JPS58210999A - Cold rolling oil for steel strip - Google Patents

Abstract

PURPOSE:A cold rolling oil for steel strips, prepared by adding a higher fatty acid (derivative) to a base oil consisting of an animal oil and a synthetic ester, and adjusting the acid value to a specific value, and capable of preventing the slipping or chattering caused by the abrasion of working rolls. CONSTITUTION:A cold rolling oil, prepared by adding (B) a higher fatty acid (derivative), e.g. stearic acid, oleic acid, dimer acid or beef tallow fatty acid, to (A) a base oil consisting of an animal oil, e.g. beef tallow or lard, and/or a synthetic ester, and having <=7.0 acid value. In case the animal fat or oil is used, the content of the free fatty acid is high. If the acid value exceeds 7.0, the disoxidizing and purifying treatment is carried out to reduce the acid value to 7.0 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cold rolling oil for reducing the occurrence of slug lag caused by wear of work rolls and chatter induced by this during cold rolling of steel strips.

Cold rolling oil is supplied in the form of emulsion between the work roll and the steel strip to be rolled (referred to as the plate roll bite) during cold rolling of the steel strip, and lowers the coefficient of friction. It has the role of suppressing heat generation and load during rolling. Base oils for rolling oils are broadly classified into three types: natural oils and fats such as palm oil and beef tallow, mineral oils, and synthetic esters.

Mineral oil based oils have inferior oil film strength, but
Excellent roll-off properties/In particular, it is used for paulownia wood with a relatively thick rolling thickness and low rolling reduction, and is suitable for the so-called zero-milk rinse process, which omits the cleaning process after rolling. There is. On the other hand, natural oils and synthetic esters such as oil and beef tallow have strong oil films, and even under high-speed rolling conditions with high rolling loads, they form an oil film on the roll bit.
Since it can exhibit excellent lubrication performance, it is suitable for thin cold-rolled steel sheets that are rolled at high rolling reduction rates and high speeds. The reasons why these natural oils and fats have poor oil film strength and lubricity are that the base oil has a large number of molecules and is highly adsorbent, as well as that it contains a certain amount of higher fatty acids. This is because there is.

Many studies have been conducted on the effects of higher fatty acids on the lubricity iH of rolling oils. It is added as an oil improver. ′-! Even in the case of natural oil 11Fj such as beef tallow, performance is controlled to a certain level by adding a certain amount of higher fatty acids to the refined base oil.

The content of fat in rolling oil is determined by the acid value (A, V, -Acid
Value KOHuq / y) is expressed as
Mineral oil-based products for milk cleaning contain 1-4% of higher fatty acids or their derivatives as an oiliness improver, and their re l11ti is usually about 2-8.
On the other hand, in synthetic ester systems for rolling thin products, 5 to 10% of higher fatty acids or derivatives thereof are usually added for the same purpose, and the acid (+m is 10 or more. In the case of animal fats and oils such as beef tallow, they contain as much free fatty acid as the base oil itself.
Although it has an acid value of ~JO, higher fatty acids or derivatives thereof are further added to this to raise the acid value to more than the desired level, thereby increasing the lubricity.

As mentioned above, the effects of higher fatty acids such as stearic acid, oleic acid, and dimer acid, or their derivatives, on lubricating performance are well known, but in recent years, the effects of higher fatty acids such as stearic acid, oleic acid, and dimer acid on lubricating performance have increased. With the advancement of continuous casting, it is said that due to the roughness and wear of the work roll surface and the excessively high +12J lubricity of the rolling oil, the friction coefficient at the roll bite becomes too low, making it easy for unstable slip phenomena to occur. Problems are starting 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 FIG. That is, the lower the friction coefficient, the lower the advance rate. When the friction coefficient becomes 0.01, the rolling reduction ratio is 35 coefficients, the advance ratio is O, and the slip is 0.
It seems to occur. The inventors have developed continuous casting materials (hereinafter referred to as C
0C material), ingot cast material (hereinafter referred to as 1-1C material), K from the rolling edge and tension value obtained during rolling of each material, and the deformation resistance value of the rolled material at that time.
When the change in friction coefficient is calculated using ARMAN's one-factor equation, it becomes as shown in Figure 2, and it is clear that the rolled material is ■, C0
It can be seen that the friction coefficient decreases faster in the case of the 00O9 material than in the case of the 00O9 material. The reason for this is not yet clear, but
O20, the moon is harder, and the higher fatty acid contained in the rolling oil or its 7ii 4 body is opposite 1. This is thought to be due to the fact that the roughness and wear of the work roll is accelerated due to the high hardness and easy formation of iron soap. Also, in this survey,
It has been found that when the friction coefficient becomes less than O1 old, chattering occurs triggered by tension fluctuations caused by unstable slip 0. Therefore, it is necessary to rearrange the work rolls to restore the friction coefficient.

