JPH05345895A - Method for hot-rolling and lubricating steel sheet - Google Patents

Abstract

PURPOSE:To obtain a hot-rolling and lubricating method, capable of suppressing local wear of a sheet passing edge part of operation roll for rolling and preventing seizing with a small amount of lubricant used without causing rolling troubles in hot-rolling of various steel sheets including stainless steel sheets. CONSTITUTION:A lubricant composition comprising 20-70wt.% highly basic Ca sulfonate is supplied only to a sheet passing edge part of operation roll 3 for rolling or is fed to the surface of operation roll for rolling in such a way that the amount of the highly basic Ca sulfonate fed is larger at the sheet passing edge part than that at the central part. Namely, the lubricant composition is supplied only to a nozzle header 1 or the amount of the lubricant composition fed to the header 1 is larger than that fed to a header 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling lubrication method for carbon steel plates, stainless steel plates and the like. For more details,
The present invention, in hot rolling of a steel sheet supplying a lubricant composition containing a highly basic Ca sulfonate in an amount of 20 to 70% by weight on the surface of a work roll for rolling, does not cause a defective biting or slipping, and the load condition The present invention relates to a hot rolling lubrication method for a steel sheet, which can prevent seizure at a threading edge portion of a severe roll surface and prevent or significantly reduce local wear of a roll at this portion.

[0002]

2. Description of the Related Art The corrosion resistance of steel can be dramatically improved by containing a large amount of Cr. High-chromium steel, typified by stainless steel, contains 13% or more by weight of Cr, so a stable chromium oxidation protection film is formed on the surface of the steel, and the surface is passivated to improve corrosion resistance. Of. However, this surface oxide film is significantly thinner than that of carbon steel and easily peels off when subjected to plastic working during rolling.

In hot rolling of carbon steel, low temperature rolling,
In high-load rolling such as high-pressure rolling, a sufficient oxidation protection film is not formed on the surface of the steel material, or even if it is formed, it is easily peeled off by undergoing large plastic working.

Under such circumstances, the work roll for rolling and the steel material are apt to seize during hot rolling, resulting in roughened roll surface and resulting flaws in the rolled product. Further, in the severe rolling situation as described above, the roll wear is large,
The rolling schedule was sometimes restricted.

Conventionally, in order to deal with such a problem,
Lubricants have been used to supply work rolls for rolling or their reinforcing rolls. The purpose of using the lubricant is to reduce the frictional force between the work roll for rolling and the steel material to prevent seizure, prevent the surface of the roll from becoming rough and wear, and improve the quality of the rolled product.

As such a lubricant, JP-A-47-1980
No. 7 discloses a lubricant composition in which a natural fatty oil is mixed with a small amount of a water displacing agent of 0.1 to 10% by weight, and optionally a mineral lubricating oil. Water-dispersing agents include oil-soluble sulfonates (eg, metal salts of petroleum sulfonate)
Is used. Lubricants in which finely powdered calcium carbonate of about 10 μm or less is dispersed in water or lubricating base oil are disclosed in Japanese Examined Patent Publication Nos. 62-14598, 62-39198 and 62-3919.
It is described in each gazette of No. 9.

However, these lubricants are intended for lubrication during rolling of carbon steel, and when used for hot rolling of stainless steel, the material to be rolled is severely seized on the surface of the work roll for rolling, resulting in rolling products. Cause flaws. Further, since the work rolls for rolling are largely worn, there is a problem that the rolling efficiency is extremely lowered.

As a lubricant for rolling stainless steel, one in which iron oxide powder is dispersed in lubricating oil is disclosed in JP-A-63-254195, and graphite powder is a viscous aqueous solution in JP-A-1-167396. It is proposed to disperse it inside.

