KR100325337B1 - Hot rollig method to prevent the sticking defect - Google Patents

Abstract

The present invention relates to a hot rolling method for the prevention of sticking phenomenon, to prevent the sticking phenomenon that occurs mainly in the filamentary rolling shear (1 to 2 stands) of a hot rolling mill that produces stainless steel. The graphite mixture (water + graphite volume fraction 10%) was injected between the F2 stands and sprayed at a pressure of 10 kgf / cm3 to deposit graphite particles on the surface of the rolled material before the stainless rolled material was rolled by the rolls of each finishing roll. It is to prevent the sticking phenomenon by making the lubrication action between the roll and the rolled material during the adsorption by rolling.

Description

Hot rollig method to prevent the sticking defect}

The present invention is a graphite (graphite) between the filament rolling inlet side and the F1 ~ F2 stand in order to prevent sticking phenomenon that occurs mainly in finishing mill 1 ~ 2 stand of a hot rolling mill that produces stainless steel The hot rolling method for the prevention of sticking phenomenon for manufacturing stainless hot rolled steel sheet with excellent surface quality by installing a mixture spray device and spraying on the surface of stainless hot rolled material to effectively prevent sticking phenomenon. In order to prevent sticking phenomenon that occurs mainly in finishing rolling shear (1 ~ 3 stand) during finishing, part of the surface layer of the workpiece moves to the tool side, which grows and damages the surface quality of the product. Effective sticking using graphite mixture liquid injector between entrance side and F1 ~ F2 stand By preventing as is for the production of stainless hot-rolled steel sheet excellent in surface quality.

In general, in the hot rolling process, a part of the rolled electrode surface layer adheres to the roll surface in the filamentary rolling shear (F1 to F3), which grows, causing sticking to the surface quality of the product.

Therefore, in the hot rolling process that produces stainless steel for the purpose of preventing such a phenomenon, a work roll is applied to the mixture of water and oil just before hot rolling for lubrication rolling between the roll and the rolled material in the rough rolling end and the finishing rolling end. It sprays on the surface and suppresses high temperature adhesion of the rolling material particle by oil film formation.

In addition, a roll material having a small coefficient of friction may be selected and applied for the purpose of suppressing the above phenomenon. These conventional technologies have caused problems of environmental problems such as dust pollution and cooling water contamination of hot rolling mills and poor mailing of hot rolled sheets by using oil, and the selection of roll materials has a limit in reducing the sticking incidence rate, and roll manufacturers It was not possible to be an effective and active way because it had to follow the change of situation.

1 shows a sticking prevention hot rolling method by hydraulic rolling of a conventional stainless hot rolled steel sheet. In the conventional method, after roughly rolling a ferritic stainless slab extracted from a heating furnace, an oil + solid lubricant is sprayed onto a filament rolling shear (F1 to F3) work roll or a back-up roll when entering into filament rolling. When 6 L nozzles are used at a work roll of F1, 2, and 3 stands at 2 L / hour and 10 kgf / cm3 of oil), an oil film is formed between the roll and the rolled material to exert a lubricating effect, thereby suppressing adhesion of the rolled material particles.

These conventional techniques can be satisfied for the purpose of preventing sticking phenomenon, but by using oil and solid lubricant, it causes environmental problems such as dust pollution and cooling water pollution in hot rolling mill, and mail order of finishing rolling process by lubrication. Frequent accidents caused by vocalization are adversely affecting productivity.

Therefore, in order to prevent the sticking phenomenon that occurs mainly in finishing mills (Finishing mill 1 to 3 stand) of a hot rolling mill producing stainless steel, a graphite (graphite) mixture between the filament rolling inlet side and the F1 to F2 stands is used. (The mixture of graphite and water with a volume fraction of 10% of the total volume of the mixture solution) A spray nozzle is mounted and sprayed to deposit graphite particles on the surface of the rolled material before the stainless rolled material is rolled by the rolls of the respective finishing rolls. Its purpose is to produce a stainless steel hot rolled steel sheet with excellent surface quality by effectively preventing sticking phenomenon by making the lubrication action between the roll and the rolled material during rolling by adsorption.

