JP2000202507A - Caliber rolling method by solid lubrication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for executing caliber rolling by supplying the necessary amount of a lubricant to only the necessary part of grooved rolls to surely prevent the burning and wear of the grooved rolls without generating rolling slip and biting slip. SOLUTION: By pressing a solid lubricant against parts where the burning and wear of the grooved rolls are liable to be generated, solid lubrication between the grooved rolls and a material to be rolled is executed. By making the solid lubricant into a proper shape or proper dimensions, supplying parts are easily controlled and the supply is strictly controlled by pressing force, hardness and fusing point of the lubricant itself. Then, without generating the rolling slip and biting slip caused by undesirable lubrication to unnecessary parts and, simultaneously, by securing the optimum lubricated state where sufficient lubricant is supplied to the necessary parts, the generation of the burning and wear of the grooved rolls is prevented. A typical solid lubricant consists of a wax-base solid lubricant alone or the one in which a solid lubricant is added to the wax-base solid lubricant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel bar or a seamless steel pipe (S) represented by a rail, an H-section steel, a sheet pile, a mast material and the like.
The present invention relates to a hole rolling method for metal profiles such as ML pipes.

[0002]

2. Description of the Related Art In general rolling of a sheet or strip, the cross-sectional shape of a material to be rolled is a simple straight line, and the cross-sectional contour is substantially a straight line (strictly speaking, a curved shape called a crown). ) Is the cross-sectional shape.

[0003] On the other hand, a strip steel or SML pipe or the like to be subjected to roll rolling has a complex uneven shape in which a convex portion having a cross-sectional contour projecting outward and a concave portion entering inward are combined. It has a cross-sectional shape. Therefore, in hole rolling,
Depending on the location of the roll, the peripheral speed of the roll and the magnitude of the frictional load with the material to be rolled are remarkably different, and there is a specific problem that roll seizure and wear easily occur locally.

Conventionally, as a countermeasure, liquid lubrication is mainly performed by spraying a liquid lubricant such as a lubricant obtained by mixing a mineral oil-based or ester-based lubricating oil and water onto a portion of a roll-shaped roll where seizure and wear are likely to occur. I was

However, in the case of liquid lubrication, if a sufficient amount of lubricant is supplied to a necessary portion of a porous roll, the supplied liquid lubricant spreads on the roll surface due to its high fluidity.
There was a dilemma that rolling slip and biting slip occurred due to lubrication to unnecessary parts, and if this was to be avoided, the supply of lubricant to the necessary parts would be insufficient.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and to provide a method of performing hole rolling by supplying a necessary amount of lubricant only to a necessary portion of a hole roll. Aim.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a solid lubricant is pressed against a portion of a roll-shaped roll where seizure and abrasion easily occur, and the roll-shaped material and a rolled material are rolled. This is achieved by a hole rolling method using solid lubrication, characterized in that solid lubrication is performed.

The supply site of the solid lubricant can be easily controlled by forming it into an appropriate shape or size, and the supply amount can be strictly controlled by the pressing force, the hardness and the melting point of the lubricant itself. Therefore, without causing rolling slip and biting slip due to undesired lubrication of unnecessary parts, at the same time, supplying a sufficient amount of lubricant to necessary parts and securing the optimal lubricating state, Can prevent seizure and abrasion.