However, even if the iron oxide powder is dispersed in order to suppress the state of direct metal-to-metal contact, it is possible to sufficiently prevent seizure and roll wear between the work roll for rolling and the stainless steel plate. Not not. Since graphite has an extremely low coefficient of friction and causes defective biting and slippage of the rolled material during rolling, it is not possible to contain graphite in an amount sufficient to exhibit seizure prevention effects and wear reduction effects. I was there. Furthermore, in the hot rolling of steel sheets,
Since the temperature at both ends of the steel sheet is likely to drop, the amount of oxide scale generated decreases and the hot deformation resistance also increases. Moreover, since the width of the roll is larger than that of the central portion of the strip, seizure is particularly likely to occur at a portion where the both ends of the steel sheet and the work roll for rolling contact with each other (referred to as a strip passing edge portion). This is a serious problem, which has been a major problem in hot rolling of steel sheets. The threaded plate edge portion is a portion where the effects of seizure and increase in roll wear appear significantly. Therefore, as shown in FIG. 3 (a), local wear called cat's eye is seen at both ends of the threading part corresponding to the threading edge part of the axial wear profile of the rolling work roll after rolling. Phenomena such as skin roughness and banding due to burning also occur.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to carry out hot rolling of various steel sheets including stainless steel sheets without causing rolling troubles such as defective biting and slippage during rolling, and the work for rolling the steel sheet. It is possible to prevent seizure on the threaded edge of the roll surface, and at the same time, to significantly reduce the wear of the threaded edge of the roll, which can significantly improve the quality of rolled products and work efficiency. It is to provide a hot rolling lubrication method.

[0011]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies in order to achieve such an object, and as a result, have found that a high basicity which has been conventionally blended only a small amount into a lubricating oil as a detergent dispersant.
It has been found that Ca sulfonate is the most suitable lubricant as a lubricant for hot rolling of steel sheet.

The highly basic Ca sulfonate is obtained by neutralizing a lipophilic petroleum sulfonic acid obtained by sulfonating an alkyl aromatic with fuming sulfuric acid or SO ₃ gas to give a Ca salt. It is produced by further reacting with CaO or Ca (OH) _{2 in} the presence of gas or the like. Highly basic Ca sulfonate contains 3 to 15 times more Ca than normal salt (Ca Sulfonate), and this Ca is mainly in the form of calcium carbonate (CaCO ₃ ).
(Average particle size) Colloidal dispersion of less than 150Å dispersed in oil is formed.

Since this highly basic Ca sulfonate has excellent heat resistance, it does not completely burn or decompose at the hot rolling temperature of the steel sheet, and it exists in a fluid or a state close to that of fluid and contributes to lubrication. It has been found that it is possible to exhibit excellent lubricity as a main lubricant. Moreover, since the surface of the steel sheet is also highly reactive with oxides, the lubricity is further improved by forming a lubricious reaction film on the surface.

Moreover, the highly basic Ca sulfonate contains fine particles of Ca salt (calcium carbonate) in oil as a colloidal dispersion having a particle size of 150 Å or less, as described above.
This finely dispersed calcium carbonate acts as a carrier (carrier) for the basic Ca sulfonate, which is the main component of the lubricating action, and even under high pressure during hot rolling, these fine particles cause the work rolls for rolling and the material to be rolled to roll. Since it is introduced in a uniform state at the friction interface with, the highly basic Ca sulphonate has a significantly high lubricating effect, and it suppresses direct metal-to-metal contact at the friction interface to prevent seizure and, at the same time, roll wear. Can be greatly reduced.

Due to such an action, the lubricant having the highly basic Ca sulfonate as the main lubricant is a seizure or roll at the edge of the threaded plate under severe load conditions, if the amount of the highly basic Ca sulfonate is increased. Local wear can also be completely prevented. However, since the highly basic Ca sulfonate has a remarkably high lubricating effect, increasing the supply amount thereof may cause a friction coefficient between the roll and the steel plate to be too low, which may cause rolling troubles such as defective biting and slipping, and This tendency is higher in highly basic Ca sulfonate having stronger lubricity.

