JPH0264196A - Lubricant for producing seamless steel pipe - Google Patents

Abstract

PURPOSE:To obtain the title lubricant capable of providing water resistance, impact resistance and good lubricating properties by adding a salt of polybasic polymeric acid to a composition consisting essential of graphite fine powder and water insoluble fine-particle synthetic resin and then dispersing the blend into water. CONSTITUTION:The aimed lubricant obtained by adding (C) one or more kind of salts of polybasic polymeric acid selected from fumic acid, nitrofumic acid and ligninsulfonic acid to a composition consisting essential of (A) graphite fine powder, preferably having <= 100mum average particle size, (B) water- insoluble fine-particle synthetic resin such as polyacrylic resin or poly(modified) acetic vinyl based, polystyrene based, polyethylene based or polyepoxy based resin and dispersing the blend into water.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a water-dispersed hot lubricant for seamless scrap pipe making, particularly to a lubricant for mandrel bars in mandrel mill pipe making. The present invention relates to a lubricant for mandrel bars which forms a uniform and thick film at a temperature of 100 to 400° C.) and which has a dry film with excellent water resistance, impact resistance, and lubricity. Therefore, the present invention is useful in the lubricant manufacturing industry and the steel snow manufacturing industry.

Conventional lubricants for seamless steel pipe manufacturing are generally oil-based lubricants that are made by mixing graphite powder with oil (e.g., heavy oil, waste oil, etc.), or water-dispersed lubricants that are made by dispersing graphite powder in water. It is used.

Oil-based lubricants generate a large amount of flame or smoke, which poses a risk of deterioration of the working environment and fire. On the other hand, water-dispersed lubricants have been developed to improve the disadvantages of oil-based lubricants.

As a water-dispersible lubricant, a composition in which graphite is dispersed in water using a dispersant (Japanese Patent Publication No. 17639)
, a composition using a synthetic resin as a binder for graphite (JP-A-58-138795, JP-A-59-3731)
7 and Japanese Patent Publication No. 62-34357).

However, in such water-dispersed lubricants, the surface temperature of the mandrel bar is in the high temperature range (100 to 40
(0°C), a uniform and thick film could not be obtained during spray application, and a sufficient lubricating effect could not be achieved.

Problems to be Solved by the Invention The present invention solves the drawbacks of the conventional water-dispersed lubricants described above, and improves the mandrel bar temperature in the high temperature range (]00 to 40
The purpose of the present invention is to provide a lubricant for seamless steel pipe manufacturing that can form a uniform and thick film on the bar surface even at 0°C and exhibit extremely good hot lubrication performance.

Means for Solving the Problems In order to achieve this objective, the present inventors have conducted various studies on improving the adhesion of graphite to the mandrel bar surface and forming a uniform film, and as a result, we have developed a polybasic polymer. ff1li
It has been found that by blending the salt of t2, a thick and uniform lubricant film can be formed, and furthermore, it can be used as a lubricant for seamless steel pipe manufacturing that exhibits extremely excellent lubrication performance. That is, the gist of the present invention is to
A composition mainly composed of fine powder graphite and a water-insoluble fine particulate synthetic resin, and one or more selected from humic acid, nitrofumic acid, and ligninsulfonic acid as a salt of a polybasic high molecular weight acid. The present invention relates to a lubricant for seamless steel pipe manufacturing, characterized in that the lubricant contains a mixture of salts of the present invention and is dispersed in water.

(Salt of polybasic polymer monoacid) Salts of polybasic polymer monoacid in the present invention include sodium salts, potassium salts, calcium salts, magnesium salts of humic acid, nitrofumic acid, and ligninsulfonic acid;
Ammonium salts, amine salts, etc. are suitable. These salts may be used alone or in combination of two or more, and the appropriate amount of the salts added is in the range of 0.01% by weight to 5% by weight in the aqueous dispersion. If the amount added is less than 0.01% by weight, it is difficult to achieve the effects of the present invention.

(Fine powder graphite) The fine powder graphite used in the present invention may be natural, synthetic, engineered, or scaly, but the average particle size is determined from the viewpoint of dispersion stability of graphite and maintenance management of the lubricant supply device. from 1
It is desirable that the thickness is 00 μm or less.

