JPS60161494A - Cold rolling oil for steel plate - Google Patents

Abstract

PURPOSE:To provide a cold rolling oil for steel plate effective to prevent the slipping, chattering and roll abrasion, by adding specific amounts of a water- soluble chelating agent and a specific water-soluble organic acid to an emulsion of a base oil having a specific viscosity and composed of a synthetic ester, etc. CONSTITUTION:The objective cold rolling oil can be prepared by compounding (A) an aqueous emulsion of a base oil (having a viscosity of <=15cst at 50 deg.C) comprising (i) a synthetic ester (e.g. methyl stearate) or (ii) a mixture of the component (i) and an animal or vegetable oil (e.g. beef tallow) with (B) a water- soluble chelating agent (e.g. ethylenediaminetetraacetic acid-4Na salt) and/or (C) a water-soluble organic acid having two or more carboxyl groups (e.g. oxalic acid). The amount of the component (B) and (C) is 0.01-1.0%, preferably 0.05- 0.5% each. EFFECT:The iron compound of said acid prevents the seizing of the work roll and the rolled material.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a cold rolling oil for steel plates used when performing high-speed rolling at a high rolling reduction ratio in cold rolling of steel plates. be.

(Prior art) Cold rolling oil is supplied in the form of an emulsion between the workpiece roll and the rolled material (hereinafter referred to as roll bite) when cold rolling a steel plate, reducing 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 represented by palm 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 even under conditions of high rolling load and high speed rolling, they can form a sufficient oil film on 0-ruvite and exhibit excellent lubrication performance, so the reduction ratio can be reduced. Finished thickness 0.4- rolled at high and high speed
It is said to be suitable for cold rolling of thin products of 1 or less. The reason why these animal and vegetable oils and fats have excellent oil film strength and 1IFR properties is that the molecules that make up the base oil are large, and the viscosity is as high as 250 St or more at 50°C.
In addition to being highly adsorbent, it also contains a certain amount of higher fatty acids. The content of fatty acids in fats and oils is determined by oxidation (AV = Acid Valve KOt-1
+io/g), but in the case of animal and vegetable oils and fats, the acid value is about 3 to 10. However, when animal and vegetable oils and fats are used as rolling oils, they are usually hydrolyzed in 1-flusion and have an acid value higher than the above-mentioned acid value.

In recent years, the continuous casting of rolling materials (cold rolled products) has progressed, and more than 90% of them are A (quilt continuous casting materials).
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 Figure 1. That is, the lower the friction coefficient, the lower the advance rate. When the friction coefficient becomes 0.01, the rolling reduction ratio becomes about 35% and the advance ratio becomes O, causing slippage. The inventors also investigated β-killed continuous cast material (hereinafter referred to as CC material), ingot cast material (hereinafter referred to as IC material), the rolling blades and tension values obtained during rolling, and the rolled material at that time. From the deformation resistance value of the material, by KARMAN's differential equation,
If we calculate the changes in the friction coefficient, we get the graph shown in Figure 2. 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 not yet 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.

(1) A comparison of beef tallow (base oil 1), which is a typical animal and vegetable oil base oil, and low viscosity ester (trial extraction 2) using the ingredients, test equipment, and test conditions shown in Table 1 below shows that the beef tallow It can be understood that since the coefficient of friction is lower in this case, the proportion of the fluid lubrication area on the friction surface is relatively high.

(See Figure 3) ■O test conditions: 3-bath rolling (total reduction 65%)
Indication) Rolling speed 1105p Test forest 5pcc-D 1.6
5 Tx20. OWx 200Li Pengko Marillon concentration 5%, temperature 60℃, flow rate 11.512/min WR roughness RZ〒 0.8us+ (x Merry paper #120 polishing) (2>CC
Compared to IC materials, this material has a higher reactivity with higher fatty acids contained in the base oil, so it is easier to produce iron soap, which is a reaction product with high cleaning properties (see Figure 4).

(3) CC material has higher hardness than IC material.

