JPS6030504A - Cold rolling method by different peripheral speeds - Google Patents

Abstract

PURPOSE:To improve slip-resisting property and to prevent the generation of a surface defect called friction pickup by using in rolling, an aqueous dispersion liquid of rolling lubricant, prepared by mixing an organic phosphate of prescribed rate in a lubricant having prescribed viscosity. CONSTITUTION:An rolling lubricant is prepared, which contains a >=50wt% mineral oil and a 0.1-10wt% (with respect to a lubricant) organic phosphate (dipolyoxyalkyl phosphate). A cold rolling by different peripheral speeds at >=1.03 the ratio between different peripheral speeds, is performed by using an aqueous dispersion liquid containing a 2-20wt% said lubricant.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aqueous dispersion of rolling oil used in different circumferential speed rolling, and involves rolling behavior that is different from normal uniform speed rolling. An object of the present invention is to provide an aqueous dispersion of a rolling oil agent that can stably perform circumferential speed rolling operations.

As is clear from the front view of the rolling mill, the variable circumferential speed rolling method can achieve the same effect as the constant speed rolling method at a lower pressure, so if the rolling load is increased with this method, the result will be the same. Although it is not easy to obtain the same effects as rolling under high pressure in high-speed rolling, and it greatly contributes to energy saving and high-performance rolling operations, in reality slips are more likely to occur, friction pickup is more likely to occur, etc. There was a problem that it was difficult to control the rolling operation.

The present inventors conducted a study using a test mill as a preliminary means to determine whether the above-mentioned problems during rolling at different circumferential speeds can be adjusted by the rolling oil used.

In different circumferential speed rolling, the neutral point moves toward the inlet side of the plate on the low-speed roll side, and moves to the outlet side of the plate on the high-speed roll side. As the inter-tool speed ratio increases, the above-mentioned movement amount increases, and eventually the plate deviates from the contact arc on the high speed side, causing slip between the plate and the roll, making the rolling operation unstable.

This movement of the neutral point is not affected by the different speed ratios, but is also affected by the sintering performance of the supplied rolling oil.

From a specific study of n-peripheral speed rolling using a test mill, we found that U4, which is generally said to have excellent lubricity, has a large neutral point movement distance that deviates from the contact arc and causes slip. water. Mineral oil-based rolling oil, which is considered to have inferior lubricity compared to beef tallow-based rolling oil, has been found to be capable of exhibiting the slip-preventing performance required in cold rolling at different circumferential speeds.

As a result of further investigation, it was confirmed that the viscosity of the mineral oil used has an extremely large effect on performance, and if the viscosity of mineral oil is too low, the amount of oil drawn into the roll bit will be small and the oil film strength will be insufficient. It became clear that this resulted in poor lubricity and increased rolling load.

In addition, in different circumferential speed rolling, the distance between the roll plates on the high-speed roll side is longer than that in conventional constant speed rolling, so 7-pull pick-up (hereinafter sometimes abbreviated as FP) is used. It is easy to cause a phenomenon called surface defects.

As for the cause of this friction pink-up generation and the process of friction generation, - although I have not yet determined the cause of the friction pink-up generation,
The wood board phenomenon is considered to be a localized overheating seizure phenomenon caused by friction.

Therefore, in order to prevent the 7-reaction pickup, it is best to use a rolling oil coated with a strong oil film that forms.

When considering the lubricating components of the rolling oil used for this purpose, it can be expected that greater oil film strength can be expected by using oil components such as beef tallow, but as mentioned above, it is possible to expect a greater oil film strength during 8E rolling work. The point tends to move toward the exit side of the plate, so the relative slip distance becomes long, and the effect of preventing the 7-reaction pickup is small.

The inventors of the present invention have conducted various studies on a method using mineral oil as described above to have a suitable level of slip resistance and do not cause leakage pickup, and have decided to use a specific additive in combination. The present invention was achieved by finding out that it is possible to form a rolling oil having lubricating properties as follows.

