JP2000178575A - Hot rolling oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a high resistance to seizure in hot rolling of a material to be rolled susceptible to seizure such as a stainless steel or the like by using a composition comprising a base oil having incorporated therein a polysulfide having a sulfur content of not less than a specific value in a specific ratio. SOLUTION: This hot rolling oil composition comprises at least one base oil selected among mineral oils, oil-and-fat, and synthetic esters, and 60-90 wt.%, based on the base oil, of a polysulfide having a sulfur content of at least 20 wt.%. As the polysulfides are exemplified dioctyl polysulfide, dinonyl polysulfide, didodecyl polysulfide and the like. The sulfur content is preferably about 20-40 wt.%. Since the hot rolling oil composition has a hot friction coefficient so high as at least 0.16 measured by the hot Timken test, it exhibits an excellent resistance to seizure while keeping a stable plate-passing property by the conventional coating method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-rolling oil composition, and relates to a hot-rolling oil composition, such as stainless steel, which is susceptible to seizure during hot-rolling, thereby preventing seizure of a work roll and a work roll and suppressing roll surface roughness. In addition, an object of the present invention is to provide a hot rolling oil composition capable of increasing the coefficient of friction between a material to be rolled and a work roll to achieve stable biting.

[0002]

2. Description of the Related Art Conventionally, fats and oils, fatty acids,
Synthetic esters, mineral oils, and the like are used and applied to backup rolls and work rolls by a water injection method, and have been applied for the purpose of reducing rolling load, suppressing roll abrasion, and preventing roll surface roughness. However, in the case of stainless steel, the surface oxide scale during hot rolling is much thinner than that of ordinary steel, so that the metal easily comes into contact with the rolling rolls, seizure occurs, and the roll surface becomes rough and covered. The rolled material is apt to have flaws, and the product having the surface flaws has a problem that polishing work is increased, cost is increased, and the basic unit of roll is increased.

[0003] Conventional hot-rolling oils cannot cope with these difficulties, and there has been a strong demand for hot-rolling oils that can prevent seizure. In addition, there has been a demand for a hot rolling oil to which a conventional water injection method can be applied without any trouble as a coating method.

To cope with this demand, for example, Japanese Patent Application Laid-Open No. Hei 6-136381 has been proposed. This is "iron oxide powder + a viscous aqueous solution of calcium carbonate", and requires a separate coating apparatus. Become. In addition,
No. 62980 proposes a combination of “iron oxide powder + polymer compound”, and a water injection method can be applied. However, both of these proposals are difficult to supply stably because they are both powder dispersions.
Requires maintenance and is not very effective.

In Japanese Patent Application Laid-Open No. 5-179276, seizure resistance of polysulfide is recognized in warm (150 to 400 ° C.) rolling, but since the friction coefficient is high, correction is made by using a phosphite together. are doing. When this rolling oil composition is used for hot rolling, it cannot be used because the coefficient of friction is too low and the biting property is reduced.

[0006]

The problem to be solved by the present invention is to solve the problems of the conventional hot rolling oil for stainless steel of this kind. More specifically, it is necessary to have high seizure resistance. An object of the present invention is to provide a hot rolling oil having high seizure resistance applicable to hot rolling of stainless steel.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive studies to develop a hot rolling oil having seizure resistance at a contact surface between a high-temperature stainless steel and a roll. As a result, the hot-rolling oil composition obtained by adding a polysulfide having a sulfur content of 20% by weight or more to one or more base oils of mineral oils, fats and oils, and synthetic esters is effective in preventing seizure during hot rolling of stainless steel. It has a friction coefficient of 0.16 or more in a hot Timken test, and has a high coefficient of friction in hot. Therefore, it exhibits high seizure resistance while maintaining stable threadability even with a conventional coating method. I found that.

[0008] In addition, it has been found that by adding 60 to 90% by weight of this polysulfide to the base oil, seizure of stainless steel during hot rolling can be prevented. Hot rolling oil was developed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The polysulfide used in the present invention is soluble in mineral oil, fats and oils, and synthetic esters, respectively, and is used alone or in a mixed base oil. The amount to be contained in this base oil is 60 to 90% by weight, and if it is less than 60% by weight, the effect of seizure resistance is small.
If it is contained in excess of% by weight, it has no further effect and is disadvantageous in terms of cost.

