JP2000197901A - Caliber rolling method by solid lubrication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a caliber rolling method by which wear in thrust collar parts of a grooved roll is reduced. SOLUTION: By supplying a solid lubricant to the thrust collar parts where there are sliding faces of upper and lower grooved rolls, solid lubrication between both the grooved rolls is executed in the sliding faces. By selectively executing the solid lubrication of, especially, the thrust collar parts of the whole of the groove, the wear in the thrust collar parts is remarkably reduced without fear that failure such as slip or the like between the roll and a material to be rolled by unnecessarily lubricating the other part of the groove occurs. A typical solid lubricant consists of a wax-base solid lubricant and the wax-base solid lubricant to which a solid lubricant is added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hole rolling method for a metal profile such as a steel bar or a steel pipe represented by a rail or an H-beam. In particular, the present invention relates to a lubricating rolling method for a portion that is rolled by contact between upper and lower rolls.

[0002]

2. Description of the Related Art In the rolling of a general plate 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 (provided that the crown has a curvature. (Disregarded).

On the other hand, a roll used in the roll rolling of a strip or a steel pipe has a complicated uneven shape in which a convex portion having a cross-sectional contour projecting outward and a concave portion having entered inward are combined. It has a cross-sectional shape. For this reason, in the roll rolling, a specific problem that does not occur in the rolling of general plate materials, strip materials, and the like occurs.

In particular, as shown in FIG. 1, in a hole-shaped portion for forming a corner portion of a cross-sectional profile of a rolled material, a roll rotation axis of upper and lower hole-shaped rolls is required to make the contour line of the corner portion continuous. There may be a portion where the roll surfaces perpendicular to each other slide (referred to as a thrust collar portion). In the thrust collar portion, the hard rolls rub against each other, so that the rolls are severely worn. If the amount of wear increases, the size and shape of the rolled product are directly affected. Conventionally, in order to avoid this, roll exchange (rearrangement) has been frequently performed. That is, even if the hole-shaped portion other than the thrust collar portion is still in a sufficiently healthy state, it is necessary to replace (rearrange) the roll when the wear amount of the thrust collar portion exceeds the management reference value. As a result, not only does the roll cost inevitably increase, but also the productivity is hindered by the stoppage of the rolling line when the rolls are replaced.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hole rolling method for reducing abrasion at a thrust collar portion of a hole roll.

[0006]

According to the present invention, a solid lubricant is supplied to a roll portion corresponding to a sliding surface between upper and lower perforated rolls to achieve the above object. The present invention provides a hole rolling method using solid lubrication, characterized in that rolling is performed while lubricating between the hole rolls with a solid lubricant on the surface.

Conventionally, as for the lubrication of the thrust collar portion, which is the sliding portion between the upper and lower rolls, no specially-considered technology has been found as far as the present inventor knows. In the present invention, by selectively solid-lubricating the thrust collar portion of the entire hole shape, the other hole-shaped portions are unnecessarily lubricated, thereby causing problems such as slip between the roll and the material to be rolled. Without fear, abrasion of the thrust collar portion can be greatly reduced.

It is desirable that the melting point of the solid lubricant is higher than the maximum temperature during rolling of a work roll for 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.

[0009] The solid lubricant comprises 10 parts of the solid lubricant.
It is desirable that the wax-based solid lubricant be contained in an amount of about 90% by weight. The wax-based solid lubricant,
Saturated fatty acids, unsaturated fatty acids, esters, fatty acid amides,
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 Or one or more cold solid substances selected from the group consisting of carnauba wax, candelilla wax, microcrystalline wax, α-olefin, white wax, tallow hardened oil, stearic acid, and fullow wax. Is desirable. The solid lubricant is graphite, molybdenum disulfide, natural mica, synthetic mica, calcium carbonate, silicon dioxide, calcium phosphate, boron nitride, tungstate compound, phosphate compound, carboxylic acid compound, sodium carbonate,
And one or more solid powdered substances selected from the group consisting of glass and glass.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The inventor of the present invention, when conceiving lubrication of a thrust collar portion of a porous roll, first conducted an experiment using the most common mineral oil-based lubricant and grease-based lubricant. . However, since the upper and lower rolls are almost flat in the thrust collar part, and because of the relative speed between the rolls, the effect of drawing in the fluid by the so-called wedge effect cannot be expected, and almost all liquid lubricant is introduced into the thrust collar part. It was found that the lubrication did not flow and the lubrication effect was not obtained.