(Fine Particulate Synthetic Resin) As the particulate synthetic resin used in the present invention, commonly used ones can be used. Examples thereof include polyacrylic resins, polyvinyl acetate resins, polymodified vinyl acetate resins, polystyrene resins, polyethylene resins, polyepoxy resins, and the like.

(Optional Additives) The lubricant of the present invention is basically composed of finely powdered graphite, a synthetic resin, and a salt of a polybasic high molecular weight acid, but for the purpose of stably dispersing these compositions in water. , other components such as surfactants, polymeric dispersants, pI-1 regulators, thickeners, etc., do not reduce the effects of the present invention, and can be added as necessary. be able to.

(How to use) When using the lubricant of the present invention, it can be diluted with water. Although it varies depending on processing conditions and application conditions, the lubricant of the present invention can be diluted and used so that the total amount of essential components and auxiliary components is 30 to 70% by weight of the diluent.

EXAMPLES In order to make the present invention easier to understand, examples are given below.

<Experimental Example> The results of examining the adhesion properties (namely, the amount of adhesion and the uniformity of the film) of the compositions shown in Table 1 are shown in FIG. 1 and Table 2.

The application of lubricant to the mandrel bar takes place during the movement of the mandrel bar (travel speed 1 to 4 m/s). Taking this into consideration, an adhesion experiment was conducted under the dynamic test conditions shown below.

After spraying sample oil onto a steel vibrator (φ90 x 4t x 150Lmm) heated to a predetermined temperature while moving at a speed of 2.0 m/s, the amount (g) of the deposited film on the surface of the steel pipe and the uniformity of the film were examined. .

The spray conditions are as follows.

Pump: Airless pump 206T (made by Graco)
, Compression ratio lO: 1 Spray gun: 24 AUA Automatic gun (Spray Ink Systems Co., Ltd.) (SPRAYING SYSTEMS Col nozzle
: φ0.61mm Spray distance: 200mm Discharge pressure: 40 K g f / cm Discharge amount: 30 g/s Steel vibrator temperature = 60 to 400°C Sample oil dilution liquid: Spray each sample oil as a 45% by weight water dispersion Coated.

Adhesion amount (g): Number of measurements: 5 times Table 1 Sample oil composition Note: (1) Samples A and B are conventional lubricants.

(2) Samples 1 to 5 are lubricants of the present invention.

(3) The composition ratios in the table are expressed in parts by weight.

Table 2 Uniformity of coated film Note: × indicates that the film was extremely uneven. ○ indicates that an undried film was formed.

0 indicates that the dried film was very dense.

Example! (Sample N [LI) Natural graphite (scaly) 65 parts by weight.

35 parts by weight of polyacrylic resin and 0.02 parts by weight of ammonium humate salt Water was added to the above composition to prepare a dispersion. The concentration of the above composition in the dispersion was 45% by weight.
Met.

This dispersion was continuously applied (200 pieces) to hot rolling of seamless steel pipes using a mandrel mill. The lubricant has a moving speed of 2
．． The coating was applied by airless spraying onto a mandrel bar at 0 m/s. At that time, the mandrel bar surface temperature was +00 to 250°C, and the lubricant film was uniform and well adhered, and the film thickness was 30 to 40 μm, which was more uniform than the conventional lubricant as a comparative example (comparative example A). A thick film was formed.

As a result, the friction coefficient was 80% or less compared to the comparative example, and improvements such as reduction in mill drive power (about 15%) and stabilization of rolling were obtained.

Example 2 (Sample Description 2) 65 parts by weight of natural graphite (scaly), 35 parts by weight of polyvinyl acetate resin, 0.05 parts by weight of sodium humate salt, and water were added to the above composition to prepare a dispersion. The concentration of the composition in the dispersion was 45% by weight.

This dispersion was continuously applied (300 pieces) to the hot rolling of seamless steel pipes using a mandrel mill, and the lubricant had a moving speed of 2.
．． The coating was applied by airless spraying onto a mandrel bar at 0 m/s. At this time, the mandrel bar surface temperature was 150 to 350°C, and the lubricant film was uniform and adhered well, and the film thickness was 40 to 50 μm, which was more uniform than the conventional lubricant as a comparative example (comparative example B). A thick film was formed.

