JPH09122733A - Method and device for supplying rolling oil in rolling mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance roll cooling capacity by lowering the temp. of a roll coolant liquid and to improve the lubricity in rolling by lowering the temp. of the roll surface. SOLUTION: At the time of supplying rolling oil to rolling rolls of each stand of a cold tandem mill 1 using a circulation type rolling oil supplying system, the temp. of the roll coolant liquid is cooled to 30-50 deg.C using a cooler unit 19. Further, by heating the temp. of a hybrit liquid up to 50-90 deg.C by using a tank 20 for elevating temp., effective rolling excellent in cooling function and lubricity is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for supplying rolling oil to a rolling mill.

[0002]

2. Description of the Related Art Generally, when supplying rolling oil to the rolling rolls of each stand of a cold tandem rolling mill, a circulation type rolling oil feeding system is used. This method is performed by a system as shown in FIG. That is, as shown in this figure, the cold tandem rolling mill 1 is composed of, for example, four stands of STD 1 to 4 are four-high rolling mills, and STD 5 is composed of five stands of six-high rolling mills. The roll coolant liquid stored in the STD 1 coolant tank 2 is supplied to the STD 1 coolant spray header S ₁ by the STD 1 coolant pump 3 via the STD 1 coolant supply pipe 4. Then, the roll coolant liquid jetted from the coolant spray header S ₁ of STD 1 to the vicinity of the roll bite inlet of the work roll R ₁ of STD 1 is collected by the coolant receiver 5 for STD 1, and returned via the return pipe 6 for STD 1. It is returned to the coolant tank 2 for STD 1 and reused.

On the other hand, for STD 2-5, STD 2-5
The roll coolant liquid obtained by emulsifying the rolling oil stock solution supplied to the coolant tank 7 for piping by the pipe 8 into the makeup water supplied by the pipe 9 is transferred to the ST by the coolant pump 10 for STD 2-5.
D coolant spray header of STD 2-5 through 2-5 for coolant supply pipe _{11 S 2, S 3, S} 4, are supplied to S _5, the work roll R ₂ of STD 2-5, R _3,
It is injected near the roll bite inlets of R ₄ and R ₅ . And the sprayed roll coolant is STD 2
Recovered by coolant receiver 12 for ~ 5, return pipe for STD 2-5
It is returned to the coolant tank 7 for STD2-5 via 13
Used for circulation.

As described above, the rolling oil used in the circulating rolling oil supply system is circulated and used, so that high emulsion stability is required. Further, in such a circulating type rolling oil supply system, the roll coolant has two roles: for rolling lubrication and for roll cooling. And, of course,
The lower the temperature of the roll coolant, the higher the cooling efficiency. However, in general, the higher the temperature of the roll coolant, the higher the efficiency of adhesion of rolling oil, and the better the rolling lubricity.

That is, the effects of the temperature of the roll coolant on the roll cooling performance and rolling lubricity are contradictory. Further, when the temperature of the roll coolant is low, the emulsion stability is deteriorated, and when the temperature is lower than the melting point, oil solidifies to cause pipe clogging and surface defects in the rolled material. In addition, if the temperature control is performed so that the temperature of the roll coolant in the coolant tank 2 for STD 1 and the coolant tank 7 for STD 2 to 5 becomes low, there is a problem that the rolling oil will rot. In consideration of such performance balance, the roll coolant used in the circulating rolling oil supply system is generally at a temperature of about 50 to 65 ° C.

By the way, Japanese Patent Publication No. 58-5731 discloses a circulating rolling oil supply system having a hybrid system. As shown in FIG. 4, the contents are the work rolls R _{1 to} R ₅ of the stands STD 1 to 5 of the cold tandem rolling mill 1, the coolant tank 2 for STD 1 and the STD 1.
The roll coolant liquid is jetted and circulated from the coolant tank 7 for 2 to 5 through the coolant spray header S ₁ of STD ₁ and the coolant spray headers S _{2 to} S ₅ of STD 2-5.