That is, the present invention is a Nirutashi machine that performs cold rolling at different circumferential speeds with a different speed ratio of 1.06 or more, and a lubricant containing 50 MN% of mineral oil.
A lubricant containing the above and having a constant viscosity of 10 centistokes or more at 50°C and 0.1 to 1
The present invention relates to a cold rolling method at different circumferential speeds, characterized in that rolling is carried out using a 2 to 20% by weight aqueous dispersion of a rolling oil containing an organic phosphoric acid ester of 0 weight i:h as an essential component.

The organic phosphate ester used here is phosphate, phosphite, or phosphonate. Compounds that are effective in preventing friction pickup are dialkyl (Cm to (J2) phosphate, boss In particular, dialkyl phosphates are easy to use because they are difficult to hydrolyze in water compared to other compounds, and dialkyl phosphates with polyoxyethylene groups have emulsifying properties, so they are representative of the compounds that are easiest to use. This is an example. In this case, the number of moles of oxyethylene groups added is preferably approximately 1 to 8. If the number is 9 or more, the phosphorus content in the molecule becomes relatively low and the hydrophilicity becomes too strong, which is not preferable.

Whether to use phosphoric acid ester, o, i, @ amount less than c,
The friction pickup prevention function is not sufficiently exhibited, and if the friction pick-up is more than 10 times, slipping is likely to occur, which is undesirable.

Furthermore, in the present invention, it is important that the lubricant component contains at least 50 l/w of mineral oil, and if this amount is small, slippage is likely to occur.

Other lubricant components include one or two selected from the group of fats and oils such as beef tallow and palm oil, ester oils such as butyl palmitate, fats such as oleic acid, and synthetic lubricating oils such as polybutene. From the viewpoint of preventing slippage during rolling, it is preferable that the amount of oils and fats be 60% by weight or less, the ester oil be 45% by weight or less, and the fatty acid be 10% by weight or less.

Furthermore, there is a limit to the viscosity of the hook lubricant made of the above-mentioned components; if the value measured at 50°C is less than 10 centistokes, the 7-reaction pick-up prevention performance will be insufficient; If the viscosity is higher than that, there is a serious risk of slipping, so the viscosity is 10
It is preferable to use between ~500 centistokes.

After satisfying the essential constituent requirements as described above, other known components such as emulsifiers used in conventional rolling oil may be used, and the degree of emulsification is similar to that of ordinary rolling oil. good.

It goes without saying that it is possible to add various additives such as antioxidants, rust preventives, etc. in required amounts to the rolling agent or rolling oil, if necessary.

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

EXAMPLE Cold rolling was carried out using a test rolling mill under conditions of different and same speed ratios, and uniform speed rolling was also carried out for comparison to evaluate the slip resistance and FP resistance of the rolling oil. The specific conditions are as follows.

Rolling car: 40 inches, Test material: 5pcc-8B rolling oil:
In the through-circumferential speed rolling shown in the table at a concentration of 5% by weight, a temperature of 50°C, and a flow rate of 2.3V, it is recognized that the rolling load is significantly reduced compared to uniform speed rolling, and according to the present invention, By using the rolling oil as described above, excellent performance in slip resistance and FP resistance can be expected.

On the other hand, as shown in the comparative example, when the number of needles containing mineral oil is small (experiment numbers Z8 and 10), the slip resistance is poor, and when the viscosity of the lubricating component is too low (times, 6), the rolling load is high and the FP resistance is poor. is insufficient, and if it does not contain phosphoric acid ester (ibid., 8) or if the content is small (
9), it is recognized that the 11FP property is insufficient.

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Claims (3)

[Claims] (1) When performing cold rolling at different circumferential speeds with a different speed ratio of 1.03 or more, the lubricant must contain mineral oil in an amount of 50 centistokes or more and have a viscosity of 10 centistokes when measured at 50°C. The lubricant which is above and 0.1 to 10 weight of the lubricant -JFl'
% of organic phosphoric acid ester as an essential component. (2) The circumferential speed cold rolling method according to claim 1, which uses mineral oil having a measured viscosity of 10 to 500 centistokes at 50°C. (3) Claim 1, wherein the organic phosphoric acid ester is a dipolyoxyalkyl phosphoric acid ester. Different circumferential speed cold rolling method.