JPS58167005A - Plug mill rolling method - Google Patents

Abstract

PURPOSE:To enable the drawing of a blank pipe which is free from pit flaw or the like by injecting highly pressurized air in front of the circumferential surface of the plug of a plug mill where the plug contacts with the inside surface of the blank pipe so as to remove scale and injecting a lubricant right after the injection of the air. CONSTITUTION:A work plug 2 provided in the forward end part of a mandrel 4 used for a plug mill is formed to a circular columnar shape in the reat half part and a circular truncated cone shape in the front half part. A guide plug 3 having a diameter slightly smaller than the diameter of the plug 2 is used to guide the insertion of the plug 2 into a blank pipe P and the reat half part thereof is formed into a short circular columnar shape and the front half part into a circular truncated cone shape of two stages. Said plug is mounted to a mandrel 4 in front of the plug 2. The mandrel 4 consists of tripleply pipes including a supply pipe 5 for highly pressurized air and a supply pipe 6 for a lubricant. The highly pressurized air is injected from the ejection port 5b in front of the flange edge 5a provided at the intermediate of the plug 2 and the plug 3 to remove scale, and right after the injection of the air, the lubricant is injected from the ejection port 6a on the rear of the edge 5a and the pipe P is rolled with caliber rolls 1u, 1d and the plug 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a plug mill rolling process in which scale is removed from the inner surface of the tube in parallel with rolling.

For example, to manufacture a seamless pipe using the Mannesmann plug mill method, first heat it using a pier, make 9 holes in the center of a round piece of steel, and then use an elongator to thin the wall and expand the diameter of the raw pipe. Pass it through a plug mill, leak, KFt side, etc. to finish it into a seamless pipe with the desired dimensions.
It has become.

By the way, tube rolling in a plug mill has conventionally been carried out as shown in FIG. 2.3. FIG. 2 is a schematic plan view showing the state of pipe rolling performed by a plug mill, and FIG. 3 is a side view.
a shows putugmil. After the raw pipe P is elongated and rolled by an elongator or the like, it is placed on a frame 20 in the direction of the white arrow.
When the upper part of the nozzle 2 is moved horizontally and reaches a position facing the high-pressure air nozzle 20a arranged on the side of the pedestal 20, the nozzle 2
(High-pressure air is injected from la into one part of the raw pipe P, and scale adhering to the inner surface of the raw pipe P is removed.

When school removal is completed, it is moved to a position facing the plug mill 21. Plug Mill 21 FiIII 3 Upper and lower caliber rolls 2 having semicircular arc-shaped holes as shown in the figure.
2u, 21d and top with mandrel 23.

It includes a work plug 24 and a guide plug 25 supported in the hole spaces of the lower caliber rolls 22m and 22d. The work plug 24 is for rolling the inner surface of the tube, and the latter half S has a short cylindrical shape, and the first half has a truncated conical shape.
It is fixed concentrically to the tip of a cylindrical mandrel 23. On the other hand, the non-work plug 24 is inserted into the plug 25#i raw pipe PK for use in the dormitory, and the maximum diameter is slightly smaller than that of the work plug 24, and it is formed into a nearly warhead shape. A support tube 26 is provided in the front and concentrically with the support tube 26. The support *26#f is formed in the shape of a short circle, and a large number of jetting ports 26 for spouting lubricant are provided on the circumference I2 at the center in the axial direction.
m, whose rear end is fixed to the front surface of the warp plug 24, and whose front end is fixed to the rear surface of the guide plug 2S.

A lubricant supply pipe 27 is disposed through the mandrel 23, and its tip passes through the center of the work plug 24 and is connected to the rear end of the support cylinder 26. It protrudes from the rear end side of the mandrel 23 and is connected to a lubricant tank 29 and high-pressure air pipes 30 and 31 via a high-pressure rubber hose 28. It is designed to be injected onto the inner surface of the raw pipe P from the 26th point onwards. When the raw pipe P is placed horizontally on the stand and stops with its one end opening facing the guide plug 25, the raw pipe P is moved by the upper and lower caliber rolls 22u by a button cylinder (not shown).
With the guide plug 25 pushed out to the 22d side and inserted into the raw pipe P, the guide plug 25 is caught between the double lever rolls 22u and 22d, and the lubricant is injected into the raw pipe P from the spout 26m while the double lever is inserted. The rolls 22u and 22d and the work plugs 24 and K stretch and roll the material from the inner and outer peripheral surfaces. However, in the conventional apparatus as described above, from the removal of scale on the inner surface of the raw pipe P to the elongation rolling by the plug mill 21,
Since a time of several seconds or more passes at the shortest, secondary scale is generated on the inner surface of the raw tube P during that time, and rolling with the Pukugumi mill 21 is performed with this secondary scale generated. Even when rolling is carried out while charging, the lubricating effect is significantly reduced, and there is a problem that scale is caught between the work plug 24 and the inner surface of the raw pipe P, and pit flaws are likely to occur.

The present invention meets such circumstances! The purpose of this method is to inject high-pressure gas to remove scale into the pipe in front of the inner surface of the pipe in contact with the plug surface during tube rolling using a plug mill, and immediately after that, apply lubricant. Plug mill rolling that blows off scale during rolling and immediately adds lubricant to roll before secondary scale occurs, eliminating scale encroachment and greatly improving internal surface properties. There is K who provides law.

