JP2000197909A - Solid lubricating method in hot rolling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely controll the feed rate and feeding part of a lubricant between a material to be rolled and work rolls in hot rolling by feeding a solid lubricant by pressing it against at least one side of the edge parts of the material to be rolled and abutting parts of the work roll on the edge parts of the material to be rolled. SOLUTION: The solid lubricant having a fusing point higher than the maximum temperature on the surface of the work roll during rolling is fed by pressing it against the work roll while pouring water. It is preferable that the pressing pressure is >=0.01 kgf/cm2. As the solid lubricant, a wax base solid lubricant such as saturated fatty acids and esters which are a solid at room temperature or the wax base solid lubricant in which added substances of the solid lubricant such as graphite and molybdenum disulphide are mixed is used. The shape of the solid lubricant is made into a square bar shape, columnar shape or elliptic columnar shape and, by pressing the one end of them, the solid lubricant is stuck to the surface of the material to be rolled or the surface of the work roll. The width of the solid lubricant is corresponded to the dimension of the edge part of the material to be rolled where burning is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of lubricating between a work roll and a material to be rolled in hot rolling of steel or the like.

[0002]

2. Description of the Related Art Hot rolling, in particular, stainless steel, electromagnetic steel,
In hot rolling of high carbon steel or the like, it is necessary to ensure lubrication between the work material and the work roll in order to prevent seizure of the material edge of the work material.

For this reason, conventionally, a mineral oil-based lubricating oil, a grease-based lubricant, or a mixture thereof with an additive such as a solid lubricant (powder) has been used in contact with the edge of the material to be rolled on the outer peripheral surface of the work roll. And lubricated.

However, in such a lubrication method, since the lubricant is in a liquid state and has a high fluidity at a hot rolling temperature, a necessary amount of the lubricant is supplied to a necessary portion and supplied to an unnecessary portion. There has been a problem that the supply amount of the lubricant and the portion to be supplied cannot be strictly controlled so as not to prevent the lubricant from being supplied.

[0005] That is, in the case of a mineral oil-based lubricating oil, the lubricating oil spreads to other than the edge of the material to be rolled, and the rolling slip,
Troubles such as bite slip are likely to occur and the amount of supply must be reduced in order to prevent such problems.Therefore, the amount of lubricant supplied to the edge of the material to be rolled necessary to obtain the lubrication effect is not sufficient. Easy to get enough.

In the case of grease-based lubricating oil, if the supply amount is controlled to a necessary minimum, the supply amount is likely to be unstable, and the supply amount must be increased more than necessary, increasing the lubrication cost. Is easy to invite. Further, although the supply amount and the supply site can be controlled to some extent, the maintenance of the piping requires a great deal of labor, which makes it difficult to use it regularly.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and provides a lubricating method capable of reliably controlling the amount and location of a lubricant supplied between a work to be rolled and a work roll in hot rolling. The purpose is to provide.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a lubricating method between a rolled material and a work roll in hot rolling, the method comprising the steps of: This is achieved by a solid lubrication method characterized in that a solid lubricant is pressed and supplied to at least one of the contact portions with the rolled material edge.

The supply site of the solid lubricant can be easily controlled by making it into an appropriate shape or size, and the supply amount can be strictly controlled by the pressing force, the hardness and melting point of the lubricant itself. Therefore, it is possible to secure an optimal lubricating state and prevent the occurrence of seizure without causing a rolling slip or a biting slip and without requiring a large amount of maintenance work. 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.

The solid lubricant typically comprises a wax-based solid lubricant or a solid lubricant added to a wax-based 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.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical object of the present invention is plate rolling. The edge portion of the plate is more severe than the central portion of the plate because the linear load increases due to the temperature drop and the sliding speed increases due to the widening. It is rolled under an appropriate friction condition, and seizure easily occurs. The range of the plate edge portion under such severe conditions is, for example, approximately 100 to 200 mm from both side edges of the plate when the plate width is approximately 1000 to 1200 mm.

In order to prevent seizure, it is necessary to maintain the edge portion in a sufficiently lubricated state, and at the same time it is necessary to prevent slippage due to unnecessary lubrication in portions other than the edge portion.

In the conventional mineral oil-based lubricating oil and grease-based lubricating oil, the viscosity is greatly reduced at the hot rolling temperature and the fluidity is increased, so that it is difficult to limit the lubricant supply range.

On the other hand, according to the present invention, since the solid lubricant is pressed against the plate edge portion and supplied, it is possible to reliably supply the lubricant only to the plate edge portion. 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, hardness and melting point of the lubricant are set according to the operating conditions of the hot rolling. A high hardness and high melting point solid lubricant is suitable for rough rolling with a high temperature of the material to be rolled, and a low melting point solid lubricant is used for finish rolling (especially the subsequent stage) with a low temperature of the material to be rolled.