[0009] 1% to 50% of the total area of the perforated roll of the perforated roll
It is desirable to supply the solid lubricant to the%. It is desirable that the melting point of the solid lubricant is higher than the maximum temperature during rolling of a work roll supplying the solid lubricant. It is preferable that the solid lubricant is supplied to the work roll while water is applied. The pressing pressure of the solid lubricant against the work roll is desirably 0.01 kgf / cm ² or more.
The solid lubricant is typically formed by adding a solid lubricant to a wax-based solid lubricant or a wax-based solid lubricant. The wax-based solid lubricant includes saturated fatty acids, unsaturated fatty acids, esters, fatty acid amides, hardened oils, hardened fatty acids, metal soaps, sodium alkylbenzene sulfonate, alcohol sulfate, alkyl methyl tauride, polyoxyethylene alkyl phenol ether, polyoxy Ethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyethylene wax, paraffin hydrocarbon wax, carnauba wax, candelilla wax, microcrystalline wax, α
-It preferably comprises one or more cold solid substances selected from the group consisting of olefins, white wax, hardened tallow oil, stearic acid, and full wax. The solid lubricant is graphite, molybdenum disulfide, natural mica,
Consisting of one or more solid powdered substances selected from the group consisting of synthetic mica, calcium carbonate, silicon dioxide, calcium phosphate, boron nitride, tungstate, phosphate, carboxylate, sodium carbonate, and glass It is desirable.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to prevent seizure and abrasion of a porous roll, it is necessary to supply a sufficient lubricant to a part where such a roll is likely to occur, and at the same time, unnecessary parts to other parts. It is necessary to prevent the occurrence of slip due to a lubricant.

Conventional mineral lubricating oils and grease-based lubricating oils have high fluidity, so it is difficult to limit the supply range of the lubricant. Necessary parts could not be lubricated sufficiently.

On the other hand, according to the present invention, since the solid lubricant is supplied by pressing against the portion of the porous roll where seizure and abrasion are likely to occur, the lubricant is supplied only to the required portion of the porous roll. Can be done reliably. Further, the supply amount can be easily controlled by optimizing the pressing force, the hardness and the melting point of the solid lubricant. The necessary pressing force, the hardness and the melting point of the lubricant are set according to the operating conditions of the hole rolling (rolled material temperature, roll temperature, etc.).

The solid lubricant used in the present invention is a solid at room temperature and independently maintains a certain shape without being put in a container.

Generally, the shape of the solid lubricant is rod-shaped, and one end thereof is pressed against a perforated roll to supply the solid lubricant on the surface of the perforated roll. The cross-sectional dimension of the rod-shaped solid lubricant is suitably determined based on the size of the roll portion where seizure and wear occur.

Even when the hole shape, that is, the caliber shape is complicated, it is possible to sufficiently supply the lubricant to the required portion by processing the tip shape of the solid lubricant in advance so as to correspond to the caliber shape, thereby achieving stable lubrication. And the seizure and wear of the roll can be prevented.

In order to stably obtain a predetermined lubricant supply amount, important properties as a solid lubricant are hardness and melting point.
The pressing force is appropriately combined with the hardness and the melting point of the solid lubricant according to the operating conditions of the groove rolling. The present inventors have conducted experiments to examine the most preferable conditions of the melting point and the pressing pressure of the solid lubricant in terms of cost and work efficiency with respect to the currently conceivable operating conditions of the hole rolling. As a result, at least the solid lubricant has a melting point higher than the highest temperature during the rolling of the surface of the roll-shaped roll supplying the solid lubricant. Was found to be faster. In general,
The melting point of the solid lubricant matches the melting point of the wax-based solid lubricant that is a component thereof.

Further, as a minimum pressing pressure condition necessary to bring out the effect of the solid lubricant, 0.01 kgf /
It was also discovered that cm ² or more is desirable. If the pressing pressure is less than 0.01 kgf / cm ² , the amount of the solid lubricant adhering to the roll is small, and the effects of suppressing roll surface roughness (including roll seizure) and reducing roll wear cannot be sufficiently obtained.

In using a solid lubricant,
It is necessary to use the solid lubricant itself while pouring water on it.
Usually, the operation is performed while applying the roll cooling water, but the roll cooling water may be supplied to the solid lubricant. That is, the solid lubricant may be supplied to the roll while the roll cooling water is being applied. of course,
A pipe dedicated to solid lubricant may be provided and water may be directly applied. The reason why the solid lubricant must be used while spraying water is that when the solid lubricant is pressed against the roll surface where there is no water, the wax and the roll are transferred in a state close to seizure, and the consumption rate is extremely low. It is because it becomes large. Therefore, when using conventional oil-based lubricating oil, lubricating oil is supplied after water on the roll surface is removed by a drainer, but solid lubricant is supplied when water is present on the roll surface. In other words, there is an advantage that a conventional drainer is not required, and an effect of further reducing the labor for equipment maintenance can be expected.

