JPH073279A - Lubricant composition for hot rolling - Google Patents

Abstract

(57) [Summary] [Purpose] When rolling stainless steel or rolling under high load conditions, it is possible to prevent seizure of the steel material on the surface of the rolling roll and to significantly reduce roll wear. A lubricant composition for hot rolling, which can prevent the occurrence of scale flaws on the surface of steel during rolling. [Constitution] Metal salt phenate with a base number of 40 mg-KOH / g or more, or this metal salt phenate and base number 40 mg-KOH / g
A lubricant composition comprising the above metal salt sulfonate in a lubricant base oil in an amount of 20 to 70% by weight based on the total weight of the composition.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention exerts an excellent lubricating effect in hot rolling such as steel plate rolling, shaped steel rolling, wire rod rolling, and tube forming rolling of various steel materials including carbon steel and stainless steel. , Relates to a lubricant composition for hot working. INDUSTRIAL APPLICABILITY The lubricant composition of the present invention is particularly effective for preventing seizure and reducing wear during hot rolling of a steel material such as stainless steel that is likely to seize, and for preventing scale defects during hot rolling of carbon steel material.

[0002]

2. Description of the Related Art During hot rolling of various steel materials, when the material to be rolled is baked on a rolling roll, various surface roughness occurs on the surface of the rolling roll, which is printed on the surface of the steel material and causes surface defects. The surface of the steel material on which the surface flaw has occurred is repaired by polishing work. However, this involves an increase in the number of man-hours required for the maintenance, and the material with the severe flaw must be scrapped, which causes a high cost.

A flaw on the surface of a steel material caused by seizure has become a serious problem particularly in hot rolling of stainless steel material. Stainless steel generally has a chemical composition containing 13% or more by weight of Cr, forms a stable chromium oxidation protection film on the surface of the steel, and by passivating the surface, it has excellent corrosion resistance and oxidation resistance. Demonstrate. However, this surface oxide film is remarkably thinner than that of carbon steel and has a high resistance to hot deformation. Therefore, the stainless steel material easily causes metal contact with the rolling roll during hot rolling,
As a result, seizure occurs, resulting in rough surface of the roll and flaws on the surface of the steel material.

As described above, the stainless steel material is apt to seize, and a stainless steel product which is generally used unpainted is required to have a particularly beautiful surface. This is a particular problem in the hot rolling of steel products.

However, the problem of seizure is not limited to hot rolling of stainless steel, but may occur in hot rolling of carbon steel or special steel. That is, while high productivity, high quality, and low cost have been aimed at in recent years, high-speed, high-pressure rolling has been carried out more than ever. For this reason, the rolling load increases, and seizure tends to occur during hot rolling.

Further, recently, with the development of schedule-free rolling, new hot rolling mills, and new wear-resistant rolls represented by high-carbon high-speed rolls, seizure prevention has become a more important issue than ever before. Has become.

Further, during hot rolling of carbon steel material, in addition to seizure, oxide scale remaining on the surface of the steel material is pushed in by rolling to cause bite scale flaws, resulting in deterioration of product quality. There was also a problem caused by.

As measures for preventing seizure, the use of lubricants such as hot rolling oil, optimization of roll cooling, and review of rolling operation conditions have been conventionally performed. In particular, it is possible to supply a lubricant to the rolling roll or its reinforcing roll for the purpose of reducing the frictional force between the rolling roll and the steel to be rolled, and preventing the roughening of the roll and reducing wear to improve the quality of the rolled product. It has been said to be effective.

As a lubricant used for hot rolling of carbon steel, Japanese Patent Laid-Open No. 19807/1972 describes that a natural fatty acid oil contains a small amount (0.1 to 10% by weight) of a water displacing agent and, if necessary, further. A lubricant composition containing a mineral lubricating oil has been proposed. Oil-soluble sulfonate as water displacing agent
(Eg petroleum sulfonic acid metal salt) is used. Lubricants in which fine powdery calcium carbonate of about 10 μm is dispersed in water or lubricating base oil are described in JP-B-62-14598, JP-B-62-39198 and JP-B-62-39199. There is.

However, although these lubricants are recognized to have the effect of lowering the friction coefficient to some extent, the present situation is that they do not have sufficient seizure prevention effect and scale flaw prevention effect.

