JPH04274820A - Receiver having flat receiver for use for extruding molding machine and method for manufacture - Google Patents

Abstract

PURPOSE: To improve the effective life of a flat receiver for an extrusion molding machine by constituting this receiver of a non-circular hole inner bushing having curvilinear chamfered part on the short sides of a cross-section and another portions shrinkage fitted thereto. CONSTITUTION: The flat receiver 1 for the extrusion molding machine comprises the inner bushing 3 having the non-circular hole 2 formed of plural portions in some cases and having the curvilinear chamfered parts 34, 34' on the short sides of the cross-section and at least another portions which are arranged nearly concentrically therewith and are coupled to the inner bushing 3 by the shrinkage fit. As a result, the effective life and reliability of the receiver 1 may be improved.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention relates to an inner bushing having a non-circular hole, possibly formed from several parts, with a curved chamfer on the short side of the cross-section, and a substantially concentric The present invention relates to a flat receiver for an extruder, comprising at least one further part connected to this inner bushing, preferably by a shrink fit, which is arranged. Furthermore, the present invention provides an inner bushing having a non-circular hole, possibly formed from several parts, with a curved chamfer on the short side of the cross section, and an inner bushing arranged substantially concentrically with the inner bushing. at least one part connected to the inner bushing, at least in the region of the curved chamfer of the hole, the wall part or the curved chamfer of the inner bushing has stresses, and these stresses The present invention relates to a method for manufacturing a flat receiver for an extruder, which is under compressive stress in the area of 2.

0002

BACKGROUND OF THE INVENTION Receptacles or block receiving devices with flat holes or receiving chambers are used in extrusion machines for producing thin-walled flat profiles made of metal or alloys. Since the extrusion process is mostly carried out isothermally, at least a portion, in particular the inner bushing of the receiver, is heated to or maintained at a processing temperature of 400 DEG C. to 550 DEG C. by means of heating means. When extruding a block through a forming die, internal pressures of 300 to 500 N/mm@2 are usually generated, and these pressures are even higher for special materials or special profiles. Such high internal pressure stresses lead to elastic deformation or expansion of the receiver during the extrusion process. As a result, the inner wall of the inner bushing is subjected to pulsating or alternating mechanical stresses on the short sides of the retaining holes or on the curved chamfers. However, due to discontinuous tensile stress, cracks can already occur even when the stress in the material is low, especially at elevated temperatures.
These cracks may require replacement of the inner bushing or even lead to failure of the receiver. In order not to exceed the crack-initiating stress of the material in the area of the hole in the inner bushing, attempts have already been made to increase the number of concentrically arranged components or support members and to use higher shrinkage stresses. However, these measures could only be a partial remedy. Particularly in the region of the transverse axis, on the short side of the hole or on the curved chamfer, peak stresses with discontinuous duration of action due to the geometry nevertheless cause material damage, which can lead to cracks. Furthermore, attempts have already been made to provide the inner wall of the inner bushing in the region of maximum stress with a groove extending in the extrusion direction and to close this groove again with an elastic welded joint (German Patent No. 2,417,815). ). A disadvantage in this case is that, in addition to the welded joint, cracks also occur in the heat-affected area of the material of the inner bushing.

0003

OBJECT AND SUMMARY OF THE INVENTION The problem underlying the invention is to avoid the risk of crack formation even in the area of the curved chamfer of the hole in the case of high internal pressures and to ensure the service life and reliability of this hole. To provide a flat receiver for an extrusion molding machine having a non-circular hole defined by a curved chamfer, which is narrow in the transverse axis direction, and which increases the resistance. Another object of the invention is to provide a method for manufacturing a receptacle with a flat hole which produces compressive stresses in the area of the inner bushing close to the inner surface.

0004

With the flat receptacle for extrusion molding machines according to the invention, this object is achieved in that the wall portion is oriented in the direction of the transverse axis or in the direction of the inner bush, at least in the area of the curved chamfer of the hole. The curved chamfer has mechanical stresses which are resolved by compressive stresses in the area of the wall or curved chamfer adjacent to the inner surface. Furthermore, according to the method for producing a flat receiver for an extrusion molding machine according to the invention, this problem is solved in that the inner bushing or the curved chamfer is mechanically or thermally treated to a certain extent, and during this treatment, Plastic deformation of the material or non-uniform plasticization over the cross-section at least partially takes place at a temperature below the tempering temperature, and at the end of this process compressive stresses are applied to the surface of the inner bushing or curved chamfer. at least in the area of the curved chamfer in a close area, after which the inner bushing is connected to at least one approximately concentrically arranged outer part, such as an outer sleeve or an intermediate bushing, preferably by a shrink fit. It is solved by

Advantageous developments and developments of the flat receiver according to the invention and of the method according to the invention emerge from the dependent claims.

