JP2643733B2 - Rolling method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention is, tungsten-containing low
Rolling method according to Le, particularly made of cemented carbide rolls, medium high speed
Semi-high-speed steel rolls or high-carbon high-speed steel
(HSS) Rolling of steel sheet by steel rolls , rolled section steel, wire rods, and hole rolling of pipes, etc., exerts lubrication effects such as prevention of roll seizure and roughening, reduction of roll abrasion, and reduction of rolling load. Rolling method.

[0002]

2. Description of the Related Art When a rolled material is baked on a rolling roll during hot rolling of various steel materials, various surface roughenings occur on the surface of the rolling roll, which are printed on the steel material surface and surface defects of the rolled product. Becomes Rolled products with surface flaws are repaired by polishing the surface.However, there is a significant increase in man-hours required for flaw care, and those with severe flaws have to be scrapped, resulting in considerable cost increase. Inviting.

[0003] The flaws on the surface of a rolled product caused by seizure are a serious problem particularly in hot rolling of stainless steel. Stainless steel generally has a chemical composition containing 13% or more Cr by weight, and exhibits excellent corrosion resistance and oxidation resistance by forming a stable chromium oxide protective film on the surface of the steel and passivating the surface. I do. However, this surface oxide film is significantly thinner than that of carbon steel, and has high hot deformation resistance. Therefore, during hot rolling, surface acid
The oxide film is peeled off and metal-to-metal contact with the rolling roll is liable to occur. As a result, seizure occurs, resulting in roll surface roughness and surface defects of the rolled product. As described above, the stainless steel material is liable to seize, and the stainless steel product requires a particularly beautiful surface, so that seizure with a roll is a particular problem in hot rolling of the stainless steel. is there.

However, this seizure problem is not limited to hot rolling of stainless steel, but may also occur in hot rolling of ordinary steel and special steel. That is,
In recent years, while high productivity, high quality, and low cost have been pursued, high-speed, high-pressure rolling has been performed more than ever. For this reason, the rolling load increases, and seizure easily occurs during hot rolling. Furthermore, in recent years, with the development of schedule-free rolling, a new hot rolling mill, and a new wear-resistant roll, prevention of seizure has become a more important issue than ever.

[0005] As measures for preventing this seizure, the use of a lubricant such as hot rolling oil, optimization of roll cooling,
Review of rolling operation conditions, etc. has been carried out. In particular, it is effective to supply 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 improving the quality of the rolled product by preventing the roll from roughening and reducing wear. It has been said that.

As a lubricant used for hot rolling of ordinary steel,
JP-A-47-18907 proposes a lubricant composition in which a small amount (0.1 to 10% by weight of the whole) of a water-replacement agent and, in some cases, a mineral lubricating oil are further added to a natural fatty oil. ing. As the water displacing agent, an oil-soluble sulfonate salt (eg, a metal salt of petroleum sulfonic acid) is used. A lubricant in which finely divided calcium carbonate of about 10 μm is dispersed in water or a lubricating base oil has been disclosed in JP-B-62-1459.
8, JP-B-62-39198, JP-B-62-391
No. 99 is described in each gazette.

However, these lubricants but acts to lower slightly the friction coefficient is observed, at present, no sufficient anti-seizing effect. In addition, these lubricants are intended for lubrication during hot rolling of carbon steel, and when used for hot rolling of stainless steel,
The material to be rolled violently seizes on the surface of the rolling work roll, causing flaws in the rolled product. Furthermore, since the roll for rolling has a large wear, there is a problem that the rolling efficiency is extremely reduced, and the roll cannot be used for hot rolling of stainless steel.

As a lubricant for stainless steel rolling, an iron oxide powder dispersed in a lubricating oil is disclosed in JP-A-63-254195. Those dispersed in an aqueous solution have been proposed.

However, even if iron oxide powder is dispersed in order to suppress the direct contact state between the metal of the rolling roll and the material to be rolled, the effect of sufficiently preventing seizure on the roll and roll wear can be obtained. Not been. In addition, graphite has an extremely low coefficient of friction, which causes poor engagement of the material to be rolled at the start of rolling and causes slippage during rolling, so that it is sufficient to exhibit an anti-seizure effect and a wear reducing effect. It cannot contain graphite in an appropriate amount.

