DE102012020142A1 - Extruding tool of strand and extrusion press for tube, has pressing frame that is provided with cylindrical spar, and main portion whose tear-endangered regions are mechanically pre-processed through shot-peening operation - Google Patents

Abstract

The extruding tool (1) has a movable running spar and a movable block pickup portion that are arranged in a pressing frame. A cylindrical spar and an associated cross beam portion are provided in the pressing frame. The tear-endangered regions of the components of an extruding tool main portion are mechanically pre-processed through shot-peening operation. The block pickup portion is provided with an inner sleeve portion (2), intermediate sleeve portion (3) and a pickup cladding portion (4). An independent claim is included for a method for processing extruding tool.

Description

The invention relates to an extrusion tool, in particular billet, a strand and tube press having a consisting of a cylinder spar and associated counter frame press frame, in which a movable spar and a movable block picker, which introduced a loading device with a block to be pressed in pressing position before the counter-spar with die spends, are arranged. Such a strand and tube press or metal extruder is from the EP 1 750 865 B1 known.

In most trained as a frame presses metal extrusion cylinder and counter-spar are connected by tie rods (columns) to form a frame. In the frame one of a running in the cylinder of the cylinder spar pressing piston movable spar is arranged. In the direct pressing method, the die and the block receiver are supported on the counter-member, while a block-pressing-out punch is moved with the spindle of the piston. In the indirect pressing method, a die stamp is supported on the counter-rail, while the billet pick-up receives a block to be pressed with a closing disk and is moved by the stamping pin of the stamping punch.

The compression of metals generally requires high extrusion temperatures, the block temperatures depending on the material can reach up to 1400 ° C. Nevertheless, the tools, such as billets, mandrels of a tube press or dies and thrust washers of extrusion and tube presses are preheated at the beginning of a pressing period to prevent tearing by large temperature differences. However, the tools must then be cooled in the course of the pressing period, because they absorb heat from the hot blocks by heat radiation and heat conduction during each pressing process. Overheating of the tool surfaces leads to their premature wear and should therefore be avoided by the cooling.

In order to protect the tools from heat absorption during the pressing process, it is known to bring thin films of heat-insulating materials between the hot block and the tools. However, since these layers are only thin, they can only hold a small proportion of the heat transferred by radiation and contact from the tools.

By the German Patent 1,452,449 it is known to protect the tool surfaces against wear and to protect the solid or hollow strand against oxidation and melting of the Oxydationsschutzfilmes to be produced, a block temperature not viscous powder mixture, optionally supplemented by a water content and a binder on the block and / or to apply the tools. Primarily to protect the mandrel and Blockaufnehmer- or recipient areas there is a powder mixture is used which contains at least one liquid mixture at room temperature mixture raumkristalliner and / or armorpher structure of mineralogical or synthetic origin in such a ratio that at least this mixture content with a portion of the metal or the metal oxides already under the block heat and then under the pressure and the heat of the short time pressing process enters into a chemical compound and / or a suspension.

However, in extrusion molding, cracks still occur on the tools, in particular on the areas which are endangered by the occurring stresses (pressure and / or thermal stresses). These are, for example, the mandrel surfaces and, in the case of a block receiver or recipient, the receiving jacket formed with coolant feeds and its bush or cans which also have distribution or annular grooves for the coolant. Such a block sensor, as from the German Patent 1,127,307 is known, usually consists of two or more concentric nested parts, namely outer shell and an inner liner with optionally intermediate sleeve, which are joined together by shrinkage.

The cracking and thus the failure of components can be prevented, which also means an extension of the component life and avoid unnecessary downtime and changeover times, if at least the rupture-prone areas, preferably the entire vulnerable surfaces of the components are provided by shot peening with a pressure bias , The shot peening simultaneously achieves a corrosion delay. This results in a total damage prevention and / or increase the life of the components.

According to the invention, this is effected by mechanical pre-processing, in particular by shot peening, wherein a compressive stress is induced by the mechanical pre-processing within the regions of the components of the extrusion die that are prone to cracking. This compressive stress must be overcome with the use of the extrusion die and the forces acting on the components of the extrusion tool tensile forces during operation before the material undergoes a tensile load through which cracks could occur within the material.

The areas susceptible to cracking are, in particular, the distributor or annular grooves, via which coolant can be distributed over the surface of the components of the extrusion tool and supplied in a targeted manner. Preferably, when all surfaces of the ring or distributor grooves both the side walls and the bottom of the groove, mechanically preprocessed, were processed in particular by shot peening.

It is particularly preferred if the compressive stress induced by mechanical pre-processing, in particular shot peening, corresponds to at least 40%, preferably at least 50%, particularly preferably up to 60% of the tensile stress expected at the site during operation of the extrusion die.

The degree of induced compressive stress of course depends to a great extent on the size of the extrusion die and the forces to be applied by the extrusion die. However, it is preferred if the compressive stress at the regions susceptible to cracking, in particular within the annular or distributor grooves, is increased by at least 400 N / mm ² , preferably by at least 500 N / mm ² , particularly preferably by at least 600 N / mm ² .

