JPS60141794A - Cold rolling oil for steel plate - Google Patents

Abstract

PURPOSE:A cold rolling oil for steel plates, obtained by adding a small amount of a water-soluble chelating agent and/or a specific water-soluble organic acid to an emulsion prepared by emulsifying an animal or vegetable oil in water, having improved roughness abrasion resistance of work rolls, and capable of preventing slip and chattering. CONSTITUTION:A cold rolling oil obtained by adding 0.01-1.0%, preferably 0.05-0.5% (A) water-soluble chelating agent, e.g. tetrasodium ethylenediaminetetraacetate, and/or (B) water-soluble organic carboxylic acid, e.g. a 6-10C fatty acid such as oxalic acid, to an emulsion prepared by emulsifying an animal or vegetable oil in water. Preferably, an extreme-pressure additive, etc. is if necessary added thereto. EFFECT:Productivity is improved, and formed iron compounds of the water-soluble organic acid are converted into a surface film, which prevents the seizure between work rolls and materials to be rolled.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cold rolling oil for steel plates used for continuous casting under high speed rolling conditions with high rolling loads in cold rolling of steel plates.

(Prior art) When cold rolling a steel plate, cold rolling oil is supplied in the form of an emulsion between the work roll and the material to be rolled (hereinafter referred to as the roll) to reduce the coefficient of friction. , has the role of suppressing heat generation and load during rolling. Base oils for rolling oils are broadly classified into three types: mineral oils, synthetic esters, and animal and vegetable oils such as gum oil and beef tallow. Mineral oil base oils have poor oil film strength but excellent burn-off properties, and are used for materials with a relatively thick finished thickness and low rolling reduction, and are used in so-called mills that omit the cleaning process after rolling. Suitable for clean processes. Synthetic esters have excellent tear-off properties and strong oil film strength, so they are generally blended in appropriate amounts with mineral oils and used in the mill clean process.

On the other hand, animal and vegetable oils have a strong oil film, and even under conditions of high rolling load and high speed rolling, they can form a sufficient oil film on the roll bite and exhibit excellent lubrication performance, resulting in a high reduction ratio. Moreover, it is said to be suitable for cold rolling of thin materials with a finishing thickness of 0.4 mm or less that are rolled at high speed. The reason why these animal and vegetable oils and fats have excellent oil film strength and lubricity is that the base oil has a high molecular weight and is highly absorbent, as well as a certain amount of higher fatty acids. be.

The content of fatty acids in fats and oils is determined by the acid value (Av==AcidVa
], ue KOHmy/f), but in the case of animal and vegetable oils and fats such as beef tallow, they generally have an acid value of about 3 to 10, except for those that have gone through a deoxidizing process. . However, when animal and vegetable oils and fats are used as rolling oils, they are usually hydrolyzed in emulsions and have an acid value higher than the above-mentioned acid value.

In recent years, continuous casting of rolled materials (cold rolled products) has progressed, and more than 90% of them are At-killed continuous casting materials. Along with this, in the rolling of thin steel sheets, especially tinplate sheets,
Due to the smoothing wear phenomenon (roughness friction) of the work rolls and the excessively high lubrication performance of the rolling oil, the friction coefficient at roll bite decreased too much, and unstable slip phenomena began to occur.

It is well known that the relationship between the coefficient of friction and the advance rate during roll bite is as shown in the graph shown in FIG. That is, the lower the friction coefficient, the lower the advance rate. Friction coefficient is 0
．． 01, the rolling reduction ratio is 35, the advance ratio is O, and slipping begins to occur. In addition, the inventors investigated At-killed continuous casting material (hereinafter referred to as CC material), ingot casting material (hereinafter referred to as IC material), the rolling blades and tension values obtained during rolling, and the material to be rolled at that time. When the change in friction coefficient is calculated from the deformation resistance value using KARMAN's differential equation, the graph shown in FIG. 2 is obtained. From this, it is clear that the friction coefficient decreases faster when the rolled material is a CC material than when the rolled material is an IC material.

The reason for this is still not clear, but since this phenomenon mainly appears in experiments conducted by the present inventors and in actual rolling using rolling oil made from animal and vegetable base oils, it can be summarized as follows.