As a result of further studies, the present inventor concentratedly supplies the highly basic Ca sulfonate to the threading edge portion of the surface of the work roll for rolling (that is, a larger amount than other roll surface portions, or The present invention has been completed by discovering that the use efficiency of the lubricant of the entire roll can be improved, and at the same time, seizure of the strip edge and local wear of the roll can be prevented by supplying the lubricant to other roll surface portions). ..

Here, the present invention relates to a hot rolling lubrication method for a steel sheet, which comprises supplying a lubricant composition containing 20 to 70% by weight of a highly basic Ca sulfonate to the surface of a work roll for rolling.
The lubricant composition is supplied only to the work roll surface for rolling contacting both ends of the steel plate to be rolled and its peripheral portion, or
Alternatively, it is characterized in that the amount of highly basic Ca sulfonate supplied to the surface of the work roll for rolling contacting both ends of the rolled steel plate and its peripheral portion is supplied so as to be larger than the amount of supply to the other roll surface portions. The hot rolling lubrication method for steel sheets is the gist.

Here, "the surface of the work roll for rolling contacting both ends of the steel sheet to be rolled and the peripheral portion thereof" means a portion where local wear of the roll or roughening of the roll has been remarkably recognized in the conventional lubrication method, that is, , The part called the strip edge where local wear is seen in the axial roll wear profile of Fig. 3 (a), generally at least 200 mm, usually 250 mm inward from both ends of the rolled steel plate The range up to the following corresponds to the strip edge.

[0019]

The alkylaromatic starting material for the highly basic Ca sulphonate used as the main lubricant in the present invention is not particularly limited, and like the conventional products, the lubricating oil fraction of mineral oil and synthetic compounds are used.
(For example, alkylbenzene, a product obtained by alkylating polyolefin with benzene, dinonylnaphthalene, etc.) can be used.

The highly basic Ca sulfonate is contained in the lubricant composition of the present invention in a proportion of 20 to 70% by weight. If this content is less than 20% by weight, the amount of roll wear increases and seizure cannot be sufficiently prevented. On the other hand, if the content of the highly basic Ca sulfonate exceeds 70% by weight, the composition becomes highly viscous and it becomes difficult to supply the lubricant, so
The content of sulfonate is 20 to 70% by weight. Highly basic
The preferable content of Ca sulfonate is 30 to 60% by weight.

Although the base number of the highly basic Ca sulfonate to be used is not particularly limited, it is preferably 40 mg-KOH / g or more, and particularly 200 to 500 mg-KOH / g has a seizure prevention ability and abrasion resistance. It is preferable because it has excellent properties and stain resistance.
When the base number is less than 200 mg-KOH / g, the amount of calcium carbonate as a carrier for improving the introduction property of the highly basic Ca sulfonate to the friction interface is small, and the introduction amount of the highly basic Ca sulfonate to the friction interface is small. Therefore, reduction of roll wear and prevention of seizure become insufficient, and stain resistance such as descaling property may be reduced. However, in the case of steel materials with light workability and relatively good workability (eg, carbon steel, SUS 304 steel), even a highly basic Ca sulfonate having a base number of less than 200 mg-KOH / g can be effectively used. On the other hand, the base number is 500 mg
A highly basic Ca sulfonate exceeding -KOH / g cannot be manufactured at the present technical level though it has an appropriate function as a rolling lubricant, for example, a viscosity. However, if it becomes possible due to manufacturing technology, a base number of more than 500 mg-KOH / g could be used. As the highly basic Ca sulfonate, those having various basicities are commercially available, and commercially available products may be used.

As described above, the lubricating method of the present invention is characterized by using a lubricant composition containing a specific amount of highly basic Ca sulfonate. That is, in order to obtain a strong lubricating action peculiar to the present invention, the presence of a highly basic Ca sulfonate as a highly basic substance highly reactive with an oxide film formed on the steel surface during hot rolling is important. is there.