The skilled person knows how he can achieve these values by using the well-known shot peening, where he the parameters of the shot peening process, in particular the nature, size and speed of the balls used in both the desired target sizes and on the site and the material tuned to surface to be machined.

Further features and details can be seen in the example of the 1 to 3 taken as a detail of a metal extruder block receiver shown.

The block receiver persists 1 from an inner sleeve, an intermediate sleeve and a Aufnehmermantel. In the pickup substantially several connections for a coolant supply, in particular cooling air, incorporated, while here the intermediate sleeve at its outer periphery with corresponding distributor or annular grooves and Spiralnutausläufen, as shown in FIG 2 to recognize is provided.

In the lower half of 2 dash-dotted lines indicated that the entire outer circumferential or lateral surface of the intermediate sleeve can be formed and compacted by shot peening with a compressive bias. Optionally, only the areas particularly endangered by the contouring or recesses in the surface, in particular only the distributor or annular grooves or partial sections thereof, can be shot-blasted.

The above applies equally to the in 3 in a longitudinal section transducer shell shown. There, the entire shell bore, which is assembled with Blockaufnehmer (see. 1 ) encloses the intermediate sleeve and receives, are shot peened. As in 3 highlighted by checkered dashes or fields, alternatively needs to be shot peened in a kind of circumferential strip only the coolant supply or a coolant connection having region of the Aufnehmermantels. This circumferential strip-like, thus overlap areas enclosing ball irradiation of the jacket bore is everywhere to make selectively where there are openings (holes) for the coolant supply.

LIST OF REFERENCE NUMBERS

1

Billet / extrusion tool

2

inner liner

3

intermediate sleeve

4

Aufnehmermantel

5

Coolant supply (cooling air)

5a

Coolant bore

6

Distributor / groove

6a

Distributor / Ringnutteilabschnitt

6b

Distributor / Ringnutteilabschnitt

7

Jacket bore (of the receiver jacket)

8th

Surface of inner liner

9

Surface of the intermediate liner

10

Surface of the receiver jacket

11

Surrounding area / area of the coolant supply

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1750865 B1 [0001]
• DE 1452449 [0005]
• DE 1127307 [0006]

Claims (12)

Extrusion tool of a strand and tube press, comprising a consisting of a cylinder spar and associated counter frame press frame, in which a movable spar and a movable Blockaufnehmer are arranged, characterized in that the crack vulnerable areas, preferably the entire vulnerable surfaces of the components of the extrusion die, mechanically preprocessed, in particular processed by shot peening. Extrusion tool according to claim 1, characterized in that the regions susceptible to cracking, preferably the entire endangered surfaces of the components of the extrusion die, have a mechanical pre-processing, in particular a compressive prestress generated by shot peening. Extrusion tool according to one of the preceding claims, characterized in that the block receiver consists of an inner sleeve, an intermediate sleeve and a Aufnehmermantel. Extrusion die according to claim 3, characterized in that in the receiving jacket connections for a coolant supply, in particular cooling air, are incorporated, and that the intermediate sleeve is provided at its outer periphery with corresponding distributor or annular grooves and Spiralnutausläufen. Extrusion tool according to one of claims 3 or 4, characterized in that the entire outer circumferential or circumferential surface of the intermediate sleeve is machined by shot peening. Extrusion tool according to one of claims 3 or 4, characterized in that only the distributor or annular grooves or subsections thereof, in particular the side and bottom walls of the distributor or annular grooves are machined by shot peening. Extrusion die according to one of claims 3 to 6, characterized in that the entire jacket bore of the receiver jacket, which encloses the intermediate sleeve when assembled block receiver, is processed by shot peening. Extrusion die according to one of claims 3 to 6, characterized in that only the coolant supply or a coolant connection having region of the Aufnehmermantels, preferably in a region around the coolant connection plus up to 5 mm surrounding area, are processed by shot peening. Extrusion tool according to one of the preceding claims, characterized in that the regions susceptible to cracking, in particular the vulnerable surfaces of the components of the extrusion die, which have openings or bores for the coolant supply, are preferably those areas which are machined by means of mechanical pre-processing, in particular by shot peening, Preferably, the surface of the openings or holes for the coolant supply plus an ambient area with a Radus of up to 5 mm. Extrusion tool according to one of the preceding claims, characterized in that the mechanical stress induced by mechanical pre-processing, in particular shot peening, at least 40%, preferably at least 50%, particularly preferably more than 60% of the expected tensile stress eiwirkt in operation on the vulnerable surfaces. Extrusion tool according to one of the preceding claims, characterized in that the compressive stress of the vulnerable surfaces, which is induced by mechanical pre-processing, in particular shot peening, at least 400 N / mm ² , preferably at least 500 N / mm ² , more preferably more than 600 N / mm ² , is. Method for processing an extrusion die according to one of the preceding claims, characterized in that the regions susceptible to cracking, preferably the entire endangered surfaces of the components of the extrusion die, are mechanically preprocessed, in particular processed by shot peening.

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