JPH08117818A - Inclined rolling method for seamless pipe - Google Patents

Abstract

PURPOSE: To improve the life of a plug by applying lubricant on the whole surface of a plug before a rolling stock is rolled. CONSTITUTION: In an inclined rolling mill 10, piercing is performed with upper and lower rolling rolls 11 arranged with a gradient to a pass line and a plug 12 arranged on the pass line. And, a spray header 16 is provided on a bar- steadier chock 15 on the front side of a nearest bar-steadier roll 14 on the outlet side of the inclined rolling mill 10. Lubricant is applied on the whole surface of the plug 12 from the spray header 16. Before the supply of the lubricant by the spray header 16, an air blow for drying water drops on the surface of the plug 12 is performed on the whole surface of the plug 12 with an air blow nozzle 17. Consequently, damage on the surface of the plug at the time of rolling can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inclined rolling of a seamless pipe such as a seamless steel pipe, and more particularly to a method for inclined rolling of a seamless pipe in which a lubricant is supplied to the surface of a plug for rolling.

[0002]

2. Description of the Related Art The Mannesmann tube making method has been widely practiced as a hot method for producing a seamless steel tube. In this method, a round steel piece heated to a predetermined temperature (hereinafter referred to as a billet) is first pierced and rolled by a piercing and rolling machine to manufacture a hollow shell (hereinafter referred to as a hollow), and the hollow is an elongator, A method of obtaining a seamless steel pipe of a predetermined size by reducing the wall thickness with a drawing mill such as a plug mill or mandrel mill, and then reheating it if necessary, and then mainly reducing the outer diameter with a drawing mill or constant diameter mill. Is.

There are various types of piercing and rolling mills. Two
A so-called Mannesmann piercer, which is a combination of two inclined rolls and a plug and two guide shoes, a so-called three-roll piercer, which is a combination of three inclined rolls and a plug, or a so-called, which is a combination of two hole-type rolls and a plug. Press roll piercers are common.

In the piercing and rolling process, the plug is constantly exposed to high temperature and high load due to constant contact with the heated billet and hollow.
Easy to wear and melt. Therefore, generally 900-10 for plugs
Scaling is performed at a high temperature of 00 ° C, and the surface of the plug is tens
A scale film of several 100 μm is formed to prevent damage. However, when such a plug is used for high alloy steel rolling, which has been particularly increased in demand in recent years, it can be used only several times.

As a method of extending the life of such a plug for piercing and rolling a seamless steel pipe, it is conceivable to apply a lubricant such as grease, water glass or graphite to the surface of the plug. Then, as such a lubricant supply method to the plug, as described in JP-A-5138213, on the outlet side of the plug cooling water tank, a graphite-based lubricant is applied to the plug after water cooling, and thereafter, Until the plug is set to the working position in the rolling mill, the cooling water system of the rolling equipment such as burst steadier roll, plug bar transfer roll, plug bar transfer table, etc. shall not be used, and the lubricant applied to the plug It has been proposed to prevent it from being washed off the surface of the.

[0006]

However, the prior art has the following problems. In order to prevent the lubricant applied to the surface of the plug from being washed away by the cooling water of the rolling equipment, the cooling water system is temporarily stopped, so the rolling equipment becomes hot and the life of those rolling equipment is shortened. .

During the moving process until the plug coated with the lubricant on the outlet side of the water tank is set to the working position of the rolling mill,
The lubricant that falls off from the plug adheres to and solidifies on the rolling equipment as described above, which is in the process of moving, and impairs the movement of the rolling equipment.

An object of the present invention is to make it possible to improve the life of the plug without impairing the operability of the seamless pipe rolling equipment.

[0009]

According to the present invention as set forth in claim 1, an inclination comprising a rolling roll arranged obliquely with respect to a pass line of a rolled material and a plug arranged on the pass line. In a seamless pipe inclined rolling method using a rolling mill, a spray header capable of applying a lubricant to the entire surface of the plug is installed on the inlet side or the outlet side of the inclined rolling machine, and the rolled material is the inclined rolling. The lubricant is applied to the entire surface of the plug by the spray header before being rolled by a machine.

