JPH079026A - Extrusion method of perforated billet using mandrel guide - Google Patents

Abstract

PURPOSE:To remarkably reduce the occurrence of the uneven thickness of a pipe extruded from an extruding machine. CONSTITUTION:A mandrel guide 6 with a prescribed diameter hole, is held between a pierced billet 1 and an extruding die 2 to be used for an extruding work. And, a mandrel 5 is inserted into the hole of the mandrel guide 6 and the hole of the pierced billet 1, the mandrel 5 is fixed by the mandrel guide 6, the mandrel guide 6 and the pierced billet 1 are extruded, and a pipe with a prescribed shape, is manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for extruding a perforated billet, and more particularly to a mandrel guide for fixing a mandrel inserted into the perforated billet during extrusion to obtain a pipe having a predetermined inner and outer diameter. It relates to a method for extruding the perforated billet used.

[0002]

2. Description of the Related Art An extruder shown in FIG. 2 is generally used for producing a pipe having a predetermined inner and outer diameter by subjecting a perforated billet to an extrusion process.

The extruder shown in FIG. 2 includes an extrusion die 2 for forming a perforated billet 1 into a tube having a predetermined shape,
The container 3 for accommodating and fixing the perforated billet 1 to be extruded, the extrusion die 2 and the cylinder 4 for exerting pressure on the perforated billet 1 housed in the container 3 and the perforated billet 1 are It is composed of a mandrel 5 for inserting a perforated billet 1 into a perforated billet hole 1a through a die hole 2a which is extruded and obtaining a perforated pipe from the perforated billet 1.

A method for producing a pipe having a predetermined shape from the above-mentioned extruder will be described below. First, the perforated billet 1 is heated so that it can be extruded, and then the container 2
Set the perforated billet 1 inside. Next, a mandrel 5 for obtaining a tube with holes is inserted from the die hole 2a into the perforated billet hole 1a. Then, the cylinder 5 applies pressure from the rear end of the perforated billet 1 to extrude the perforated billet 1 from the extrusion die 2 to manufacture a pipe having a predetermined shape.

[0005]

However, in the above-described conventional method for extruding a perforated billet, the mandrel inserted into the perforated billet hole is only fixed at one end inserted into the perforated billet hole. , The other end is not fixed at all. Therefore, when pushing out with pressure by the cylinder, the mandrel will be bent if there is a difference in the wall thickness of the material in the circumferential direction of the perforated billet, and the thickness of the extruded tube will differ in the circumferential direction. There was a problem of so-called uneven thickness. This uneven thickness is particularly remarkable in the billet having no holes, and the mandrel was greatly bent at the stage of piercing for inserting the mandrel into the billet, and the uneven thickness at the extruding tip was large.

Therefore, it is an object of the present invention to provide a method for extruding a perforated billet using a mandrel guide, which can greatly reduce the occurrence of uneven wall thickness of a pipe extruded from an extruder.

[0007]

In order to solve the above-mentioned problems, the present invention comprises a mandrel guide having a hole having a predetermined diameter, which is sandwiched between a perforated billet and an extrusion die used for extrusion. Insert the mandrel into the hole of the mandrel guide and the hole of the perforated billet from the die hole of the die, fix the mandrel with the mandrel guide, and following extrusion from the extrusion die of the mandrel guide,
A method for extruding a perforated billet using a mandrel guide, which comprises extruding the perforated billet from an extrusion die.

The mandrel guide is made of the same material as the perforated billet, and has a pipe portion having a hole with an inner diameter similar to the outer diameter of the mandrel so that the mandrel can be inserted and the mandrel can be fixed. And a conical portion provided at one end of the pipe. Then, in the mandrel guide, the pipe portion is inserted into the extrusion die hole.

[0009]

[Function] Since the mandrel guide is inserted between the extrusion die and the perforated billet and the mandrel inserted into the perforated billet is fixed in the die hole of the extrusion die, the mandrel can be bent during extrusion. The extruded pipe has a uniform wall thickness.

Incidentally, the mandrel guide is pushed out of the extruder together with the billet with holes being pushed out while fixing the mandrel. And even after the mandrel guide is extruded, the mandrel is fixed in the die hole by the tubular shaped perforated billet, so the mandrel does not bend and the thickness of the extruded pipe is Are kept even.

[0011]

Embodiment 1 An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1A shows an extruder for carrying out the method for extruding a perforated billet according to this embodiment, and FIG. 1B shows a mandrel guide 6. Since the extruder used is the same as the extruder shown in FIG. 2 described in the section of the prior art, description of the configuration of the extruder is omitted.

In order to obtain a predetermined pipe with the above extruder, the perforated billet 1 is extruded as follows.