The present inventors have conducted experiments to examine the most favorable conditions of the melting point and the pressing pressure of the solid lubricant from the viewpoint of cost and work efficiency with respect to the currently conceivable operating conditions of hot rolling. As a result, at least the melting point of the solid lubricant, unless the solid lubricant having a melting point higher than the maximum temperature during the rolling of the roll surface supplying the solid lubricant is used, the consumption speed of the solid lubricant is increased by the heat of the roll. I found out. In general, the melting point of a solid lubricant matches the melting point of a wax-based solid lubricant that is a component thereof.

Further, the minimum pressing pressure required to bring out the effect of the solid lubricant is 0.01 kgf / cm ²
We have also found that the above is desirable. Pressing pressure is 0.0
If it is less than 1 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 abrasion cannot be sufficiently obtained.

In using a solid lubricant,
It is desirable 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.

When using a solid lubricant, it is desirable to use the solid lubricant while sprinkling water. When the solid lubricant is pressed against a roll surface without water, the wax and the roll transfer to each other in a state close to seizure, and are consumed. This is because the speed becomes very 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. Is preferred, in other words,
There is also an advantage that a conventional drainer is not required, and an effect of further reducing the labor for equipment maintenance can be expected.

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.

In general, the shape of the solid lubricant is a square rod, a column, or an elliptic column, and one end of the solid lubricant is pressed against a material to be rolled or a rolled work roll to adhere the solid lubricant to the surface of the material to be rolled or the surface of the work roll. Supply by Therefore, the width of the solid lubricant corresponds to the dimension of the rolled material edge where seizure occurs.

In order to stably obtain a predetermined lubricant supply amount, important properties as a solid lubricant are hardness and melting point.
The pressing force and the hardness and the melting point of the solid lubricant are appropriately combined according to the operating conditions of the hot rolling.

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 acids, metal soaps, sodium alkylbenzene sulfonates, alcohol sulfates, and alkyl methyl taurides. , Polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyethylene glycols, polyethylene waxes, paraffin hydrocarbon waxes, carnaupa waxes, candelilla wax, microcrystalline Waxes, α-olefins, etc., waxy (solid at room temperature) substances such as white wax, hardened tallow oil, stearic acid, and enamel wax,
Among the above, one or a combination of two or more kinds, such as graphite, molybdenum disulfide, natural and synthetic mica, calcium carbonate,
Silicon dioxide, potassium phosphate, boron nitride, titanium oxide, tungstate compound, phosphoric acid compound, carboxylic acid compound, sodium carbonate, sodium chloride, glass powder,
etc. Of the above, any one conventionally used, such as one type or a combination of two or more types, may be used.

[0023]

[Embodiment 1] According to the present invention, a solid lubricant is applied to a work roll surface by pressing a solid lubricant against a steel plate edge portion of a work roll using a solid lubricant supply device shown in FIG. It was supplied and hot rolled.

As shown in FIG. 1 (1), this feeding device is fixed to the wall surface of a rolling tester, and a square rod-shaped wax-based solid is attached to a chuck at the tip of a piston reciprocally driven by an air cylinder. One end of the lubricant is grasped, and the other end is pressed against the outer peripheral surface of the rolled work roll. Air cylinder / piston system is a general pneumatic circuit (not shown)
The drive is controlled by The square rod-shaped solid lubricant, one end of which is gripped by the chuck, is guided by a guide at a portion on the side of pressing against the work roll, and is reliably pressed against a predetermined portion of 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.

As shown in FIG. 1 (2), a supply device equipped with a square rod-shaped solid lubricant as shown in FIG. 1 (1) is attached to an edge portion near both sides of a steel material where seizure may occur. Each one was arranged (a pair including both edges).

FIG. 1 shows the state before the lubricant is pressed, but at the time of actual rolling, the piston is actuated to push out the lubricant and press it against the roll surface. Although FIG. 1 shows only one side of the steel sheet, a solid lubricant was actually supplied to both sides of the steel sheet as shown in FIG.

In the present embodiment, a 200 mm SUS4 steel sheet is used by using a coil rolling tester of 4Hi (a type in which one pair of upper and lower work rolls are provided with one backup roll each).
A 30 ferrite stainless steel sheet was hot-rolled.

A solid lubricant obtained by mixing 30% by weight of graphite powder as a solid lubricant in a wax base material having a melting point of 215 ° C. was used. The size is 10 mm × 15 mm × 300 mm.
This solid lubricant is applied to the roll surface corresponding to the portion up to 10 mm from both ends of the steel sheet with a pressing pressure of about 2 kgf /
pressed at cm ^2, the work roll diameter 165mm, rolling speed 30 mpm, rolling under the conditions of inlet and outlet tension 1 kgf / mm ² was carried out.