These phenomena not only reduce rolling efficiency, but also cause abnormalities such as poor plate thickness and plate breakage.

The present inventors succeeded in reproducing these phenomena in the actual machine in a laboratory test, and in order to maintain the friction coefficient in the roll bite at the value necessary for stable rolling, we It has been found that it is effective to limit the acid value of higher fatty acids or derivatives thereof to 7.0 or less, leading to the present invention.

The present invention will be explained in detail below.

As the base oil, animal fats and oils such as beef tallow and pork fat, and synthetic esters are used.

Typical examples of higher fatty acids and their derivatives that adjust the acid value include nononophosphoric acid, lauri 71'+2, myristic acid, valmitic acid, stearic acid, oleic acid, linoleic acid, dimer acid, trimer 11, Maleated fatty acids, alkenyl succinates, etc.1. In the case of animal fats and oils, the free fatty acids that are present in themselves from the beginning are also acids (ah
as if above. Play 1. If there are a lot of IL fat-bodied temples and the acid value exceeds 7.0, deacidification and purification treatment may be performed to reduce the acid value to 7.0 or less.

The reason why the acid value must be lower than 7.0 is as shown in Figure 3. Higher fatty acids react with iron to produce iron soap, but when the acid value exceeds 7.0, the production stops. This is because the speed increases rapidly and the amount of iron soap in the oil increases to 1.The relationship between the iron soap [T; As shown in the figure, when the iron soap content is j''rJ, the friction coefficient decreases, and when the content exceeds 1 coefficient, the friction coefficient becomes Ll, 1 or less. Iron soap content 1.0% is acid + 111i 7. The iron soap produced in υ is a value commensurate with the amount produced.

-Ry on the crotch: If the coefficient is 1λ, the lubricity will be improved.
However, as mentioned above, in the case of C, C, material rolling, the roughness and wear of the work roll surface are significant and the roll surface itself is affected. As the friction coefficient decreases, the jψ friction coefficient within the roll bite further decreases, leading to unstable slitting and chattering.

If the acid value is set to 7.0 or less and seize resistance becomes a problem, increase the seize resistance by -1 without producing iron soap.
This does not mean that cooling phosphoric acid esters, 4F phosphoric esters, etc.

The effects of the present invention will be explained by examples.

Example 1 (1) Sample oil light phase 1 book, 1., 11 ('A91 in content) (2)
Test method■ Rolling quality 0 test material 1.6mmt X50mmW X C15P
CC prite O work roll diameter 150 body φ roughness
Rz 0.6μIn (lower roughness on actual machine) RZ 1,500μm (initial roughness on actual machine) Q rolling speed 30m/+n1n O rolling reduction rate approx. 50%, Riemal Noyon concentration 4% Temperature 55~000C Flow rate 2.517m1n ■ Review Expressed in one song.

Chattering occurs above HJ% The test results are shown in Figures 5 and 6.

In all of the products of the present invention, chattering does not occur, and the rollability when the roll roughness is reduced is almost the same as that of the ratio IN example when the roll roughness is not reduced.