Particle size contained in highly basic Ca sulfonate 1
Calcium carbonate below 50Å spontaneously precipitates during the production of highly basic Ca sulphonate, forming a colloidal dispersion in oil. This colloidally-dispersed calcium carbonate is prepared by dispersing a separately prepared finely powdered calcium carbonate having a particle size of about 1 to 10 μm in a lubricating base oil as shown in Japanese Patent Publication No. 62-14598. The action and effect are clearly different from those of the above lubricants. In this prior art lubricant, calcium carbonate powder itself exerts a lubricating effect.

On the other hand, calcium carbonate having a particle size of 150Å or less, which is precipitated as a salt in the highly basic Ca sulfonate, has no lubricating effect, and exhibits the high lubricating effect of the highly basic Ca sulfonate. To make it easier
It is considered that it acts as a carrier for transporting the highly basic Ca sulfonate to the friction interface, and plays a role of assisting the introduction property and reactivity of the highly basic Ca sulfonate under the high surface pressure interface.

As described above, highly basic Ca showing high lubricity
Particle size of colloidal dispersion formed in sulfonate and oil
Due to the synergistic effect with calcium carbonate of 150Å or less, it exerts remarkable effects of improving seizure resistance, wear resistance, and stain resistance on steel materials.

The lubricant composition used in the method of the present invention is generally prepared by admixing the lubricating base oil used with a highly basic Ca sulfonate. The overbased Ca sulfonate is added in an amount within the range of 20 to 70% by weight of the entire composition as described above. A composition consisting only of a highly basic Ca sulfonate and a lubricating base oil is also sufficiently effective, but one or more other additives may be added if necessary. Additives that can be used include solid lubricants, extreme pressure additives, antioxidants, pour point depressants, and viscosity index improvers.

Suitable lubricating base oils include oils and fats such as mineral oils, synthetic lubricating oils, rapeseed oil and lard oil, higher fatty acids and their esters, and the like. Examples of solid lubricants include graphite, molybdenum disulfide, boron nitride, mica, talc and the like.

Examples of extreme pressure additives include sulfur-based extreme pressure additives such as sulfurized fats and oils, sulfurized mineral oils, dinonyl polysulfide, and phosphorus-based extreme pressure additives such as tricresyl phosphate and dioctyl phosphate.

Examples of antioxidants include methylene-4,4
Examples thereof include bisphenols such as -bis (2,6-di-tert-butylphenol), alkylphenols such as di-tert-butylcresol, naphthylamines and the like. Examples of pour point depressants and viscosity index improvers include polymethacrylates and polyolefins.

The solid lubricant is added in an amount of about 1 to 10% by weight, the extreme pressure additive is added in an amount of about 1 to 15% by weight, the antioxidant is added in an amount of about 0.01 to 1.0% by weight, and a pour point depressant is added. The addition amount of the viscosity index improver may be about 1 to 5% by weight, respectively.

In the hot rolling lubrication method of the present invention, the lubricant composition containing 20 to 70% by weight of highly basic Ca sulfonate is contacted with the both ends of the rolled steel sheet, and the work roll surface and its peripheral portion. Only, or supply so that the amount of highly basic Ca sulfonate supplied to the surface of the work roll for rolling contacting both ends of the steel plate to be rolled and its periphery is greater than the amount supplied to other roll surface parts. To do. That is, since the supply of the highly basic Ca sulfonate is carried out only on the strip edge of the work roll for rolling, or with a gradient of the supply amount such that the strip edge is larger than the strip central part, is there.

In this way, by supplying the highly basic Ca sulfonate concentratedly to the rolled strip edge portion, the frictional state at the strip edge portion where the load is severe and the lubrication effect can be enhanced preferentially. It is possible to prevent seizure and local wear of the roll or to significantly reduce it.