The present invention will be specifically described below based on embodiments shown in the drawings. FIG. 1 is a schematic diagram showing the implementation state of the plug mill rolling method according to the present invention (hereinafter referred to as the method of the present invention), and in the figure P
Reference numerals denote the raw pipe J u and 1 d ti caliber roll, 2 a work plug for rolling the inner surface of the raw pipe, and 3 a guide plug for inserting the work plug 2 into the raw pipe P. The caliber rolls la and ld are disposed facing each other at the top and bottom with their axes being horizontal. Further, the work plug 2 is for rolling the inner surface of the raw pipe P, and the rear half is formed into a short cylindrical shape and the front half is formed into a truncated cone shape. The latter part is formed into a short cylindrical shape, and the first half is formed into a truncated conical shape with a diameter reduced in two stages. The work plug 2 is placed concentrically on both caliber rolls.
, facing the center of the ld hole mold and supported in good condition. The mutual arrangement of the two caliber rolls lu, ld, work plug 2, and guide plug 3 is the same as in the conventional smFi. In the apparatus for carrying out the method of the present invention, a high-pressure air supply pipe 5 and a lubricant supply pipe 6 are arranged concentrically within the mandrel 4 so as to form a triple pipe as a whole with a required interval between them. It is arranged in a shape. The base end of the mandrel 4 is pivoted to be movable up and down on a horizontal axis (not shown), and the tip of the high-pressure air supply pipe 51 and the lubricant supply pipe 6 are connected to the work plug 2.
The front part of the Klvr is protruded through it. The high-pressure air supply pipe S and the smooth and rigid supply pipe 6 are also protruded slightly forward, and the guide plug 3 is concentrically fixed at the tip of the supply pipe 50.

Near the tip of the high-pressure air supply pipe 5, a rim S-maro whose diameter is slightly smaller than that of the guide plug 3 is provided. A plurality of jet ports 5b are opened at equal intervals in the circumferential direction on the peripheral wall of the supply pipe 50.

On the other hand, the tip of the lubricant supply pipe 6 protruding forward of the work plug 2 is fixed to the rear surface of the flange 5m, and the supply pipe 6 is located between the flange 5a and the work plug 2.
A plurality of lubricant jet ports 6a are opened at equal intervals in the circumferential direction on the zero circumferential wall.

As a result, the high-pressure air injected from the jet nozzle 5b and the lubricant jetted from the jet nozzle 6a are separated by the flange 51 and are respectively jetted onto the peripheral wall of the raw pipe P, but with respect to the rolling direction with respect to the raw pipe P. First, high-pressure air is injected and then lubricant is injected.

Mandrel 40 base end circumference! IK is connected to a cooling water supply hose 4a and a discharge hose 4b, and is connected to an i9 supply pipe 5.
．． Both of the proximal ends of the mandrel 60 are closed, and a hose 5 for supplying high-pressure air is inserted through the mandrel wall near the peripheral wall.
c. A hose 6b for supplying lubricant is connected to each.

Hose 4aFi is connected to a pump (not shown), etc.
Cooling water is made to flow through the mandrel 4 at a required pressure. In addition, the hose 5C is connected to a compressor or the like (not shown), and injects the required high-pressure air (approximately 10 fi pressure) into the raw pipe P through the supply pipe 5 from the spout 5b to peel off the scale on the inner surface of the raw pipe P. It is designed to be discharged toward the rear end side (in front of the guide plug 3).

Furthermore, the hose 6b is connected to a compressor and a lubricant tank, and is configured to inject the lubricant together with high-pressure air into the raw pipe P from the jet port 8m.

Therefore, the raw pipe P is removed from the outside by the upper and lower caliber rolls lu and ld, and from the inner surface side by the work plug 2.
Prior to rolling by the work plug 2 in the stretching process 1i1, high-pressure air is first injected onto the inner surface of the raw tube P from the injection port 5b to peel off the scale formed on the inner surface of the raw tube P and form the raw material. The lubricant is blown to the rear end of the tube, and then the lubricant is injected through the spout 6a before a secondary star is formed in the part where the scale has peeled off, and the lubricant is
The pipe is rolled into a scale-free state S by the work plug 2, so that the lubricating function of the lubricant is effectively exhibited and the inner surface properties of the pipe are improved.

In the illustrated embodiment, the high-pressure air outlet sb is provided between the guide plug 3 and the flange 51, but the invention is not limited to this. 1, or the tip of the supply pipe 5 may be made to protrude in front of the guide plug 3 and provided on the front end or peripheral wall thereof.

As described above, in the method of the present invention, the inner surface of the raw tube is rolled in a scale-free state, and the lubricating effect of the lubricant is effective, the inner surface properties of the tube are significantly improved, and the quality of the tube is also greatly improved. The present invention exhibits excellent effects such as improved performance.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the implementation state of the method of the present invention, FIG. 4S2 is a schematic plan view showing the implementation state of the conventional method, and FIG. 3 is a schematic side view showing the implementation state of the conventional method. lu, ld...Caliber roll 2...Work plug 3...Guide plug 4...Mandrel 5...
・Supply pipe 5b... spout 6... supply pipe 6a...
・Gate outlet frame Applicant: Sumitomo *Gei Kogyo Co., Ltd. Agent Patent attorney: Noboru Kawano

Claims (1)

[Claims] 1. In the process of rolling a pipe with a plug mill, a high-pressure gas is injected to remove sedges and slugs to a part of the pipe in front of the plug surface that contacts the inner surface of the pipe, and immediately after that, a lubricant is injected. Plug mill rolling method.