Further, these lubricants are intended for lubrication at the time of hot working rolling of carbon steel material. When used for hot rolling of stainless steel material, the material to be rolled is severely seized on the surface of the rolling work roll. However, there is a problem that the rolling efficiency is extremely lowered, and it cannot be used for hot rolling of stainless steel.

As a lubricant for hot rolling a stainless steel material, JP-A-63-254195 discloses a lubricant in which iron oxide powder is dispersed. JP-A-1-167396 discloses graphite. A dispersion of powder in a viscous aqueous solution has been proposed.

However, even if the oxide powder is dispersed in order to suppress the direct contact between the rolling roll and the material to be rolled, it is still possible to sufficiently prevent the seizure of the roll and the abrasion of the roll. Not not. Further, since graphite has an extremely low friction coefficient, it causes defective biting of the material to be rolled at the start of rolling and occurrence of slip during rolling, so it is sufficient to exert the seizure prevention effect and the friction reduction effect. It is not possible to contain graphite in a large amount.

[0014]

An object of the present invention is to prevent seizure on the surface of a rolling roll of a material to be rolled and to significantly reduce roll wear in hot rolling of various steel materials including stainless steel. Moreover, it is also possible to prevent the occurrence of scale flaws on the surface of the steel material in the hot rolling processing of carbon steel material, and thereby it is possible to improve the quality of rolled products and the work efficiency, and the lubricant composition for hot rolling processing. To provide things.

[0015]

The present inventor has found that a lubricant composition for hot rolling in which a highly basic metal salt sulfonate is contained in a lubricating base oil can achieve the above object, I applied for a patent (Japanese Patent Application No. 4-276249). Subsequent research shows that, like the highly basic metal salt sulfonate, the highly basic metal salt phenate is also effective in preventing seizure on the rolling roll of steel and reducing roll wear,
It has been found that the effect of preventing scale flaws generated on the surface of steel materials is high, and this highly basic metal salt phenate, either alone or as a mixture with this metal salt sulfonate, is contained in the lubricating base oil. It has been found that the composition is also most suitable for achieving the above object.

Therefore, the gist of the present invention is that the base number is 40 mg-
20-70% by weight, based on the total weight of the composition, of a metal salt phenate of KOH / g or more, or a mixture of this metal salt phenate and a base number of 40 mg-KOH / g or more metal salt sulfonate.
The lubricant composition for hot rolling is characterized in that the lubricant composition is contained in the lubricating base oil in an amount of.

When a small amount of phosphonate is added to this lubricant composition, the lubricating effect is further enhanced. Therefore, in a preferred embodiment, the composition further comprises a phosphonate in an amount of 5% by weight or less, based on the total weight of the composition.

The metal salt phenate used in the present invention is highly basic, that is, has a base number of 40 mg-KOH / g or more. The metal salt sulfonate, which may be used as a mixture with the metal salt phenate in the present invention, also has a similar basic 40 mg-
It is highly basic with KOH / g or higher.

The base number of the metal salt phenate and the metal salt sulfonate can be measured by the potentiometric titration method specified in JIS K2501. 1 metal salt phenate used
If it is a type, its base number must be 40 mg-KOH / g or more. When two or more metal salt phenates are used, the weighted average value of the base numbers of those metal salts (average value considering each amount, hereinafter, simply referred to as average value) is 40 mg-KOH / g. If it is above, it is good. That is, in this case, by using in combination with a high base number,
Those with a base number of less than 40 mg-KOH / g can be mixed. The same applies when two or more metal salt sulfonates are used.

For both the highly basic metal salt phenate and the highly basic metal salt sulfonate, alkaline earth metal salts (eg, Ca, Mg, Ba salts) are preferable, but other metal salts such as alkali metal salts are also preferable. Can be used.

These highly basic metal salt phenates and highly basic metal salt sulfonates were all developed as detergent dispersants for lubricating oils, and are incorporated in small amounts in engine oils, gear oils, industrial lubricating oils, etc. Is one type of lubricating oil additive. However, it has never been attempted to use these highly basic metal salts themselves as a main lubricant for a lubricant composition.

[0022]

[Function] A highly basic metal salt phenate is a metal salt of a long-chain alkylphenol derivative (sulfurized alkylphenol). Excess metal salt of alkylphenol derivative in the presence of alcohol, ketone, or polyoxyl alcohol (eg, (Carbonate, oxide, hydroxide, etc.). The resulting overbased metal salt phenate contains an excess of fine metal salt, which is present in oil as a colloidal dispersion.

