JPS583444B2 - How to prevent guide shoe defects on seamless steel pipes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing guide shoe flaws from being formed on a round steel material or a blank pipe during the process of manufacturing seamless steel pipes using the Mannesmann method.

When manufacturing seamless steel pipes using the Mannesmann method,
For example, to obtain small diameter steel pipes, a round steel material is passed through a piercer to make a hole in its axial center, and the raw material pipe thus obtained is passed through a brag mill and a reeler, rolled, and polished to produce pipes. When obtaining a diameter steel pipe, a first piercer is used to drill a hole in the axial center of a round steel material to obtain a blank tube, and after passing this blank tube through a second piercer to enlarge the diameter, a plug mill is used as in the above case. It is rolled through a reeler and polished to make a tube.

Incidentally, the piercer (the first and second piercers are structurally the same) used in such a pipe manufacturing process, and the reeler, are a pair of barrel-shaped units that roll against the outer peripheral surface of the round steel material or material from both the left and right sides. A roll or a cylindrical roll, together with a plug that is penetrated into the axial center of the round steel material or raw pipe to perforate or expand the diameter, in the vertical direction perpendicular to the direction of pressure contact of the barrel roll or cylindrical roll against the round steel material or raw pipe, It is equipped with a guide shoe that prevents the round steel material or the raw pipe from escaping in the direction of vertical force, properly arranges the outer peripheral surface properties of the round steel material or the raw pipe, and regulates the outer diameter.

This is illustrated by taking the case of the second piercer as an example, as shown in FIG.

In the figure, HS is a blank pipe (hollow shell) obtained by drilling into the axial center of a round steel material using a first piercer, 51 and 52 are barrel-shaped rolls, 53 is a hollow bullet-shaped plug, and 54 and 55 are guide shoes. The inner circumference of the raw pipe HS is regulated by a plug 53 penetrated into the core hole, and the outer circumference is controlled by guide shoes 54 and 55 at the top and bottom, and by barrel-shaped rolls 5 at the left and right sides.
1. Both barrel-shaped rolls 51 are regulated by 52.
．． While rotating under the thrust force from 52, it is successively rolled in the direction of the axial force.

Each guide shoe 54.55
It is usually made of high chromium (Cr) heat-resistant cast steel because it is constantly in sliding contact with the raw pipe HS heated to a high temperature of about ℃, but it may suffer from defects such as minute cracks. Once a flaw occurs, it is magnified by the influence of heat, so a spiral-shaped flaw that is visible to the naked eye is formed on the outer circumferential surface of the raw pipe HS that comes in sliding contact with the flaw, which affects the appearance. may be significantly damaged.

As a means to prevent this, various attempts have been made to improve the material and shape of the guide shoe itself, but it has not yet been sufficiently effective, and once the flaws in the guide shoe have grown to a certain extent, it is difficult to replace the guide shoe with a new one. Currently, the guide shoe is replaced with a new one, or the guide shoe is removed from the support, the scratches are removed using a glider, etc., and the guide shoe is reused.The wear and tear on the guide shoe is extremely large, and during this period, pipe manufacturing work is temporarily suspended. The downside was that I had to stop.

The present invention has been made in view of the above circumstances, and an object of the present invention is to interpose powder particles such as sand on the sliding contact surface between the guide shoe and the round steel material or the raw pipe. The generated flaws are removed by grinding during pipe making work, and direct contact between guide shoe flaws and round steel materials and raw pipes is prevented, thereby preventing guide shoe flaws from forming on the outer peripheral surface of round steel materials and raw pipes. The present invention provides a method for preventing guide shoe flaws in seamless steel pipes.

The method for preventing guide shoe flaws in seamless steel pipes according to the present invention involves rolling a roll that presses a round steel material or a blank pipe obtained by drilling a hole in the axial center of a round steel material from both the left and right sides onto the outer peripheral surface of the material from the top and bottom sides. In the manufacturing process of seamless steel pipes, which are drilled, rolled, or refined using a guide shoe that abuts and restricts the guide shoe and a plug that penetrates into the shaft center, the above is opposed to a round steel material or a blank pipe at the id shoe. This method is characterized by supplying sand-like powder and granules between the parts.

