JPS60161487A - Cold rolling oil for steel plate - Google Patents

Abstract

PURPOSE:To provide the titled rolling oil effective to prevent the generation of slipping and chattering caused by the abrasion of work roll, and suitable to a high-speed rolling at a high rolling reduction, by adding a specific amount of a higher alcohol or an unsaturated fatty acid to a base oil comprising an animal or vegetable oil or fat. CONSTITUTION:The objective rolling oil can be produced by using an animal or vegetable oil (e.g. beef tallow, palm oil, etc.) as a base oil, and adding 5-20%, preferably 7-15% higher alcohol (e.g. lauryl alcohol, stearyl alcohol, beef tallow alcohol, etc.) or unsaturated fatty acid (e.g. oleic acid, linoleic acid, etc.) to the base oil.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) 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 copper plate, cold rolling oil is supplied in the form of a mulchion between the work roll and the material to be rolled (hereinafter referred to as roll bite) to lower the coefficient of friction. It has the role of suppressing heat generation and Ml 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 the roll bite and exhibit excellent lubrication performance, resulting in a high reduction ratio. And finished thickness 0.41 rolled at high speed
It is said to be suitable for cold rolling of thin products of 11 or less. The reason why these animal and vegetable oils and fats have excellent oil film strength and lubricity is that the base oil has a large molecular weight and is highly absorbent, and also because it contains a certain amount of higher fatty acids. be. Typical fatty acids present in animal and vegetable oils include stearic acid, oleic acid, palmitic acid, etc. These higher fatty acids have strong adsorption properties on the surface of steel sheets, and as a reaction product, they produce viscous substances with high lubricity. It is generally thought that it produces high ironstone sulfur content and improves lubricity. The content of fatty acids in fats and oils is determined by the acid value (AV = Aci
dValueKOHIl1g/g),
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 those that have undergone a deacidification process. However, when animal and vegetable oils and fats are used as rolling oils, they are usually hydrolyzed in the 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% of them are continuous casting materials of β-quilt. 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 0-rubyte 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 advance rate becomes O when the rolling reduction rate is about 35%, and slipping begins to occur. The inventors also investigated the values of the rolling edge and tension obtained during rolling of β-quilt continuous cast material (hereinafter referred to as CC material), ingot cast material (hereinafter referred to as IC material), and the rapid rolling at that time. From the deformation resistance value of the material, by KARMAN's differential equation,
Calculating the change in the coefficient of friction results in a graph like the one 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.

In other words, in addition to having higher hardness than IC materials, CC materials have a third
As shown in the figure, it has a long reactivity with the higher fatty acids contained in the rolling base oil and is likely 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 more quickly in the case of the CC material. It has been found that due to the smoothing wear phenomenon of the surface of the workpiece wheel, unstable slip is likely to occur as described above, and the tension fluctuations caused by this tend to cause chatter. 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 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 provides a cooling method for steel sheets, characterized in that animal and vegetable oils are used as base oils, and 5 to 20% of higher alcohols or unsaturated fatty acids are added to the base oils. The base oil of the inter-rolling oil includes beef tallow, palm oil, liver fat, coconut oil, rapeseed oil, etc., or a mixture thereof. Examples of the higher alcohol to be added include lauryl alcohol, myristyl alcohol, valmityl alcohol, stearyl alcohol, behenyl alcohol, oleyl alcohol, tallow alcohol, and coconut alcohol. The amount added is 5 to 20%, preferably 7 to 15%. When the amount added is less than 5%, the solubility of beef tallow fatty acid in iron soap is low as seen in the graph of Figure 4, and
If it exceeds 0%, the solubility will be saturated and the effect of addition will not be obtained.

Examples of the unsaturated fatty acids to be added include seamarinic acid, oleic acid, linoleic acid, liluic acid, gadolenic acid, erucic acid, and lysyllic acid. The amount added is 5 to 20%, preferably 7 to 15%.

When the amount added is less than 5%, the solubility of beef tallow fatty acid in iron soap is low, as shown in the graph in Figure 5, and when it exceeds 20%, the solubility becomes saturated and the effect of adding it cannot be obtained. do not have. In the detection of solubility in FIG. 4, oleyl alcohol was added as an additive to the test oil using 5% beef tallow (AV=7) ten tallow fatty acid iron soap. In detecting solubility in FIG. 5, the same sample oil as in FIG. 4 was used, and linoleic acid was added as an additive.

In each case, the solubility of ironstone was investigated using the following test method.

Test method: Using a lubricating oil demulsification tester (JIS-Ni-2520), put the sample oil into an 80g graduated test tube, stir at 1500 rpm for 5 minutes at an oil temperature of 60°C, and remove the upper layer after standing for 8 hours. The iron concentration was measured using an atomic absorption spectrophotometer, and the solubility was examined according to the formula shown below.

Iron content in the layer after standing for 8 hours 0rW/M, (%> - Iron concentration when uniformly stirred x 10
0 (Function) As mentioned above, the smoothing wear phenomenon on the surface of the work roll is caused by the high viscosity of the produced higher fatty acid iron soap (expanding the lubrication area 610) and reducing the wear of the sharp protrusions on the polished surface. However, the present invention improves the roughness wear resistance from the aspects described below and aims at rolling with a stable friction coefficient in the roll bite.

In other words, the highly viscous and highly lubricating ironstone produced in the roll bite is dissolved and removed from the work roll surface by adding higher alcohols or unsaturated fatty acids.
This eliminates the adverse effect of the above-mentioned ironstone on the smoothing abrasion phenomenon of the roll surface and improves the roll smoothing abrasion resistance.

In addition, the addition of neutral phosphate ester, which is an additive that does not produce ironstone as a reaction product (reacts to a minimum extent on the friction surface), and solid lubricants, refuses to enhance boundary lubrication performance. It's not a thing.

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

Examples...Evaluation of roll wear resistance (1) Test oil (2) Test method ■Test machine Large Chimken testing machine ■Ring block 0 ring (assumed rolling roll) 62 ■φx 19s+mW
Material: SUJ 2 (Hv 〒800) Compatibility: Rz=
1.8 to 2.2 μm (C direction) O block (rolled material) Actual machine cold rolling material (CC material, processing rate approx. 50%) ■Test conditions 0 ring rotation speed 600 rpm + n 0 load 45 K (1 (Hertz pressure 18,2ko/ll1m
2) 0 hours 3 hours 0 emulsion Concentration 5%, temperature 60'C (3) Measure the surface roughness of the ring before and after the evaluation test (Rz C direction) and judge based on the decrease in roughness m.

The test results are shown in Figure 6. 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 the base oil, and by adding a 6th grade alcohol or an unsaturated fatty acid to this, the cold rolling oil for steel sheets improves the stability of work rolls during CCC positive rolling. It has excellent roughness wear resistance, can prevent slipping and chattering during cold rolling of thin steel sheets, and has the excellent effect of significantly improving productivity.

[Brief explanation of the drawing]

Figure 1 is a graph showing the friction coefficient and rolling reduction ratio in steel plate rolling. Figure 3 is a graph showing the reactivity of fatty acids with CG materials and IC materials.
The figure is a graph showing the relationship between the amount of oleyl alcohol added as a higher alcohol and the solubility of iron soap when oleyl alcohol is added as a higher alcohol to a sample oil made by adding 5% of beef tallow and iron soap. Figure 5 is similar to Figure 4. A graph showing the relationship between the amount of linoleic acid added and the solubility of iron soap when linoleic acid is added as an unsaturated fatty acid to the same sample oil. Figure 6 shows the test results of the inventive product and the comparative example using a large Chimken tester. This is a graph showing. Patent applicant Nippon Kokan Co., Ltd. Nippon Parriki Rising Co., Ltd. Continued from page 1

Claims (1)

[Claims] A cold rolling oil for steel sheets, characterized in that animal and vegetable oils and fats are used as the base oil, and 5 to 20% of higher alcohols or unsaturated fatty acids are added to the base oil.