EP2226135A1 - Method for making a forged part - Google Patents

Abstract

The method involves deforming a forged blank (2) in a forging device (3) with a cavity upper part (4) and a cavity lower part (5), where the forged blank consists of damask steel. The forged blank is asymmetrically deformed with respect to a primary middle plane, which runs perpendicular to a forged cam. The cavity upper part and/or the cavity lower part is penetrated into the forged blank, where the upper part and/or the lower part comprises a bowl-shaped molding (9), which is attached to a bolt.

Description

The present invention relates to two processes for producing a forged part made of damascus steel according to the preamble of claims 1 and 2 and a forged part made of damascus steel produced by this process as such according to claim 15.

The use of damascus steel, which is also referred to as Damascus steel, is known ahem from the field of knives blacksmiths.

Damascus steel is a composite material composed of at least two grades of steel. For further explanation please refer to the reference " Damaszener-Stahl.Mythos.Geschichte.Technik.Anwendung. ", Manfred Sachse, Stahleisen-Verlag 1993, ISBN 978-3514005204 to get expelled.

Damascus steel is regularly processed by forging. In all known forging processes, the material displacement in the direction of the forging is kept as low as possible in order not to damage the structure of Damascus steel. Thus, the scope of Damascus steel is limited to knives-forged products and a few jewelry items.

The invention is based on the problem to provide a method for producing a forged Damascus steel, which increases the scope of Damascus steel.

The above problem is solved in a method according to the preamble of claim 1 by the features of the characterizing part of claim 1.

Essential is the consideration to make the deformation of the forging blank in a drop forging method, wherein a Gesenkoberteil and a lower die part is used by very specific shape.

According to the proposal, the wearer is unbalanced in relation to his original center plane perpendicular to the forging stroke.

It has been recognized that damascus steel can be significantly asymmetrically deformed relative to the original center plane of the forging blank without damaging the structure of the damascus steel. It has been shown that a targeted adjustment of the damask image visible on the surface of the forging part can be set by means of an appropriate selection of the process parameters with the asymmetrical shaping in the above manner.

By "original, perpendicular to the Scbmiedehub center plane of the forging blank" is meant in the present case, the center plane dividing the block or disc-shaped forging blank before processing into two equal halves.

The term "asymmetrical" in the present case means that the material displacement is different at two points with respect to the center plane in the forging blank. One could also say that the forming of the forging blank with respect to the center plane is not mirror-symmetrical.

According to a further teaching according to claim 2, which has independent significance, it is proposed that the die top part and / or the die bottom part penetrate or penetrate into the forging blank in the forging step. This introduces a discontinuity in the material, in particular in the fiber flow of the material, the Schmiederoblings, through which the resulting damask image is in turn selectively adjustable.

In the preferred embodiment according to claim 3, the upper die part or the lower die part is substantially convex and correspondingly the lower die part or the upper die part is substantially concave. Due to the mutually corresponding shaping of the upper die part and the lower die part, the above asymmetric deformation as well as the above penetration of the upper die part and / or lower die part into the slaving blank can be easily realized.

Claim 5 relates to preferred variants, which are directed in particular to the deformation of the forging blank in a substantially ring-like shape.

Such an annular shape can be advantageously used in the context of the realization of a watch case or the like, as will be explained below.

According to claim 6 has further been recognized that the mandrel can even pass through the original center plane of the forging blank. Here it is clear that the proposed method opens up a large number of new design options for the forged part in question, which leads to the mentioned increase in the scope of Damascus steel.

According to another teaching according to claim 125, which has independent significance, the forged part produced by the proposed method is claimed as such. Reference may be made to all statements on the proposed method, provided that they are suitable for describing the forged part itself.

In particular, a designed as a watch case forged part is claimed. It is further preferably so that the watch case has the above, substantially ring-like shape. Other forms are conceivable.

Fig. 1

in einer schematischen, perspektivischen Ansicht ein Gesenkoberteil und ein Gesenkunterteil für die Durchführung des vorschlagsgemäßen Verfahrens mit dazwischenliegendem Schmiederohling bei der Entnahme,

Fig. 2

in einer schematischen, geschnittenen Seitenansicht das Gesenkoberteil und Gesenkunterteil gemäß Fig. 1 bei eingesetztem Schmiederohling zu Beginn des Gesenkschmiedens,

Fig. 3

in einer Ansicht gemäß Fig. 2 eine zweite Momentaufnahme im weiteren Verlauf des Gesenkschmiedens,

Fig. 4

in einer Ansicht gemäß Fig. 2 eine dritte Momentaufnahme im weiteren Verlauf des Gesenkschmiedens,

Fig. 5

in einer Ansicht gemäß Fig. 2 eine vierte Momentaufnahme im weiteren Verlauf des Gesenkschmiedens.

