JPH04118101A - Cold rolling method - Google Patents

Abstract

PURPOSE:To offer the technique for preventing the seizure and surface roughening of a stainless steel, etc., at the time of cold rolling of this steel, etc., by using an aq. emulsion having the average grain size of a specific value or below to form a rolling mill lubricant which consists essentially of a lubricating component having the viscosity at a specific temp. of a specific value or above. CONSTITUTION:The lubricating component having >=80cSt viscosity at 40 deg.C is used at >=5wt.%, more preferably 10 to 90wt.% of the total weight of the rolling mill lubricant. The more preferable lubricating component is the ester of hindered alcohol, such as trimethylol propane and pentaerithritol, without having a hydrogen atom in the carbon atom adjacent to carbon having an OH group, and higher fatty acid. A good result is obtd. with the emulsion of superfine particles of <=2mum, more particularly <=1mum average grain size. The concn. of the rolling mill lubricant in the cold rolling mill lubricant emulsion is 1 to 20wt.%, more particularly preferably 2 to 5wt.%. The adhesion of the rolling mill lubricant on a steel sheet is 50 to 200mg/m<2>, more particularly preferably 50 to 200mg/m<2>.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a cold rolling method.

Prior Art Stainless steel is harder than steel and requires high pressure for rolling, so the roll surface is easily scratched and seizes easily. Particularly recently, chromium-rich high chromium steel, which has good wear resistance, has begun to be used in rolling work rolls, and when stainless steel is rolled using this high chromium steel, a problem has arisen in that seizure is more likely to occur.

One way to solve this problem is to use rolling oil to improve the lubricity between the rolled steel plate (strip) and the work rolls, but in order to improve lubricity, it is necessary to thicken the oil film, resulting in poor finish. This will cause the surface of the product to become rough.

Another strategy is the use of extreme pressure additives. The representative ingredients conventionally known as effective extreme pressure additives for stainless steel are halides such as iodine, but their effects are not satisfactory and are not sufficient to prevent seizure during rolling of stainless steel. .

Problem to be Solved by the Invention The present invention provides a technique for preventing seizure and surface roughening during cold rolling of stainless steel and the like.

Means for Solving the Problems The present invention involves forming an aqueous emulsion of a rolling oil whose main component is a lubricating component with a viscosity of 8Qcst or more at 40°C and having an average particle size of 2μ or less, and supplying this onto a steel plate to be rolled while cooling it. This article relates to a method of rolling steel plates that are subjected to inter-rolling.

The rolling oil used in the present invention uses a lubricating component having a viscosity of 3Qcst or more at 40°C. This lubricating component is used in an amount of 5% by weight or more, preferably 10 to 90% by weight, based on the total weight of the rolling oil.

This lubricating component may be used dissolved in a diluent that itself hardly functions as a lubricant, such as low-viscosity mineral oil, or mixed with other lubricating components. When diluting with low viscosity mineral oil etc., the viscosity of the diluent containing this lubricating component is 3Qcst.
It is not necessary to have more than 5Qcst at 40℃, but preferably
It is good to have more than that.

In addition, when used in combination with other lubricating components, especially esters of higher fatty acids and polyhydric alcohols, the viscosity of the mixture is 8Q.
It is preferable that there is more than cst. In rolling oil with a content of lubricating components of 5% by weight or more and 80cst or more at 40°C,
By blending other esters, the viscosity of the entire lubricating component may be reduced to 80 cst or less, but preferably 60 cst.
t (40°C) should not be exceeded.

The lubricating component used in the present invention may be one that satisfies the above requirements, but such a lubricating component is difficult to obtain from natural animal and vegetable oils, so it is preferable to modify natural oils or fats or use synthetic esters. .

Examples of modified natural fats and oils include fats and oils having hydroxyl groups such as castor oil and hydrogenated castor oil, as well as mono- or polycarboxylic acids, such as aliphatic carboxylic acids of 01 to C3°, such as octylic acid, lauric acid, stearic acid, and oleic acid. acid,
Examples include erucic acid, abietic acid, ricinoleic acid, hydroxystearic acid; esters with polycarboxylic acids such as maleic acid, 7-maric acid, abietic acid, sebacic acid, 7-taric acid and the like.