Examples of the polysulfide used in the present invention include dialkyl polysulfides such as didodecyl polysulfide, dihexyl polysulfide, dioctyl polysulfide and dinonyl polysulfide containing 20% by weight or more of S.

In this case, alkyl having 6 to 15 carbon atoms can be used. S is 2
If it is less than 0% by weight, the seizure resistance is small, and it tends to be uneconomical even if it is added.

The base oil used in the present invention is one or more of mineral oils, fats and oils and synthetic esters. These base oils have been conventionally used in this type of rolling oil composition, and various kinds of base oils are widely used. For example, a typical example is as follows.

As mineral oil, for example, spindle oil, machine oil, motor oil, cylinder oil, etc.
t (40 ° C.).

The fats and oils include, for example, beef tallow, lard, palm oil, coconut oil, rapeseed oil, soybean oil and the like.

The synthetic ester is usually an ester synthesized from a fatty acid and an alcohol. The fatty acid is a monobasic or dibasic acid of C12 to C36, and the alcohol is a monovalent or polyvalent C1 to C18. Alcohol.

Specific examples include ethylhexyl palmitate, butyl oleate, butyl carbitol isostearate, lauryl behenate, neopentyl glycol oleate, trimethylolpropane laurate, trimethylolpropane isostearate. And pentaerythritol oleate, trimethylolpropane dimer acid and the like.

In the present invention, as a conventional base oil,
Fatty acids that may be used alone are not used alone, but are used in combination with the above base oil as needed.

As the fatty acid, those conventionally used are widely used, for example, monobasic acids such as lauric acid, palmitic acid, oleic acid and tallow fatty acid and dibasic acids such as sebacic acid and dimer acid. This can be exemplified as an example.

Examples of the material to be rolled when using the composition of the present invention include stainless steel, and can be widely used for various grades of stainless steel. For example, martensitic stainless steel (13 chromium type) represented by SUS403,
Examples include austenitic stainless steel (nickel and chromium-based) represented by SUS304, ferrite stainless steel (18-chromium-based) represented by SUS430, high-purity ferrite stainless steel represented by SUS444 and SUS434, and duplex stainless steel of SUS329.

In the present invention, known additives such as esters and fatty acids can be used in combination, if necessary.

The hot rolling oil of the present invention is applied to a backup roll or a work roll by a water injection method usually applied in hot rolling.
Alternatively, a supply method in which the solution is applied as it is and an air injection coating, and any supply method can be adopted. Further, the refueling amount and concentration may be appropriately selected and supplied as needed.

[0022]

EXAMPLES Examples and comparative examples are set forth below to facilitate understanding of the present invention.

[0023]

Examples 1 to 7 The prescribed components shown in Table 1 below were blended in prescribed amounts to produce a hot-rolled oil composition of the present invention.

[0024]

Comparative Examples 1 to 4 The prescribed components shown in Table 1 below were blended in prescribed amounts to produce hot rolling oil compositions for comparative examples.

For each of the compositions of Examples 1 to 7 and Comparative Examples 1 to 4, a seizure resistance test and a measurement of friction coefficient by a hot Timken test were measured. However, the test method is as follows.

<Seizure Resistance Test> Test piece: SUS-304 Test piece temperature: 900 ° C. Roll: high-speed roll Number of rotations: 300 rpm Load: The load is increased by 5 kg every 2 min until seizure occurs. (Max 50kg) Refueling method: Water injection, 150ml /
min Lubricating amount: 3 ml / min Method: The test piece in the apparatus shown in FIG. 1 is heated by a high-frequency heating coil, the temperature is measured and recorded by a thermocouple, and the roll contacts the heated test piece. Then, oil is supplied from the water injection with the load applied, the air is drained off, and the maximum load until burning is measured in a hot state.

<Friction Coefficient Measurement Test> Specimen: SUS-304 Specimen temperature: 900 ° C. Roll: High-speed roll Rotational speed: 150 rpm Load: 40 kg constant Oiling method: water injection, 150 ml /
min Lubricating amount: 3 ml / min Friction coefficient: Torque / load / roll radius Method: A test piece in the apparatus shown in FIG. 1 was heated by a high-frequency heating coil, and its temperature was measured and recorded by a thermocouple. The roll and the heated test piece come into contact with each other, supply oil by water injection with a load of 40 kg applied, perform air drainage, and measure the torque to measure the friction coefficient.