[0010] The occurrence of surface flaws due to the rough surface of the roll surface is as follows.
This is particularly problematic in the finish rolling step for finally determining the surface properties of the rolled product. Rolls made of a high-speed steel containing a large amount of tungsten and rolls made of a tungsten carbide dispersed alloy are known as rolling rolls particularly suitable for the finish rolling step. Since the tungsten-containing roll has excellent wear resistance, it is used in a rolling finishing step, particularly in hot rolling of a high-strength wire.

[0011] However, in the case of the roll containing tungsten, roll surface roughening due to corrosion mainly occurs during rolling in a relatively short period of time, and the surface properties of the product are deteriorated.
It is necessary to interrupt the rolling in a relatively short time, replace the roll with another roll, and then smooth and finish the damaged roll surface again by grinding and polishing. This operation leads to a reduction in rolling efficiency, and the finishing operation shortens the life of the very expensive tungsten-containing roll,
There is also a cost issue.

The present applicant has previously disclosed in Japanese Patent Application No. 3-290180, as a measure for preventing roughening of a tungsten-containing hot rolling roll, an alkaline aqueous solution containing calcium ions (Ca ²⁺ ) having a pH of more than 8 was rolled. It has been proposed that a crystal coating film of calcium tungstate (CaWO ₄ ) be formed on the surface of a high-tungsten-containing roll by using it as at least a part of the cooling water, thereby suppressing roll abrasion and suppressing skin roughness.

However, as described above, under the recent severe rolling environment (high surface pressure, high temperature, high-speed rolling, etc. of difficult-to-process materials), CaWO ₄ , which should originally precipitate on the surface of a tungsten-containing rolling roll, The formation of a crystal coating was hindered, and sufficient wear reduction and skin roughness prevention effects could not be obtained.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the abrasion of a roll, to prevent seizure, and to prevent roughening in the rolling process of a steel material by a roll containing tungsten, thereby improving the quality of a rolled product and the work efficiency. An object of the present invention is to provide a rolling method that can be improved.

[0015]

Means for Solving the Problems The present inventor has conducted intensive studies on methods for reducing roll wear, preventing seizure, and preventing roughening in the rolling process using a tungsten-containing rolling roll. When a lubricant composition containing a high proportion of sulfonate is supplied, the precipitation of CaWO _{4 on} the roll surface is greatly promoted, and the friction between the roll and the steel material is reduced.
Knowing that WO ₄ can stably exist, the present invention has been completed.

Here, the gist of the present invention is that when a roll containing tungsten is rolled,
20 to 70% by weight of Ca sulfonate based on the total weight of the composition
The rolling process is characterized in that a lubricant composition containing at a ratio of is supplied in the presence of water.

In the case where a rolling roll having a relatively low tungsten content is used, the above-mentioned effect becomes more remarkable when the lubricant composition contains tungstate ions. Further, the above-mentioned tungsten-containing rolling roll is an example.
For example, cemented carbide rolls and semi-high speed steel
Roll or roll made of high-carbon high-speed steel (HSS)
If there is, the above effect becomes more remarkable. In the present invention, “highly basic Ca sulfonate” refers to a base number (J
Measured by potentiometric titration method specified in ISK2501) is 4
It means 0 mg-KOH / g or more of Ca sulfonate.

[0018]

The tungsten-containing rolling roll used in the rolling method of the present invention may be a cemented carbide (WC-12% Co to WC-25% C) used for finishing rolling of wire rods.
o) rolls or semi-high-speed steel (semi-high speed: main component 0.
7 to 1.2% C-4 to 8% Cr-1 to 3% Mo-0.3
-1.5% V-2-6% W) roll, high-carbon high-speed steel (high-speed steel: main component 1.5-2.5% C-2-8% Cr)
−2 to 9% Mo−3 to 15% V−3 to 15% W) rolls, but are not limited thereto. The tungsten content in the rolling roll is not particularly limited, but is preferably 8% by weight or more from the viewpoint of the effect of the present invention.
More preferably 20 wt% or more.

As described above, tungsten-containing rolls are very expensive and are often used for finish rolling. Therefore, wear, seizure and roughening of the rolls are particularly important.