According to a second aspect of the present invention, in addition to the first aspect of the present invention, the spray header is provided on a circumference perpendicular to the longitudinal direction of the plug bar, and on the circumference thereof. It is installed in the burst tier chocks on the delivery side of the rolling mill so that the intervals are even.

According to a third aspect of the present invention, in addition to the first aspect of the present invention, the spray header is provided on the circumference perpendicular to the longitudinal direction of the plug bar, and on the circumference thereof. It is installed in the rolled material insertion guide on the rolling mill entrance side so that the intervals are even.

The present invention according to claim 4 is based on claims 1 to 3.
Further, in the present invention described in any one of the above, before the supply of the lubricant by the spray header, an air blow for drying water droplets on the surface of the plug is applied to the entire surface of the plug.

[0013]

According to the present invention described in claim 1, the following effects are obtained. Immediately before performing the inclined rolling, the lubricant is supplied to the plug surface at the inlet side or the outlet side in the immediate vicinity of the inclined rolling machine, so that the lubricant is applied immediately after the plug is cooled by water and the plug is conveyed to the rolls or conveyed. Lubricants are not washed off by the cooling water for the rolling equipment such as the carrier rolls and the conveying table as compared with the case where they are moved to the inclined rolling mill with the rolling equipment such as the table, and remain attached to the entire surface of the plug. Since it is set in the working position of the rolling mill and rolled, damage to the plug surface during rolling is reduced and the life of the plug can be extended.

Since the rolling equipment between the plug cooling water tank and the rolling mill conveys the plugs not yet coated with the lubricant, it is necessary to suspend the cooling water system to prevent the lubricant from being washed out. , The rolling equipment is surely water-cooled and the life is maintained. Further, the lubricant does not drop and adhere to the rolling equipment from the plugs, and the operability of the rolling equipment is not impaired.

The present invention according to claims 2 and 3 has the following effects. The lubricant from the spray header must be applied to the entire plug surface, that is, to the entire plug surface in contact with the billet or hollow by piercing or drawing. Therefore, in order to supply the lubricant over the entire surface of the plug, the center of the circular cross section of the plug bar and the center of a circle larger than the circumference of the plug in the cross section coincide with each other in the cross section perpendicular to the longitudinal direction of the plug bar. In such a circle, it is preferable that the spray headers arranged at equal intervals (or angles) on the circumference of the circle inject the lubricant toward the center of the circle.

According to the present invention described in claim 4, the following effects are obtained. In order to improve the adhesion of the lubricant to the plug surface, it is good practice to completely remove the water droplets on the plug surface by air blow when the water-cooled plug is moved to the vicinity of the inclined rolling mill by the transfer rollers etc. You can improve more.

[0017]

1 is a schematic view showing a first embodiment of the present invention, FIG. 2 is a view taken along the line II--II of FIG. 1, and FIG. 3 is a second view of the present invention.
FIG. 4 is a schematic view showing an embodiment, FIG. 4 is a view taken along the line IV-IV of FIG. 3, and FIG. 5 is a schematic view showing a lubricant application process of the second embodiment.

(First Embodiment) (FIGS. 1 and 2) As shown in FIG. 1, an inclined rolling mill 10 includes upper and lower rolling rolls 11 and 11 which are inclined with respect to a pass line, and arranged on the pass line. And a plug 12 that is formed, and the billet is piercing-rolled (or hollow is stretch-rolled). Reference numeral 13 is a plug bar, and 14 is a burstereda roll.

The plug 12 is circulated and used in the rolling mill 10. Plug 12 used for rolling one rolled material
Is introduced into a water tank together with the plug bar 13 and cooled, and thereafter, is carried by a plug bar carrying roll and a plug bar carrying table, and is carried into the rolling mill 10 again.
The plug 12 carried into the rolling mill 10 is used for rolling the next rolled material while the plug bar 13 is held by the burst teddy roll 14. The bursteredia roll 14 is opened until the plug 12 passes, and closed when the plug 12 is loaded into the rolling mill 10.