On the other hand, a hybrid tank 14 is arranged and a rolling oil stock solution is supplied from a pipe 15, and a part of the roll coolant solution is supplied to this rolling oil stock solution by a coolant supply pipe 11 for STD 2-5.
It is extracted from a diluting liquid supply pipe 16 branched from the above to dilute it to obtain a high-concentration hybrid liquid for rolling lubrication, which is supplied by a hybrid pump 17 to a hybrid spray header T _{1 to} T ₅ of each stand via a hybrid supply pipe 18. Then
The work rolls R _{1 to} R ₅ of each stand are sprayed as a rolling lubricant before they are caught. Then, it collects in the coolant receiver 5 for STD 1 and the coolant receiver 12 for STD 2-5, and the coolant spray header S ₁ , STD 2 of STD 1 is collected.
5 is intended to circulate respectively are merged into a roll coolant sprayed from the coolant spray header S ₂ to S ₅ of.

In this case, in order to change the concentration of the hybrid liquid in a short time, the hybrid tank 14 has a small capacity, for example, about 1,000 l. Therefore, even if the temperature of the hybrid tank 14 is set to, for example, 70 ° C., it is easily affected by the temperature of the roll coolant liquid that is the diluting liquid, and when the roll coolant liquid that is the diluting liquid is frequently replenished, Since the liquid temperature drops to, for example, about 60 ° C., there is a problem that it is difficult to constantly obtain the target temperature.

For this hybrid tank 14, STD
The coolant tank 7 for 2 to 5 has a large capacity of about 100,000 l, and the temperature of a large amount of roll coolant liquid returned from the coolant receiver 12 for STD 2 to 5 after injection is raised by roll cooling. Therefore, for example, even if the set temperature of the coolant tank 7 for STD 2 to 5 is 40 ° C, it is very difficult to always obtain the target temperature because it depends on the temperature of the roll coolant liquid returning to the tank. is there.

Therefore, the temperature of the roll coolant is
The temperature is 50 ° C or higher, and the temperature of the hybrid liquid, which is a rolling lubricant, can only be raised by about 10 ° C from the temperature of the roll coolant liquid. For this reason, the cooling efficiency is remarkably deteriorated as compared with the direct rolling oil supply system in which the roll is usually cooled by cooling water having a temperature of about 25 to 35 ° C. Furthermore, since oil is mixed in the roll cooling water in the circulating rolling oil supply system,
The heat efficiency is poor. As described above, since the roll cooling capacity is insufficient in the circulation type rolling oil supply system, the steel sheet surface quality such as the defective shape due to the increase of the thermal crown of the work roll and the seizure accompanying the rise of the roll surface temperature is deteriorated.

The hybrid liquid is sprayed directly on the steel sheet between the stands, but generally, as shown in FIG. 5, the rolling lubricants a, b, c in an emulsion state in which various rolling oils are mixed. The relationship between the emulsion temperature and the adhered amount was investigated for four types, d, and d. The higher the emulsion temperature, the higher the adhered efficiency, that is, the larger the oil film thickness of the rolling oil flowing into the roll bite, and the better lubricity was obtained. To be On the contrary, when the temperature of the hybrid liquid is low, the amount of rolling oil adhered to the steel sheet is reduced, which leads to deterioration of lubricity and deterioration of rolling oil consumption.

[0012]

SUMMARY OF THE INVENTION The present invention can effectively solve the problems of the conventional circulating rolling oil supply system, such as the reduction of roll cooling ability and the reduction of rolling lubricity. An object is to provide a rolling oil supply method and device for a rolling mill.

[0013]

The present invention circulates a roll coolant liquid containing low-concentration rolling oil injected as a coolant near the roll bite inlet of each rolling roll of each stand of a cold tandem rolling mill, while A high-concentration hybrid liquid obtained by diluting a part of the roll coolant liquid and diluting the rolling oil stock liquid is injected as a rolling lubricant before each stand bites, and then merged with the roll coolant liquid. In a rolling oil supply method to a rolling mill using a rolling oil supply system, the temperature of the roll coolant is cooled to a range of 30 to 50 ° C, and the temperature of the hybrid liquid is heated to a range of 50 to 90 ° C. Is supplied to a rolling roll. The rolling stock solution may be diluted with water.