According to the present invention, by supplying a lubricant composition containing a highly basic Ca sulfonate to a tungsten-containing roll, it is possible to reduce the abrasion of the roll and prevent seizure and rough skin. As described later in detail, this highly basic Ca sulfonate itself exhibits excellent lubricity as a whole, so that even when applied to a roll for rolls containing no tungsten at all, the roll is used as a lubricating main agent. It can exert a great effect on reducing abrasion, preventing seizure, and preventing rough skin.

Further, in the present invention, by supplying this lubricant composition to a roll in the presence of water, the lubricant composition also functions as a Ca ²⁺ ion supply source. This Ca
²⁺ interacts with the tungsten in the roll to form a calcium tungstate (CaWO ₄ ) film on the roll surface. This film formation also has a remarkable effect on reducing roll abrasion, preventing seizure and roughening of the surface.

The reaction process in which a film of calcium tungstate is formed on the roll surface is presumed as follows. Tungsten (existing mainly as WC) in the roll structure is dissolved in water by the reaction of the following formula (1) to form tungstic acid, and the generated tungstate ions are dissolved from the lubricant composition into Ca ions dissolved in water. Reacts with the following formula (2) to precipitate CaWO ₄ crystals on the roll surface.

[0023]

## STR1 ## _{^{W + 8OH - → WO 4 2+}} 4H 2 O + 6e - (1) for _{^{Ca 2+ + WO 4 2- → CaWO}} 4 ↓ (2) CaWO 4 precipitated is sparingly soluble in water, once roll surface CaWO _When the roll is covered with the coating composed of _four crystals, the subsequent corrosion of the roll surface is suppressed, and as a result, surface roughening is prevented and wear is reduced.

In order for the above reaction to take place, it is necessary that the water containing Ca ²⁺ ions be alkaline, as can be seen from the equation (1). However, the highly basic Ca sulfonate used in the present invention has a high basicity. Since it is a basic substance, when it is mixed with water, an alkaline aqueous solution in which Ca ²⁺ ions are dissolved in water is formed. Therefore, when a lubricant composition containing a highly basic Ca sulfonate is supplied to a tungsten-containing roll in the presence of water, CaW is added to the roll surface through the above reaction process.
The O ₄ film is quickly formed.

When the material of the rolling roll has a relatively low tungsten content, such as high-speed steel or semi-high-speed steel, the reaction of the above formula (1) is not sufficient because the amount of tungsten eluted is small. CaWO deposited on the roll surface without occurring
The amount of ₄ may be insufficient for sufficient improvement of the rough and abrasion resistance. In such a case, by previously containing tungstate ions in the lubricant composition, more CaWO ₄ can be precipitated on the roll surface.

The amount of tungstate ion added in this case is not particularly limited. However, even if it is added in a large amount, it only reacts with calcium in the lubricant composition and increases the portion not used for the precipitation of CaWO ₄ . A small amount is sufficient. Preferably it is at least 10 ppm, more preferably in the range of 20 to 50 ppm, based on the total weight of the lubricant composition. A preferred source of tungstate ions is an alkali metal tungstate (eg, sodium salt, potassium salt, etc.).

In the case where the tungsten content of the roll is as high as 20% by weight or more, such as a roll made of cemented carbide,
Since the reaction of formula (1) occurs at a sufficient rate, it is usually unnecessary to include tungstate ions in the lubricant composition of the present invention.

In the present invention, a highly basic Ca sulfonate is used as a main lubricant and a Ca ²⁺ ion source. Highly basic
Ca sulfonate is obtained by adding Ca sulfonate, which is a Ca salt of petroleum sulfonic acid obtained by sulfonation of alkyl aromatic, to CaO or Ca (OH) _{2 in} the presence of carbon dioxide or the like.
And contains 3 to 15 times as much excess Ca as the normal salt (Ca sulfonate). This excess Ca forms a colloidal dispersion mainly dispersed in oil in the form of calcium carbonate (CaCO ₃ ) having a particle size (average particle size) of 150 ° or less. This calcium carbonate is decomposed at high temperatures during hot rolling to decompose calcium oxide (C
aO).

Highly basic Ca sulfonate has been developed as a detergent and dispersant for lubricating oils such as engine oils, and has been used in a small amount in a lubricant composition. There is no. The present inventor has proposed a highly basic Ca
Due to its excellent heat resistance, sulfonate does not completely burn or decompose at the hot rolling temperature of steel, but exists at the roll / steel interface in a fluid or near fluid state,
It has been found that it can contribute to lubrication and exhibits excellent lubricity as a lubricating agent.