The present invention will be specifically described below based on drawings showing its implementation state.

Fig. 1 is a plan view schematically showing the implementation state of the method for preventing guide shoe flaws in seamless steel pipes according to the present invention (hereinafter referred to as the method of the present invention), Fig. 2 is a front view, and Fig. 3 is a plain pipe. FIG. 4 is an enlarged sectional view of the rolling part taken along the line IV-IV in FIG. This raw tube HS is transferred from the outlet side of the first piercer to the entrance table T placed on the inlet side of the second piercer SP by appropriate means, and then transferred to the second piercer by a pusher (not shown). Piasa S
A pair of barrel-shaped rolls 11, 12 and a plug 13 at P
caught in between.

The barrel-shaped rolls 11 and 12 are located approximately symmetrically with respect to the axis of the raw pipe HS on both the left and right sides sandwiching the movement range of the raw pipe HS, respectively, and their rotation axes 11a and 12a are the same as the rotation axes 11a and 12.
In the vertical plane including the axial center line of a, they are arranged at an inclination of 6° to 12° with respect to the horizontal force direction so that the upper and lower directions are opposite to each other, and the rotating shafts are rotated at the same speed around the rotating shafts 11a and 12a, respectively. The plug 13 is rotated in the direction 1 and the plug 13 is driven by the rod 1.
3a and is opposed to the core hole of the blank pipe HS at a substantially central portion between both barrel-shaped rolls 11 and 12.

The inner circumference of the raw pipe HS is regulated by a plug 13,
In addition, the right and left sides are rolled by the barrel rolls 11 and 12, and the upper and lower sides are further regulated by the guide shoes 14.15. While being rotated, it is rolled in the axial direction from the top side to the bottom side in the direction of the white arrow.

The guide shoes 14 and 15 are disk bodies with a rectangular cross section as shown in FIGS. 3 and 4, and are formed to have the same or slightly longer length in the axial direction of the barrel rolls 11 and 12, and have a width that is equal to or slightly longer than the length in the axial direction of the barrel rolls 11 and 12. The shape rolls 11 and 12 are formed to be slightly longer than the separation dimension, and contact surfaces 14a and 15a each having an arcuate cross section are provided on the upper and lower surfaces facing the raw pipe Hs along the transport direction of the raw pipe HS. It is formed.

The guide shoe 14 located below is supported on the base 16 of the second piercer SP so as to be adjustable up and down by a set screw (not shown), and one end thereof is disposed on the entry side of the second piercer SP. The other end of the entrance table T is placed on the entrance table T, and the other end is placed on the exit table T of the second piercer SP.
′ respectively.

In addition, the guide shoe 15 located on the upper side is connected to the second piercer S.
It is supported by a hanger 17 fixed to the machine frame B of P using a connecting rod 18 so that it can be raised and lowered.

During rolling of the raw pipe HS, sand 20, which is particulate material, is continuously supplied onto the lower guide shoe 14 through the pipe 19.

The pipe 19 is arranged vertically through the gap between the machine frame B and the hanger 17, and the lower end opening faces the outer peripheral surface of the approximately central part in the axial direction of the barrel roll 12, and the upper end faces the machine The frame B has an opening at the top, and sand 20 is supplied into the pipe 19 from this upper end opening, falls onto the outer peripheral surface of the barrel-shaped roll 12 under its own weight, and as the barrel-shaped roll 11 rotates. The guide shoe 14 is successively dropped onto the contact surface 14a.

The sand 20 is interposed between the raw pipe HS and the contact surface 14a of the guide shoe 14 due to the rotation of the raw pipe HS, and prevents the raw pipe HS from directly sliding on the contact surface 14a, and also prevents the raw pipe HS from directly sliding on the contact surface 14a. 1
Defects such as cracks formed on 4a are removed by grinding as the raw tube HS rotates.