In the following, the invention will be explained in more detail with reference to a drawing showing only an exemplary embodiment. In the figure shows

Fig. 1

in a schematic, perspective view of a Gesenkoberteil and a die base for carrying out the proposed method with intermediate Schmiederohling at the removal,

Fig. 2

in a schematic, sectional side view of the Gesenkoberteil and Gesenkunterteil according to Fig. 1 with inserted forging blank at the beginning of drop forging,

Fig. 3

in a view according to Fig. 2 a second snapshot in the course of the drop forging,

Fig. 4

in a view according to Fig. 2 a third snapshot in the course of the drop forging,

Fig. 5

in a view according to Fig. 2 a fourth snapshot in the course of drop forging.

The proposed method is explained below by way of example with reference to a designated for a watch case Scbmiedeteils 1. It may be pointed out in advance that a variety of other forgings 1 can be produced by the proposed method.

The proposed method is used to produce the respective forging 1 from a substantially block or disk-shaped. Forged blank 2, which in a cut side view in Fig. 2 is shown. Here and preferably, the forging blank 2 is designed round in cross-section.

Of particular importance in the present case is the fact that the forging 2 consists essentially of damascus steel. Preferred variants for the choice of damascus steel will be explained below.

It can be a synopsis of Fig. 2 to 5 It can be seen that the forging blank 2 is formed in the forging step in a forging unit 3 with the die upper part 4 and the die bottom part 5.

In Fig. 2 is the original, perpendicular to the forging 6 extending center plane 7 of Schnüederohlings 2 indicated. Here it turns out that this original center plane 7 of the forging blank 2 divides the still undeformed forging blank 2 into two equal halves. This center plane 7 serves in the following as a reference plane for the explanation of the forging step.

From the into the Fig. 2 to 5 illustrated course of the forging step is clear that the deformation of the forging blank 2 relative to its original center line 7 in the above sense takes place asymmetrically. Here and preferably, a shift in material takes place mainly in the direction of the forging stroke 6. Consequently, in the final state shown in FIG. 6, the majority of the material of the forging blank 2 is located on the side of the original center plane 7 of the forging blank 2 facing away from the forging 6.

According to another teaching, which has independent significance, it is provided that the upper die part 4 and / or the lower die part 5 penetrate or penetrate into the forging blank 2 in the forging step. For this purpose, it is preferably provided that the upper die part 4 and / or the lower die part 5 is or are equipped with a dome-like shape, as will be explained below.

In the illustrated preferred embodiment, the upper die part 4 is substantially convex and the lower die part 5 is substantially concave. This can also be provided vice versa. It may be pointed out at this point that the described embodiments of the upper die part 4 and the lower die part 5 are generally interchangeable, so that the terms "die top part" and "die bottom part" are correspondingly interchangeable.

It may also be pointed out that the statements "convex" and "concave" refer here only to the superordinate shaping of the respective upper body part 4 or lower part 5 of the mold. With this information, no ideal convex and concave embodiments are meant.

In a particularly preferred embodiment, both the upper die part 4 and the lower die part 5 are designed substantially convex. In particular, the equipment of both the upper die part 4 and the lower die part 5 with a thorn-like shape is advantageous here, as will also be explained below.

In any case, the above forging step may also be attributed to the method of enforcement. When enforcing is a one-sided displacement of sub-masses of a workpiece from a given axis, here an axis lying in the center plane 7. It is conceivable here that the method of penetration is combined with other forging processes.

It can be a synopsis of Fig. 2 and 3 see that the die top 4 with a mandrel 8 or the like during the forging step enters the forging blank 2. The lower die part 5 has here a mandrel 8 associated, cup-shaped formation 9, which serves to receive the displaced by the mandrel 8 material. This can also be provided vice versa, as explained above.

Accordingly, when the mandrel 8 penetrates into the forging blank 2, the material of the forging blank 2 flows outward relative to the longitudinal axis of the mandrel 8 and fills the free volume 10 of the die bottom part 5, in particular the cup-shaped formation 9.

It can be the representation in Fig. 5 It can be seen that the forging blank 2 is converted into a substantially ring-like shape by equipping the upper die part 4 with the mandrel 8 and the lower die part 5 with the cup-shaped molding 9. This ring-like shape is particularly suitable for the realization of a watch case of a wristwatch, as will be explained below.

It may also be advantageous that, as already indicated, both the upper die part 4 and the lower die part 5 are equipped with a mandrel 8, so that both the upper die part 4 and the lower die part 5 during the forging step with the respective mandrel 8 in the forging blanket 2 penetration. The two domes are preferably aligned on the same axis and move towards each other during the forging step. The domes may have an identical diameter or just different diameters. The design depends on whether the transformation in the above sense with respect to the original center plane 7 of the forging blank 2 is to be symmetrical or even asymmetric.