On the other hand, the highly basic metal salt sulfonate is obtained by neutralizing a lipophilic petroleum sulfonic acid obtained by sulfonating an alkylaromatic with fuming sulfuric acid or SO ₃ gas with a metal compound to obtain a metal salt, and then dissolving the solution. In the presence of carbon dioxide gas in the form of a metal carbonate or hydroxide [eg CaO or Ca (OH)]
₂ ] to be produced. Like the highly basic metal salt phenate, this highly basic metal salt sulfonate also contains a metal salt in a form of a carbonate (eg, CaCO ₃ ), which is ₃ to 15 times as much as the normal salt in excess, and The excess metal salt is dispersed in the oil as a colloidal dispersion.

Since these highly basic metal salt phenates and highly basic metal salt sulfonates have excellent heat resistance, they do not completely burn or decompose even during hot rolling, and they are in a fluid or a state close to a fluid. It was found that by contributing to lubrication, excellent lubricity is exhibited as a main lubricant. In addition, it has reactivity and adsorption to the metal and oxides on the surface of the steel material, so by forming a lubricious reaction film on the surface, the state of direct metal contact at the friction interface (roll / steel material) can be improved. It can be suppressed, and exhibits seizure prevention and wear reduction effects.

The excess metal salt contained in the overbased metal salt phenate and the metal salt sulfonate, typically carbonate (for example, CaCO ₃ ) is used in the process of producing the overbased metal salt sulfonate or metal salt phenate. It is fine particles that spontaneously precipitate from the liquid, usually with a particle size of 150 Å or less, and forms a colloidal dispersion in oil. If the metal salt is carbonate, part of the carbonate is an oxide at high temperature during hot rolling.
(Eg CaO, MgO, etc.).

These excess metal salts and the fine particles of the metal oxides dissociated from them do not have any lubricating effect, but are highly effective against the metals and oxides of the highly basic metal salt phenates and metal salt sulfonates. In order to make it easier to exert the lubricating effect due to the adsorption action (particularly, high chemical adsorption to oxides), it plays a role as a carrier that carries highly basic metal salt phenate and metal salt sulfonate to the friction interface. At the same time, the metal salt fine particles uniformly carried to the roll / steel friction interface completely prevent direct metal contact between the rolling roll and the steel and prevent seizure.

Thus, the highly basic metal salt phenate and metal salt sulfonate are due to the lubricating effect of the metal salt phenate or metal salt sulfonate itself and the deposited metal salt fine particles forming a colloidal dispersion in oil. By the synergistic effect of the carrier effect and the intermetallic contact prevention effect, the seizure resistance and wear resistance improving effects on the steel material can be remarkably exhibited. This effect is recognized when the particle size of the metal salt fine particles is 500 Å or less, and the effect becomes remarkable especially when it is 150 Å or less.

Therefore, a conventional method in which fine powdery calcium carbonate having a particle size of about 1 to 10 μm, which is separately prepared and used in the conventional technique described in Japanese Patent Publication No. 62-14598, is dispersed in a lubricating base oil. The lubricant is clearly different in its action and effect. That is, in this conventional lubricant, it is said that the calcium carbonate powder itself exerts a lubricating effect.

Further, since the highly basic metal salt phenate and the highly basic metal salt sulfonate were originally developed as a detergent dispersant, they have a strong dispersive cleaning action and an oxide film remaining on the surface of the steel material after rolling. Foreign substances such as (oxidized scale) and abrasion powder can be removed, and it is also effective in preventing scale defects that are generated when they are pushed into the steel surface.

Due to the above-mentioned effects, the lubricant composition of the present invention can prevent seizure on the rolling roll during hot rolling and can significantly reduce roll wear, and at the same time, can effectively prevent scale flaws. Can be prevented. as a result,
It is possible to ensure good rolled product quality and high work efficiency.

The lubricant composition of the present invention has a base number of 40 mg-
KOH / g or higher metal salt phenate, or base number 40 mg-
A mixture of KOH / g or higher metal salt phenate and a base number of 40 mg-KOH / g or higher metal salt sulfonate in an amount of 20 to 70% by weight based on the total weight of the composition. If this amount is less than 20% by weight, the lubricating effect of the metal salt phenate / metal salt sulfonate will be insufficient, the amount of roll wear will increase, seizure cannot be sufficiently prevented, and scale flaws will also be difficult to prevent. On the other hand, if this amount exceeds 70% by weight, the viscosity of the lubricant composition becomes high and it becomes difficult to supply the lubricant. A more preferable range of the amount of the highly basic metal salt phenate or the mixture of the metal salt phenate and the metal salt sulfonate is 30 to 60% by weight based on the total weight of the composition.