If there are compressive stresses in the area close to the inner surface of the inner bushing, at least in the area of the curved chamfer, it is possible to avoid high internal pressure stresses during the extrusion process which give rise to discontinuous pulsating or alternating material stresses. It has been found that cracks can be prevented from forming in the inner wall or inner wall portion of the inner bushing. Furthermore, even if peak stresses occur in the extended range, these peak stresses, even if they often occur, can have an adverse effect if the height of the tensile stress is less than the crack initiation stress of the material at operating temperature. I found out that it doesn't work. However, what must be considered in this case is that
This means that the temperature of the inner surface is usually higher than the temperature inside the inner bushing.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows a cross-section of a three-part flat receiver, which has a transverse axis AB.
It has a flat hole 2 or a flat storage chamber for the block in the direction of the block. This flat hole 2 is concentrically arranged with a heating means hole 32.
It is arranged in an inner bushing 3 with a concentric intermediate bushing 4 and an outer cylinder 5 having a hole 51 for the heating means. By means of heating rods or the like, the flat receiver 1, in particular the inner bushing 3, is heated to an operating temperature of 500 DEG to 540 DEG C., thereby making it possible to achieve a sufficiently isothermal extrusion process. As is conventionally done, the inner bushing 3, the intermediate bushing 4, and the outer shell 5 are joined by shrink fitting, but the elastic expansion of the flat receiver 1 is caused by the high internal pressure in the hole during extrusion molding. happen. Due to the geometry, maximum tensile stresses occur in the outer part of the inner bushing 3 in the area of the inner surfaces 31 and 31' of the curved chamfers, and these tensile stresses exceed the crack initiation stress value of the surface. In some cases, cracks may occur during continuous operation.

It has been found that even at an operating temperature of 540° C., the compressive stress on the inner surface of the inner bushing 3 can prevent crack formation. Furthermore, it is possible to reduce the dimensions or high loads of supporting parts such as the intermediate bushing 4 and the sleeve 5 and to obtain economic advantages.

FIG. 2 shows an inner bushing 3 consisting of one part.
2 schematically shows the mechanical treatment according to the invention of . In this case, a pressing force is applied centrally via the pressing surface 7 by the pressing means 8 on the inner surface of the inner bushing at right angles to the dependent area AB of the hole 2, which pressing force causes an enlargement or rectangle 9 of the inner bushing. . In this case, mechanical stresses are created in the wall areas AA' and BB' of the short sides, which, if the pressure is correspondingly high,
This causes plastic deformation of the material in the areas located at 1 and 31'. Owing to the non-uniform plasticization of the material in the wall areas AA' and BB' over the thickness of these wall areas, compressive stresses occur during load relief, at least in the area of the inner surfaces 31, 31' of the curved chamfers. . As the pressing means 8, a hydraulic device, a wedge, etc. can be used.

FIG. 3 shows the stress distribution S over the wall thickness AA' after mechanical treatment of the inner bushing, in which the tensile stress is designated Z and the compressive stress is designated D. In the region A' close to the inner surface there is a high compressive stress d, and the resulting tensile stress z in the remaining wall region is small.

FIG. 4 shows a flat receiver 1' with a multi-part inner bush. The inner bushing forming the bore 2 consists of curved chamfers 34 and 34' and flattened parts 35 and 35' provided with holes 32 for heating means. The inner bushing is surrounded by an intermediate bushing 4 and an outer cylinder 5 having a hole 51 for heating means. In the conventional flat receiver 1' configured in this way, despite the fan-shaped structure of the inner bushing, the central area 31 of the curved chamfered portions 34 and 34' is
, 31'. According to the invention, crack formation can be prevented if there is an increased compressive stress in the material in the area in the area of the inner surfaces 31 and 31' of the curved chamfers 34, 34'.

FIG. 5 shows a device with which curved chamfers 34, 34' can be easily processed. On a support piece 10, 10' with a preferably concave support surface that can act as a scale, a curved chamfer 34, 34' with an approximately sector-shaped cross section is placed with at least one sector-shaped end. Provided at a distance from the surface. Pressing means 8
2, the curved chamfers 34, 34' are bent outwards, with a non-uniform plasticization over the cross section and, after the load is relieved, a stress distribution as shown in FIG. 3 is obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a flat receiver.

FIG. 2 is a cross-sectional view of the inner bushing.

FIG. 3 is a diagram showing the stress distribution in the wall region of the inner bush;

FIG. 4 is a cross-sectional view of a flat receiver with a multi-part inner bush;

FIG. 5 is an explanatory diagram of a processing device for a curved chamfer.

