least one of alkylation, alkenylation or anhydride on malonic acid, succinic acid or glutaric acid. Or two or more,
The cold-rolled oil for electrical steel sheets, wherein the content of the oil-soluble aliphatic dicarboxylic acid or the oil-soluble aliphatic dicarboxylic acid derivative with respect to the base oil is 3.1 to 10.0% by mass. A cold rolling method characterized by using, in a rolling mill, an emulsion obtained by diluting the cold rolling oil for electrical steel sheets according to claim 1 to 0.2 to 20% by volume in a circulating manner.