In other words, CC material not only has higher hardness than IC material, but also has higher reactivity with higher fatty acids contained in the rolling base oil, and as shown in Figure 3, it is easier to produce iron soap, and the higher The high viscosity of fatty acid iron soap reduces the metal contact area on the friction surface, expands the hydrodynamic lubrication area, and prevents large adhesive wear with roughness regeneration. Therefore, only the protrusions at the tip of the polished surface of the roll are eliminated, and as a result, the smoothing of the work roll surface and the reduction in friction are promoted, which seems to be the reason why the coefficient of friction decreases more quickly in the case of the CC material. It has been found that due to the smoothing of the work roll surface and the reduction in friction, unstable slip is likely to occur as described above, and the tension fluctuations caused by this tend to cause chattering. Therefore, it is necessary to rearrange the work rolls to recover the friction coefficient. These reductions not only reduce rolling efficiency but also have the drawback of causing abnormalities such as poor plate thickness and plate breakage.

(Object of the Invention) The present invention has been made in order to eliminate these drawbacks, and has a structure that is less prone to slip caused by friction of work rolls and chittering induced by this, and has good roll wear resistance. The object of the present invention is to provide a cold rolling oil for steel plates that has a stable coefficient of friction within the roll bite.

(Structure of the Invention) In order to achieve the above object, the present invention includes adding a water-soluble chelating agent and/or calcium to an emulsion in which animal and vegetable oils and fats are emulsified in water. A water-soluble organic acid having two or more xyl groups at 0.
A cold rolling oil for steel sheets characterized by the addition of 01 to 1%, in which chelating agents and organic acids react with iron before higher fatty acids in animal and vegetable oils and fats in the roll bite, resulting in ironstone of higher fatty acids. The generation of Ken can be prevented.

The animal and vegetable oils referred to in Zhuang include beef tallow, rum oil, liver fat, coconut oil, rapeseed oil, etc., which are commonly used as rolling oils, and are mixtures thereof.

The water-soluble chelating agent to be added is, for example, KDTA-4,N.
a (ethylene diamine tetraacetic acid)
4Na salt), BDTA-2Na, FjDTA-4
NH4, BDTA-2NH4, DTPA-5Nl],
(Diethylene triamine interacetate acid-5Na salt), DTPA-3Na, sodium gluconate, sodium tripolyphosphate, sodium birophosphate,
NTA-3Na (triacetic acid and -3Na salt), etc.

The water-soluble organic acids to be added include, for example, oxalic acid, succinic acid, citric acid, adipic acid, and malic acid.

The amount added to the emulsion is 0.01~
The ratio is 1.0, preferably 0.05 to 0.5.

When the ratio is less than 0.01%, the amount of iron soap produced was investigated using a known rotary deterioration tester, and as shown in Figure 4, it was significantly increased, and when it exceeded 1.0%, the production of iron soap was suppressed. The result was that the effect was saturated.

(Function) As mentioned above, the smoothing wear phenomenon on the work roll surface is caused by the high viscosity of the produced higher fatty acid ironstone expanding the fluid lubrication area and causing wear of the sharp protrusions on the polished surface of the roll. However, the present invention improves the smoothing wear resistance by the following effects and aims at rolling with a stable friction coefficient in the roll bit.

That is, as mentioned above, water-soluble chelating agents and water-soluble organic acids added to animal and vegetable oils have higher reactivity with iron than higher fatty acids contained in animal and vegetable oils, and they react with iron before the higher fatty acids react to produce iron soap. to form iron compounds. The iron compound produced by the reaction with the water-soluble chelating agent is dissolved in the water layer of the emulsion and is not present in animal or vegetable oils or fats. Further, iron compounds formed by reaction with water-soluble organic acids are neither dissolved in the water layer in the emulsion nor in animal or vegetable oils or fats. In short, in any case, it does not dissolve in animal or vegetable oils and fats, so it does not have the effect of increasing the viscosity of the oil film in roll bite and expanding the fluid lubrication area like iron soaps made of higher fatty acids. Therefore, the smoothing wear phenomenon of the work roll can be prevented.

In the case of a water-soluble organic acid, it reacts with iron to form a water-insoluble iron compound, which forms a film on the work roll surface and the surface of the rolled material, which causes direct contact between the work roll and the rolled material. It also has the effect of preventing burn-in by preventing contact with other surfaces.

Surfactants are used when emulsifying animal and vegetable oils and fats, but even when adding water-soluble chelating agents or water-soluble organic acids, general anionic surfactants, cationic surfactants, and nonionic surfactants can be used. can also be used.

We do not refuse to add extreme pressure additives, antioxidants, fungicides, etc. as necessary.

Examples of the products of the present invention are shown below along with comparative examples.