[Explanation of symbols]

2 hole 3
Inner bushings 31, 31' Inner surfaces 34, 34' Curved chamfered portions AA', BB' Wall range

Claims (13)

[Claims] 1. At least in the area of the curved chamfer of the hole (2), the wall part in the direction of the transverse axis (AB) or the curved chamfer (34, 34') of the inner bushing (3) is provided with mechanical stresses. These stresses are applied to the inner surface (31, 31')
Adjacent to the wall (AA', BB') or curved chamfer (
34, 34') characterized by compressive stress in the area, sometimes formed from several parts,
consisting of an inner bushing having a non-circular hole with a curved chamfer on the short side of its cross section, and at least one further part arranged approximately concentrically and connected to this inner bushing;
Flat receiver for extrusion molding machine. 2. A wall section or a curved chamfered section (34, 34') in the direction of the transverse axis (AB) of the inner bushing (3).
), the local compressive stress within the curved chamfered portion (31,
2. Flat receptacle according to claim 1, characterized in that it increases towards 31'). [Claim 3] The stress in the wall part of the inner bushing is superimposed by the shrinkage stress of the part connected to the inner bushing (3), for example the outer cylinder (5) or the intermediate bushing (4). 3. The flat receiver according to claim 1, wherein the flat receiver has a characteristic. 4. Flat receiver according to claim 1, characterized in that the local compressive stress in the wall section is equal to or smaller than the compressive yield stress of the material at the operating temperature. vessel. 5. Claim 1, characterized in that the stresses in the inner bushing (3) are at least in part internal stresses or residual stresses of local plastic deformation or non-uniform plasticization of the material. 4. The flat receiver according to any one of 4 to 4. 6. Flat receiver according to claim 1, characterized in that the stresses in the inner bushing are at least partly internal stresses or residual stresses of the heat treatment. [Claim 7] Inner bushing (3) or curved chamfered portion (
34) is mechanically or thermally treated over a range of
During this process, at least partially plastic deformation or non-uniform plasticization over the cross-section of the material takes place at temperatures below the tempering temperature, and at the end of this process compressive stresses are applied to the inner bushing (3) or the curved chamfer (34, 34') is produced at least in the area of the curved chamfer in the area close to the surface, after which the inner bushing is connected to at least one outer part arranged approximately concentrically; an inner bushing having a non-circular hole with a curved chamfer on the short side of the cross section, possibly formed from several parts, and an inner bushing arranged approximately concentrically; and at least one part connected to the inner bushing, at least in the area of the curved chamfer of the hole, the wall part or the curved chamfer of the inner bushing has stresses, and these stresses are
A method of manufacturing a flat receiver for an extruder, which is under compressive stress in the area of the wall or curved chamfer adjacent to the inner surface. 8. The inner bushing (3) is moved perpendicularly to the direction of the transverse axis (AB) or in the hole by pressing means (8) acting over the pressing surface (7) in the hole (2). Cross section (2
) is subjected to an outwardly directed force at right angles to the subordinate area of the hole (2), and in particular in the area of the curved chamfer of the hole (2), the thickness of these wall parts (AA′,
8. Process according to claim 7, characterized in that the plasticization of the material is unevenly distributed over BB') and the formation of the oblong shape (9) of the inner bushing (3). 9. Claim 7 or 8, characterized in that the width of the pressing surface (7) is selected to be at most 40%, preferably at most 25%, in particular 15%, of the dependent area of the hole cross-section. The method described in. [Claim 10] An inner bushing consisting of a plurality of parts,
The curved chamfered portions (34, 34') having an approximately fan-shaped cross section are
The mounting piece (10, 10') is held so as to be in contact with the outer surface (36) along the generatrix of the outer surface (36), or is brought into contact with this outer surface, and is pressed approximately perpendicularly to the subordinate area by the pressing means (8'). The curved chamfered part (
34, 34'), characterized in that a deformation or enlargement of the annular shape of the curved chamfers (34, 34') is carried out, at least in part, a plasticization of the material is unevenly distributed over the wall thickness of these curved chamfers, The method according to claim 7. 11. The inner bushing (3) is removed from the tempering temperature by enhanced heat dissipation, such as injection cooling, so that the hole (2)
8. Method according to claim 7, characterized in that the cooling is carried out on the inner surface (31, 31') of the curved chamfer. 12. Into the hole (2) of the inner bushing (3) an object having at least partially larger dimensions is passed, the area close to the surface being at least in the area of the curved chamfer (
8. Method according to claim 7, characterized in that in steps 31, 31') plastic deformation is carried out while creating compressive stresses. 13. A process according to claim 7, for producing thin-walled flat profiles of aluminum and aluminum alloys by extrusion of blocks at temperatures in the range from 450° to 600° C. Use of flat receiver.