As a result, the friction coefficient was 75% or less compared to the comparative example, and improvements such as reduction in mill drive power (approximately 20%) and stabilization of rolling were obtained.6 Example 3 (Sample Wall 3) Natural graphite ( Scales) 65 parts by weight, polyvinyl acetate resin 34.5 parts by weight nitrofumic acid ammonium salt 0.5 parts by weight Water was added to the above composition to prepare a dispersion. The concentration of the composition in the dispersion was 45% by weight.

This dispersion was continuously applied (400 pieces) to the hot rolling of seamless steel pipes using a mandrel mill, and the lubricant had a moving speed of 2.
．． The coating was applied by airless spraying onto a mandrel bar at 0 m/s. At this time, the mandrel bar surface temperature was +50 to 350°C, and the lubricant film was uniform and adhered well, and the film thickness was 40 to 55 μm, which was more uniform than the conventional lubricant as a comparative example (comparative example B). A thick film was formed.

As a result, the friction coefficient was 75% or less compared to the comparative example, and improvements such as reduction in mill driving power (about 20%) and stabilization of rolling were obtained.

Example 4 (Sample Sample 4) 65 parts by weight of natural graphite (scaly), 34 parts by weight of polyacrylic resin, 1 part by weight of sodium ligninsulfonate, and water were added to the above composition to prepare a dispersion. The concentration of the above composition in the dispersion is 4
It was 5% by weight.

This dispersion was continuously applied to hot rolling of seamless steel pipes (350 pipes) using a mandrel mill. The lubricant has a moving speed of 2
．． The coating was applied by airless spraying onto a mandrel bar at 0 m/s. At this time, the mandrel bar surface temperature was 150 to 300°C, and the lubricant film was uniform and well adhered, and the film thickness was 45 to 55 μm, which was more uniform than the conventional lubricant as a comparative example (comparative example A). A thick film was formed.

As a result, the friction coefficient was 70% or less compared to the comparative example, and improvements such as reduction in mill drive power (about 20%) and stabilization of rolling were obtained.

Example 5 (Sample size 5) 65 parts by weight of natural graphite (scaly), 31 parts by weight of polyacrylic resin, 3 parts by weight of ammonium humate salt, 1 part by weight of sodium ligninsulfonate Salt Add water to the above composition and disperse. It was made into a liquid. The concentration of the composition in the dispersion was 45% by weight.

This dispersion was continuously applied (400 pieces) to the hot rolling of seamless steel pipes using a mandrel mill, and the lubricant had a moving speed of 2.
．． The coating was applied by airless spraying onto a mandrel bar at 0 m/s. At this time, the mandrel bar surface temperature was +50 to 350°C, and the lubricant film was uniform and well adhered, and the film thickness was 45 to 55 μm, which was more uniform than the conventional lubricant as a comparative example (comparative example A). A thick film was formed.

As a result, the friction coefficient was 70% or less compared to the comparative example, and improvements such as reduction in mill track drive power (about 20%) and stabilization of rolling were obtained.

Effects of the Invention Conventional lubricants for seamless steel pipe manufacturing, which are mainly composed of graphite powder and fine-grained synthetic resin, have poor adhesion when the surface temperature of the mandrel bar is high (150°C or higher), resulting in a uniform dry film. I can't get it.

However, it was selected from salts of humic acid, nitrofumic acid, and ligninsulfonic acid, which are polybasic polymeric arsenic acids!
The lubricant for seamless steel pipe manufacturing of the present invention containing a or a mixture of two or more forms a uniform and thick dry film and exhibits good rolling lubrication performance.6 Therefore, the lubricant of the present invention By using mill drive power reduction,
This makes it possible to stabilize rolling.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the adhesion of the lubricant of the present invention and the lubricant of the prior art.

Claims (2)

[Claims] (1) Seamless, characterized in that it is made by dispersing the salt of a polybasic high molecular weight acid in a composition whose main components are fine powder graphite and a water-insoluble fine particulate synthetic resin, and dispersing it in water. Lubricant for steel pipe manufacturing. (2) The lubricant for seamless steel pipes according to claim 1, wherein the polybasic high molecular weight acid is one or a mixture of two or more selected from humic acid, nitrofumic acid, and ligninsulfonic acid.