Synthetic esters include polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, polyglycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitan, etc. and fatty acids such as lauric acid, myristic acid, palmitic acid,
Esters with stearic acid, oleic acid, linoleic acid, erucic acid, ricinoleic acid, hydroxystearic acid, etc.;
Esters of castor oil or hydrogenated castor oil with higher fatty acids or polyesters with polycarboxylic acids; esters of higher fatty acids with higher aliphatic alcohols, polyesters of ricinoleic acid, higher aliphatic alcohols such as lauryl alcohol, cetyl alcohol, stearyl alcohol , oleyl alcohol, various synthetic alcohols, alcohols with side chains, and polycarboxylic acids such as maleic acid, fumaric acid, succinic acid, adipic acid, azelaic acid,
Sebacic acid, hexanetricarboxylic acid, trimellidic acid,
Examples include esters with 7-tar acid and the like.

Particularly preferred lubricating components for the present invention are esters of higher fatty acids and hindered alcohols, such as trimethylolpropane and pentaerythritol, which do not have a hydrogen atom adjacent to a carbon having an OH group. These esters are generally called hindered esters,
These esters not only have excellent heat resistance, but also have little increase in the viscosity of the oil film even under high extreme pressure, and do not cause oil film breakage, so metal contact between the roll and the strip can be avoided. As a result, seizure of the steel plate can be prevented with a thin oil film, and since the oil film can be made thinner, surface roughness of the finished product can be eliminated. As will be described later, particularly good results are obtained when an acidic phosphoric acid ester is used in combination with an aromatic amine.

Higher fatty acids suitable for esterification with hindered alcohols may be any of the fatty acids mentioned above, but ricinoleic acid or hydrogenated ricinoleic acid may be used partially or completely, and some of the remaining hydroxyl groups of ricinoleic acid may be used. or all are further esterified with other fatty acids, such as monocarboxylic acids such as acetic acid, octylic acid, lauric acid, stearic acid, ricinoleic acid, oleic acid, dicarboxylic acids such as fumaric acid, phthalic acid, maleic acid, adivic acid, etc. The molecular weight may also be increased. Alternatively, the molecular weight may be increased by using dimer acid as part of the fatty acid. Alternatively, natural animal and vegetable oils may be mixed with hindered alcohols and higher fatty acids, and transesterified.

When these lubricating components are used in cold rolling oil, the viscosity of the lubricating components at 40° C. is preferably adjusted to 8QcsL or more. At this viscosity, it is possible to prevent seizure of steels that are prone to seizure, such as stainless steel.

If the viscosity is too lower than 3QcsL, the oil film becomes thin and is likely to break down under high pressure. When a high reduction ratio is obtained in cold rolling stainless steel, the rolling pressure is very high, for example, 1000 MPa to 5000 MPa. If the viscosity of the lubricating component is low, the oil film cannot be thick enough under high pressure, resulting in metal-to-metal contact, resulting in scratches and seizures. Use of a large amount of lubricant causes surface roughness due to lubricant entrapment. In order to maintain an oil film thickness that does not cause metal contact under high pressure, it is necessary to increase the viscosity of the lubricant, but there is a limit to this alone.

Aromatic amine salts of organic acidic phosphate esters are particularly useful for increasing oil film strength and preventing oil film breakdown under high pressure. Ma I
As the lubricating component, it is preferable to use synthetic esters, especially hindered esters, which have relatively high viscosity at room temperature but are difficult to solidify under high pressure, such as esters of hindered alcohols such as trimethylolpropane and fatty acids.

When diluting with low viscosity mineral oil etc., the viscosity of the diluent should be 8Qc.
Although it does not need to be more than sL, preferably 2Qc at 40℃
It is better to have SL or more. When used in combination with other lubricating components, especially esters of higher fatty acids and polyhydric alcohols, the viscosity of the mixture is preferably 8QcsL or more.

In a rolling oil in which the content of lubricating components of 8QcsL or more at 40°C is 5% by weight or more, the viscosity of the entire lubricating component may be reduced to 80 cst or less by blending other esters, but preferably 60 cst (at 40°C ) should not be cut.