The inclined rolling mill 10 has a plurality of (3 in FIG. 1) bursteedia rolls 14 arranged at each of a plurality of positions (4 positions in FIG. 1) in the longitudinal direction of the plug bar 13. The plurality of bursteedia rolls 14 arranged around the plug bar 13 at the same position in the longitudinal direction of the plug bar 13 are on the circumference perpendicular to the longitudinal direction of the plug bar 13 and the circumference thereof. They are evenly spaced above.

On the exit side of the inclined rolling mill 10, however, the burst teddy chocks 15 on the front side (the side close to the rolling roll 11) of the burst teddy roll 14 closest to the rolling mill 10 are provided.
Is provided with a spray header 16. As shown in FIG. 2, the spray header 16 is installed in each of the chocks 15 of the above-described three bursteredia rolls 14 on the circumference around the plug bar 13, and as a result, the spray header 16 is placed in the longitudinal direction of the plug bar 13. On the other hand, it is set so that it is on a circumference that is perpendicular to the circumference and that the circumferences are evenly spaced. The spray header 16 can apply a lubricant to the entire surface of the plug 12. Therefore, in the rolling mill 10, the lubricant is applied to the entire surface of the plug 12 by the spray header 16 before the rolled material is rolled by the rolling mill 10.

Further, in the inclined rolling mill 10, an air blow nozzle 17 is installed in the burst teddy chocks 15 on the rear side (the side far from the rolling roll 11) of the above-mentioned burst eddy roll 14 which is closest to the rolling mill 10. The air blow nozzle 17 blows air for drying water drops on the surface of the plug 12 onto the entire surface of the plug 12 before supplying the lubricant by the spray header 16.

The operation of this embodiment will be described below. Immediately before the inclined rolling, the lubricant is supplied to the surface of the plug 12 immediately before the inclination rolling machine 10 so that the lubricant is applied to the surface of the plug 12 immediately after cooling with water and the plug 12 is removed. Compared with the case of moving to the inclined rolling mill 10 in a rolling facility such as a transport roll and a transport table, the lubricant is not washed away by the cooling water for the rolling facility such as the transport roll and the transport table, and the plug 12 Since it is set in the working position of the rolling mill 10 and is rolled while being attached to the entire surface, damage to the surface of the plug 12 during rolling is reduced and the life of the plug can be improved.

Since the rolling equipment between the plug cooling water tank and the rolling mill conveys the plug 12 which is not yet coated with the lubricant, the cooling water system is temporarily stopped in order to prevent the lubricant from being washed out. There is no need, and those rolling facilities are reliably water-cooled and have a long service life. Further, the lubricant does not drop and adhere to the rolling equipment from the plug 12 and the operability of the rolling equipment is not impaired.

The spray header 16 was installed on the burst steadie chocks 15 on the exit side of the rolling mill 10. Therefore,
The lubricant can be supplied to the entire surface of the plug 12.

By the air blow nozzle 17, before the supply of the lubricant by the spray header 16, an air blow for drying water drops on the surface of the plug 12 is applied to the entire surface of the plug 12. Therefore, after the water droplets on the surface of the plug 12 are completely removed, the lubricant is applied by the spray header 16, and the adhesion of the lubricant to the surface of the plug 12 can be improved.

The concrete results of the implementation of the inclined rolling mill 10 of the first embodiment will be described below. (1) A 175 mm diameter 13% Cr steel billet heated to 1250 ° C. is pierced and rolled into a hollow having a diameter of 185 mm, a wall thickness of 18 mm and a length of 7.5 m.

(2) The plug has a diameter of 145 mm, 3% Cr-1%
It is made of Ni-based material for hot tools, and has a scale of several hundred μm generated on its surface by heat treatment.

