JPH0211640B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an aqueous temper rolling fluid that is applied to temper rolling of single-sided galvanized steel sheets. Conventionally, there are methods for skin pass rolling of cold-rolled steel sheets, including methods using an oil-based skin-pass rolling fluid, methods using an aqueous skin-pass rolling fluid, and methods using a dry method. Each of these methods has its own characteristics, and the method using oil-based temper rolling fluid has the drawbacks of flammability and poor transfer of roll roughness to the steel plate surface due to the low coefficient of friction, while the dry method This method had the disadvantage that iron powder and other foreign matter adhered to the roll surface, damaging the surface of the temper-rolled steel sheet. Although the above-mentioned drawbacks can be solved by the method using a water-based temper rolling fluid, there are various cases in which steel sheets are shipped as is after temper rolling or are passed on to the next process within the company. The temper rolling fluid is required to have primary rust prevention or a certain degree of long-term rust prevention performance. Wet temper rolling uses a water-based temper rolling fluid to apply the temper rolling fluid using work rolls, but most of the water-based temper rolling fluids that have been used in the past are mainly composed of sodium nitrite. It was hot. These temper rolling fluids impart good corrosion resistance to cold-rolled steel sheets, but cannot impart any corrosion resistance to galvanized steel sheets, and have not been applied to galvanized steel sheets. Ta. Particularly in the case of single-sided galvanizing, there have been no examples of the use of water-based temper rolling fluids due to corrosion caused by the electrochemical action of iron and zinc due to moisture. An object of the present invention is to provide an aqueous temper rolling fluid that imparts good corrosion resistance to single-sided galvanized steel sheets. The aqueous temper rolling fluid in the present invention includes borax,
It is characterized by containing one selected from the group consisting of orthophosphoric acid ester, phosphoric acid ester amine salt, and alkali metal salt of acidic phosphoric acid ester. Borax prevents rust from forming on the surface of steel, especially on galvanized parts, and its concentration is
It is used at 2 to 100 g/as Na ₂ B ₄ O _{7.10H 2} O. If the amount of borax is less than 2 g/l, sufficient corrosion resistance cannot be imparted to the coated surface, and if it is more than 100 g/l, it cannot be used due to solubility. Phosphate esters and their salts act as lubricants during cold rolling and prevent crystallization of borax, but their concentration is 2 g/~100 g/, and the pH of the aqueous temper rolling fluid is 8. The blending amount is adjusted so as not to result in the following conditions and to prevent crystallization of borax in the aqueous temper rolling solution after coating and drying. If the pH is less than 8, corrosion resistance will deteriorate, and if the amount of phosphate ester is too small, borax will crystallize. PH is 10
If the temperature exceeds that level, zinc will dissolve, which is inappropriate. The phosphoric acid ester in the present invention is, for example, a normal phosphoric acid ester, and also includes salts such as phosphoric acid ester amine salts and alkali metal salts such as Na, K, and Li of acidic phosphoric acid esters. The aqueous temper rolling fluid of the present invention is used in the same manner as conventional temper rolling fluids. Next, an example using an aqueous temper rolling fluid of the present invention will be described. Example 1 10 g of borax (Na ₂ B ₄ O _{7.10H 2} O), 7 g of phosphoric acid ester amine salt (triethanolamine salt of mono- and di-butyl phosphate) and 3 g of glycol were dissolved in 1 part of water at PH8. Table 1 shows the results of a corrosion resistance test conducted by immersing a single-sided galvanized steel sheet in an aqueous temper rolling solution of .5 for 48 hours. The coefficient of friction against a steel surface is 0.17 in the case of an oil-based material, but in this example it was 0.24. Example 2 10 g of borax (Na ₂ B ₄ O ₇ 10H ₂ O), 10 g of acidic phosphate ester Na salt (sodium salt of mono- and di-butyl phosphate) and an anionic surfactant were dissolved in 1. Table 1 shows the results of a corrosion resistance test conducted by immersing a single-sided galvanized steel sheet in an aqueous temper rolling solution with a pH of 9.35 for 48 hours. Example 3 10 g of borax (Na ₂ B ₄ O ₇ 10H ₂ O) and 10 g of orthophosphoric acid ester (triethyl phosphite) were dissolved in 1 part of water to make an aqueous temper rolling solution with a pH of 9.5.
Table 1 shows the results of a corrosion resistance test by immersing a single-sided galvanized steel sheet for 48 hours. Comparative example 1 Dissolve 10 g of orthophosphoric acid ester (triethyl phosphate) in 1 part water and PH with sodium hydroxide.
A single-sided galvanized steel plate was added to an aqueous solution adjusted to 9.5
Table 1 shows the results of a corrosion resistance test after immersion for a time. Comparative Example 2 A corrosion resistance test was conducted by immersing a single-sided galvanized steel sheet in an aqueous solution of 10 g of sodium nitrite dissolved in 1 part of water for 48 hours. The results are shown in Table 1. Comparative Example 3 A commercially available nitrite-based aqueous temper rolling fluid for cold-rolled steel sheets was added to
Table 1 shows the results of a corrosion resistance test by immersing a single-sided galvanized steel sheet for 48 hours. Comparative Example 4 A single-sided galvanized steel plate was immersed in deionized water for 48 hours and a corrosion resistance test was conducted. The results are shown in Table 1.

