JP2000230187A - Hot rolling oil composition for stainless steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hot rolling oil composition having high baking resistance, capable of applying to hot rolling of stainless steel for which high baking resistance is required. SOLUTION: This composition is obtained by adding 40-90 wt.% sulfide ester having >=10 wt.% sulfur content or mixture of the sulfide ester with a polysulfide having >=20 wt.% sulfur content to one or more kinds of base oils among a mineral oil, oil and fat and a synthetic ester. The composition is used as a hot rolling oil for stainless steel.

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 for stainless steel, which prevents the rolling material and work rolls from seizing during hot rolling of stainless steel, suppresses roll surface roughness, and reduces the rolled material and workpiece. An object of the present invention is to provide a hot-rolling oil composition capable of increasing the coefficient of friction of a roll and achieving 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 it is easy to cause metal-to-metal contact with the rolling rolls, seizure occurs, and the roll surface becomes rough and the rolling occurs. There is a drawback that the material flaws are apt to appear, and the product having the surface flaws requires more polishing work, which leads to an increase in cost and an increase in roll unit consumption.

[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 Publication No. Hei 6-136381 has been proposed, which is “iron oxide powder + a viscous aqueous solution of calcium carbonate”, and requires a separate coating device. 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 stably supply because of the dispersion of the powder, require maintenance to protect the powder in a dispersed state, and are not very effective.

In Japanese Patent Publication No. 5-179276, the seizure resistance of polysulfide is recognized in warm (150-400 ° C.) rolling, but the friction coefficient is high. 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, hot rolling in which one or more base oils of mineral oils, fats and oils, and synthetic esters contain a sulfurized ester alone having a sulfur content of 10% by weight or more and a polysulfide having a sulfur content of 20% by weight or more. The oil composition
It has the effect of preventing seizure during hot rolling of stainless steel, shows a friction coefficient of 0.12 or more in a hot Timken test, and has a high coefficient of friction in hot. It has been found that high seizure resistance is exhibited while maintaining.

[0008] Further, by adding the sulfide ester alone or the sulfide ester and polysulfide in an amount of 40 to 90% by weight based on the base oil, seizure of stainless steel during hot rolling can be prevented. With this knowledge, the target hot rolling oil was developed here.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The sulfurized ester and polysulfide used in the present invention are both soluble in mineral oils, fats and oils, and synthetic esters, respectively, and are used alone or in a mixed base oil. The amount to be contained in this base oil is 40 to 90% by weight, and if it is less than 40% by weight, the effect of seizure resistance is small, and if it exceeds 90% by weight, there is no further effect and the cost is low. Disadvantageous.

In the present invention, a part of the sulfurized ester can be replaced by a polysulfide having a sulfur content of 20% by weight or more. This substitution amount is from 0.6: 1.0 to 8.0: 1.0 (weight ratio) of sulfide ester: polysulfide.

Examples of the sulfide ester include oils and fats having an unsaturated fatty acid group, such as lard sulfide containing at least 10% by weight of S, sulfide rapeseed oil and the like, and sulfide simple substances of esters and composites thereof.

More specifically, examples of the sulfurized fats and oils and sulfurized esters include sulfurized low melting point lard, sulfurized soybean oil methyl ester, sulfurized macaw oil, sulfurized soybean oil, sulfurized bran oil and the like.

At this time, if the S content is less than 10% by weight, the anti-seizure effect tends to be small, and the addition thereof tends to be uneconomical. Preferably, the S content is about 10 to 20% by weight.

Examples of the polysulfide include dialkyl polysulfides such as didodecyl polysulfide and dihexyl polysulfide containing 20% by weight or more of S.

[0015] In addition, the alkyl in this case is a compound having 6 carbon atoms.
~ 15 can also be used. If the S content is less than 20% by weight, the anti-seizure effect tends to be small, and even if added, it tends to be uneconomical. Preferably, the S content is about 20 to 40% by weight.

In the present invention, a mixture of a sulfurized ester and polysulfide is more effective than the use of a sulfurized ester alone.

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.

Mineral oils include, 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, Examples thereof include pentaerythritol oleate and trimethylolpropane dimer ester.

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 bovine fatty acid and dibasic acids such as sebacic acid and dimer acid. This can be exemplified as an example.

The object to which the composition of the present invention is used is stainless steel, and various grades of stainless steel are widely used. For example, martensitic stainless (13 chromium) represented by SUS403, SUS304, etc.
Austenitic stainless steel (nickel, chromium type), ferrite stainless steel (18 chromium type), typically SUS430, SUS444 and SUS434
High purity ferritic stainless steel and SUS3 represented by
29 duplex stainless steels and the like.

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.

[0027]

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

[0028]

Examples 1 to 8 The prescribed components (% by weight) shown in Table 1 below were blended to prepare a hot-rolled oil composition of the present invention.

[0029]

Comparative Examples 1-4 Predetermined components (% by weight) shown in Table 2 below were blended to produce hot rolling oil compositions for comparative examples.

For each of the compositions of Examples 1 to 8 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 Rotational speed: 300 rpm Load: Increase the load by 5 kg every 2 min until seizure occurs. (Max. 50 kg) Lubrication method: water injection, 150 ml /
min. Oiling amount: 3 ml / min. Method: The test piece in the apparatus shown in Fig. 1 was heated by a high-frequency heating coil, the temperature was measured and recorded by a thermocouple, and the roll was in contact with the heated test piece and a load was applied. Oil is supplied from the water injection at, and air is drained to measure the maximum load before burning in a hot state.