(3) The following three kinds of lubricants A, B and C were used. A: Mineral oil 50% + Synthetic ester 50% B: Water glass (SiO ₂ 70%, Na ₂ O 30%) 40% +
Water C: 35% graphite + 26% resin + water

[0030] A, B, both C, the lubricant injection rate was to one of the plug 100 cc, injection pressure (air atomizing) lubricant 3 kgf / cm ^2, an air 2 kgf / cm ^2.

(4) In the inclined rolling mill 10, eight plugs and plug bars were circulated (rolling-cooling by a water cooling tank). 500 billets were rolled and the results shown in Table 1 and Table 2 were obtained.

In Tables 1 and 2, the method of the present invention,
Uses only the spray header 16 and the air blow nozzle 1
No. 7 is used, the method of the present invention is spray header 1
6 and the air blow nozzle 17 are both used.

[Table 1]

[Table 2]

It is recognized that the method of the present invention significantly improves the life of the plug and the life of rolling equipment as compared with the conventional method, and that the method of the present invention can further improve these.

(Second Embodiment) (FIGS. 3 to 5) As shown in FIG. 3, an inclined rolling mill 10 includes upper and lower rolling rolls 11 and 11 which are inclined with respect to a pass line, and arranged on the pass line. The billet 1 is piercing-rolled (or hollow is stretch-rolled). Reference numeral 13 is a plug bar, and 14 is a burstereda roll.

The plug 12 is circulated and used in the rolling mill 10. Plug 12 used for rolling one rolled material
Is introduced into a water tank together with the plug bar 13 and cooled, and thereafter, is carried by a plug bar carrying roll and a plug bar carrying table, and is carried into the rolling mill 10 again.
The plug 12 carried into the rolling mill 10 is used for rolling the next rolled material while the plug bar 13 is held by the burst teddy roll 14.

The inclined rolling mill 10 includes a rolled material insertion guide 2 for guiding the billet 1 into the rolling roll 11.
It has 0 (common name: Canon Guide).

On the entrance side of the inclined rolling mill 10, however, the front end face of the rolled material insertion guide 20 (the side close to the rolling roll 11).
A spray header 21 is provided around it. 22 is a ring-shaped pipe. As shown in FIG. 4, the spray header 21 is installed at each of four positions on the circumference (it is enough that the positions are three or more), and as a result, the plug bar 13 is provided.
Are set on a circumference perpendicular to the longitudinal direction of and at equal intervals on the circumference. The spray header 21 is adapted to apply a lubricant to the entire surface of the plug 12. Therefore, in the inclined rolling mill 10, the lubricant is applied to the entire surface of the plug 12 by the spray header 21 before the rolled material is rolled (FIG. 5). That is, at the same time when the plug 12 enters the rolling mill 10 for setting, as shown in FIG. 5 (A), the injection of the lubricant is started toward the tip end surface of the plug 12, and further injection is performed as it is. By continuing, plug 12
When the setting is completed (FIG. 5 (B)), the entire surface of the plug 12 can be coated with the lubricant.

The operation of this embodiment will be described below. Immediately before the inclined rolling, the lubricant is supplied to the surface of the plug 12 immediately before the inclination rolling mill 10 at the inlet side, so that the lubricant is applied immediately after the plug 12 is cooled by water and the plug 12 is removed. Compared with the case of moving to the inclined rolling mill 10 in a rolling facility such as a transport roll and a transport table, the lubricant is not washed away by the cooling water for the rolling facility such as the transport roll and the transport table, and the plug 12 Since it is set in the working position of the rolling mill 10 and is rolled while being attached to the entire surface, damage to the surface of the plug 12 during rolling is reduced and the life of the plug can be improved.

Since the rolling equipment between the plug cooling water tank and the rolling mill conveys the plug 12 which is not yet coated with the lubricant, the cooling water system is temporarily stopped in order to prevent the lubricant from being washed out. There is no need, and those rolling facilities are reliably water-cooled and have a long service life. Further, the lubricant does not drop and adhere to the rolling equipment from the plug 12 and the operability of the rolling equipment is not impaired.