[0028]

[Table 1]

However, the components used in Table 1 are as follows. Polysulfide: dioctyl polysulfide (S
= 39%) Polysulfide: ditertiary nonyl polysulfide (S = 37%) Polysulfide: ditertiary decyl polysulfide (S = 32%) Sulfurized ester: Active type lard sulfide (S = 15%) Synthetic ester: Pentaerythritol oleic acid full ester Oils and fats: liquid lard Fatty acids: oleic acid Mineral oil: motor oil (viscosity 150 cst / 40 ° C)

The following can be clearly seen from Table 1 above. (1) The lubrication state of hot rolling was simulated, and the anti-seizing load of the stainless steel was measured hot. As a result, the conventional oil of the comparative example seized at 5 kg, but 60 to 80% by weight of polysulfide was added. Examples 1 to 7 are all 30
40kg without 80kg%
g, and showed much better anti-seizure performance than the comparative example. (2) As a result of measuring the friction coefficient in the same manner, in Examples 1 to 7, the addition amount of polysulfide was 0.16 or more, the higher the addition amount of polysulfide, the slightly higher, and the shorter alkyl group, dioctyl or dinonyl, had a slightly higher friction coefficient. Show. Further, since it is much higher than synthetic esters, fats and oils and fatty acids usually used in hot rolling of ordinary steel, it is judged that there is no problem such as biting or slipping in actual rolling, and that the sheet passing property is good. (3) In Comparative Example 1 in which the sulfide ester was added in an amount of 80% by weight, the seizure resistance was the highest at 50 kg and the seizure resistance was good, but the friction coefficient was slightly lower. A higher coefficient of friction is desired for stable rolling in coating, and polysulfide is more suitable for this purpose.

[0031]

Examples 8 to 9 The prescribed components shown in Table 2 below were blended in prescribed amounts to produce a hot-rolled oil composition of the present invention.

[0032]

Comparative Example 5 Predetermined components shown in Table 2 below were blended in predetermined amounts to prepare a hot-rolled oil composition for comparison. However,
The components used in Table 2 are the same as those in Table 1.

For the examples 8 to 9, the examples 1 and 4 to 6 and the comparative examples 3 to 4 and the comparative example 5, the anti-seizure and rough surface tests and the measurement of the friction coefficient by the hot rolling test machine were carried out using the apparatus shown in FIG. ,
The procedure was as follows. Table 2 shows the results.

However, in FIG. 2, 11 is a work roll (a is an upper roll, b is a lower roll), 12 is a mixing device, 13 is a spray nozzle, 14 is a gear pump, 15
Denotes a water tank, 16 denotes a water pump, 17 denotes a rolling oil tank, 18 denotes a rolling oil pump, and 19 denotes a rolled material (strip).

<Seizure Resistance / Surface Roughness Test> (Conditions equivalent to the former stage of finishing mill) Rolled material: SUS-444 equivalent C = 0.003 wt%, Cr = 18.5 wt% Mo = 2.0 wt%, Ti = 0.2 wt% , The remaining Fe dimensions: thickness 15 × width 100 × length 500 mm Heating temperature: 1000 ° C Reduction: rolling from 15 mm to 7 mm in 4 passes Roll diameter: 200 mm (barrel length 200 mm) Roll roughness: 1.0 μm Ra Lubrication method: water injection Method Rolling oil: 30 mL / min Warm water (40 ° C.): 3 L / min Evaluation: Seizure resistance and surface roughness were evaluated based on the ratio of the seizure area on the rolled material surface after rolling. ◎: No baking ○: Baking area 5% or less △: Baking area 20% or less ×: 100% baking

<Measurement of Hot Friction Coefficient> (Conditions equivalent to the former stage of finishing mill) Rolled material: SUS-444 equivalent C = 0.003 wt%, Cr = 18.5 wt% Mo = 2.0 wt%, Ti = 0.2 wt% , Balance Fe and SUS-304 and SS-41 Dimensions: thickness 15 × width 100 × length 500 mm Heating temperature: 1000 ° C Rolling down: Rolling at a draft that allows biting (1 pass rolling) Roll diameter: 200 mm (barrel length 200 mm) Roll roughness: 1.0 μm Ra Lubrication method: Water injection method Rolling oil: 30 mL / min Hot water (40 ° C.): 3 L / min Evaluation: To evaluate the biting property, use the rollable biting angle θ = T-an (θ) to calculate the bite friction coefficient. FIG. 3 shows the bite angle θ. However, the numbers in FIG. 3 represent the same as in FIG.