Particle size 15 contained in highly basic Ca sulfonate
The carbonate (CaCO ₃ ) of 0% or less is naturally precipitated during the process of producing a highly basic Ca sulfonate, and forms a colloidal dispersion in oil. The colloidally dispersed calcium carbonate itself does not exhibit any lubricating action, and the highly basic Ca sulfonate is rubbed with a highly basic Ca sulfonate in order to more easily exert a lubricating effect due to its high adsorption action on metals and oxides. It simply serves as a carrier that carries it to the interface. Even under high pressure during hot rolling, these fine particles are introduced in a uniform state at the friction interface.
The lubricating effect of the sulfonate is extremely high, and the direct contact state between the metals at the friction interface is suppressed to prevent seizure, and at the same time, the abrasion of the roll can be greatly reduced. That is,
Outstanding seizure resistance, abrasion resistance, and stain resistance on steel due to the synergistic effect of highly basic Ca sulfonate showing high lubricity and calcium carbonate with a particle size of 150 mm or less formed as a colloidal dispersion in oil It has the effect of improving the properties.

As described above, the highly basic Ca sulfonate supplies a sufficient amount of Ca ²⁺ ions to the surface of the tungsten-containing rolling roll and reduces friction by its own lubricating action. CaWO ₄ can be stably generated on the roll surface even under severe rolling conditions.

Accordingly, a conventional calcium carbonate-containing lubricant prepared by dispersing separately prepared finely divided calcium carbonate having a particle size of about 1 to 10 μm in a lubricating base oil as described in JP-B-62-14598 mentioned above. The effect is clearly different from the composition. That is, in this prior art, it is said that the calcium carbonate powder itself exerts a lubricating action.

The highly basic Ca sulfonate is contained in the lubricant composition of the present invention at a ratio of 20 to 70% by weight. If the content is less than 20% by weight, the precipitation of CaWO ₄ is small, the roll wear is increased, and seizure cannot be sufficiently prevented. On the other hand, when the content of the highly basic Ca sulfonate exceeds 70% by weight, the composition becomes highly viscous, it becomes difficult to supply a lubricant, and the precipitation of CaWO ₄ is saturated. The preferred content of the overbased Ca sulfonate is 30 to 60% by weight.

Base number of highly basic Ca sulfonate used
(Measured by the potentiometric titration method of JIS K2501) is 40 mg-KOH /
g-KOH
/ g is preferable because it has excellent seizure prevention ability, abrasion resistance and stain resistance. When the base number is less than 200 mg-KOH / g, the amount of calcium carbonate or calcium oxide dissociated therefrom as a carrier for improving the introduction of the highly basic Ca sulfonate to the friction interface is small, and the high basicity is low.
Since the amount of Ca sulfonate introduced into the friction interface and the amount of CaWO ₄ precipitated are reduced, reduction of roll abrasion and prevention of seizure and surface roughness may be insufficient. However, light-working and steel materials with relatively good workability (eg, carbon steel, SUS 304
In the case of (Steel), highly basic with a base number of less than 200 mg-KOH / g
Ca sulfonate can also be used effectively.

On the other hand, a highly basic Ca sulfonate having a base number exceeding 500 mg-KOH / g cannot have a suitable function as a rolling lubricant, for example, a material having a viscosity or the like at the current state of the art. However, if the production technology makes it possible,
More than 500 mg-KOH / g could be used. Highly basic Ca sulfonates having various basicities are commercially available as detergent dispersants.

Since the lubricant composition of the present invention is extremely excellent in lubricity as described above, the coefficient of friction at the friction interface becomes too small depending on the material of the steel material and rolling conditions, so that the Of the steel sheet into the rolling roll may be defective, or slip may occur during the rolling. In such a case, when the calcium carbonate precipitated in the highly basic Ca sulfonate is subjected to grain growth, the friction coefficient can be increased without significantly affecting the seizure resistance and wear resistance improving effect, and Poor biting and slippage can be prevented. However, even in such a case, it is preferable that the particle size of the calcium carbonate is 500 mm or less. From the viewpoint of lubricity, the particle size of calcium carbonate is optimally 150 ° or less as described above.

As a method of growing calcium carbonate grains, a method of promoting the growth of crystal grains by adding a polar substance such as water or methanol from a highly basic Ca sulfonate containing fine-grained CaCO ₃ of 150 ° or less as a raw material. Etc. are available.