Example 2 (1) Test oil Same as Example 1 (2) Test method ■ Testing machine Large Chimken testing machine (see Figure 7) (■ Ring, block 0 ring (rolling roll) diameter 62 mmφ 11) 1 g tone Material SUJ 2 (HV 780~800,) Roughness R
Z-ki 1.5μm (C direction) 0 block (pressure abrasive) Actual machine cold rolling material (a, c, material) Processing degree Approximately 50% to p Test conditions ○Ring rotation speed 6oo' rpm () Cart 45 90 hours 4 hours Q emulsion Concentration 4 Temperature 55-600C Flow rate 1.5 L/min Attach roll 3 to the rotating shaft of the testing machine and insert block 1 into the corner of the rod 4. Create an emulsion of the sample oil in container 9 and add I? West from nozzle 2 at ring 6 - 3
and injection supply to block 1. Emulsion is in receiver tank 7
Then, the receiver is returned to the container 9 and used repeatedly through the nozzle 2. turtle.

The heater 8 is a heating device that keeps the temperature of the emulsion constant. The minute button 15 is used to set the load between the roll and the block. Set the roll 3, block, and weight 5, and start the test by spraying EMARNOYO/ from the nozzle. After a predetermined period of time, the roll 3 is removed and the amount of decrease in roughness is measured using a surface roughness test.

(3) Evaluation Measure the roughness (RzC direction) of the ring of the layer before the test, and judge the roughness with a low number of man-hours.

The test results are shown in Figure 8. It can be seen that the product of the present invention causes less reduction in ring roughness due to friction with C90,4-4 than conventional rolling oil.

Example 3 Among the test oils of Example 1, rolling oils of Nα3 and N[LII were used for comparison in an actual machine.

The rolling mill used had the following specifications.

0 Number of stands 5 0 Roll dimensions Work roll 61 (l mark φX 14
25mm 1 back up roll 1455mmφXl:
370 O rolling speed Maximum 1830 mpm The results are shown in the following table. 0, C by using the rolling oil of the present invention once
, 1 was rolled, the addition of higher fatty acids was lower than that of conventional rolling oil, so the chemical reaction on the roll surface was suppressed, the decrease in roughness was small, and the average roll life was extended by about 30%.

In addition, there are few companies that produce iron soap, and there are many companies that produce iron soap. Wow°
; (U・, 11 (inside 'i'i'!: no vi') The decrease in the friction coefficient of the rolling oil is suppressed, and combined with the small decrease in the surface roughness of the work roll mentioned above, it is possible to , chattering became less likely to occur, and the rolling speed increased by about 15%.

Note: (1) 11-ru life Rolling load until replacement of the rolling roll ■ Decrease in roll roughness When rolling at 500T ■ The rolled material has a finish thickness of 3II + IM or less.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between advance ratio, rolling reduction ratio, and friction coefficient during copper strip rolling. FIG. 2 is a graph showing changes over time in work roll wear and friction coefficient in a rolling mill using conventional rolling oil. FIG. 3 is a graph showing the results of testing using an oil emulsification tester regarding the relationship between acid value and iron soap production h1. Figure 4 shows the relationship between iron soap content and friction coefficient.
Chimke/Shiken) Shows unity due to Iku. FIG. 5 is a graph showing the rollability by 7J in coil rolling in Example 1 of the present study. FIG. 6 is a graph showing torque fluctuations in coil rolling in the same actual rolling mill 11. Figure 7 is a schematic diagram of the large Chimkeno test rock. Figure 8 is a graph showing the lowest roughness of the ring using the large Chimken test rock. 1 Block (assumed to be a pressurized abrasive) 2 Nozzle 3 Roll 4 Bar 5 Copper 6 Emulnoyon circulating mortar 0 7 Receiving tank 8 Electric heater 9 Waste container □ Fig. 3 0/. Figure 4 Figure 5 Figure 6
R1'-1,5) 1m Figure 7 Figure 8 Procedural amendment (method) % formula %) ■, Minor incident indication 1982 Patent Application No. 93862 2 Name of invention Cold rolling oil for copper strip 3 Relationship with the case of the person making the amendment Applicant 4, agent address: 1-1 Minami Aoyama-chome, Minato-ku, Tokyo Pages 8 and 13 of the specification are amended as shown in the attached sheet.

Claims (1)

[Claims] A cold rolling oil for copper strips, characterized in that the base oil is animal fat and/or synthetic ester, and the acid value is adjusted to 7.0 or less using higher fatty acids and/or derivatives thereof.