JP2509960B2 - Manufacturing method of deformed tube by hot extrusion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is a hot extrusion processing of a deformed pipe such as a metal pipe having a plurality of holes parallel to the length direction or a metal pipe having an eccentric hole. The present invention relates to a method of manufacturing the same.

[Conventional technology]

The deformed tube having a plurality of holes in parallel with the length direction as shown in FIG. 4 (a) is used for sending a plurality of liquids or gases. Conventionally, in order to manufacture such a deformed pipe, there is a method of drilling a round bar and further reducing the diameter by cold drawing if necessary, but it is difficult to drill parallel to the round bar. In addition, there is a problem that a long material cannot be manufactured. A deformed tube having an eccentric hole as shown in FIG. 4 (b) is manufactured by hot extrusion, etc., and is cut to be used for various applications such as an eccentric cam. There was a problem in ensuring accuracy.

[Problems to be solved by the invention]

An object of the present invention is to manufacture a deformed tube having a plurality of holes parallel to the length direction or a deformed tube having an eccentric hole with a long length, with high yield, with high accuracy, and efficiently.

[Means / actions for solving problems]

According to the present invention, a composite billet is formed by fitting a charging material made of a material having a thermal expansion coefficient larger than that of the billet in the length direction of the cylindrical billet and being hard to melt into a composite billet, and heating the composite billet to perform hot extrusion. After processing, one end of the extruded material is removed by removing the outer periphery by leaving the loading material, and the exposed portion of the loading material is chucked to remove the loading material.

Hereinafter, the present invention will be described by taking as an example the production of a deformed tube having two holes in the length direction.

As shown in FIG. 1, a hole is made in the lengthwise direction of the cylindrical billet 1, and a loading material 2 made of a material having a thermal expansion coefficient larger than that of the cylindrical billet 1 and less likely to melt is fitted into the hole. Form a composite billet 4. Billet 1 and charging material 2 at this time
In order to prevent the formation of metallic bonds during the hot extrusion process, it is desirable to insert an appropriate separating material 3 between them. Next, the composite billet 4 is heated, inserted into a container 6 as shown in FIG. 2, and hot extruded through a die 8 by a stem 7 to obtain an extruded material 9. Next, as shown in FIG. 3, the outer periphery of the extruded material 9 after cooling is removed by melting, leaving the loading material 2, and the exposed portion 10 of the loading material 2 is chucked to remove the loading material 2.

When the composite billet 4 is extruded, if the loading material 2 is exposed on the extrusion top side, the deformation resistance of the loading material 2 and the cylindrical billet 1 becomes unbalanced, which may cause abnormal deformation. As shown in FIG. 1B, the hole of the cylindrical billet 1 is not penetrated, or as shown in FIG. 1C, the lid 5 is attached to the top side.
It is desirable to

Further, if the loading material 2 is exposed on the extrusion bottom side of the composite billet 4, the loading material 2 may be displaced when the composite billet 4 is heated or conveyed, so that FIG.
It is desirable to cover the bottom side with the lid 5 as shown in (c).

In order to extract and remove the charging material 2 from the extruding material 9 after hot extrusion, the extruding material 9 is rectified, the charging material 2 is exposed by the above-described method, and the exposed portion 10 of the charging material 2 is chucked and extracted. Etc. are used. At this time, if the outer periphery of the extruded material 9 is heated, it can be easily extracted and removed. Further, when the charging material 2 is fitted to the cylindrical billet 1, if a glassy material, graphite powder, cloth, or a low-melting metal foil such as aluminum is sandwiched between them, the mother material is not subjected to hot extrusion. Material (Cylindrical billet 1)
Therefore, it is possible to prevent the charging material 2 from forming a metallic bond, and to add a lubricating effect at the time of extraction to facilitate the extraction.

The charging material 2 has a coefficient of thermal expansion higher than that of the cylindrical billet 1 and is made of a material which is difficult to melt. This is because when the extruded material 9 is cooled, the amount of shrinkage of the loading material 2 is made larger than that of the base material (cylindrical billet 1) to facilitate extraction. Further, in order to expose the chuck portion when the loading material 2 is extracted, a material that is less likely to melt than the base material (cylindrical billet 1) is used as the loading material 2. For example, when ordinary steel is used as the base material, the austenite that has a thermal expansion coefficient of about 50% higher than that of the base material as the filler material 2 and also has the property of forming a refractory Cr oxide near the melting temperature range and making it difficult to melt Based stainless steel is used.

The deformed tube from which the charging material 2 is extracted can be manufactured as a product through a normal refining process. Further, this product can be further drawn or drawn to form a deformed pipe having a smaller diameter.

〔Example〕

A cylindrical billet made of S45C (plain steel) with a diameter of 170 mm and a length of 400 mm is opened in parallel with the lengthwise direction of two 60 mm diameter holes with a center distance of 75 mm, and is made of SUS304 (austenitic stainless steel). Wrapped aluminum foil was fitted, and both ends were capped with S45C and heated, and hot extruded to an outer diameter of 38 mm. After straightening this with a roller straightener,
The base material portion was ablated with acetylene gas to expose the loading material in the range of the length of one end of 200 mm, and the exposed portion of the loading material was chucked by a tension straightening machine to extract the loading material. As a result, a 2-hole deformed tube having an outer diameter of 38 mm, a hole diameter of 13 mm and a center-to-center distance of 17 mm was obtained with a length of about 5 m. The hole positions and dimensions were as designed, with little variation in the length direction and good shape.

〔The invention's effect〕

According to the present invention, hot extrusion of a deformed pipe can be performed without using a mandrel, so that a deformed pipe such as a pipe having a plurality of holes or a pipe having an eccentric hole in the cross section can be used as a hole position. It can be manufactured with high precision and shape. Further, since drilling unlike the conventional method is unnecessary, it is possible to manufacture a long-sized deformed pipe with high yield and high efficiency.

[Brief description of drawings]

1, 2 and 3 are diagrams for explaining the method of the present invention, and FIG. 4 is a diagram showing an example of a deformed pipe which is the subject of the present invention. 1: Cylindrical billet, 2: Loading material 3: Separation material, 4: Composite billet 5: Lid, 6: Container 7: Stem, 8: Die 9: Extruded material, 10: Exposed part

Claims (1)

(57) [Claims] 1. A composite billet is formed by fitting a charging material made of a material having a thermal expansion coefficient higher than that of the billet and hardly melting, into a composite billet in the lengthwise direction of the cylindrical billet and heating the composite billet. After the hot extrusion process, the outer periphery of the extruded material is melted away while leaving the loading material at one end, and the exposed portion of the loading material is chucked to remove the loading material. For manufacturing deformed pipes.