The raw material alkyl aromatic of the highly basic Ca sulfonate used in the present invention is not particularly limited, and the lubricating oil fraction of mineral oil and synthetic compounds (eg, alkylbenzene, polyolefin is alkylated to benzene) as in the conventional product. And dinonylnaphthalene) can be used.

[0039] The lubricant composition for hot rolling of the present invention is generally produced by mixing a highly basic Ca sulfonate with a lubricating base oil to be used. The overbased Ca sulfonate is incorporated in an amount ranging from 20 to 70% by weight of the total composition, as described above. Although a composition comprising only a highly basic Ca sulfonate and a lubricating base oil is sufficiently effective, one or more other additives may be further blended if necessary. Additives that can be used include solid lubricants, extreme pressure additives, antioxidants, pour point depressants, viscosity index improvers, and the like.

Suitable lubricating base oils include mineral oils, synthetic lubricating oils, oils such as rapeseed oil and lard oil, higher fatty acids and esters thereof, 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, sulfide mineral oil, dinonyl polysulfide, and phosphorus-based extreme pressure additives such as tricresyl phosphate and dioctyl phosphate.

Examples of antioxidants include methylene-4,4
Bisphenols such as -bis (2,6-di-tert-butylphenol); alkylphenols such as di-tert-butylcresol; and naphthylamines. Examples of the pour point depressant and the viscosity index improver include polymethacrylate, polyolefin and the like.

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

The lubricant composition of the present invention is supplied in the presence of water. This lubricant composition may be supplied after being mixed with water in advance, but since a roll containing tungsten is weak in thermal shock resistance, a large amount of roll cooling water is usually used. Even without pre-mixing the composition with water,
Water supplied by the cooling water is present on the roll surface. Therefore, there is no need to particularly consider mixing with water.

Specific supply methods include an air atomization method in which the mixture is supplied with the compressed air and sprayed in accordance with the required viscosity and concentration, and a water injection method in which the mixture is further mixed with water and supplied. Further, it may be appropriately selected from a steam atomizing method or the like, which is supplied by atomizing with heated steam, and any method can obtain the remarkable lubrication and descaling effects of the present invention. Of course, a method of supplying the undiluted solution may be used, or a general lubrication method other than the above may be used. When supplied as a stock solution, the lubricant composition of the present invention may be made water-soluble to make it nonflammable, if necessary.

The lubricant composition may be supplied directly to the rolling roll, or may be supplied to the reinforcing roll and indirectly supplied to the rolling roll. Further, the lubricant composition may be further supplied to the steel material before rolling.

As described above, in order for calcium ions supplied from the lubricant composition to react with tungsten in the roll, the aqueous solution needs to be alkaline, but the lubricant composition of the present invention has a high basicity. Since the Ca sulfonate is contained in a high ratio, the resulting aqueous solution is always alkaline at pH 8 or more, and there is no need to control and adjust the pH.

The lubricant composition of the present invention can be used not only for general stainless steel but also for highly corrosion-resistant stainless steel having a Cr content of 20% by weight or more, which is particularly used as a material for automobile exhaust gas.
(Eg, 20% Cr steel, 20% Cr-2% Mo steel, 20% Cr-5% Al steel, etc.)
The effect is particularly remarkably exhibited in high-load rolling such as hot rolling of carbon steel, low-temperature rolling of carbon steel, and high-pressure rolling.
Of course, it can also be used for the hot rolling lubrication method during normal rolling of general steel materials. Also, not only sheet rolling, but also shaped steel, wire rod,
It is also useful for hole rolling of pipes and the like, and particularly useful for finish rolling of wires.

[0049]

Next, a description will be given of a specific embodiment. In Examples,% is% by weight unless otherwise specified.

Examples 1 to 8 and Comparative Examples 1 to 8 of the present invention shown in Table 1
2. Eleven types of lubricant compositions of Conventional Example 1 were prepared by mixing the components at a predetermined ratio using a homomixer, and various rolling tests were performed using this lubricant composition.