As the solid lubricant of the present invention, a wax-based solid lubricant or a mixture of a wax-based solid lubricant and an additive such as a solid lubricant is used.

Examples of the wax-based solid lubricant include saturated fatty acids, unsaturated fatty acids, esters, fatty acid amides, hardened oils,
Hardened fatty acid, metal soap, sodium alkylbenzene sulfonate, alcohol sulfate, alkyl methyl tauride, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyethylene wax, paraffin hydrocarbon wax, carnauba One or more cold solid materials selected from the group consisting of wax, candelilla wax, microcrystalline wax, α-olefin, white wax, tallow hydrogenated oil, stearic acid, and full wax can be used.

In the case of a combination of two or more kinds, it is desirable to use a wax as a main component and up to 50% by weight of fats and oils such as fatty acids and esters.

Solid lubricants to be added to these wax-based solid lubricants include graphite, molybdenum disulfide, natural mica, synthetic mica, calcium carbonate, silicon dioxide, calcium phosphate, boron nitride, tungstate compound, phosphate compound, One or more solid powdery substances selected from the group consisting of carboxylic acid compounds, sodium carbonate, and glass can be used.

By adjusting the amount of the solid lubricant to be added to the solid lubricant, it is possible to selectively enhance the performance particularly required among seizure resistance, wear resistance and the like. In addition, since a solid lubricant in which solid lubricant powder is uniformly dispersed in a wax-based solid lubricant can be easily manufactured, uniform lubrication performance can be ensured in the cross section and length direction of the rod-shaped solid lubricant,
As a result, stable lubrication can be ensured in the required area of the hole-shaped roll and for the elapsed time.

The amount of the solid lubricant added to the solid lubricant is 80.
It is desirable that the content be up to wt%. If it exceeds 80% by weight, the amount of the wax-based solid lubricant as a binder becomes too small, and the strength of the rod-shaped solid lubricant as a composite material becomes insufficient.

In the profile of the cross section of the hole roll crossing the portion where the hole roll and the material to be rolled come into contact, the total contact length between the hole roll and the material to be rolled (hereinafter referred to as the cross-section contact length of the hole roll). ), It is desirable to supply a solid lubricant to the portion of the porous roll corresponding to a length of 1% to 50%. Usually, the seizure / wear portion of the porous roll is 1% or more of the contact length of the cross-section of the porous roll, and a lubricating action can be obtained by supplying the solid lubricant to an area corresponding to this. On the other hand, when the supply area of the solid lubricant exceeds 50% of the contact length of the cross-section of the roll-shaped roll, not only the lubricating action at a necessary portion is saturated, but also a rolling slip or a biting slip is likely to occur.

[0026]

[Embodiment 1] Hot rolling of a rail was performed by applying the hole rolling method using solid lubrication according to the present invention. The solid lubricant supply device shown in FIG. 1 was installed on the upper roll of a rough rolling mill at a rail rolling factory, and the lubricant was supplied by pressing the solid lubricant against a hole-shaped roll portion where seizure and abrasion easily occur.

As shown in FIG. 1, this supply device is fixed to a gantry, and grips one end of a rod-shaped wax-based solid lubricant with a chuck at the tip of a piston reciprocally driven by an air cylinder. The other end is pressed against a predetermined portion of the roll. The drive of the air cylinder / piston system is controlled by a pneumatic circuit (not shown). The rod-shaped solid lubricant, one end of which is gripped by the chuck, is guided by a guide at a position on the pressing side of the porous roll, and is reliably pressed against a predetermined position on the roll surface. The guide further serves to protect the long rod-shaped solid lubricant from being broken by the bending load due to the rotation of the roll. In FIG. 1,
Although the state before pressing the lubricant is shown, the piston is actuated to extrude the lubricant and press it against the roll surface during actual rolling.