When the highly basic metal salt phenate is used as a mixture with the highly basic metal salt sulfonate, both of these components are approximately as effective as lubricant components, so that the metal salt phenate in the mixture is The ratio with the metal salt sulfonate is not particularly limited. That is, the content of the highly basic metal salt phenate in the case of the mixture can be varied within a wide range from about 1% by weight (or less) to 70% by weight of the entire composition.

In the case of alkaline earth metal salts, when comparing the lubrication effect with the same content and the same base number, Ca salt is higher than Ba salt, Mg, etc. in both metal salt phenate and metal salt sulfonate. Most effective. Therefore, it is preferable to select Ca salt as the metal salt when a steel material such as stainless steel that is particularly susceptible to seizure or when the rolling load is particularly severe.

As the metal salt phenate and the metal salt sulfonate, those having a base number of 40 mg-KOH / g or more are used as described above. When the base number is less than 40 mg-KOH / g, the lubricating effect required for the hot rolling lubricant cannot be exhibited. The lubrication effect improves as the base number increases, and especially those with a base number of 200 mg-KOH / g or more have excellent anti-seizure ability and wear resistance. The preferred base value of metal salt phenate and metal salt sulfonate is 200-500 mg-KOH
The range is / g.

When the base value is less than 200 mg-KOH / g, a metal salt (eg, carbonate) as a carrier for improving the introduction property of the metal salt phenate or metal salt sulfonate to the friction interface.
Of the metal salt phenate and the metal salt sulfonate are reduced in the frictional interface, the roll wear reduction and the seizure prevention effect may be insufficient.
However, even if stainless steel is rolled, if the workability is low, or if the workability is relatively good, the base number is
Even highly basic metal salt phenates and highly basic metal salt sulfonates less than 200 mg-KOH / g can be effectively used.

On the other hand, highly basic metal salt phenates and metal salt sulfonates having a base number of more than 500 mg-KOH / g have a suitable function as a lubricant for rolling, such as viscosity, at the present technical level. Since it cannot be produced, the preferred upper limit of the base number was set to 500 mg-KOH / g, but if the production technology makes it possible, a base number of more than 500 mg-KOH / g could be used.

As the highly basic metal salt sulfonate and the highly basic metal salt phenate, those having various base numbers are commercially available as detergent-dispersants, and commercially available products can also be used.

If the particle size of the metal salt (mainly carbonate) is 500 Å or less even when grown, the effect of the present invention is not significantly impaired, but as described above, 150 Å or less is most suitable.

As a method of grain-growing a carbonate, 150
Å It is possible to use a method in which a highly basic metal salt sulfonate or a metal salt phenate containing the following fine-grain carbonates is used as a raw material and a polar substance such as water or methanol is added to promote crystal grain growth.

The lubricant composition for hot rolling of steel according to the present invention is a commonly used lubricating base oil, which comprises a highly basic metal salt phenate alone or a highly basic metal salt phenate and a highly basic metal salt sulfonate. And both of them are mixed. As described above, the total amount of the metal salt phenate and the metal salt sulfonate is 20 to 70% by weight of the composition.
The range is. Further, it is desirable to adjust the metal species, base number, and blending amount of the highly basic metal salt phenate and the highly basic metal salt sulfonate to be used according to the degree of lubricating performance required for the hot rolling to be applied. . For example,
In hot rolling of stainless steel where seizure easily occurs, it is desirable to use a highly basic Ca phenate and / or a highly basic Ca sulfonate having a base number of 200 mgKOH / g or more.

The adjustment of the base number of the highly basic metal salt phenate and the metal salt sulfonate may be carried out on the basis of Ca sulfonate, Mg sulfonate, Ca phenate and Mg phenate, which are available in a wide range of base number products.

The lubricant composition of the present invention comprises 20 to 70% by weight of a highly basic metal salt phenate, or 20 to 70% by weight of a mixture of a highly basic metal salt phenate and a highly basic metal salt sulfonate, and the balance. A composition consisting only of a lubricating base oil can be used, and such a composition is also sufficiently effective as a lubricant for hot rolling.