A synopsis of the example Fig. 2 and 3 shows that in the proposed method during the forging step in the region of the original center plane 7 of the forging blank 2, a flow of the material of the forging blank 2 at least in the direction of the forging stroke 6 takes place. It is clear that the flow movement of the material of the forging blank 2 never takes place exactly in the direction of the forging stroke 6, but at best has components of movement in this direction.

In a particularly preferred embodiment, it is such that the mandrel 8 passes through the original center plane 7 of the forging blank 2 during the forging step. This shows a synopsis of Fig. 3 and 4 ,

For the design of Damascus steel numerous advantageous variants are conceivable. Preferably, the damascus steel has a plurality of layers 11, 12 of different types of steel, wherein here and preferably the layers 11, 12 consist alternately of two different types of steel.

It has been shown in tests that the proposed method can be used particularly well with a forging blanket 2 made of band-Damaststahl. Conceivable is the application of the proposed method to all other types of Damascus steel.

In general, the use of forged, especially hand-forged Damascus steel has proven to be advantageous.

In order to realize a high skin compatibility especially for the designed as a watch case forged part 1, the damascus steel is preferably designed with low nickel content. The nickel content of the damascus steel is preferably below 0.13% by weight and more preferably below 0.12% by weight. However, it is also conceivable to use a Damascus steel with a higher nickel content, in particular to reduce susceptibility to rust.

For the proposed method, it has been found to be particularly advantageous if the Damascus steel used is designed stainless and in particular exclusively has layers 11, 12 made of stainless steel.

In particular, when using band-damascus steel, the layers 11, 12 of the damascus steel before the forging step are substantially flat. The in the Fig. 2 to 5 shown process sequence shows that the layers 11, 12 of Damascus steel are increasingly "bulged" during the Schmiedcschntts and finally after the forging step at least partially each have a three-dimensional shape. Surprisingly, the transfer of the layers 11, 12 caused a planar shaping in a three-dimensional Shaping neither destroying individual layers 11, 12 nor separating adjacent layers 11, 12.

The representation in Fig. 5 It is also possible to deduce the fact that after the forging step, the layers 11, 12 located in the area of the die top 4 have a different three-dimensional shape than the layers 11, 12 located in the area of the die bottom 5. This is due to the shape of the die top 4 and of the Lower part 5 back.

As shown in the Fig. 2 to 5 the penetration depth here of the upper die part 4 into the forging blank 2 is a multiple of the average original height of the layers 11, 12, in particular even more than three times the average height of the layers 11, 12.

The illustration in Fig. 5 in that the penetration of the dome 8 into the forging blank 2 causes a height offset Δh within the layers 11, 12 which takes place in the area of the side face 13 of the mandrel 8, the height offset Δh here and preferably substantially corresponding to the height of the dome 8. Such height offsets within the layers 11, 12 can also be realized if, as mentioned above, both the upper die part 4 and the lower die part 5 are equipped with a corresponding mandrel 8.

Preferably, the respective height offset .DELTA.h has a considerable extent, so that the resulting damask image is significantly influenced by the forging step. In this case, it is preferably the case that the respective height offset Δh is a multiple of the average height of the layers 11, 12, in particular more than three times the average height of the layers 11, 12.

It has already been pointed out that a largely arbitrary adjustment of the damask image can be set by a suitable choice of the forging parameters. These Schmiedeparametem include in addition to the configuration of the upper die part 4 and lower die part 5 and the alignment of the forging blank 2 during the forging step.

In a preferred embodiment, the layers 11, 12 of the damascus steel of the forging blank 2 are substantially perpendicular to the direction of the forging stroke 6 aligned. Due to the correspondingly large height offset .DELTA.h within the layers 11, 12 can be produced with appropriate post especially striking damask.

It is also conceivable that the layers 11, 12 of the damascus steel of the forging blank 2 are aligned at an angle to the forging 8. Here it becomes clear that even with the choice of the orientation of the forging blank 2 an almost unlimited variety of variants for the resulting damask image is given.

In principle, the design of the upper die part 4 and the lower die part 5 and the orientation of the forging blank 2 can be determined in experiments.

In a particularly preferred embodiment, however, it is provided that the course of the layers 11, 12 and thus the resulting damask image is computer simulated in dependence on the above forging parameters. In principle, a modified software for the visualization of fiber gradients can be used for forging conventional materials. The simulation is preferably attributed to the simulation of the reshaping of each individual layer. With the above simulation of the damask image, you can even create damask images according to customer requirements.

It should also be pointed out that the forging step described above is preferably followed by a deburring step in which the burr 14 is removed. Alternatively or additionally, a hole step may be followed, in which the opening 15 of the forged ring is produced.