A base material (melting point: 2) in which a rod-shaped solid lubricant according to the present invention is injected with 30% by weight of a monoester into a wax-based solid lubricant (material: paraffin-based hydrocarbon wax).
It was prepared by mixing 40% by weight of graphite powder at 35 ° C. and a hardness of 70 Hv (Vickers hardness (1 g load)).

FIG. 2 shows a conventional liquid lubricant supply device for comparison with the present invention, which is a typical type used in both hot rolling and cold rolling. . The supply device shown in the drawing injects a liquid lubricant (oil only, or an emulsion of water and oil, etc.) from the nozzles arranged in the header onto the surface of the work roll. Since the liquid lubricant does not stay at the sprayed work roll portion but spreads to the surroundings, the lubrication portion cannot be strictly controlled, and the lubricant supply amount to the required portion cannot be strictly controlled. In this embodiment, a conventional liquid lubricant obtained by adding 20% of an ester to a mineral oil-based lubricating oil was used.

The solid lubricant was supplied to a portion corresponding to a length corresponding to 40% of the contact length of the cross section of the porous roll.

At the time of rolling about 800 tons by each of the lubricating methods described above, the surface roughness of the roll was examined.
Conventional rolls rolled by liquid lubrication suffered severe seizure accompanied by plastic flow, whereas hole rolls rolled by solid lubrication of the present invention hardly suffered seizure. And the same good roll skin as before the start of rolling was maintained.

Example 2 Wax-based solid lubricant (material: paraffin-based wax in which 10% of monoester was injected, melting point: 103 ° C., hardness: 65 Hv (load: 1 g))
And a solid lubricant obtained by mixing 50 wt% of any one of graphite, calcium carbonate and mica powder as a solid lubricant, and 90 wt%
% Solid lubricant was prepared.

For comparison, a conventional liquid lubricant obtained by adding 20% ester to a mineral oil-based lubricant was used.

Using these lubricants, seizure resistance and wear resistance were evaluated by a hot rolling wear tester. The test was performed using a high chromium cast iron disk-shaped test piece corresponding to a roll, S45C (for a wear test) corresponding to a material to be rolled, and SUS430.
The test was performed for a combination with a counterpart made for (a printing test). The test conditions were as follows: the rotational peripheral speed of the test piece was 100 m / min,
The sliding speed was variously changed by setting the temperature to 200 ° C. and the temperature of the mating piece to 800 ° C., the slip rate to 10% in the wear test, and the speed of the mating piece to change in the burning test. The seizure resistance was evaluated by the slip rate at which seizure occurred, and the abrasion resistance was evaluated by the abrasion weight (number of rolling: 10,000 times) of the test piece.

The lubricant was supplied by pressing the solid lubricant of the present invention against a test piece with a force of ² kgf / cm ² .
The conventional liquid lubricant is water: 99 in the tank while lubricant:
500cc per minute of emulsion mixed and stirred at ratio of 1
Performed by feeding.

As a result of the above test, when the solid lubricant of the present invention was used in an amount of 50 wt% of the solid lubricant powder, the seizure resistance was improved three times as compared with the conventional liquid lubricant, and the wear resistance was improved. Has improved about 4-5 times. 90wt% solid lubricant
In the case of, the amount of the wax-based solid lubricant that functions as a binder in the solid lubricant is too small, and the strength is reduced,
The experiment was interrupted because the solid lubricant was cracked and broken while being pressed against the rotating test piece.

Example 3 According to the present invention, a solid lubricant was applied to a caliber of a grooved rolling mill in advance, and a 1-m-long rail steel material was subjected to a hot rolling experiment.

