Extrusion billet and method for heating an extrusion billet in a pusher-type furnace

Abstract

The invention relates to an extrusion billet having two end sides, characterized in that the surface of at least one end side has a three-dimensional topography which is composed of a substantially planar end side face from which local elevations protrude.

Description

Further advantages and embodiments of the invention are explained in more detail on the basis of the schematic drawings, in which:

FIG. 1 shows a side view, and the corresponding front view, of a billet with four pins arranged on the end side,

FIG. 2 shows a side view of two billets, which are in contact, with a central arrangement of a plate with a slightly beveled section,

FIG. 3 shows a side view, and the corresponding front view, of a billet with a centrally arranged spherical cap,

FIG. 4 shows a longitudinal section, and the corresponding front view, of a billet with convexities on the outer periphery,

FIG. 5 shows a longitudinal section, and the corresponding front view, of a billet with an annular bead, and

FIG. 6 shows a detail of a billet shaped by means of backward extrusion, before and after shaping.

Corresponding parts are provided with the same reference symbols in all of the figures.

FIG. 1 shows a side view, and the corresponding front view, of an extrusion billet 1 with four pins 3 arranged on the end side 2 as an embodiment of the invention in which additional material is used. Small pins 3, made from the same material as the billet 1 for recycling reasons, are attached so as to be distributed on the end side of the billet 1. The size of the overall area of all of the pins 3 is fixed by the tearing force when extracting the billet 1.

FIG. 2 shows a side view of two billets 1, which are in contact, with a central arrangement of a plate 4 on the end side 2 of the billet 1, with a slightly beveled section. The plate 4 can for example be punched from a material strip. Its thickness must be at least great enough that, even with a lightly beveled section, the billet and adjacent billet come into contact with one another only in the region of the plate 4. The size of the area is in turn fixed by the tearing force when extracting the billet 1. The pins 3 and plate 4 can then for example be joined on to the billet for example by means of welding, adhesive bonding or riveting.

FIG. 3 shows a side view, and the corresponding front view, of a billet 1 with a centrally arranged spherical-cap-shaped convexity 5.

FIG. 4 illustrates a further example in which no additional material is required. The aim in principle is to obtain elevations according to the invention on the end side of the billet 1. The figure shows a longitudinal section, and the corresponding front view, of a billet 1 with convexities on the outer periphery 6. In order to produce the convexity 6, a punch is pressed radially into the billet material in the region of the peripheral edge of the billet. Depending on the possibilities of the axial support of the billet 1, the edge can be broken. The displaced material flows in the direction of least resistance and thereby forms a bulge on the free end side 2. Some further locally arranged bulges can be distributed over the periphery. The detail A shows an enlarged illustration of a convexity 6.

FIG. 5 shows a longitudinal section, and the corresponding front view, of a billet 1 with an annular bead 7. The bead 7 is generated by means of rolling of the billet edge in the transition of the end side to the side face.

FIG. 6 shows a detail of a billet 1 shaped by means of backward extrusion, before and after shaping by means of a pressing tool 8. The material flows counter to the direction of action of the tool movement. By means of end-side upsetting of the billet 1 using a tool, the billet material is caused to flow. The tool 8 must be constructed such that it has cutouts for the pin-shaped convexities 3. If the flow resistance in the other spatial directions is too great, the material will flow through the cutouts counter to the tool movement. If appropriate, the billet 1 must be correspondingly supported.

LIST OF REFERENCE SYMBOLS

• 1 Extrusion billet
• 2 End side
• 3 Pins
• 4 Plate
• 5 Spherical-cap-shaped convexities
• 6 Convexities on the outer periphery
• 7 Annular bead
• 8 Pressing tool

Claims

1. Extrusion billet (1) having two end sides (2), characterized in that the surface of at least one end side (2) has a three-dimensional topography which is composed of a substantially planar end side face from which local elevations protrude.

2. Extrusion billet according to claim 1, characterized in that a pin (3), a plate (4) or a spherical-cap-shaped convexity (5) is arranged as a local elevation.

3. Extrusion billet according to claim 2, characterized in that a pin (3), a plate (4) or a spherical-cap-shaped convexity (5) is arranged centrally.

4. Extrusion billet according to claim 1, characterized in that a plurality of pins (3), plates (4) or spherical-cap-shaped convexities (5) are arranged so as to be distributed over the end side (2).

5. Extrusion billet according to claim 4, characterized in that the pins (3), plates (4) or spherical-cap-shaped convexities (5) are made from the same material as the extrusion billet.

6. Extrusion billet according to claim 4, characterized in that the pins (3), plates (4) or spherical-cap-shaped convexities (5) are attached by means of a welded connection.

7. Extrusion billet according to claim 4, characterized in that the pins (3) are in each case arranged in bores.

8. Extrusion billet according to claim 1, characterized in that the respective end side (2) has convexities (6) on the outer periphery.

9. Extrusion billet according to claim 1, characterized in that the respective end side (2) has an annular bead (7) on the outer periphery.

10. Method for heating extrusion billets (1) in a pusher-type furnace, characterized in that at least one end side (2), which comes into contact with the in each case adjacent extrusion billet (1), has a three-dimensional topography which is composed of a substantially planar end side face from which local elevations (4, 5, 6, 7) protrude, with the common contact face being so small that, in the case of a cohesive connection being generated by the heating, the extrusion billet (1) which emerges at the exit-side end of the furnace can, with little force expenditure, be separated from the adherent adjacent extrusion billet (1) by means of a separating device or even by means of its own weight.