The lubricating components may be used alone or in combination. It may also be blended with other common lubricating ingredients, such as natural animal and vegetable oils, such as lard, head, soybean oil, castor oil, rapeseed oil, palm oil, and the like. Also, some mineral oil may be used as a lubricating component.

The rolling oil used in the present invention contains, in addition to the above-mentioned lubricating components, other additives that are normally added to rolling oils, such as extreme pressure additives, rust preventives, emulsifying dispersants, etc.

Examples of extreme pressure additives include phosphoric acid esters, phosphorous acid esters, acidic phosphoric acid ester amine salts, zinc dithiophosphate, sulfurized oils and fats, disulfides, and molybdenum disulfide. In particular, by using an aromatic amine salt of an organic acidic phosphate ester, an outstanding anti-seizure effect can be obtained.

Organic acid phosphate ester is an ester of a hydroxyl group-containing organic compound and phosphoric acid, and examples of the hydroxyl group-containing organic compound include aliphatic alcohols, alicyclic alcohols, aliphatic alcohols, aromatic hydroxy compounds, and polyhydric alcohols. , polyether hydroxy compounds, polyester hydroxy compounds, etc. In these hydroxyl group-containing organic compounds, after the phosphoric acid group is chemically adsorbed on the surface of metal such as stainless steel,
It is thought that it forms an organic molecular film on its surface, which acts as an oil film itself, or acts as a group with affinity for other lubricating components used at the same time, making it easier to form an oil film. Therefore, from this point of view, those having relatively long-chain hydrocarbon groups are preferable, but if a large amount of long-chain hydrocarbons is used, the content of phosphoric acid groups decreases, and its activity decreases. Therefore, the number of carbon atoms is about 1 to 30, especially 1 to 12.
Preferably.

Examples of aliphatic alcohols include saturated or unsaturated alcohols that may have a side chain having 1 to 30 carbon atoms, or aliphatic alcohols in which some of the hydrogens are substituted with halogens such as iodine and fluorine. Illustrated. Preferred is an aliphatic alcohol having 1 to 12 carbon atoms. Of course, mixed alcohols may also be used. Using an unsaturated alcohol can lower the viscosity, and using an alcohol with a side chain, such as 2-ethylhexanol, can improve the spreadability of the oil film.

Examples of the alicyclic alcohol include cyclohexanol and cyclopentanol, and examples of the aliphatic alcohol include benzyl alcohol.

Aromatic hydroxy compounds include phenol, t-7'
Examples include octylphenol, nonylphenol, and cresol.

Examples of polyhydric alcohols include ethylene glycol, propylene glycol, glycerin, pentaerythritol, trimethylolpropane, and sorbitan. Examples of polyether hydroxy compounds include polyethylene glycol, polypropylene glycol, polyoxyethylene alkyl ether, polyoxypropylene alkyl ether, and polyether hydroxy compounds. Examples of the polyester hydroxy compound such as oxyethylene alkyl phenyl ether include castor oil, hydrogenated castor oil, and the like. Therefore, when a hydroxyl group-containing compound such as castor oil is used as a rolling oil, a portion thereof may be phosphorylated.

Particularly preferred phosphoric acid ester residues (hydroxyl group-containing compounds) include aliphatic compounds having a molecular weight of 15 to 4211, particularly 15 to 167;
It is an alicyclic residue or a polyester hydroxy compound residue.

At least one of the three OH groups of phosphoric acid forms an ester with the above-mentioned hydroxyl group-containing compound, and the remaining at least one forms a salt with an aromatic amine. one other OH
may be an ester, a salt with an aromatic amine, a free OH group, or a salt with an alkali other than the aromatic amine. The organic phosphate ester may be water-soluble or water-insoluble. The number of ester residues is 1 to 1 per molecule of organic phosphate ester.
It is preferable to have 2 OH groups, and the degree of neutralization is 4% of the remaining OH groups.
It is preferred that 0% or more, especially 50 to 70%, is neutralized, especially all of it is neutralized with aromatic amines.