As the lubricating base oil, oils and fats such as mineral oils, synthetic lubricating oils, rapeseed oil and lard oil, higher fatty acids and esters thereof, etc. can be used, and they may be used alone or in a mixture of two or more kinds. A commercially available hot rolling oil can be used as it is as a base oil.

If desired, the lubricant composition of the present invention comprises
Further, it may contain one or more other additives. Examples of additives that can be added to the lubricant composition of the present invention include phosphonates, solid lubricants, extreme pressure additives, antioxidants, pour point depressants, and viscosity index improvers.

As the phosphonate (phosphonate ester), a trialkyl ester of phosphonic acid (eg, di-n
-Butylhexylphosphonate), acid phosphonate and the like can be used. When the phosphonate is blended with the highly basic metal salt phenate and / or the highly basic metal salt sulfonate, the lubricating effect is further improved, so that the phosphonate is added in an amount of 5% by weight or less based on the total weight of the composition. It can be incorporated into the composition.

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 the like, and tricresyl phosphate, dioctyl phosphate and other phosphoric acid-based extreme pressure additives.

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, and naphthylamines. 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, and the antioxidant is added in an amount of about 0.01 to 1.0% by weight. The addition amount of the point depressant and the viscosity index improver is 1 to 5% by weight, respectively.
It is a degree.

The lubricant composition of the present invention is used for not only general stainless steel but also high corrosion-resistant stainless steel having a Cr content of 20% by weight or more, which is particularly used for materials for automobile exhaust gas.
In hot rolling (eg, 20% Cr steel, 20% Cr-2% Mo steel, 20% Cr-5% Al steel, etc.) and high load rolling such as low temperature rolling of carbon steel and high pressure rolling, The effect is remarkable.
Of course, even if it is used as a hot rolling lubricant at the time of normal rolling of general steel, 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.

As a method of supplying the lubricant according to the present invention, 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 which is mixed and supplied with water is supplied. An injection method, a steam atomizing method in which atomization with heated steam is performed, and the like are possible, and any method can obtain the remarkable lubricating effect of the present invention. Of course, a method of supplying the undiluted solution as it is may be used, and in that case, the lubricant composition of the present invention may be dispersed in water with a dispersant to make it a water-soluble type to make it slightly nonflammable. Oiling methods other than the above can also be used.

[0051]

EXAMPLES The present invention will be described in more detail with reference to specific examples.

Example 1 The lubricant compositions of Examples 1 to 4 of the present invention and Comparative Examples 1 and 2 shown in Table 1 were prepared by mixing the components with a homomixer. Table 1 shows the type of basic metal salt phenate used and its base number (average base number when two or more types are used). The mixing ratio was such that the lubricating base oil was 60% by weight, and the remaining 40% by weight was a uniform ratio occupied by the metal salt phenate or the mixture of the metal salt phenate and the metal salt sulfonate. The commercially available hot rolling oil used as the lubricating base oil was a mixed oil composed of mineral oil, rapeseed oil, and α-olefin polymerized oil.

[0053]

[Table 1]

(Example 2) In the same manner as in Example 1, Examples 5 to 8 of the present invention and Comparative Example 3 having an average base number of 300 to 400 mg-KOH / g and a different content of highly basic metal salt phenate. .About.5, Examples 9 to 11 of the present invention to which a phosphonate was added, and conventional lubricant compositions of Conventional Examples 1 and 2, which are known lubricants for rolling stainless steel, were prepared. The compounding composition is shown in Table 2.

[0055]

[Table 2]

Using the lubricant compositions prepared in Examples 1 and 2, the hot rolling test described below was conducted.

(Test 1) In a hot steel rolling mill line
JIS SUS 430 stainless steel and ordinary steel (0.08% C-1.0% Mn)
(Approx. 1800 tons and 2500 tons, respectively) Thin finish (1.6
(mm thickness) During rolling, high-carbon high-speed steel rolls for the rolling of three 4-stage hot rolling mills before the finishing tandem mill (main component: 2.2% C-3.0% Cr-4.0% Mo-6.0% V-1.0 % W) with a water injection type lubricant supply device.
Then, each lubricant composition shown in Table 2 was supplied, and the surface properties (presence or absence of surface flaws) of the steel plate after seizure of the rolling roll and rolling pickling were examined by visual observation.

Further, in order to examine the wear of the rolling rolls after rolling, the maximum wear depth of the upper and lower rolling rolls of the finishing No. 2 stand was measured by a profile meter, and the average value was calculated to obtain the maximum wear depth of the rolls. Satoshi The results are shown in Table 3 (JIS SUS 430) and Table 4 (carbon steel).