In short, the high viscosity of animal and vegetable oils and fats, 25 cst or more at 50°C, and the iron soap of higher fatty acids, which are reaction products.
Due to the synergistic effect with the high viscosity of υ, the metal contact area on the friction surface is reduced, the fluid 111 sliding 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 wear 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 abrasion 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 chatter. Therefore, it is necessary to rearrange the work rolls to recover the friction coefficient.

These reductions not only reduce rolling efficiency but also
There are drawbacks such as 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 been made to avoid slippage caused by wear of work rolls and chatter induced by this, and to have good roll wear resistance. 〇-The objective is to provide a cold rolling oil for steel plates with a stable friction coefficient in rubite.

(Structure of the Invention) In order to achieve the above object, the present invention uses a synthetic ester or a mixed oil of this and an animal or vegetable oil as a base oil,
The viscosity of this base oil is 1,508 or less at 50°C, and it is emulsified in water to form an emulsion, and a water-soluble chelating agent and/or a water-soluble organic acid having two or more carboxyl groups is added to the emulsion at 0. A cold rolling oil for steel sheets characterized in that 01 to 1.0% is added, and the synthetic esters used as the base oil include stearic acid methyl ester, beef tallow fatty acid methyl ester, stearic acid octyl ester, beef tallow fatty acid. Examples include octyl ester, stearic acid butyl ester, stearic acid neopentyl glycol ester, and coconut oil fatty acid neopentyl glycol ester. Beef tallow, palm oil, liver fat, coconut oil, rapeseed oil, etc. may be added as animal and vegetable oils and fats, but it is essential that the viscosity of the mixture is 15 cst or less at 50°C. When the viscosity exceeds 15 cst, rough wear rapidly increases as seen in the examples.

The above base oil is made into an emulsion, and the water-soluble chelating agent added thereto is, for example, EDTA-4,Na (ethylene diamine tetraacetic acid-4Na).
salt), EDTA-2Na, EDTA-4NH4, ED
TA-2NH4, DTPA 5Na (diethylene triamine pentaacetic acid-5Na salt),
DTPA-3Na.

These include NTA-3Na, trilotriacetic acid-3Na salt)2, sodium gluconate, sodium tripolyphosphate, and sodium pyrophosphate.

The water-soluble organic acids added to the emulsion include, for example, oxalic acid, succinic acid, citric acid, adipic acid, and malic acid. All of the added stones are 0 to emulsion.
,01 to 1.0%, preferably 0.05 to 0.5%. When the iron content is less than 0.01%, we tested the production amount of ironstone using a known rotary deterioration tester, and as shown in the graph of Figure 5, we found that the iron content in the extracted oil increased rapidly. It can be seen that a significantly large number of
It has become clear that when more than 0% of iron is added, the effect of suppressing iron soap formation becomes saturated because no reduction in iron content in the extracted oil is observed.

The demonstration and test conditions for the above test are as follows.

(1) Beef tallow (AV==near) was used as the test base oil, and a chelating agent (EDTA-4Na salt) was added in an amount of O to 1.5%, and an organic m<citric acid) was added in an amount of O to 1.5%. Tests were conducted for each case where 1.5% was added.

(2) Test method Using a known rotational deterioration tester, the emulsion is subjected to rotational deterioration for the purpose of producing ironstone.

From the emulsion after deterioration, ironstone is extracted by solvent fractionation, and after acid decomposition and methyl esterification, the fatty acid composition is determined by gas chromatography.

(3) Deterioration test conditions Atmosphere = 80°C Air Rolling speed: 60rpl Test oil: 5% emulsion steel Balls: 100 1/2 inch balls Cutting: 30g Rotation time: 56Hr (Function) As mentioned above, work roll The surface smoothing wear phenomenon is due to the synergistic effect of the high viscosity of the base oil and the viscosity of iron soap produced by higher fatty acids, which expands the fluid lubrication area and causes wear of the sharp protrusions on the roll polished surface. However, the present invention aims to improve the smoothing wear resistance from the two aspects mentioned below, and to achieve rolling with a stable friction coefficient in the roll bit.