Further, according to the present invention, a coolant tank for storing a roll coolant liquid containing a low concentration of rolling oil, and the roll coolant liquid supplied through a coolant supply pipe are used for rolling rolls of each stand of a cold tandem rolling mill. A coolant spray header for injecting near the roll bite inlet, a diluting liquid supply pipe branched from the coolant supply pipe for extracting a part of the roll coolant liquid, and a roll coolant liquid extracted by the diluting liquid supply pipe. A hybrid tank for storing a high-concentration hybrid liquid obtained by diluting a rolling oil stock solution, a hybrid spray header for injecting the hybrid liquid supplied through a hybrid supply pipe before biting of each stand, and the injection The collected coolant and hybrid liquid are collected to recover the coolant tank. In a rolling oil supply device for a rolling mill comprising a coolant receiver to be returned, a cooler unit for cooling the roll coolant liquid is connected immediately before the coolant spray header of each of the stands, and the extracted liquid is supplied in the middle of the diluent supply pipe. A rolling oil supply device for a rolling mill, which is connected to a temperature raising tank for heating a roll coolant liquid. A pipe for supplying makeup water may be connected to the temperature raising tank instead of the diluting liquid supplement pipe for extracting the roll coolant liquid.

[0015]

[Operation] According to the present invention, since the temperature of the roll coolant is set to 30 ° C or higher and 50 ° C or lower, a good cooling capacity can be obtained. This usually means that the work roll surface temperature when the work roll thermal crown is saturated
The temperature is around 60 ° C, and the effect increases as the cooling liquid used for cooling is lower than 60 ° C. However, if the temperature of the cooling liquid is excessively lowered, excessive lubrication occurs. This will cause problems such as chattering.

Good lubricity can be obtained by controlling the temperature of the hybrid liquid, which is a rolling lubricant, to be 50 ° C. or higher and 90 ° C. or lower. This is because the higher the temperature of the emulsion, the higher the adhesion efficiency of the rolling oil to the steel sheet, however, however, when the temperature is excessively increased and the rolling oil becomes significantly deteriorated at a high temperature of more than 90 ° C, This is because the performance of rolling oil is reduced and the lubricity is also reduced. On the other hand, if the temperature is lower than 50 ° C., it is difficult to increase the efficiency of rolling oil adhesion to the steel sheet.

Regarding the problems of the emulsion stability at low temperature and the trouble induction due to the solidification of rolling oil, an emulsifier effective in a temperature range of 50 ° C. or lower is commercially available,
Further, even in a thin rolling mill having a recent hybrid system, a low-melting rolling oil is applied, and an anti-corrosion agent is also applied to the rotting of the rolling oil. Can be solved.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an embodiment of the present invention. In the figure, the same members as those of the conventional technique are designated by the same reference numerals and the description thereof will be omitted. In this figure, 19 is a cooler unit, and the coolant supply pipe 11 for STD 2-5
Connected between each coolant spray header S ₂ to S ₅ of STD 2 to 5, each coolant spray header S ₂ to S
Cool the roll coolant supplied to ₅ to the target value. Further, 20 is a temperature raising tank, which is connected in the middle of the diluting liquid supply pipe 16 and heats the roll coolant liquid supplied as a diluting liquid to the hybrid tank 14 to a target value.

Therefore, the target temperatures of the roll coolant liquid and the hybrid liquid are, for example, the roll coolant liquid.
To set the temperature to 40 ° C and the hybrid liquid to 75 ° C, set the temperature of the cooler unit 19 to 40 ° C and keep the temperature raising tank 20 at 75 ° C to keep the roll coolant liquid in the tank at 75 ° C. Try to keep At this time, ST
The temperature of the roll coolant liquid ejected from each of the coolant spray headers S _{2 to} S _{5 of} D 2 to 5 and returned via the coolant receiver 12 for STD 2 to 5 is about 50 ° C. Therefore, the tank for STD 2 to 5 The temperature of the roll coolant in 7 also reaches about 50 ° C.

Thus, by setting the temperature of the roll coolant to the optimum temperature for cooling the roll and setting the temperature of the hybrid liquid to a temperature at which a good plate-out property can be obtained,
Various problems in operation or quality due to insufficient roll cooling and various problems due to insufficient lubrication can be solved. In the above embodiment, a part of the roll coolant liquid was supplied as the dilution liquid of the hybrid liquid, but the present invention is not limited to this, and as shown in FIG. Supply water to the temperature raising tank 20,
Alternatively, the water may be heated to a predetermined temperature and supplied to the hybrid tank 14.