Examples: Evaluation of surface 10-ru friction properties (1) Test oil pholyoxyethylene nonylphenol ether (EO1
Beef tallow (A, V-7
Prepare a 5% emulsion in step 3) and add water-soluble chelating agents and/or water-soluble organic acids as shown in the table below to make the test oil (the numbers in the table are the amounts added to the emulsion). (indicates the person in charge)

9- (2) Test method ■Testing machine Large Chimken testing machine ■Ring block O-ring (assuming rolling roll) 62 throat φX 19 m+n
W material: SUJ” (Hv=:=soo) Compatibility:
RZ=1. ．． 8 to 2.211 m (C direction) 0 block (rolled material) Actual machine cold rolling material (CC material, working degree approximately 50 inches) ■Test conditions O-ring rotation speed 600 rpm O load 45 Kg 0 hours 3 hours 0 emulsion concentration 5chi, temperature 60°C (3) Review
Measure the surface roughness (RzC direction) of the ring before and after the test,
Measured by the amount of decrease in roughness.

The test results are shown in Figure 5. The product of the present invention shows less decrease in roughness of the ring surface due to friction with the CC material than the comparative example.

(Effects of the Invention) As explained above, the cold rolling oil for steel sheets of the present invention uses animal and vegetable oil as a base oil, and by adding a lower fatty acid having 6 to 10 carbon atoms to this, the cold rolling oil for steel sheets can be applied to the work roll during CCC positive rolling. It has excellent roughness and friction resistance, and has the excellent effect of preventing slip and chattering during cold rolling of thin steel sheets, and significantly improving productivity.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the coefficient of friction during rolling of a steel plate and the advance rate during roll bite, and Figure 2 is a graph showing the relationship between the coefficient of friction during rolling of a steel plate and the advance rate during roll bite. A graph showing changes in the coefficient of friction. Figure 3 is a graph showing the state of iron soap formation between CC and 1C materials in base oil. Figure 4 shows the amount of iron soap produced using a known rotational deterioration tester. Graph, FIG. 5 is a graph showing the test results of the product of the present invention and the comparative example. Int, C1,' Identification code Office serial number 40:2
4 Z-7824-4H Procedure No. 111 Official Book October 2, 1982 Patent Application No. 247899 2, Title of invention Cold rolling oil for steel plates 3, Relationship with the person making the amendment Name of patent applicant Name Nippon Kokan Co., Ltd. Baka 1 person 4, agent 5, date of amendment order voluntary amendment 6, application to be amended (furigana of the inventor's address and name) Full text of the specification drawings (Figure 1) 7. Contents of amendment (1) In the application, the furigana of the inventor's address and the pseudonym of his/her name will be corrected as shown in the attached sheet. The full text of the specification is corrected as shown in the attached sheet. (3) In the drawings, Figure 1 will be corrected as shown in the attached sheet. Description 1. Name of the invention Cold rolling oil for steel sheets 2. Claims A water-soluble chelating agent and/or a water-soluble emulsion containing two or more carboxyl groups in an emulsion of animal and vegetable oils and fats in water. A cold rolling oil for steel sheets, characterized in that 0.01 to 1% of an organic acid is added. 6. Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a cold rolling oil for steel plates used when performing high-speed rolling at a high reduction rate in cold rolling of steel plates. (Prior art) When cold rolling a steel plate, cold rolling oil is supplied in the form of an emulsion between the work roll and the material to be rolled (hereinafter referred to as roll bite) to reduce the coefficient of friction and improve rolling. It has the role of suppressing heat generation and load during. Base oils for rolling oils are broadly classified into three types: mineral oils, synthetic esters, and animal and vegetable oils represented by gum oil and beef tallow. Mineral oil base oils have poor oil film strength but excellent burn-off properties, and are used for materials with relatively thick finished thickness and low rolling reduction, and are used in so-called mills that omit the cleaning process after rolling. Suitable for clean processes. In addition, synthetic esters have excellent burn-off properties and a fairly strong oil film strength, so they are generally blended in appropriate amounts with mineral oils and used in the mill clean process. On the other hand, animal and vegetable oils have a strong oil film and can be used under high rolling loads.
Even under high-speed rolling conditions, it is possible to form a sufficient oil film on the roll bite and exhibit excellent lubrication performance, resulting in a high rolling reduction and a finish thickness of 0.4 that can be rolled at high speed.
It is said to be suitable for cold rolling of thin products with a thickness of less than 100 mm. The reason why these animal and vegetable oils and fats have excellent oil film strength and lubricity is that the base oil has a high molecular weight and is highly absorbent. : OaK, #F [Fat IF [AE6Ziitt