The aromatic amine may be any amine having at least one aromatic group, but preferably an amine having two or more aromatic groups, such as the general formula: % formula % [where Ar and Ar' are each an aromatic group which may independently have a substituent, R represents hydrogen or an alkyl group], preferably Ar and Ar', at least one of which has a substituent; One is a phenyl group which may have a substituent, and the other is a phenyl group or a naphthyl group which may have a substituent. As a substituent, carbon number 1
Hydrocarbon groups such as saturated or unsaturated alkyl groups, alkenyl groups, aralkyl groups, cycloalkyl groups, and aromatic groups that may have ~18 side chains, particularly preferred are alkyl groups having 1 to 12 carbon atoms. . In addition, the substituent is θ~
You may have 4 bonds. Particularly good results are obtained when the compound has 0 to 2 substituents. When Ar is a naphthyl group, N
may be bonded to the a-position or the β-position.

Particularly preferable Ar groups are phenyl group, naphthyl group, 2-alkylphenyl group, 4-alkylphenyl group, and 2,4-dialkylphenyl group.

R is hydrogen or a saturated or unsaturated aliphatic hydrocarbon group having 1 to 18 carbon atoms and optionally having a side chain. Particularly good results are obtained when R is hydrogen or a lower alkyl group.

Examples of typical aromatic amines preferred for the present invention are diphenylamine, 4-octyldiphenylamine, 4-octyldiphenylamine,
-nonyldiphenylamine, 4゜4゛-dioctyldiphenylamine, 4.4'-dinonyldiphenylamine,
2.2',4.4-tetrabutyldiphenylamine, 2
．． Examples include 2'-dibutyl-4,4-dioctyldiphenylamine, 2,2'-dimethyl-4,4'-dioctyldiphenylamine, and 2,2-diethyl-4,4-dioctyldiphenylamine. Particularly preferred aromatic amines are 4-octyldiphenylamine, 4-nonyldiphenylamine, 4.4-dioctyldiphenylamine, 4.4'-dinonyldiphenylamine, and the like.

The aromatic amine may be used in an excess amount relative to the acidic phosphoric acid ester.

The rolling oil used in the present invention contains 100 parts by weight of the lubricating component.
It is preferable to use 0.2 to 5 parts by weight, more preferably 0.5 to 3 parts by weight of the acidic phosphate ester amine salt. The organic acidic phosphoric acid ester and the aromatic amine may be reacted in advance or may be mixed separately in rolling oil. Alternatively, they may be used in such a way that they are mixed into the rolling oil at the same time or separately at the time of use.

The amount of aromatic amine salt of organic acidic phosphate ester (including the excess amount when an excess amount of aromatic amine salt is used) for the lubricant component is 100 parts by weight of the former and 0 parts by weight of the latter.
．． The amount is 2 to 5 parts by weight, more preferably 0.5 to 3 parts by weight.

In the present invention, the rolling oil is supplied as an emulsion. Good results can be obtained with emulsions using ultrafine particles with an average particle size of 2 μm or less, particularly 1 μm or less.

As mentioned above, when obtaining a high reduction rate in cold rolling of stainless steel etc., the rolling pressure is very high, for example l 0
00MPa to 5000MPa. One way to prevent this is to use lubricating components with high oil film strength.

Oil with high viscosity as a lubricating component, e.g. 3 at 40℃
An extremely excellent anti-seizure effect can be achieved by using an oil having a viscosity equal to or higher than Qcst, especially hindered esters that can maintain fluidity without reducing the degree of molecular freedom even under high pressure. On the other hand, however, because of its high viscosity, the oil film tends to become thick, and as a result, the surface of the rolled steel sheet is roughened due to the entrapment of lubricating components.

In the present invention, by reducing the emulsion particle size of the refueling emulsion, it is possible to cold-roll steel plates that are prone to seizure, such as stainless steel, at a high reduction rate without deteriorating the surface gloss.

The concentration of rolling oil in the cold rolling oil emulsion is preferably 1 to 20% by weight, particularly 2 to 5% by weight, and the amount of rolling oil deposited on the steel plate is preferably 50 to 200 mg/m2. If the emulsion concentration is too high or the amount of emulsion deposited is too large, the surface gloss of the finished product will be reduced.