As shown in FIGS. 1 and 2, one end of a spring feeder 21 is connected to the upper end opening of the pipe 19, and the other end of the spring feeder 21 is connected to, for example, a sand supply device 23 disposed below the control room 22. There is.

The spring feeder 21 is a relatively flexible tube 2Ia.
One end of the spring 21b on the pipe 19 side is a free end, and the other end of the spring 2lb is connected to the tank of the sand supply device 23. It is connected to a motor 23b with a speed reducer (Beyer Cyclo speed reducer) through the lower part of the discharge port which opens below 23a.

The sand 20 is transferred to the motor 23b at the point where it exits the outlet of the tank 23a.
The tube 21a is rotated by the spring 2lb.
After reaching the upper end opening of the pipe 19, it falls freely inside the pipe 19.

The amount of sand supplied onto the guide shoe 14 is normally 10cc/s.
There is approximately ec, and this supply amount can be freely set as necessary by operating the reducer.

The drive of the sand supply device 23 may be stopped by a switch mechanism that detects the presence or absence of the raw pipe HS.

In the embodiment, sand 20 is used as the powder to be supplied onto the guide shoe 14, but the material is not limited to sand; for example, superalloy powder, abrasive powder, and other conventionally known materials may be used. Powder and granule materials having such effects may be selected as appropriate.

There are no particular limitations on the particle size or hardness of such sand-like powder, but if it is too large or hard, it may be difficult to use the raw pipe HS, guide shoe 14, or other barrel-shaped roll 11.
, 12, and if the hardness is too small, it will not be possible to grind the scratches on the guide shoe 14, so the particle size of the sand-like powder is 0.1 to 1 mm.
The hardness is Hs 3 0-Hs
A hardness of about 60 (Shore hardness) is desirable.

In addition, a spring feeder 2 is used as a means for supplying sand 20, etc.
Of course, the present invention is not limited to 1, and any conventionally known means such as a screw conveyor or a gas conveying means using an inert gas may be adopted as appropriate.

Further, in the embodiment, the case where the method of the present invention is applied to the second piercer SP has been described, but it goes without saying that it can be similarly applied to other first piercers, reelers, etc.

As described above, in the method of the present invention, during the manufacturing process of seamless steel pipes such as the drilling process for round steel materials, the rolling process for raw pipes, and the refining process, sand-like particles are deposited on the surface of the guide shoes that come into sliding contact with round steel materials or raw pipes. Even if there are flaws on the surface of the guide shoe, the round steel material or raw pipe will not come into direct contact with the guide shoe, or any flaws that occur on the surface of the guide shoe will be caused by sandy particles. As a result, it is not necessary to remove the guide shoes and perform glider treatment each time as in the conventional method, and the present invention has an excellent effect in improving the quality of the tube surface.

[Brief explanation of the drawing]

FIG. 1 is a plan view schematically showing the implementation state of the method of the present invention;
Fig. 2 is a longitudinal sectional view, Fig. 3 is an enlarged sectional view showing the rolled state of the raw pipe, Fig. 4 is a sectional view taken along the TV-IV line in Fig. 3, and Fig. 5 is a general sectional view of the second pipe. FIG. 3 is an enlarged cross-sectional view schematically showing the rolled state of the raw pipe in the piercer. 11, 12... Barrel-shaped roll, 13... Plug, 14
, 15... Guide shoe, 19... Pipe, 20...
...Sand, 21...Spring feeder, 23...Sand supply device.

Claims (1)

[Claims] 1 A round steel material or a blank pipe obtained by drilling a hole in the axial center of a round steel material, and rolls that roll to press against the outer peripheral surface of the material from both the left and right sides, guide shoes that contact from both the top and bottom sides, and a plug that penetrates the narrow part. In the manufacturing process of seamless steel pipes, which are performed by drilling, rolling, or refining using the guide shoe, supplying and intervening hard sand-like powder that does not burn or melt into the gap between the guide shoe and the round steel material or the raw pipe. A guide shoe flaw prevention method featuring: