JPS6049679B2 - Cold rolling oil for steel plates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides, by adding a neutral inorganic phosphate,
This invention relates to a cold rolling oil with improved friction pick-up resistance (hereinafter referred to as FP resistance).

Conventional cold rolling oil for steel sheets is made of animal and vegetable oils such as palm oil, beef tallow, and castor oil, various synthetic esters, mineral oil, or a mixture of these oils, with the addition of oiliness improvers, scraping additives, emulsifying and dispersing agents, etc. It is used by emulsifying and dispersing it in water.

The purpose of adding scraping additives is to improve FP resistance, and from the viewpoint of their effectiveness and rust prevention properties, phosphate ester-based scraping additives are generally used, and chlorine-based and sulfur-based scraping additives are is rarely used in cold rolling of steel sheets. In recent years, with the aim of saving energy and improving productivity, efforts have been made to increase the speed of rolling and increase the processing rate, and on the other hand, continuous casting materials have been increasing as materials to be rolled.

For this reason, rolling conditions have become more severe, making it easy for FP to occur. In order to cope with these problems, it is becoming increasingly necessary to add scraping additives to rolling oil. Phosphate esters include phosphoric acid type and phosphorous acid type, and are generally made oil-soluble by esterification with higher alcohol.

There are various theories regarding the lubricating effect of phosphoric acid esters, and although the mechanism by which the phosphoric acid ester exhibits its squeezability is not clear, it is believed that it forms a kind of film on the steel surface to prevent seizure. Since phosphoric acid esters have the property of causing hydrolysis with use, they tend to be missing from lubricating oils, causing fluctuations in lubrication, lowering the pH, and increasing corrosivity. Further, since phosphoric acid esters are oil-soluble, iron reaction products tend to be present in the oil, resulting in contamination of the coolant. The present invention has been made in view of these circumstances, and its purpose is to achieve high rolling speed and high processing rate, as well as to improve F resistance.
The objective is to provide a cold rolling oil with improved P properties.

The present invention, which has been made to achieve this object, is a cold rolling oil for steel sheets, characterized in that 50 to 500 ppm of neutral inorganic phosphate is added as a phosphate group to a liquid in which a lubricating oil is emulsified and dispersed. In general, since an oil film is formed on the steel surface, it is difficult for water-soluble substances to reach the copper surface, and the effect of adding it was thought to be small, but neutral inorganic phosphate is sufficiently effective. It was confirmed.

In this case, it is assumed that the neutral inorganic phosphoric acid reacts with the steel surface to form a film, thereby exhibiting extreme pressure properties. According to the present invention, since a neutral inorganic phosphate is used, it does not undergo hydrolysis unlike phosphoric acid esters, and stable lubrication can be achieved. Pressure can be controlled.

In addition, the iron reaction product is not oil-soluble and is separated from the oil system, so that the coolant liquid is unlikely to be contaminated. Phosphoric acid exhibits extreme pressure properties, but adding phosphoric acid alone will lower the pH and cause problems such as corrosion, so it is necessary to form a salt to make it neutral.

Partners for salt formation include alkali metals such as sodium and potassium, amines such as ethanolamine, aliphatic amines, and cationic polymers. The extreme pressure effect can be obtained by adding and dissolving 50 to 500 ppm of phosphate as a phosphate group into the lubricating oil emulsion dispersion. If it is less than 50 ppm, the effect will be small, and if it exceeds 500 ppm, the oil stain resistance will deteriorate.

Next, when triethanolamine phosphate was added to a commercially available beef tallow-based rolling oil roll coat 44B (manufactured by Nippon Parkerizing) 5% solution (stirred with a homomixer at 1000 rpm, temperature 60°C), phosphoric acid! Root mass, shell type four-ball test pressure resistance (0K load) and coil rolling (1.6t x 50
The oil stain resistance after 0.8t x 50'f$L) is shown. As shown in the table above, if the phosphate radical content is 30 ppm or less, the pressure resistance will not increase, and if the content is 600 ppm or more, oil stain will occur over the entire surface, resulting in poor results.

A plurality of experimental examples and comparative examples are shown below, and evaluations for each are shown in a table.

Experimental Example Test Oil 1: 100 ppm of triethanolamine phosphate was added as a phosphorus content to a commercially available tallow-based rolling oil roll coat 44B 5% emulsion to which no extreme pressure additives were added and subjected to a test.

Test oil 2: 100 ppm of phosphate of NN dimethylaminoethyl polymethacrylate was added as a phosphorus content to a commercially available beef tallow-based rolling oil roll coat 44B 5% emulsion to which no extreme pressure additive was added and subjected to the test. Test oil 3;
To a commercially available tallow-based rolling oil roll coat 44B 5% emulsion containing no extreme pressure additives, 100 ppm of sodium phosphate was added as a phosphorus content and subjected to a test.

Test oil 4: To a commercially available beef tallow-based rolling oil roll coat 44B 5% emulsion to which no extreme pressure additives were added, 100 ppm of octylamine phosphate was added as a phosphorus content and subjected to the test.

(Test condition) ○Pressure resistance The 0K load was determined using a Shell type four-ball tester.

Shell type four-ball tester is a tester suitable for evaluating extreme pressure properties. ○Oil stain resistance The rolled plates were stacked together without draining and left for 90'C x 1 side, and the occurrence of oil stain was observed.

○Amount of oil molten iron The amount of oil-soluble iron in the sample oil after rolling was measured.

This amount is a measure of coolant contamination. ○ Stability over time The pH was measured before and after stirring for 24 hours with a homomixer at 10,000 rpm while maintaining the temperature at 60°C.

The change in pH value before and after stirring is observed and used as a measure of stability. The evaluation results are shown in the table below.

Comparative Example Comparative Example 1: 5% of commercially available beef tallow-based rolling oil roll coat 44B to which no extreme pressure additives were added and 3% of oleyl acid phosphate (acidic phosphate ester) added.
It was made into an emulsion and subjected to a test.

Comparative Example 2: Trioleyl phosphate (
Comparative Example 3 in which a 5% emulsion containing 3% of neutral phosphate ester was added to the test; dioleylhydrodiene phosphite was added to commercially available tallow-based rolling oil roll coat 44B to which no extreme pressure additives were added. A 5% emulsion containing 3% of (neutral phosphite) was tested.

Comparative Example 4: A 5% emulsion was prepared by adding 3% of triethanolamine salt of oil acid phosphate (neutralized phosphate ester) to commercially available tallow-based rolling oil roll coat 44B to which no extreme pressure additives were added. Tested.

Comparative Example 5: A commercially available beef tallow-based rolling oil roll coat 44B to which no extreme pressure additive was added was subjected to a test as a 5% emulsion.

The test conditions were the same as those for the test oil, and the evaluation results are as shown in the table below.

Claims (1)

[Claims] 1. A cold rolling oil for steel sheets, characterized in that 50 to 500 ppm of neutral inorganic phosphate is added as a phosphate group to a liquid in which a lubricating oil is emulsified and dispersed.