The steel plate of the material to be rolled is heated by an infrared heating furnace provided on the entry side of the rolling mill, and the temperature of the steel sheet is about 900
° C.

In order to examine the lubrication effect, rolling was started by pressing a lubricant on one steel sheet coil, and rolling was performed halfway without pressing the lubricant.

As a result of performing the hot rolling in this way, seizure occurred in a "C" shape on both edges of the steel sheet in the latter half of the steel sheet rolled without lubrication. No seizure was observed in the first half of the steel sheet.
The reason why the seizure was in the shape of "C" is that this rolling involves a widening. Further, in rolling at the time of lubrication, meandering of the rolled material and disorder of the plate shape did not occur, and the rolling could be smoothly performed.

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.

On the other hand, in the present invention, a predetermined amount of solid lubricant can be supplied to a predetermined portion by a supply device as shown in FIG. Example 2 According to the present invention, a solid lubricant supply machine was installed on the exit side of the No. 2 stand of the finishing hot rolling line in a factory as in FIG. 1 to perform rolling. However, the feeder was arranged only on the upper surface side of the steel plate. The same solid lubricant as in Example 1 was used. A heat shield plate was provided between the supply device and the steel material so that the wax was not melted by the thermal influence of the radiant heat from the steel material.

In this embodiment, the SUS having a width of 1180 mm is used.
430 ferritic stainless steel sheet was hot rolled.

The above solid lubricant was applied to both sides of the steel plate at 40
It was pressed at a pressing pressure of about 2 kgf / cm ² onto the roll surface corresponding to the part up to mm. Immediately after the end of the steel sheet bit into the roll, pressing was started, that is, lubrication was started. The work roll material used was not a high-speed roll generally used for ferritic stainless steel, but a high-chromium cast iron roll, which easily causes seizure, so that the presence or absence of seizure due to the presence or absence of lubrication can be clearly determined.

As a result of the hot rolling, no seizure occurred on the upper roll and the upper surface of the steel plate which had been subjected to the solid lubrication according to the present invention. "C" -shaped image sticking occurred at both edges.

[Example 3] As in Example 2, a solid lubricant supply device using an air cylinder was installed at the outlet side of two stands of a finishing hot rolling line in a factory, and the melting point of the solid lubricant and pressing were performed. The effects of pressure and the presence or absence of watering on the solid lubricant on the occurrence of roll seizure were investigated.
As a result, when using a solid lubricant under the conditions of the present invention,
As shown in Table 1, it became clear that the occurrence of roll surface roughness (seizure) can be sufficiently suppressed, and it is possible to use several lots without grinding (without care for the rolls).

[0038]

[Table 1]

[0039]

As described above, according to the solid lubrication method of the present invention, it is possible to reliably control the amount and location of the lubricant supplied between the material to be rolled and the work roll in hot rolling. As a result, seizure, which is particularly likely to occur at the edge of the material to be rolled, can be reliably prevented, and rolling slip and biting slip due to undesired lubrication at unnecessary parts can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structural example of a solid lubricant supply device used in a solid lubrication method according to the present invention, wherein (1) is a cross-sectional view of the device viewed from a side end of a material to be rolled; 2) is a plan view of the material to be rolled as viewed from the plate surface direction.

FIG. 2 is a diagram showing a typical example of a lubricant supply device used in a conventional liquid lubrication method, where (1) is a sectional view of the device as viewed from a side end of a material to be rolled, and (2). FIG. 2 is a plan view of the material to be rolled as viewed from the plate surface direction.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C10N 40:24 50:08 (72) Inventor Shoichi Aratani 20-1 Shintomi, Futtsu City, Chiba Prefecture New Japan (72) Shuichi Hamazuzu, Inventor 5-1 Nisone, Kokura Minami-ku, Kitakyushu-shi, Fukuoka Prefecture Kiko Works, Mishima Kosan Co., Ltd.

Claims (5)

[Claims] 1. A method of lubricating between a material to be rolled and a work roll in hot rolling, wherein at least one of an edge portion of the material to be rolled and a contact portion of the work roll with the edge portion of the material to be rolled is solidified. A solid lubrication method characterized in that a lubricant is pressed and supplied. 2. The solid lubrication method 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. 3. The solid lubrication method according to claim 1, wherein the solid lubricant comprises a wax-based solid lubricant or a solid lubricant added to a wax-based solid lubricant. 4. The solid lubrication method according to claim 1, wherein the solid lubricant is supplied to a work roll while water is applied to the solid lubricant. 5. The solid lubrication method according to claim 1, wherein a pressing pressure of the solid lubricant against a work roll is set to 0.01 kgf / cm ² or more.