The Scbuniedeteil 1 is preferably a part of a clock, in particular a wristwatch, and in a particularly preferred embodiment to a watch case. A designated for a watch case forging 1 show the Fig. 1 and 5 , It is to be considered for the understanding that within the framework of the trimming step and / or by means of a further, downstream mechanical processing, the side surfaces of the watch case and recesses for the connection of the bracelet are generated. This is not shown in the drawing.

In principle, the forged part 1 can also be a rosette for a wristwatch or a link of the wristband of a wristwatch. Other application examples are conceivable.

Finally, it should be pointed out that, according to another teaching, which also has independent significance, the forged part 1 produced by the proposed method, in particular the watch case, is claimed as such. Reference may be made to the above statements, insofar as they are suitable for describing the forged part 1 or the watch case as such.

Claims (15)

Method for producing a forged part (1) from a substantially block- or disc-shaped forging blank (2), wherein the forging blank (2) consists essentially of damascus steel, wherein the forging blank (2) is formed in at least one forging step,
characterized,
that the forging blank (2) in the forging step in a forging unit (3) with the die top (4) and die base (5) is formed and that the forging blank (2) relative to its original, perpendicular to the forging (6) extending center plane (7 ) is deformed asymmetrically. Method for producing a forged part (1) from a substantially block- or disc-shaped forging blank (2), wherein the forging blank (2) consists essentially of damascus steel, wherein the forging blank (2) is formed in at least one forging step,
characterized,
that the forging blank (2) in the forging step in a forging unit (3) with the die top (4) and die base (5) is formed and that the die top (4) and / or the die base (5) in the forging step in the forging blank (2 penetrates or penetrate. Method according to claim 1 or 2, characterized in that the upper die part (4) or the lower die part (5) has a substantially convex shape and the die lower part (5) or the die upper part (4) is substantially concave, or that both the Die upper part (4) and the lower die part (5) are configured substantially convex. Method according to one of the preceding claims, characterized in that the forging blank (2) is deformed during the forging step by means of penetration. Method according to one of the preceding claims, characterized in that the upper die part (4) or the lower die part (5) with a mandrel (8) o. The like. During the forging step penetrates into the forging blank (2), preferably, that correspondingly the lower die part (5) or the upper die part (4) has a cup-shaped formation (9) associated with the mandrel (8), preferably that the material of the forging blank is inserted into the forging blank (2) when penetrating the mandrel (8) (2) with respect to the longitudinal axis of the dome (8) flows to the outside and the free volume (10) of the cup-like formation (9) fills. A method according to claim 5, characterized in that the mandrel (8) passes through the original, perpendicular to the forge (6) extending center plane (7) of the forging blank during the forging step. Method according to one of the preceding claims, characterized in that the damascus steel has a plurality of layers (11, 12) of different steel types, preferably that the layers (11, 12) alternately consist of two different types of steel. Method according to one of the preceding claims, characterized in that the damascus steel is designed low in nickel, preferably, that the nickel content of Damascus steel is below 0.13 wt .-%, in particular below 0.12 wt .-%. Method according to one of the preceding claims, characterized in that the damascus steel is designed to be stainless, preferably, that the damascus steel exclusively has layers (11, 12) made of stainless steel. Method according to one of the preceding claims, characterized in that the layers (11, 12) of the damascus steel before the forging step are substantially flat and that the layers (11, 12) after the forging step at least partially each have a three-dimensional shape, preferably that after the forging step, the layers (11, 12) located in the region of the upper part of the blank (4) have a different three-dimensional shape than the layers (11, 12) located in the region of the lower part (5). Method according to one of the preceding claims, characterized in that the penetration depth of the upper die part (4) and / or the lower die part (5) in the forging blank (2) is a multiple of the average Height of the layers (11, 12), in particular more than three times the average height of the layers (11, 12). Method according to one of the preceding claims, characterized in that the penetration of the mandrel (8), possibly the dome, in the forging blank (2) causes a height offset (Δh) within the layers (11, 12), which in the region Side surface (13) of the mandrel (8) takes place, preferably that the height offset (Δh) substantially corresponds to the height of the dome (8), more preferably that the height offset (Δh) is a multiple of the average height of the layers (11, 12 ), in particular more than three times the average height of the layers (11, 12). Method according to one of the preceding claims, characterized in that the layers (11, 12) of the damascus steel are oriented substantially perpendicular to the direction of the forging slide (6), or that the layers (11, 12) of the damascus steel are at an angle to that Forging stroke (6) are aligned. Method according to one of the preceding claims, characterized in that the forging part (1) is a component of a wristwatch, in particular the watch case and / or the rosette and / or a link of the wristband of a wristwatch. Forged part made of damascus steel, which has been produced by a method according to one of the preceding claims.

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