JPH04253513A - Method for applying solid lubricant for stainless steel rolling - Google Patents

Abstract

PURPOSE:To evade the trouble at the time of using nozzle and to realize the uniform applying of the paint on the roll by applying the solid lubricant with the electrostatic coating device. CONSTITUTION:The electrostatic coating devices are arranged at the upper side and the lower side by inserting the rolled stock 2 between them on the inlet side of the rolling mill 1. the solid lubricant of the iron oxide powder, etc., is ejected with the spray gun in the powder supplying device 3. The negative side of the direct current power source 4 are connected to each powder supplying device 3 of the upper and lower sides, and the positive side is connected to the grounded roll 5 and earthed. On this device, the trouble existing in the method that the solid lubricant is ejected in the state mixed in the viscosity water solution or the lubricating oil is eliminated, and the effective coating can be realized.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a method for applying a solid lubricant such as iron oxide powder to prevent seizing on the rolled material or the parts that come into contact with the rolled material such as rolls and liners during hot rolling of stainless steel. Regarding.

0002

BACKGROUND OF THE INVENTION Stainless steel products are required to have excellent surface texture, and the quality requirements are becoming increasingly strict, but stainless steel has the disadvantage of being prone to seizure during hot rolling. The reason for this is that stainless steel has excellent oxidation resistance, so the formation of oxide scale is slow, and when a new surface occurs during multi-stage rolling, there is not enough time to form a scale layer to protect the new surface. As a result, the scale layer becomes thinner and metal-to-metal contact between the rolling material and the rolling roll becomes more likely to occur, and the rolling material seizes onto the rolling roll, resulting in repeated transfer of seizure to the rolling material.

One way to prevent the occurrence of scratches on the surface of stainless steel due to seizure is to apply various animal fats, mineral-based or synthetic lubricating oils used in the rolling industry of ordinary steel to stainless steel. Attempts have also been made to use this method, but in reality, a sufficient burn-in effect has not been obtained. As an alternative to the above-mentioned lubricants, a solid lubricant such as iron oxide powder or graphite powder dispersed in a viscous aqueous solution or rolling oil can be used as the lubricant. A method has been developed to replenish the thinning of the scale layer. According to this method, even if a high Cr roll that is highly compatible with stainless steel is used as a work roll,
Roll seizure of stainless steel can be prevented even when hot rolling is performed at a high temperature of 1200° C. while applying a high load of 10 to 50 Kgf/mm2.

0004

A solid lubricant such as iron oxide powder is mixed with a viscous aqueous solution or rolling oil and is sprayed from a nozzle onto a roll or the like. When a solid lubricant is mixed with a viscous aqueous solution or rolling oil, a simple aqueous solution not only has poor adhesion to the roll;
This is because lubricants tend to precipitate and agglomerate in conduits, but even when mixed with viscous aqueous solutions or rolling oil, it is difficult to maintain a uniformly dispersed state. Furthermore, such lubricants have high viscosity and require high output. In the present invention, a solid lubricant mixed with a viscous aqueous solution or rolling oil is injected from a nozzle and the nozzle is easily clogged due to foreign matter mixed in or agglomerated flocs of the solid lubricant. The purpose of the present invention is to solve the above-mentioned problems caused by the spraying method.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention attempts to apply a solid lubricant to a rolled material using an electrostatic coating device or to a location such as a roll, a liner, etc. that comes into contact with the rolled material. That is, the present invention is characterized in that, during hot rolling of stainless steel, a solid lubricant is applied by an electrostatic coating device to the rolled material or to the portions that come into contact with the rolled material such as rolls and liners.

[0006] Here, as the solid lubricant, for example, Fe2
O3,, Fe3O4, MoS2, BN, PbO, P
One or more of bS, CaF2, Al2O3, Ti, Ni oxide, Cr oxide, inorganic silicate, etc. is used.

[0007]

[Operation] The solid lubricant applied by the electrostatic coating device to the rolled material or the location where it comes into contact with the rolled material such as a roll or liner compensates for the thinness of the scale layer on the surface of the stainless steel.

[0008]

[Example] The figure shows an apparatus for carrying out the method of the present invention, that is, a rolling mill 1 equipped with an electrostatic coating device. It consists of a spray gun-shaped powder supply device 3 which is arranged above and below and sprays solid lubricant such as iron oxide powder onto the rolled material 2 from above and below, and a DC power supply 4, and one side of the power supply 4 is connected to the upper and lower supply devices. 3, and the + side is connected to the ground roll 5 in front of the powder supply device and is grounded.

[0009] Before being sent to the rolling mill 1, the rolling material 2 is electrostatically coated with a solid lubricant and then rolled.

0010

[Effects of the Invention] According to the present invention, the mixing process, the maintenance of uniform dispersion of the solid lubricant, and the nozzle clogging, which were present in the method of spraying the solid lubricant mixed with a viscous aqueous solution or lubricating oil through a nozzle, can be improved. Problems such as these are eliminated, and powder solid lubricants can be applied efficiently without waste.

[Brief explanation of the drawing]

FIG. 1 shows a schematic diagram of an apparatus in which a solid lubricant electrostatic coating device is incorporated into a rolling mill.

[Explanation of symbols]

1 Rolling mill
2 Rolled material 3 Powder supply device
4 Power supply 5
ground roll

Claims (2)

[Claims] 1. A solid lubricant for rolling stainless steel, characterized in that a solid lubricant is applied by an electrostatic coating device to the rolled material or to the parts that come into contact with the rolled material such as rolls, liners, etc. during hot rolling of stainless steel. How to apply the agent. [Claim 2] The solid lubricant is Fe2O3, Fe3O
4, MoS2, BN, PbO, PBS, Caf2,
The method for applying a solid lubricant for rolling stainless steel according to claim 1, wherein the solid lubricant is one or more of Al2O3, Ti, Ni oxide, Cr oxide, inorganic silicate, etc.