That is, in general, the lubricant is generally supplied uniformly over the entire surface of the work roll for rolling, but an amount sufficient to prevent seizure of the strip edge and local wear of the roll under severe load conditions. When the lubricant composition of the present invention is uniformly supplied to the entire surface of the roll, the highly basic Ca sulfonate has a high lubricating effect, so that the lubricating effect becomes excessive in the central portion where the load is small, and rolling such as defective biting or slip of the steel sheet occurs. Trouble is likely to occur and stable rolling may be difficult. Moreover, such a uniform supply is highly basic.
A large amount of Ca sulfonate is used, which is economically disadvantageous. However, according to the present invention, such an adverse effect in the case of using a highly basic Ca sulfonate as a lubricant main agent is eliminated, and a necessary lubricating effect can be sufficiently obtained.

Even if the lubricant composition is supplied only to the threading edge portion of the surface of the work roll for rolling, as the roll rotates,
The lubricant composition spreads toward the center of the roll,
Since the lubricant composition is distributed over the entire surface of the roll with a concentration gradient such that the amount of the highly basic Ca sulfonate increases toward the periphery, the lubricating effect can be spread over the entire surface of the roll. Therefore, even in this case, it is not necessary to supply another lubricant to the central portion of the roll.

However, if desired, for example, a commercially available hot lubricant may be supplied to the entire surface of the work roll for rolling or only the central portion of the roll surface, and at the same time, the lubricant composition used in the present invention may be applied only to the edge of the strip. Alternatively, a larger amount may be supplied to this portion. Or, especially when supplying the above-mentioned lubricant composition only to the strip edge, in order to prevent lubrication failure in the central part at the beginning of rolling, a general hot-lubrication operation is performed only at the beginning of rolling. It may be supplied to the entire surface of the roll or the central portion.

The supply of the lubricant composition to the work rolls for rolling may be carried out directly on the work rolls for rolling, or in the case of a multi-stage rolling mill, through other rolls such as reinforcing rolls and intermediate rolls. You can go.

As a method for supplying the lubricant composition, depending on the required viscosity and concentration, an air atomizing method in which it is mixed with compressed air and supplied in the form of a spray, or a water injection method in which it is mixed and supplied with water is supplied. Further, it may be appropriately selected from a steam atomizing method or the like which is atomized with heated steam and supplied, and any method can obtain the remarkable lubricating / descaling effect of the present invention. Of course, a method of supplying the undiluted solution as it is may be used, and a general oil supply method other than the above may be used. When supplied in undiluted form, the lubricant composition of the present invention may be made water-soluble to make it nonflammable, if necessary.

In order to supply the highly basic Ca sulfonate only to the edge portion of the rolling work roll, a lubricant composition containing 20 to 70% by weight of the highly basic Ca sulfonate used in the present invention may be used, for example. In the example shown in FIG. 1, the lubricant composition may be supplied to the work roll 3 for rolling only from the two nozzle headers 1 located at the edges on both sides of the steel plate 4.
In this case, other lubricant may be supplied from the header 2 located in the remaining central portion if necessary, or nothing may be supplied from this header.

In order to supply a large amount of highly basic Ca sulfonate to the strip edge of the work roll for rolling from the central portion, when the above lubricant composition is mixed and supplied with water or air, the mixture thereof is mixed. It suffices to change the ratio between the edge portion and the central portion of the roll passing plate. That is, in the example shown in FIG. 1, if the mixing ratio of water or air in the header 1 is made lower than the mixing ratio in the header 2 and the flow rates are the same in the headers 1 and 2, a larger amount of lubrication from the header 1 is obtained. The agent composition, and thus the highly basic Ca sulfonate, can be supplied. When the lubricant composition is supplied as an undiluted solution, the supply flow rate may be simply controlled to supply a larger amount of the lubricant composition from the header 1. Alternatively, the headers 1 and 2 may change the highly basic Ca sulfonate concentration in the lubricant composition to be supplied. That is, the highly basic Ca sulfonate supplies the lubricant composition with a higher concentration from the header 1.

As described above, when a large amount of highly basic Ca sulfonate is supplied to the edge portion from the central portion of the strip of the work roll for rolling, as long as the object of the present invention is achieved, the high basicity of the central portion and the edge portion is high. There is no limitation on the supply amount ratio of Ca sulfonate, but generally, the supply amount to the edge portion is preferably about 2 to 3 times the supply amount to the central portion.