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

[0033]

[Table 1]

[0034]

[Table 2]

The components used in Tables 1 and 2 are as follows. Sulfurized ester: Sulfurized lard (S = 10%) Sulfurized ester: Low melting point sulfided sulphide (S = 15%) Sulfurized ester: Active type sulfided lard (S = 15%) Sulfurized ester: Composite sulfided ester (S = 11%) Polysulfide : Ditertiary decyl polysulfide (S = 32%) Synthetic ester: Pentaerythritol oleic acid full ester Fats and oils: Liquid lard Fatty acids: Oleic acid Mineral oil: Motor oil (viscosity 150 cst / 40 ° C.)

The following can be clearly seen from Tables 1 and 2 above. (1) The lubricating state of hot rolling was simulated, and the anti-seizure load of the stainless steel was measured hot. As a result, the conventional oil of the comparative example seized at 5 kg, but 50 to 80% by weight of sulfide ester was added. Examples 1 to 8 were all 40 kg
50kg without 80% by weight
(Max.), And showed much better seizure resistance than the comparative example.

(2) As a result of measuring the friction coefficient in the same manner, in Examples 1 to 8, the addition amount of the sulfide ester and the polysulfide was slightly higher when the addition amount was 0.12 or more. Since it is higher than the applied synthetic esters, fats and oils and fatty acids, it is judged that there is no problem such as biting or slipping in actual rolling, and that the sheet passing property is good.

The hot rolling oil for the purpose of reducing the load and the friction coefficient of ordinary steel has a friction coefficient of 0.08 to 0.10. Good plateability.

[0039]

Examples 9 to 10 The predetermined components shown in Table 3 below were blended in predetermined amounts (% by weight) to produce hot rolling oil compositions of the present invention.

[0040]

Comparative Example 5 The prescribed components (% by weight) shown in Table 4 below were blended to prepare a hot-rolled oil composition for comparison. However, the components used in Tables 3 and 4 are the same as those in Table 1.

With respect to Examples 9 to 10, Examples 2, 6, 7, and 8 and Comparative Examples 4 to 5 and Comparative Example 2, a seizure resistance / roughness test and a coefficient of friction measurement with a hot rolling test machine were performed using the apparatus shown in FIG. It carried out by the following method. The results are shown in Tables 3 and 4.

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 the 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 preceding 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 Dimensions: thickness 15 × width 100 × length 500 mm Heating temperature: 1000 ° C Reduction: Rolling at a reduction ratio that allows biting (1 pass rolling) Roll diameter: 200 mm (barrel length 200 mm) Roll roughness : 1.0 μmRa Lubrication method: Water injection method Rolling oil: 30 mL / min Hot water (40 ° C.): 3 L / min Evaluation: To evaluate the biting property, μ = t-an using the rollable biting angle θ. The biting friction coefficient was calculated by (θ). FIG. 3 shows the bite angle θ. However, the numbers in FIG. 3 represent the same as in FIG.

[0045]

[Table 3]

[0046]

[Table 4]

However, the coefficient of friction represents the value at the time of biting.

The following can be clearly seen from Tables 3 and 4. (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 2 to 10 in which the sulfide ester was added in an amount of 50 to 80% by weight were good, and in particular, those in which 80% by weight were added did not generate any seizure flaw.

(2) As a result of measuring the friction coefficient at the time of biting in the same manner, Examples 2 to 10 show the case of SUS-444.
0.29 or more, and SUS-304 also
The coefficient of friction was as high as 0.26. The conventional oils of Comparative Examples 2 and 4 exhibited low friction coefficients of 0.17 to 0.18.

When the friction coefficient at the time of this biting is 0.20 or more, there is no problem such as biting and slipping, and the sheet passing property in the actual machine is good.

[0051]

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, at least one of mineral oils, fats and oils and synthetic esters is used as the base oil.
Since the effect can be exerted by applying to a roll by the existing water injection or air injection method, it is industrially extremely advantageous without the necessity of making new oil supply and application 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 long 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) 11a. Upper roll of work roll 11b. Roll below work roll

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10M 135/20 C10M 135/20 // C10N 30:06 40:24 (72) Inventor Shinzo Uchimaki Chiba 1 Kawasaki-cho, Chuo-ku, Chiba-shi Kawasaki Steel Co., Ltd.Chiba Works (72) Inventor Ken Okamoto 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. 1 Kawasaki-cho, Chuo-ku, Chiba-shi Kawasaki Steel Corporation Chiba Works (72) Inventor Masami Sumitomo 1021 Kitamachi, Natabe, Yamatokoriyama, Nara Prefecture Daido Chemical Industry Co., Ltd. 1021, Nitabe Kitamachi, Yamatokoriyama City, Japan Daito Chemical Industry Co., Ltd. (72) Inventor Tetsuya Suga10 Natabekitamachi, Yamatokoriyama City, Nara Prefecture 21F Daido Chemical Co., Ltd. Technical Research Laboratory F term (reference) 4E002 AA07 AD04 BC01 BC05 BC08 CB03 CB05 4H104 BG04C BG12C DA02A DA06A EA21C EA30Z EB02 LA03 PA26 PA35

Claims (3)

[Claims] 1. Hot rolling for stainless steel, wherein one or more base oils of mineral oils, fats and oils and synthetic esters contain 40 to 90% by weight of a sulfide ester having a sulfur content of 10% by weight or more. Oil composition. 2. A method according to claim 1, wherein a part of said sulfide ester has a sulfur content of 2.
The hot rolling oil composition for stainless steel according to claim 1, wherein the composition is substituted with 0% by weight or more of polysulfide. 3. The coefficient of friction in the hot Timken test is 0.
The hot-rolling oil composition for stainless steel according to claim 1, which is 12 or more.