[0021]

As described above, according to the present invention,
By setting the temperature of the roll coolant to 30 ° C. or higher and 50 ° C. or lower, the roll cooling capacity can be increased, so that the thermal crown of the roll can be suppressed,
This can improve the flatness of the steel sheet. Also, since the roll surface temperature can be lowered,
It is possible to improve rolling lubricity.

Further, by setting the temperature of the hybrid liquid used as the rolling lubricant to 50 ° C. or higher and 90 ° C. or lower, the efficiency of adhesion of rolling oil to the steel sheet can be increased and the lubricity can be improved. is there.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention.

FIG. 2 is a schematic diagram showing another embodiment of the present invention.

FIG. 3 is a schematic diagram showing a conventional example.

FIG. 4 is a schematic diagram showing another conventional example.

FIG. 5 is a characteristic diagram showing a relationship between an emulsion temperature and a roll adhesion amount.

[Explanation of symbols]

1 Cold tandem rolling mill 2 Coolant tank for STD 1 3 Coolant pump for STD 1 4 Coolant supply pipe for STD 1 5 Coolant receiver for STD 1 6 Return pipe for STD 1 7 Coolant tank for STD 2-5 8, 9, 15 , 21 Piping 10 Coolant pump for STD 2-5 11 Coolant supply pipe for STD 2-5 12 Coolant receiver for STD 2-5 13 Return pipe for STD 2-5 14 Hybrid tank 16 Diluent supply pipe 17 Hybrid pump 18 Hybrid supply Tube 19 Cooler unit 20 Temperature rising tank R ₁ , R ₂ , R ₃ , R ₄ , R ₅ Work roll (rolling roll) S ₁ , S ₂ , S ₃ , S ₄ , S ₅ Coolant spray header T ₁ , T ₂ , T ₃ , T ₄ , T ₅ hybrid spray header

Claims (4)

[Claims] 1. A roll coolant liquid containing a low concentration of rolling oil injected as a coolant is circulated in the vicinity of a roll bite inlet of a rolling roll of each stand of a cold tandem rolling mill, while a part of the roll coolant liquid is circulated. A high-concentration hybrid liquid obtained by extracting and diluting the rolling oil stock solution was injected as a rolling lubricant before each stand biting, and then a circulating rolling oil supply method was used in which it was merged with the roll coolant. In the method of supplying rolling oil to a rolling mill, the temperature of the roll coolant is cooled to a range of 30 to 50 ° C., and the temperature of the hybrid liquid is heated to a range of 50 to 90 ° C. and supplied to a rolling roll. A method of supplying rolling oil to a rolling mill, which is characterized. 2. The rolling oil supply method for a rolling mill according to claim 1, wherein the rolling oil stock solution is diluted with water. 3. A coolant tank for storing a roll coolant liquid containing a low concentration of rolling oil, and a roll bite inlet of a rolling roll of each stand of a cold tandem rolling mill for supplying the roll coolant liquid supplied through a coolant supply pipe. A coolant spray header for injecting in the vicinity, a diluting liquid supply pipe branched from the coolant supply pipe to extract a part of the roll coolant liquid, and a rolling oil stock liquid with the roll coolant liquid extracted by the diluting liquid supply pipe. A hybrid tank for storing a high-concentration hybrid liquid obtained by dilution, a hybrid spray header for injecting the hybrid liquid supplied through the hybrid supply pipe before each stand is bitten, and the injected roll coolant. Coolant that collects the liquid and hybrid liquid and returns it to the coolant tank In a rolling oil supply device of a rolling mill comprising a receiver, a cooler unit for cooling the roll coolant liquid is connected immediately before the coolant spray header of each stand, and the extracted roll coolant is provided in the middle of the diluent supply pipe. A rolling oil supply device for a rolling mill, which is connected to a temperature raising tank for heating a liquid. 4. A rolling oil supply for a rolling mill according to claim 3, wherein a pipe for supplying make-up water is connected to the temperature raising tank instead of a diluting liquid replenishing pipe for extracting the roll coolant liquid. apparatus.