FIG. 2 shows the case where the lubricant is supplied to the work rolls 3 for rolling the steel plate 4. As described above, the lubricant is supplied to the work rolls 3 for rolling through the reinforcing rolls 5. May be supplied. Alternatively, one roll may be supplied with the lubricant used in the present invention, and the other roll may be supplied with another lubricant. Further, the lubricant composition of the present invention may be supplied in a small amount to the steel sheet before rolling in addition to the work roll for rolling, whereby the lubrication and cleaning effect is further enhanced.

According to the hot rolling lubrication method of the present invention, with a small amount of the highly basic Ca sulfonate-containing lubricant composition,
In particular, it is possible to efficiently prevent local wear, rough skin, and seizure of the edge portion of the work roll passing plate for rolling under a severe rolling load. Therefore, as shown in Fig. 3 (b), the axial wear profile of the rolling work roll after rolling eliminates or greatly reduces the local wear at the threading edge called the cat's eye. Phenomena such as skin roughening and banding due to seizure of are also prevented.

The lubricant composition of the present invention comprises a ferrite-based material,
Cr content used not only for general austenitic stainless steel but also for automobile exhaust materials
20% or more by weight of highly corrosion-resistant stainless steel (for example, 20% Cr steel,
Hot rolling of 20% Cr-2% Mo steel, 20% Cr-5% Al steel, etc.,
The effect is particularly remarkable in high-load rolling such as low-temperature rolling and high-pressure rolling of carbon steel. Of course, even if it is used for a hot rolling lubrication method at the time of general rolling of a general steel material, its effect is great. Further, it is useful not only for plate rolling but also for hole rolling of shaped steel, wire rods and pipes.

[0044]

EXAMPLE Next, a description will be given based on a specific example. Example 1 Inventive Examples 1 to 8 shown in Table 1, Comparative Examples 1 and 2, Conventional Example 1
Twelve lubricant compositions of No. 2 were prepared by mixing the ingredients in the given proportions using a homomixer and tested using the lubricant compositions as described below.

In a four-stage hot strip rolling mill of the hot strip rolling mill line equipped with the lubricant supply device shown in FIGS. 1 and 2, carbon steel of about 3000 tons and stainless steel (SUS 304) of about
A rolling test of 1800 tons was conducted. During each rolling, the rolling lubrication method A of the present invention shown in Table 2 (a large amount of highly basic Ca sulfonate was supplied to the threading edge of the roll) and B (highly basic Ca) were used.
Sulfonate is supplied only to the strip edge of the roll), and each lubricant composition shown in Table 1 is supplied to prevent seizure of the strip edge of the rolling work roll (made of high Cr cast iron) after rolling. The local wear (difference from the wear amount at the center of the strip) was examined.

The lubricant composition was diluted with a water injection type lubricant supply device to a concentration of about 0.1 to 0.5% by weight and supplied at a pressure of 3 to 4 kgf / mm ² . The strip width after rolling was about 1000 mm, and the widths of the strip edges on both sides were about 200 mm. The test results are shown in Table 3 (carbon steel) and Table 4 (stainless steel).

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

[Table 3]

[0050]

[Table 4]

As is clear from the results of Tables 3 and 4, according to the hot lubrication method of the present invention, regardless of the type of steel, the hot rolling method of the present invention is independent of the steel grade, and the strip edge portion of the work roll for rolling is used. It has been proved that the seizure of the film is prevented and the rough skin and banding in this part are avoided. Also, FIG.
As shown in (a), there is no or little local wear of the roll at the strip edge, which was remarkable in conventional hot rolling, and roll wear at the edge is reduced to wear at the center. It was possible to obtain the roll wear profile shown in FIG. 3 (b), which was suppressed to almost the same level.