1 is a schematic view showing a conventional hot rolling method

2 is a schematic view showing a hot rolling method of the present invention

[Code Description of Main Part of Drawing]

1: hot rolled sheet 2: work roll

3: oil spray device 4: mixed liquid spray device

Figure 2 is a schematic diagram showing a hot rolling method for preventing the sticking phenomenon of the present invention, unlike the conventional method of Figure 1, the mainly produced in the hot rolling shear (1-2 stands) of the hot rolling mill to produce stainless steel In order to prevent king phenomenon, a graphite mixture solution (a mixture of graphite and water with a volume fraction of 10% based on the total volume of the mixture solution) was inserted between the filamentary rolling shear inlet side and the F1 to F2 stands. The stainless steel roll is adsorbed by the graphite particles on the surface of the rolled material before being rolled by each finishing roll stand to prevent the sticking phenomenon by performing the lubrication action between the roll and the rolled material.

On the other hand, the sticking phenomenon occurs in the contact arc between the roll and the rolled material. If a lubricating agent is present between the roll and the rolled material, the nucleation area of the sticking occurrence during rolling is reduced by rolling rolling, which greatly reduces the sticking occurrence rate. Can be.

The reason for using the graphite mixture is that it is ineffective because the amount generated by dust is higher than the amount adsorbed on the surface of the rolled plate when spraying the graphite powder, so it is ineffective to mix with water and spray it into the turbid solution at 1000 ~ 1100 ℃. The turbid liquid sprayed on the surface of the rolling plate is boiling and the water evaporates and the graphite particles remain and are adsorbed on the surface of the rolling plate.

Therefore, when the graphite mixture is sprayed onto the hot-rolled sheet surface at the finishing rolling side point as described above, lubrication rolling by graphite can be prevented.

Hereinafter, the present invention will be described in detail with reference to the following Examples.

EXAMPLE

Table 1 below shows the sticking occurrence tendency according to the graphite mixing ratio and the mixed liquid spraying pressure when the graphite mixed liquid is sprayed on the surface of the STS430J1L rolled sheet, and is classified into the following three stages according to the tendency.

O: Large amount of sticking, △: Low sticking, ×: No sticking

First, in the case of graphite mixing ratio, the sticking tendency decreases as the mixing ratio increases, and it is found that the sticking phenomenon does not occur at 10% or more.

In the case of the mixed liquid injection pressure, the sticking tendency decreased as the injection pressure increased, and the sticking phenomenon did not occur from 10 kgf / cm 3 or more. Therefore, in order to prevent the sticking phenomenon of stainless steel, the graphite fraction of the mixed liquid was 10% and the mixed liquid injection pressure was 10 kgf / cm 3, which was the most effective and economical.

TABLE 1

Table 2 below shows the tendency of sticking in the case of using the stainless hot rolling method according to the prior art and the present invention. First, the conventional rolling method (hydraulic rolling method using oil and solid lubricant) is used when using the STS430 rolled plate. When using STS430J1L rolled plate with high sticking rate of 0 to 5% and Cr content, it shows relatively good quality with 10 to 20%, but environmental pollution is caused by the use of oil and solid lubricant. Can't.

However, the stainless hot rolling method according to the present invention was able to produce a stainless hot rolled steel sheet having a very good quality of 0 to 5% when the STS430 rolled plate was used to produce a sticking rate of 0% and STS430J1L rolled plate.

TABLE 2

The present invention as described above is to prevent the sticking phenomenon by spraying the graphite mixed solution on the surface of the rolling material at the side of the finishing mill work roll in order to prevent the sticking phenomenon occurring during hot rolling of stainless steel in the hot rolling process equipment There is no effect that can produce a stainless hot rolled steel sheet of excellent surface quality without.

Claims (1)

In order to prevent the sticking phenomenon that occurs mainly in the filamentary rolling shear (1-2 stand) of the hot rolling mill that produces stainless steel, a graphite mixed liquid injection device is installed between the filament mill shear shaft and the F1 to F2 stand, and the mixed liquid is used. A mixture of graphite and water with a volume fraction of 10% of the total volume is sprayed onto the surface of the stainless hot rolled material at a pressure of 10 kgf / cm 3 to effectively prevent sticking. Hot rolling method.

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