h-cv. This is for the purpose of The content of fatty acids in fats and oils is determined by the acid value (AV-AcidVal).
It is expressed as ue KOH/2), and in the case of animal and vegetable oils and fats represented by beef tallow, they generally have an acid value of about 3 to 10, except those that have gone through a deoxidizing process. However, when animal and vegetable oils and fats are used as rolling oils, they are usually hydrolyzed in an emulsion and have an acid value higher than the above-mentioned acid value. In recent years, continuous casting of rolled materials (cold-rolled products) has progressed, and more than 90 inches of rolled materials have become A4 killed continuous casting materials. Along with this, in the rolling of thin steel sheets, especially tinplate sheets,
Due to the smoothing wear phenomenon (rough wear) of the work rolls and the excessively high lubrication performance of the rolling oil, the friction coefficient at roll bite decreased too much, and unstable slip phenomena began to occur. It is well known that the relationship between the friction coefficient, rolling reduction rate, and advancement rate during roll bite is as shown in the graph shown in FIG. That is, the lower the friction coefficient, the lower the advance rate. When the friction coefficient becomes 0.01, the advance rate becomes O when the rolling reduction rate is about 35%, and slipping begins to occur. The inventors also investigated the rolling edge and tension values obtained during rolling of A4 killed continuous cast material (hereinafter referred to as CC material), incot cast material (hereinafter referred to as IC material), and the values of the tension at that time. When the change in friction coefficient is calculated from the deformation resistance value of the material to be rolled using KARMAN's differential equation, the graph shown in FIG. 2 is obtained. From this, it is clear that the friction coefficient decreases faster when the rolled material is a CC material than when the rolled material is an IC material. Although the reason for this is not clear, it can be summarized as follows since this phenomenon mainly appears in experiments conducted by the present inventors and in actual rolling using rolling oil made from animal and vegetable base oils. In other words, in addition to having higher hardness than IC material, Ca material has a third
As shown in the figure, it has high syncompatibility with the higher fatty acids contained in the rolling base oil, making it easy to produce iron soap. Due to the high viscosity of the produced higher fatty acid iron soap, the metal contact area on the friction surface is reduced, the hydrodynamic lubrication area is expanded, and large adhesive wear accompanied by roughness regeneration does not occur. Therefore, only the protrusions at the tip of the polished surface of the roll are eliminated, and as a result, the smoothing abrasion phenomenon of the work roll surface is promoted, which seems to be the reason why the coefficient of friction decreases faster in the case of the CC material. It has been found that due to the smoothing wear phenomenon of the work roll surface, unstable slip is likely to occur as described above, and the tension fluctuation caused by this tends to cause chattering. Therefore, it is necessary to rearrange the work rolls to recover the friction coefficient. These phenomena not only reduce rolling efficiency but also have the drawback of causing abnormalities such as poor plate thickness and plate breakage. (Object of the Invention) The present invention has been made to eliminate these drawbacks, and has a structure that is less prone to slip caused by wear of work rolls and chatter induced by this, and has good roll wear resistance. The object of the present invention is to provide a cold rolling oil for steel plates that has a stable coefficient of friction within the roll bite. (Structure of the Invention) In order to achieve the above object, the present invention adds a water-soluble chelating agent and/or a water-soluble organic acid having two or more carboxyl groups to an emulsion obtained by emulsifying animal and vegetable oils and fats in water.
A cold rolling oil for steel sheets characterized by adding 0.01 to 1.0 g of iron, in which the chelating agent and organic acid react with iron before the higher fatty acids in animal and vegetable oils in the roll bite to form ironstone of higher fatty acids. The generation of Ken can be prevented. The animal and vegetable oils referred to in (2) include beef tallow, gum oil, liver fat, coconut oil, rapeseed oil, etc., which are commonly used as rolling oils, or mixtures thereof. The water-soluble chelating agent to be added is, for example, EDTA-4Na (
Ethylene diamine tetraacetic acid-4N
a salt), EDTA-2Na, EDTA-4NH4, E
DTA-2NH4, DTPA-5Na (diethylene/
triamine pentaacetic acid-5Na salt),
DTPA-3Na. Sodium gluconate, sodium tripolyphosphate, sodium birophosphate, NTA-3Na and triacetic acid-3Na salt), etc. The water-soluble organic acids to be added include, for example, oxalic acid, succinic acid, citric acid, adipic acid, and malic acid. The amount added to the emulsion is 0.01~