In order to adjust the emulsion particle size to 2 μm or less, it is important to select an emulsifier. Examples of such emulsifiers include polyoxyalkylene alkyl ether, polyoxyalkylene phenyl ether, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene alkylamine, fatty acid alkanolamide, alkanolamine, alkylamine, alkyl It can be obtained by appropriately combining diamines and the like. The amount of emulsifier used is 3 to 20% by weight, more preferably 5 to 15% by weight, based on the total amount of rolling oil. If the amount of emulsifier is too large, the lubricity and oil film strength will decrease, and as a result, damage to the roll, seizure, etc. will likely occur.

The present invention will be explained below with reference to Examples.

Examples Table 1 shows the rolling oil formulations of Examples and Comparative Examples, their viscosity, and the average particle size of the emulsions. The results of these four-ball friction tests are shown in Table 2.

Further, the rolling performance in a rolling test in a small rolling mill using these 5% by weight emulsion A is shown in FIGS. 1 and 2, and the glossiness of the rolled copper plate is shown in Table 3.

The test esters and organic acidic phosphate ester amine salts are as follows.

Pentaerythritol mixed fatty acid ester 25 parts by weight of pentaerythritol, 62.5 parts by weight of oleic acid, and 22.5 parts by weight of Dimer M were reacted at 260° C. for 8 hours under a nitrogen stream to obtain an ester with an acid value of 10.

Organic acid phosphate ester aromatic amine salt phosphoric anhydride 20
．． 80~2 parts by weight and 31.7 parts by weight of butyl alcohol
The reaction was carried out at 85°C for 2 hours, and then neutralized with 48.1 parts by weight of 4-octyldiphenylamine.

The viscosity at 40°C of the ester used is shown below.

Pentaerythritol trioleate 89.5cs
t-pentatrithritol mixed fatty acid ester 674.1
cst trimethylolglobantrioleate 49.4cst
Beef tallow 4L6cst Table-2 Four-ball friction test results (withstand load, kgf) Table-3 Rolling test results (gloss) Evaluation method Four-ball friction test Measured using a high-speed four-ball friction tester under the following conditions.

Sample 2 neat measurement temperature: 50°C Rotation speed: 500rp+i Pole: l 1/2 inch 5UJ-2 and 5US440 Loading speed: 120kg/win Rolling test Using a two-high compact rolling mill with WR dimension 10 (11 x 130 L (+am)) A rolling test was conducted under the following conditions.

Roll peripheral speed: 12w/win Roll roughness: RaO, 2μ sheet Rolling oil concentration: 5% Rolling oil temperature: 50℃ The total strain (%) was calculated using the following formula.

Ho: jl [board thickness, h: exit side board thickness 9 fish! Glossiness was measured using Suga Test Machine UGV-4D at an incident angle of 206 degrees and a light receiving angle of 20 degrees perpendicular to the rolling direction.

Effects of the Invention By using the rolling oil of the present invention, it is possible to cold-roll stainless steel with good surface gloss at high pressure and at high speed without causing seizure.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are graphs showing the results of rolling tests obtained in Examples and Comparative Examples of the present invention. Patent applicant: Japan Quaker Chemical Co., Ltd.
Person Bento delivery mountain 葆 Haka 1 person 1111! 1 1 Meng Shu M Dan L (Le drama 1 basket) 2゜Figure 2 J Wolf Lp! Fukimari 1 (rolling performance)

Claims (1)

[Claims] 1. Rolling oil mainly composed of a lubricating component with a viscosity of 80 cst or more at 40°C is made into an aqueous emulsion with an average particle size of 2 μ or less, and this is supplied onto a steel plate to be rolled while cold rolling. Rolling method for steel plates. 2. The rolling method according to claim 1, wherein the lubricating component is a hindered ester of higher fatty acid. 3. The rolling method according to claim 1, wherein the rolling oil contains an aromatic amine salt of an organic acid phosphate in addition to the lubricating component. 4. Claim 1, wherein the emulsion concentration is 1 to 20% by weight.
Rolling method described. 5. The rolling method according to claim 1, wherein the steel plate is stainless steel.