(Example 1) An example in which the rolling method of the present invention was carried out in a finishing tandem mill four-stage hot steel sheet rolling machine of a hot steel sheet rolling mill line will be described. The work roll for rolling used was a high-carbon high-speed steel roll having the chemical composition shown in Table 2 on both the upper and lower sides. To each of the lubricant compositions shown in Table 1, 20-30 ppm of tungstate ions were added as sodium tungstate with respect to this composition, and then a water injection type lubricant supply method (concentration of 0.2-0.5%) was used. ) Indicates that the steel type JIS SUS 304 stainless steel sheet has a thin finish (1.6 mm) during rolling (rolling amount
2000 tons) directly to the upper and lower rolling work rolls. Roll cooling water was supplied at a rate of 40 l / min per work roll, and water was removed immediately before the lubricant supply position to adjust the amount of water. After the completion of the rolling, the surface condition of the roll (roll surface roughness, seizure) was examined by visual observation. In addition, the amount of wear of the upper and lower rolling rolls after rolling (the maximum wear depth of each roll was measured and represented by the average value of all rolls) was also determined. Table 3 shows the test results.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

As is clear from the results shown in Table 3, in the case of the present invention, the roughening and seizure of the rolling roll were prevented, and the roll abrasion was significantly reduced as compared with the comparative example and the conventional example. . Analysis of residual elements on the roll surface after rolling (using EPMA and ESCA analyzers)
It was confirmed that is covered with crystals of WO _4.

In Conventional Example 1 using a commercially available hot-rolling oil as a lubricant, it is apparent that none of the surface roughening resistance, seizure resistance and abrasion resistance are sufficient. From the results of analysis of the remaining elements on the roll surface after rolling, CaWO was found on the roll surface.
It was observed that ₄ was almost absent. As shown in Comparative Examples 1 and 2, even when the base number or the content of the highly basic Ca sulfonate is too low, the improvement of the rough surface resistance, the seizure resistance and the abrasion resistance is not so different from the conventional example, and the present invention Effect has not been obtained.

(Example 2) An example in which the rolling method of the present invention was applied to a group of final stands (8 stands) of a wire rod mill will be described. Cemented carbide (W
Using C-12% Co) manufactured roll, steel wire hot rolling conditions shown in Table 4 (the Kodowai Ya chromatography material) for tire diameter 7
mm to 5.4 mm. During this rolling, each lubricant composition shown in Table 1 was directly added to each rolling roll of all stands by a water injection type lubricant supply method (concentration: 0.2 to 0.5%) without adding tungstate ions. Supplied directly to Roll cooling water was supplied at a rate of 20 l / min per roll. After rolling,
The surface condition of the roll (roughness of the roll, seizure) was examined by visual observation. Further, the maximum wear depth of the roll after rolling was obtained by measuring the maximum wear depth of each rolling roll of the first stand and displaying the average value. Table 5 shows the test results.

[0058]

[Table 4]

[0059]

[Table 5]

As is evident from the results shown in Table 5, in Comparative Examples 1 and 2 and Conventional Example 1, the surface roughness and seizure after rolling were noticeable, whereas in Examples 1 to 8 of the present invention, the surface roughness and seizure No sticking occurred. Further, it can be seen that in the example of the present invention, the abrasion amount of the roll is also very small.

When rolling the cord wire material for tires under these conditions, the surface was roughened in 2 hours and the time required for the roll change could be extended to 5 hours.

[0062]

As described above, according to the rolling method of the present invention, roughening and seizure of the rolling roll are effectively prevented during hot rolling of the steel material by the roll containing tungsten. At the same time, excellent effects can be exerted on a significant reduction in roll wear and a reduction in frictional force during rolling. As a result, the life of the roll is extended, the quality of the rolled product is improved, and the number of maintenances is reduced, so that the efficiency of the rolling operation is also improved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C23C 22/50 C23C 22/50 // (C10M 169/04 109: 02 125: 10) C10N 10: 12 30:06 40:24

Claims (3)

(57) [Claims] In a rolling process using a tungsten-containing rolling roll, a lubricant composition containing 20 to 70% by weight of a highly basic Ca sulfonate based on the total weight of the composition is rolled in the presence of water. A rolling method characterized by supplying. 2. The rolling method according to claim 1, wherein the lubricant composition further contains tungstate ions. 3. The roll containing tungsten for rolling according to claim 1,
Cemented carbide roll, semi-high speed steel roll or high carbon
2. The high-speed steel roll according to claim 1, wherein
Or the rolling method according to 2.