[0059]

[Table 3]

[0060]

[Table 4]

As can be seen from the results shown in Tables 3 and 4, in each of the examples of the present invention, seizure of the rolling roll was almost prevented, and seizure flaws and scale flaws were found on the surface of the steel sheet. There wasn't. Also, the amount of roll wear was significantly reduced compared to the comparative example and the conventional example. Further, from Examples 5 to 8 of the present invention and Comparative Examples 3 to 5, that the lubricant containing 20 to 70% by weight (particularly 30 to 60% by weight) of the highly basic metal salt phenate exhibits a great lubricating effect. I understood.

Inventive Example 1 having a base number of 40 to 200 mg-KOH / g,
Inventive Examples 3, 5 with 2, 4 and a base number of 200-500 mg-KOH / g
As you can see from the comparison with 11, base number 200-500 mg-KOH
The lubricant composition containing / g of highly basic metal salt phenate was further excellent in the lubricating effect (wear resistance, seizure resistance). Further, as can be seen from the comparison between Inventive Example 3 and 9, 10, and 11, lubricating performance was further improved when 5% or less of phosphonate was contained.

The lubricant composition of Inventive Example 4 consisting of a phenate mainly containing Ba as a metal salt was slightly inferior in the effect of the Inventive Example, and slight seizure occurred on the roll. It did not affect the properties. That is, it can be seen that even in this case, the lubricity is superior to that of the conventional lubricant. In each of Conventional Examples 1 and 2, neither seizure resistance nor abrasion resistance was sufficient.

Even when other rolling rolls such as a high Cr cast iron roll, a high alloy grain cast iron roll and an adamite roll are used as the rolling rolls, the high carbon high speed steel
It goes without saying that the same effect as when using the (high speed) roll is obtained.

(Test 2) Steel pipes in a mandrel mill line (JIS SUS 304 stainless steel, carbon steel) At the time of hot rolling, the hole rolls (sizer rolls, mandrel mill rolls, reducer rolls, etc.) of all rolling stands were When the lubricant compositions shown in Table 1 and Table 2 were supplied as undiluted solutions, as in Test 1, when the lubricant composition of the present invention was supplied, no seizure occurred on the high Cr cast steel roll. It did not occur and no flaw was observed in the product.

On the other hand, when the lubricant compositions of the comparative example and the conventional example were supplied, severe seizure and large abrasion of the rolls occurred, and as a matter of course, scale flaws also occurred in the product.

(Test 3) During hot rolling of H-shaped stainless steel (SUS304, SUS430, etc.) and carbon steel in a shaped steel rolling line, Table 1 was compared with horizontal rolls and vertical rolls of the finishing mill.
And each lubricant composition shown in Table 2 was supplied to the water injection system by an oil supply device, and the test 1
Similarly to the above, when the lubricant composition of the present invention was supplied, seizure did not occur on any of the rolls, wear was small, and no flaws were observed on the product.

On the other hand, when the lubricant compositions of the comparative example and the conventional example were supplied, severe seizure and large wear occurred on both rolls. Many rolled products also had severe defects that required maintenance with a coil grinder.

[0069]

As described above, when the steel composition is hot-rolled using the lubricant composition of the present invention, seizure such as rolling of stainless steel or rolling under high load conditions easily occurs. Even under rolling conditions, it exhibits excellent effects in preventing seizure of steel materials on rolling rolls, significantly reducing wear of rolling rolls, and reducing frictional force during rolling. It is possible to prevent the occurrence of scale flaws during rolling. As a result, the quality of rolled products is improved and work efficiency is improved.

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Claims (3)

[Claims] 1. A heat treatment, characterized in that a metal salt phenate having a base number of 40 mg-KOH / g or more is contained in a lubricating base oil in an amount of 20 to 70% by weight based on the total weight of the composition. Lubricant composition for hot rolling. 2. A mixture of a metal salt phenate having a base number of 40 mg-KOH / g or more and a metal salt sulfonate having a base number of 40 mg-KOH / g or more of 20 to 70% by weight based on the total weight of the composition. A lubricant composition for hot rolling, characterized in that it is contained in a lubricating base oil in an amount. 3. The lubricant composition for hot rolling according to claim 1, further comprising a phosphonate in an amount of 5% by weight or less based on the total weight of the composition.