[0037]

[Table 2]

However, the coefficient of friction represents the value at the time of biting. The following can be clearly seen from Table 2. (1) The lubrication state of hot rolling was simulated, and the surface roughness of stainless steel (SUS-444) in hot rolling was evaluated. As a result, seizure flaws occurred on the entire rolled material in the conventional oil of the comparative example. However, Examples 1, 4 to 6, and 8 to 9 in which polysulfide was added in an amount of 60 to 80% by weight were good, and in particular, those in which 80% by weight were added did not generate any seizure flaws. (2) Similarly, as a result of measuring the friction coefficient at the time of biting, in each of the examples, SUS-444 shows 0.29 or more, and SUS-304 has a high friction coefficient of 0.26 to 0.28. showed that. In addition, the conventional oils of Comparative Examples 3 and 4 were 0.1.
The coefficient of friction was as low as 17 to 0.18. (3) In addition, when the friction coefficient at the time of biting was measured even with ordinary steel (SS-41), the friction coefficient was as high as 0.23 to 0.27, and the conventional oils of Comparative Examples 3 and 4 were 0.14. ~ 0.1
5 showed a low coefficient of friction. Since the friction coefficient at the time of this biting is 0.20 or more, there is no problem of biting and slipping even in hot roughing of any of ordinary steel and stainless steel, and in rolling by applying rolling oil to finish rolling. Shows stable threadability.

[0039]

As described above, seizure during hot rolling of stainless steel could not be suppressed by conventional oils, but the hot rolling oil of the present invention can prevent seizure and has good biteability, so that it is stable. It can be applied to all stainless steel materials and is effective. In addition, the productivity and operability of hot rolling of stainless steel can be improved, and the surface quality in the steps after cold rolling can also be improved.

In addition, mineral oils, fats and esters are used as the base oil, and since it is a stable liquid type, there is no operational problem, and the effect can be obtained by applying it to a roll by the existing water injection or air injection method. Since it can be used, it is extremely advantageous industrially without the necessity of making new oil supply and coating equipment.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a hot Timken testing machine.

FIG. 2 is a schematic explanatory view of a hot-rolled test material.

FIG. 3 is an explanatory diagram showing a biting angle.

[Explanation of symbols]

 1. 1. Heated test piece (30φ × 50mm length cylinder) 2. High frequency heating coil 3. Roll (50φ x 8mm width ring) 4. Water injection coating 5. Air drainer Thermocouple 11. Work roll 12. Mixing device 13. Spray nozzle 14. Gear pump 15. Water tank 16. Water pump 17. Rolling oil tank 18. Rolling oil pump 19. Rolled material (strip) a. Upper roll of work roll b. Roll below work roll

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10M 125: 22) C10N 30:06 30:08 40:24 (72) Inventor Toshiki Hiruda Kawasaki, Chuo-ku, Chiba-shi No. 1 Kawasaki Steel Corporation Chiba Works (72) Inventor Ken Okamoto 1 Kawasaki-cho, Chuo-ku, Chiba Kawasaki Steel Corporation Chiba Works (72) Inventor Koji Kawashima 1 Kawasaki-cho, Chuo-ku, Chiba Kawasaki Steel (72) Inventor Jiro Ikeda 1021 Natabe Kitamachi, Yamatokoriyama City, Nara Prefecture Daido Kagaku Kogyo Kogyo Co., Ltd. (72) Inventor Masami Sumitomo 1021 Natabe Kitamachi, Yamatokoriyama, Nara Prefecture (72) Inventor Tetsuya Suga 1021 Kitamachi, Natabe, Yamatokoriyama-shi, Nara Japan Daido Kagaku Kogyo Co., Ltd. Company Nara production technology workplace F-term (reference) 4H104 BG12C CG03C DA02A DA06A EA21C EA30Z EB02 LA03 PA26

Claims (3)

[Claims] 1. A hot-rolling oil composition characterized in that one or more base oils of mineral oils, fats and oils and synthetic esters contain 60 to 90% by weight of a polysulfide having a sulfur content of 20% by weight or more. 2. A hot rolling oil composition according to claim 1, wherein the polysulfide is dioctyl, dinonyl or didodecyl polysulfide. 3. The coefficient of friction in the hot Timken test is 0.
The hot-rolled oil composition according to claim 1, wherein the number is 16 or more.