It is preferably 0.05 to 0.5%. When the amount is less than 0.01%, the amount of iron soap produced was examined using a known rotary deterioration tester, and as shown in Figure 4, it was significantly increased, and when it exceeded 1.0%, the production of iron soap was suppressed. The result was that the effect was saturated. (Function) As mentioned above, the smoothing wear phenomenon on the work roll surface is caused by the high viscosity of the produced higher fatty acid ironstone expanding the fluid lubrication area and causing wear of the sharp protrusions on the polished surface of the roll. However, the present invention improves the smoothing wear resistance by the following effects and aims at rolling with a stable friction coefficient in the roll bite. That is, as mentioned above, water-soluble chelating agents and water-soluble organic acids added to the emulsion of animal and vegetable oils and fats have higher reactivity with iron than higher fatty acids contained in animal and vegetable oils, and the higher fatty acids react to form iron soap. react to form iron compounds before making. The iron compound produced by the reaction with the water-soluble chelating agent is dissolved in the water layer of the emulsion and is not present in animal or vegetable oils or fats. Further, iron compounds formed by reacting with water-soluble organic acids are difficult to dissolve in the water layer of the emulsion and in animal and vegetable oils and fats. In short, in either case, it does not dissolve in animal or vegetable oils and fats, so it does not have the effect of increasing the viscosity of the oil film in roll bite and expanding the fluid lubrication area, unlike iron soaps made of higher fatty acids. Therefore, the smoothing wear phenomenon of the work roll can be prevented. In addition, in the case of water-soluble organic acids, they react with iron to create water-insoluble iron compounds, so they form a film on the work roll surface and the surface of the rolled material, and the film is directly connected between the work roll and the rolled material. It also has the effect of preventing burn-in by blocking contact. Surfactants are used when emulsifying animal and vegetable oils, but even when adding water-soluble chelating agents or water-soluble organic acids, general anionic surfactants, cationic surfactants, and nonionic surfactants can be used. can also be used. Furthermore, it is not prohibited to add extreme pressure additives, antioxidants, bactericides, etc. to animal and vegetable oils and fats as necessary. Examples of the products of the present invention are shown below along with comparative examples. Examples: Evaluation of roll abrasion resistance (1) Test oil phorioxyethylene nonylphenol ether (m01
Beef tallow (A, V = 7
and 3) A 5% emulsion is prepared, and a water-soluble chelating agent and/or a water-soluble organic acid as shown in the following table is added thereto as a test oil (the numbers in the table are the amounts added to the emulsion). ). 9- (2) Test method ■Testing machine Large Chimken testing machine ■Ring block Q ring (assuming rolling roll) 6:2+n+nφX 19
tan W material: SUJ 2 (HVV6O13 roughness: RZ=1.8~2.2 Pm (O direction) 0 block (rolled material) Actual machine cold rolling material (CC material, working degree of approximately 50 inches) ■Test conditions 0 ring rotation speed 600 rl) m O load 45 to 7 (Hertz pressure 18.2 Ky/mm2) 0 hours 3 hours 0 emulsion Concentration 5 inches, temperature 60°C (3) Ring surface roughness before and after evaluation test in RzC direction ),
Judgment is made based on the amount of decrease in roughness. The test results are shown in Figure 5. The product of the present invention shows less decrease in roughness of the ring surface due to friction with the CC material than the comparative example. 10- (Effects of the Invention) As explained above, the cold rolling oil for steel sheets of the present invention uses animal and vegetable oil as a base oil, and by adding a lower fatty acid having 6 to 10 carbon atoms to this, the cold rolling oil for steel sheets can be improved during rolling of Co material. This results in excellent roughness wear resistance of the work rolls, which has the excellent effect of preventing slip and chattering during cold rolling of thin steel sheets, and significantly improving productivity. 4. Brief explanation of the drawings Figure 1 is a graph showing the relationship between the friction coefficient and rolling reduction rate in steel plate rolling and the advancement rate during roll bite. Figure 2 is a graph showing changes in the friction coefficient during rolling. The diagram shows fatty acids and C
A graph showing the reactivity with C material and IC material, Fig. 4 is a graph showing the amount of ironstone produced by a known rotational deterioration tester, and Fig. 5 is a graph showing the test results of the product of the present invention and a comparative example. It is.

Claims (1)

[Claims] A cold rolling oil for steel sheets, characterized in that 0.01 to 1% of a water-soluble chelating agent and/or a water-soluble organic acid having two or more carboxyl groups is added to an emulsion of animal and vegetable oils and fats in water.