【table】

[Table] Example 4 An aqueous temper rolling solution similar to that in Example 1 was applied to an alloyed single-sided hot-dip galvanized steel sheet, and rust preventive oil (NOXRUST530F
(40). (manufactured by Parker Kosan Co., Ltd.) was applied, and the appearance was observed after two sheets were stacked and left indoors, and the results are shown in Table 2. Comparative Example 5 Table 2 shows the results of the same process as in Example 4, except that the aqueous temper rolling fluid in Example 4 was replaced with deionized water.

[Table] Example 5 An actual machine application test was conducted using the water-based temper rolling fluid shown in Example 1 in a continuous temper rolling mill for hot-dip galvanized steel sheets. Temper rolling conditions: 4-layer type temper rolling mill Work roll dimensions: 420φ x 1800 mm Rolling speed: 90 m.pm Elongation rate: 1.0% Temper rolling fluid supply conditions: Supply amount from the input side of the rolling mill using a flat spray nozzle 4 /min Rolled steel plate: One side galvanized steel plate 0.8mm x 1540mm
(Thickness x Width) Apply rust preventive oil (NOXRUST530F (40), manufactured by Parker Kosan Co., Ltd.) using the oil applicator on the exit side of the hot-dip galvanizing equipment, and then wind the coil using the winder inside the factory building. Table 3 shows the results of observing the external appearance on the recoil ring line after leaving the sample in place. Additionally, as a result of trial rolling, the aqueous temper rolling fluid of the present invention has a high friction coefficient;
Compared to oil-based temper rolling fluid, it does not cause slips or meandering of the steel plate on the rolls installed between the exit side of the temper rolling mill and the winder, and the rolling load is high and the roughness of the work roll is not transferred. It was confirmed that it had a good and beautiful appearance.

[Table] As described above, the aqueous temper rolling fluid of the present invention can be applied to a temper rolling mill of a hot-dip galvanizing facility as a rolling fluid for single-sided galvanized steel sheets, and can be applied to a temper rolling mill of a hot-dip galvanizing facility. One method is to roll a single-sided galvanized steel sheet using a dry method in a hot-dip galvanizing machine, or to roll a single-sided galvanized steel sheet without heat-rolling in a hot-dip galvanizing equipment, and then roll a single-sided galvanized steel sheet using an oil-based heat rolling fluid in a separate heat-rolling machine. This enables a manufacturing process for single-sided galvanized steel sheets that is superior in terms of quality and productivity compared to rolling. The water-based temper rolling fluid of the present invention has anti-rust properties on both iron and zinc surfaces, so it can be used not only as a temper rolling fluid but also for cooling and cleaning single-sided galvanized steel sheets. It can also be applied to other uses.

Claims (1)

[Scope of Claims] 1. 2 to 100 g of borax per 1 part of water; 2 to 100 g of borax selected from the group consisting of orthophosphoric acid esters, phosphoric acid ester amine salts, and alkali metal salts of acidic phosphoric acid esters; An aqueous temper rolling fluid for single-sided galvanized steel sheets, characterized in that it contains 100 g and has a pH adjusted to 8 to 10. 2. An aqueous temper-rolling fluid for single-sided galvanized steel sheets, in which a required amount of surfactant is added to the aqueous temper-rolling fluid according to claim 1.