On the other hand, when a solid lubricant such as a wax-based solid lubricant is directly pressed and supplied to a roll portion corresponding to the sliding surface of the upper and lower rolls, the lubricant adheres firmly to the sliding surface. It has been found that the lubrication of the thrust collar portion is carried out effectively.

[0012] In addition, since conventional mineral lubricating oils and grease lubricating oils have high fluidity, even if a certain lubricating effect is obtained in the thrust collar portion, the lubricant spreads to unnecessary portions. Inevitably, rolling slip and biting slip occur to hinder rolling.

According to the present invention, it is possible to reliably supply the solid lubricant only to the thrust collar portion of the porous roll. 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 is supplied to the thrust collar portion by pressing the solid lubricant onto the upper and lower roll thrust collar portions before rolling to form a lubricant film, and pressing the solid lubricant during rolling. Is a basic supply mode, but since the abrasion of the thrust collar portion does not occur too early, it may be applied by pressing after the start of rolling, or a necessary lubricant film is maintained during rolling. As far as possible, the pressing during rolling may not be performed, or may be performed intermittently instead of continuously.

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 rolling operation conditions. As a result, at least the solid lubricant has a melting point higher than the maximum temperature during the rolling of the roll surface at the portion where the solid lubricant is supplied. Was found to be faster. In general, the melting point of a solid lubricant matches the melting point of a wax-based solid lubricant that is a component thereof.

[0016] Furthermore, the minimum pressing pressure condition required to bring out the effect of the solid lubricant is 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 abrasion 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. However, the roll cooling water may be supplied to the wax 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. The reason is that when the solid lubricant is pressed against the roll surface without water, the solid lubricant and the roll transfer to each other in a state close to seizure. This is because the consumption 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. 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.

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 dimensions and shape of the rod-shaped solid lubricant are determined based on the dimensions and shape of the thrust collar portion.

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.

More specifically, the presence or absence of the solid lubricant component or the amount of the solid lubricant may be determined according to the magnitude of the thrust load applied to the thrust collar portion.

As the solid lubricant of the present invention, a wax solid lubricant or a mixture of a wax 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.

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 added to the solid lubricant, an optimum lubricating state according to the thrust load of the thrust collar portion can be obtained. 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,
Thereby, stable lubrication can be ensured for the position in the thrust collar portion and the elapsed time.

The amount of the solid lubricant added to the solid lubricant is 10
It is desirable that the content be in the range of wt% to 90 wt%. The effect of the addition of the solid lubricant is actually obtained when the addition amount is 10 wt% or more, and when the addition amount exceeds 90 wt%, the amount of the wax-based solid lubricant as the binder becomes too small, and the rod-shaped composite material is used. The strength of the solid lubricant becomes insufficient, and the solid lubricant is easily broken by pressing.

[0028]

[Example 1] The method of the present invention for rolling a hole by solid lubrication was applied to a thrust collar portion of a hole roll of a rough rail rolling mill. The solid lubricant according to the present invention has a melting point of 1
A mixture obtained by mixing 30% by weight of graphite powder with a wax-based solid lubricant at 30 ° C was used.

The supply of the solid lubricant to the thrust collar portion was performed by installing a solid lubricant supply device shown in FIG. 2 above the upper roll.