First, the mandrel guide 6 is attached to the extrusion die 2.
Set. This mandrel guide is made of the same material as the perforated billet 1, and is composed of a pipe 6a having a hole having an inner diameter similar to the outer diameter of the mandrel 5 and a conical portion 6b provided at one end of the pipe. Is. The mandrel guide 6 is set by inserting the pipe portion 6a from the inside of the extrusion die 2 into the die hole 2a of the extrusion die 2.

Next, the perforated billet 1 is heated to such an extent that it can be extruded, and then set in the container 3.

Then, the mandrel 5 is inserted into the perforated billet hole 1a through the die hole 2a. At this time, since the mandrel guide 6 is set in the die hole 2a, the mandrel 5 is also inserted in the hole of the mandrel guide 6. Therefore, one end of the mandrel 5 is positioned via the mandrel guide 6 so that the central axes thereof coincide with each other in the die hole 2a, and the preparation for extrusion is completed.

Then, a perforated billet 1 with a cylinder 4
Apply pressure to. As a result, the mandrel guide 6 which has fixed the tip of the mandrel 5 is pushed out by pushing out the perforated billet 1, and subsequently the perforated billet 1 is pushed out. At this time, since the mandrel 5 is fixed to the mandrel guide 6, the mandrel 5 is not bent by the perforated billet 1 to be extruded, and the extruded tube has a uniform wall thickness.

Even after the mandrel guide 6 is extruded, since the mandrel 5 is positioned in the die hole 2a by the perforated billet 1 which is extruded as a tube, the meat of the extruded tube is formed. There is no uneven thickness.

When the perforated billet 1 is extruded by the above-described method, the uneven thickness produced in a pipe having an outer diameter of about 100 mm is about 1 / thick as compared with the uneven thickness produced in a pipe produced by the conventional extrusion method. It was confirmed to be reduced to 20.

Further, as shown in FIG. 1C, a groove 6c may be provided on the outer circumference of the conical portion 6b of the mandrel guide 6. As a result, the weight of the mandrel guide 6 is reduced, and the temperature drop of the perforated billet 1 at the extrusion tip can be reduced. Therefore, it is possible to prevent the extrusion pressure from rapidly increasing at the extrusion tip end and the product quality from becoming non-uniform.

Further, as shown in FIG. 1D, a groove 6d may be provided on the inner circumference of the hole of the mandrel guide 6. Thus, the air existing between the mandrel guide 6 and the perforated billet 1 at the initial stage of extrusion is compressed, and the accident that the mandrel guide 6 jumps out of the hole 2a of the extrusion die 2 can be prevented.

The shapes of the grooves 6c and 6d shown in FIGS. 1 (c) and 1 (d) are generally rectangular.
The shape is not limited to a semicircular shape, a V shape, or the like. Also, the illustrated grooves 6c and 6d
Is provided only on the conical portion 6b, but the pipe 6a
A groove may be provided up to. Further, considering the relationship between the weight of the mandrel guide 6 and the temperature decrease of the perforated billet 1 described above, the grooves 6c and 6d of the mandrel guide 6 are taken into consideration.
It is desirable to change the depth and pitch.

[0022]

As described above, in the method for manufacturing a perforated billet according to the present invention, the mandrel guide is provided to fix the mandrel, so that the uneven thickness generated in the extruded pipe is significantly reduced. Therefore, the quality of the product obtained by processing the extruded pipe is significantly improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional method for extruding a perforated billet.

[Explanation of symbols]

1 Perforated billet 1a Perforated billet hole 2 Extrusion die 2a Die hole 3 Container 4 Cylinder 5 Mandrel 6 Mandrel guide

Claims (3)

[Claims] 1. A metal perforated billet having a circular cross section and a hole at the center is extruded,
In the extrusion method of a perforated billet for producing a predetermined tube, between the perforated billet and the extrusion die used for extrusion, sandwich a mandrel guide having a hole of a predetermined diameter, from the die hole of the extrusion die. Insert the mandrel into the hole of the mandrel guide and the hole of the perforated billet, fix the mandrel with the mandrel guide, following extrusion from the extrusion die of the mandrel guide, the perforated billet A method for extruding a perforated billet using a mandrel guide, which comprises extruding from an extrusion die. 2. The mandrel guide is made of the same material as the perforated billet, and has the same inner diameter as the outer diameter of the mandrel so that the mandrel can be inserted and the mandrel can be fixed. The method for extruding a perforated billet using a mandrel guide according to claim 1, comprising a pipe portion having a hole and a conical portion provided at one end of the pipe. 3. The method for extruding a perforated billet using a mandrel guide according to claim 2, wherein the mandrel guide has the pipe portion inserted into the extrusion die hole.