In the lubrication method A in which a small amount of the highly basic Ca sulfonate was supplied also to the central portion of the threaded plate of the roll, as compared with the lubricating method B in which the highly basic Ca sulfonate was not supplied to the central portion, It can be seen that not only the roll wear but also the wear itself at the center of the roll is reduced.

In a more severe rolling situation such as stainless steel rolling, the lubricant composition of Examples 4, 5 and 6 of the present invention containing 30 to 60% by weight of a highly basic Ca sulfonate is more preferable. It exerts a great lubricating effect. Highly basic
Regarding the base number of Ca sulfonate, as can be seen from the comparison of the lubricant compositions of the present invention examples 1 to 6 and the present invention examples 7 to 8, those having a base number of 200 to 500 mg-KOH / g have a lubricating effect ( It can be seen that it has excellent wear resistance and seizure resistance).

As shown in Comparative Example 1, the highly basic Mg sulfonate has a poor lubrication effect even when the base number is as high as 400 mg-KOH / g, and it has the effect of preventing seizure at the edge of the strip and the local effect. The effect of reducing roll wear cannot be obtained. Further, when the content of the highly basic Ca sulfonate is less than 20% by weight as in Comparative Example 2 and the lubricant compositions of Conventional Examples 1 and 2, the lubricating effect is extremely high by any lubricant supply method. Was inferior to

When the lubricant Nos. 1 to 8 of the present invention are used by the conventional hot lubrication method C, rolling trouble such as slip does not occur, but seizure and local wear of rolls occur at the edge of the strip. Also, the wear of the central part of the roll cannot be sufficiently suppressed.

On the other hand, when the lubricants Nos. 1 to 8 of the present invention are used by the conventional lubrication method D, rolling troubles such as slip frequently occur at the central portion of the strip, which causes strip thickness variation and load variation. Becomes unstable.

As a work roll for rolling, a high carbon type high speed steel (high speed steel) roll, a high alloy grain cast iron roll,
When using any of the hot rolling rolls such as high Cr cast iron rolls and adamite rolls,
Similar results are obtained as above.

[0058]

As described above, according to the hot lubrication method of the present invention, it is possible to reduce the amount of the highly basic Ca sulfonate-containing lubricant composition used, particularly in the strip edge portion where the rolling load condition is severe. It is possible to efficiently reduce the frictional force during rolling and improve the lubricating action, and it is possible to eliminate or significantly reduce the local wear of the work rolls for rolling in this part, and at the same time, to prevent seizure and rolls resulting from it. Rough skin and banding can also be prevented. In addition, rolling rubles such as defective biting and slip can be avoided. Therefore, the hot rolling lubrication method of the present invention remarkably improves the quality of rolled products and improves working efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory view showing from above a method of supplying a lubricant in a hot rolling lubrication method of the present invention.

FIG. 2 is an explanatory view showing a side view of a lubricant supply method in the hot rolling lubrication method of the present invention.

FIGS. 3 (a) and 3 (b) are diagrams illustrating roll wear profiles after rolling by a conventional method (uniform) and the hot rolling lubrication method of the present invention, respectively.

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Claims (2)

[Claims] 1. Highly basic Ca sulfonate 20 to 70% by weight
In a hot rolling lubrication method for a steel sheet supplying a lubricant composition containing it to the surface of a work roll for rolling, the lubricant composition is applied only to the work roll surface for rolling in contact with both ends of the steel sheet to be rolled and its peripheral portion. A method for hot rolling lubrication of a steel sheet, characterized by supplying the steel sheet. 2. The high basic Ca sulfonate is 20 to 70% by weight.
In a hot rolling lubrication method for a steel sheet supplying a lubricant composition containing it to a work roll surface for rolling, the lubricant composition is applied to the work roll surface for rolling in contact with both ends of the steel sheet to be rolled and its peripheral portion. A method for hot rolling lubrication of a steel sheet, characterized in that the supply amount of the highly basic Ca sulfonate is larger than the supply amount to the other roll surface portions.