The range of application of the solid lubricant is as follows.
30%, 50%, 70%, and 100%. As the solid lubricant, a wax-based solid lubricant (material: paraffin-based wax, melting point 125 ° C., hardness 47 Hv (load 1
For g)), a mixture obtained by injecting 30 wt% of graphite powder and 20 wt% of ester was used.

As a result of the above experiment, when the material was supplied to the portions corresponding to 10%, 30%, and 50% of the contact length of the cross section of the hole-shaped roll, there was no biting slip or rolling slip, and the material passed normally. However, when it was supplied to a portion corresponding to 70% or 100% of the contact length of the cross section of the hole-shaped roll, a biting slip and a rolling slip occurred, and normal threading was not possible.

[Example 4] A solid lubricant supply device using an air cylinder was installed on the entrance side of a rough mill in a rail rolling line of a factory, and the melting point of the solid lubricant, the pressing pressure, and the pressure applied to the solid lubricant were set. The effect of watering on the occurrence of roll seizure was investigated. As a result, when a solid lubricant is used under the conditions according to the present invention, as shown in Table 1, the occurrence of roll surface roughness (seizure) can be sufficiently suppressed, and several lots can be used without grinding (without roll care). It turned out to be possible.

[0041]

[Table 1]

[0042]

As described above, according to the present invention,
Since the required amount of lubricant can be supplied only to the necessary part of the roll, the roll can be rolled, so that seizure and wear of the roll can be prevented without causing rolling slip or biting slip. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a structural example of a solid lubricant supply device used in a solid lubrication method according to the present invention.

FIG. 2 is a sectional view showing a typical example of a lubricant supply device used in a conventional liquid lubrication method.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shoichi Aratani 20-1 Shintomi, Futtsu City, Chiba Prefecture Nippon Steel Corporation Technology Development Division (72) Inventor Shuichi Hamazuzu 5-1 Mishima Kosan Co., Ltd. Kiko Division

Claims (8)

[Claims] The present invention is characterized in that a solid lubricant is pressed against and supplied to a portion of a roll-shaped roll where seizure and abrasion tend to occur, and that a solid lubricant is used to lubricate between the roll-shaped roll and a material to be rolled. A hole rolling method using solid lubrication. 2. 1% to 5% of the total area of the hole-shaped roll.
2. A solid lubricant is supplied to 0%.
2. A hole rolling method using solid lubrication according to item 1. 3. The hole rolling by solid lubrication according to claim 1, wherein a melting point of the solid lubricant is higher than a maximum temperature during rolling of a work roll supplying the solid lubricant. Method. 4. The hole rolling method using solid lubrication according to claim 1, wherein the solid lubricant is supplied to a work roll while water is applied to the solid lubricant. 5. The hole by solid lubrication according to claim 1, wherein a pressure of pressing the solid lubricant against a work roll is 0.01 kgf / cm ² or more. Shape rolling method. 6. The solid lubricant according to claim 1, wherein the solid lubricant is formed by adding a solid lubricant to a wax-based solid lubricant or a wax-based solid lubricant. Hole rolling method by lubrication. 7. The wax-based solid lubricant includes a saturated fatty acid, an unsaturated fatty acid, an ester, a fatty acid amide, a hardened oil,
Hardened fatty acid, metal soap, sodium alkylbenzene sulfonate, alcohol sulfate, alkyl methyl tauride, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyethylene wax, paraffin hydrocarbon wax, carnauba A wax, candelilla wax, microcrystalline wax, α-olefin, white wax, hardened tallow oil, stearic acid, and one or more cold solid substances selected from the group consisting of full wax. 7. The method of hole rolling by solid lubrication according to claim 6. 8. The solid lubricant includes graphite, molybdenum disulfide, natural mica, synthetic mica, calcium carbonate, silicon dioxide, calcium phosphate, boron nitride, tungstate compound, phosphate compound, carboxylic acid compound, sodium carbonate,
8. The method according to claim 6, wherein said method comprises one or more solid powdery substances selected from the group consisting of glass and glass.