As shown in FIG. 2, the supply device is fixed to a gantry, and holds one end of a rod-shaped wax-based solid lubricant by a chuck at a 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. 2,
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.

With the above-mentioned supply device, solid lubrication was continuously performed during the rolling before the start of the rolling.

For comparison, conventional non-lubricating rolling and liquid lubricating rolling were performed under the same conditions as above except that solid lubrication was not performed.

For the liquid lubrication rolling, a liquid lubricant supply device used for general rolling other than the conventional hole rolling shown in FIG. 3 was used. The illustrated supply device 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 example, a commercially available mineral lubricating oil (viscosity:
50 cSt) was used at a concentration of 100%.

As a result of each of the above rollings, in the conventional lubrication-free rolling, the wear depth of the thrust collar portion was 2.1 mm at the time of 470 ton rolling.

In the liquid lubrication rolling, the abrasion depth of the thrust collar portion was 2.0 mm at the time of 510 ton rolling.

On the other hand, when the solid lubrication rolling of the present invention was performed, the wear depth of the thrust collar portion was 0.5 mm at the time of 490 ton rolling.

As described above, the solid lubricating rolling of the present invention can greatly reduce the wear of the thrust collar portion as compared with the conventional non-lubricating rolling. Even with liquid lubrication, although a slight wear reduction effect is recognized as compared with non-lubrication, a significant improvement effect cannot be obtained.

Example 2 A solid lubricant supply device using an air cylinder was installed almost directly above the upper roll of the thrust collar portion of a coarse mill in a rail rolling line, and the melting point of the solid lubricant, the pressing pressure, and The effect of the presence or absence of watering on the solid lubricant on the occurrence of roll seizure was 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).

[0039]

[Table 1]

[0040]

As described above, according to the solid lubrication of the present invention, the wear at the thrust collar portion of the grooved roll in the grooved rolling can be greatly reduced.

As a result, the life of the roll is substantially improved, so that the cost of the roll is reduced and the productivity of the rolling line is greatly improved by reducing the number of times of changing the roll.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional view of a surface including an upper and lower roll shaft, showing a thrust collar portion on which the side surfaces of upper and lower grooved rolls slide in the roll rolling.

FIG. 2 is a sectional view showing a structural example of a solid lubricant supply device used in the solid lubrication method according to the present invention.

FIG. 3 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 (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10N 50:08 (72) Inventor Shoichi Aratani 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Within the Development Division (72) Inventor Shuichi Hamazuzu 5-1 Nisone, Kokuraminami-ku, Kitakyushu-shi, Fukuoka Pref.

Claims (8)

[Claims] 1. A solid lubrication hole characterized in that a solid lubricant is supplied to a sliding surface between upper and lower perforated rolls, and rolling is performed while lubricating between the perforated rolls on the sliding surface. Shape rolling method. 2. The hole rolling method using solid lubrication according to claim 1, wherein the melting point of the solid lubricant is higher than a maximum temperature during rolling of a work roll supplying the solid lubricant. 3. The hole rolling method using solid lubrication according to claim 1, wherein the solid lubricant is supplied to a work roll while being sprinkled with water. 4. The hole formed by solid lubrication 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. Shape rolling method. 5. The solid lubricant according to claim 1, wherein the solid lubricant is a wax-based solid lubricant or a solid lubricant added to a wax-based solid lubricant.
4. A hole rolling method using solid lubrication as described in item 6. 6. The solid lubricant comprises one solid lubricant.
The hole rolling method using solid lubrication according to any one of claims 1 to 5, wherein the content is 0 to 90 wt%, and the balance is made of the wax-based solid lubricant. 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, tallow hardened oil, stearic acid, and one or more cold solid materials selected from the group consisting of full wax. 7. The method of hole rolling by solid lubrication according to claim 5. 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 hole rolling method by solid lubrication according to claim 5, wherein the method comprises one or more solid powdery substances selected from the group consisting of glass and glass.