The spray header 21 was installed on the rolled material insertion guide 20 on the entry side of the rolling mill 10. Therefore, the lubricant can be supplied to the entire surface of the plug 12.

The concrete results of the implementation of the inclined rolling mill 10 of the second embodiment will be described below. (1) A 175 mm diameter 13% Cr steel billet heated to 1250 ° C. is pierced and rolled into a hollow having a diameter of 185 mm, a wall thickness of 18 mm and a length of 7.5 m.

(2) The plug has a diameter of 145 mm, 3% Cr-1%
It is made of Ni-based material for hot tools, and has a scale of several hundred μm generated on its surface by heat treatment.

(3) The following three kinds of lubricants A, B and C were used. A: mineral oil 50% + synthetic ester 50% B: water glass (SiO ₂ 70%, Na ₂ O 30%) 40% +
Water C: 35% graphite + 26% resin + water

[0044] A, B, both C, the lubricant injection rate was to one of the plug 100 cc, injection pressure (air atomizing) lubricant 3 kgf / cm ^2, an air 2 kgf / cm ^2.

(4) In the inclined rolling mill 10, eight plugs and plug bars were circulated (rolling-cooling by a water cooling tank). 500 billets were rolled and the results shown in Tables 3 and 4 were obtained.

[Table 3]

[Table 4]

It is recognized that the method of the present invention can remarkably improve the plug life and the rolling equipment life.

The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific structure of the present invention is not limited to this embodiment, and changes in design within the scope not departing from the gist of the present invention can be made. Even if it exists, it is included in the present invention. In the present invention, the lubricant may be applied to the entire surface of the plug by at least three spray headers on the inlet side or the outlet side of the inclined rolling mill. At this time, the spray header does not necessarily have to be installed in the same plane perpendicular to the longitudinal direction of the plug bar, and the lubricant is appropriately supplied to the entire plug surface depending on the material of the rolled material and the surface condition of the plug. It suffices if they are arranged in such positions. Further, the spray header does not necessarily need to be arranged at equal intervals around the circumference of the plug, and a certain amount / area of lubricant may be applied to the entire surface of the plug.

[0048]

As described above, according to the present invention, the plug life can be improved without impairing the operability of the seamless pipe rolling equipment.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a schematic diagram showing a second embodiment of the present invention.

FIG. 4 is a view taken along the line IV-IV of FIG.

FIG. 5 is a schematic view showing a lubricant application process of the second embodiment.

[Explanation of symbols]

 1 Billet (Rolled Material) 10 Inclination Rolling Machine 11 Rolling Roll 12 Plug 13 Plug Bar 14 Burstedia Roll 15 Burstedia Chock 16 Spray Header 17 Air Blow Nozzle 20 Rolled Material Insertion Guide 21 Spray Header

Claims (4)

[Claims] 1. A seamless pipe tilt rolling method using a tilt rolling machine comprising a rolling roll arranged obliquely with respect to a pass line of a rolled material and a plug arranged on the pass line, A spray header capable of applying a lubricant to the entire surface of the plug is installed on the inlet side or the outlet side of the inclined rolling mill, and the plug is attached to the plug by the spray header before rolling material is rolled by the inclined rolling mill. A seamless pipe tilt rolling method, characterized in that a lubricant is applied to the entire surface of the. 2. The spray header is installed on the burster chocks on the delivery side of the rolling mill on a circumference perpendicular to the longitudinal direction of the plug bar and at equal intervals on the circumference. The method of claim 1, wherein the inclined pipe mill is a seamless pipe. 3. The spray header is installed on a rolling material insertion guide on the rolling mill entrance side on a circumference perpendicular to the longitudinal direction of the plug bar and at equal intervals on the circumference. The seamless pipe inclination rolling method according to claim 1. 4. The seamless pipe tilt rolling method according to claim 1, wherein before the lubricant is supplied by the spray header, an air blow for drying water droplets on the plug surface is performed on the entire surface of the plug.