(1) By lowering the viscosity of the base oil, the boundary lubrication area is expanded, preventing wear of the tip of the polished surface of the roll and promoting the regeneration of rough marks.

(2) Adding a water-soluble chelating agent and/or a water-soluble organic acid to the emulsion prevents the formation of ironstone with high lubricity of higher fatty acids, suppresses the expansion of the fluid lubrication area, and sharpens the roll-polished surface. Prevents wear on the protrusions.

That is, as mentioned above, the water-soluble chelating agent and water-soluble organic acid added are highly reactive with iron, and higher fatty acids in synthetic esters produced by hydrolysis and higher fatty acids contained in animal and vegetable oils and fats are highly reactive with iron. It reacts to form iron compounds before reacting to produce ironstone with high lubricating properties. The iron compound produced by reacting with the water-soluble chelating agent dissolves 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 m-acids do not dissolve in the water layer in the emulsion or in animal or vegetable oils or fats.

In short, in any case, it does not dissolve in animal or vegetable oils, so it works by increasing the viscosity of the oil film in 0-sivite and expanding the fluid lubrication area, like iron soap with high lubricity of higher fatty acids. There isn't.

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. It also has the effect of preventing direct contact and preventing seizure.

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

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

Example (1) Test Part: A 5% base oil emulsion was prepared, and a water-soluble chelating agent and/or water-soluble organic acid as shown in the following table was added thereto to form a test part.

(2) Test method ■Testing machine Large Chimken testing machine ■Ring block 0 ring (assuming rolling roll) 62 ■φX 1911mW
Material: 5UJ2 (Hv = 800> Phase: Rz
= 1.8 to 2.2 μg + (C direction) 0 block (rolled material) Actual machine cold rolling material (CC material, degree of processing 50%) ■Test conditions 0 ring rotation speed 600 rpm 1 m. Load: 45 KO (Hertzian pressure: 18.2 ko/-1) 0 hours 3 hours 0 emulsion Concentration: 5%, temperature: 60°C Measure with.

The test results are shown in Figure 6. It can be seen that the product of the present invention is a rolling oil with less decrease in roughness of the ring surface and excellent roll wear resistance than the comparative example with high viscosity rolling oil.

(Effects of the Invention) As explained above, the cold rolling oil for steel sheets of the present invention uses synthetic ester or a mixed oil of this and animal and vegetable oil as a base oil, emulsifies it in water to form an emulsion, and creates an emulsion. Add a water-soluble chelating agent and/or a water-soluble acid having two or more carboxyl groups from 0.01 to 1.
By adding 0%, the work rolls have excellent anti-corrosion wear resistance when rolling CC materials, and have the excellent effect of preventing slip and chattering during cold rolling of thin steel sheets, and significantly improving productivity. The Qin Dynasty.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the friction coefficient, rolling reduction rate, and advance rate in 0-sivite during rolling of a steel plate, Figure 2 is a graph showing changes in the friction coefficient during rolling, and Figure 3 is a graph showing beef tallow and low viscosity. Figure 4 is a graph showing the coefficient of friction with ester, Figure 4 is a graph showing the reactivity of fatty acids with CC materials and IC materials, and Figure 5 is a graph showing the reactivity of fatty acids with CC materials and IC materials. A graph showing the relationship with iron content. FIG. 6 is a graph showing the test results of the product of the present invention and a comparative example using a large Chimken tester. Patent applicant Nippon Kokan Co., Ltd. Nippon Bariki Rising Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4 Continued from page 1

Claims (1)

[Claims] Synthetic ester or a mixed oil of this and animal or vegetable oil is used as the base oil, the viscosity of this base oil is 15 cst or less at 50°C, this is emulsified in water to form an emulsion, and the emulsion is mixed with a water-soluble chelating agent and/or Or a water-soluble organic acid having two or more carboxyl groups of 0.01 to 1.
A cold rolling oil for steel sheets characterized by adding 0%.