DE2304228A1 - Process for the production of conical or truncated pyramid-shaped recesses in metal sheets, especially those made from aluminum - Google Patents

Description

Process for the production of depressions in the shape of a cone or a truncated pyramid in sheet metal, in particular those made of aluminum materials. The invention relates to a process for the production of conical or truncated pyramidal depressions in Metal sheets, especially those made of aluminum materials, by pressing, drawing, or similar forming process.

Such sheets can be used, for example, to produce so-called Bumped sheet metal plates are used, i.e. plate elements in which the connection two or more plates happen over these humps. Here you can either Connect the humps of one sheet with a sheet free of bumps or both Metal sheets are provided with bosses, which are then connected to one another at the boss tips will.

The prior art is that the production of such hump plates is only possible when the material is warm. For this it is necessary for curable Aluminum alloys to bring the sheets into the tool at solution annealing temperature and to deform, with the press die cooled and the die at hot working temperature of the respective material must be heated.

This process requires a lot of tools (cooling, heating) and in addition to the generally difficult production (narrow temperature range during deformation, uneven heating of the starting sheet, etc.) due to the hot deformation requires a high level of straightening effort.

According to the invention, the production of conical and truncated pyramids takes place Depressions in sheet metal, in particular made of aluminum materials, thereby that the unheated sheet is either in the naturally hard or cold-hardened state is deformed in two successive stages, being continuous in the first The preferred deformation stage is a spherical cap and, in the second stage, the final shape will be produced.

In this way it is achieved that when, for example, the tapered or truncated pyramid-shaped recess in hardenable Al alloys in a for a series production reasonable time after the quenching at any point of the same tearing occurs, especially not in the area at risk of breakage at the hump tips. It is useful that the entire material strain caused by the hump shape is already introduced into the material through the spherical cap-shaped projection. In addition to the naturally hard alloys, the hardenable high-strength alloys are used as the material AlZnMg and AlMgSi alloys are particularly suitable because they have high strength with low Have their own weight, adequate corrosion resistance and good weldability. Through an additional heat treatment of the smooth starting sheets after the solution heat treatment and quenching it is also possible with the alloy AlMgSi cold age hardened, perform the deformation independently of the curing time.

The drawing illustrates the formation of the hump as well as example of the two press stages. Figure 1 shows the two pressing stages with the die 1 and the male part 3 as a preference and 4 as a finished draw. The smooth sheet 5 is thereby first pushed under the patrix 3, where a spherical cap-shaped hump as Preference is minted. The sheet is then conveyed further in the direction of deformation until the spherical cap-shaped boss lies under the patrix 4. Through the next Stroke, the hump end shape and at the same time the next spherical cap is produced.

The external shape of the hump is determined by the formation of the Draw edge 2 of the die 1 and the male mold 4, which is of the conical or pyramid shape of the hump are adapted. In the production of truncated pyramid-shaped depressions care must be taken that pyramid edges are rounded.

For the production of hump plates, it is useful that you have the The ratio of the hump height H to the sheet thickness S (see FIG. 2) is chosen to be as large as possible, since one then receives a large section modulus with a low dead weight.

The compressive strength of the hump can be increased if you do that Ratio d: D can be approximated as close as possible to 1: 1.

According to the method according to the invention, cupping ratios in Dependence of the sheet thickness S to H: S Z 18: I with a ratio of D: d = 4.0: I can be achieved, the diameter of the ball DK being equal to the depth H 1 of the Preferably in a ratio of DK: H 1 = 4 to 4.3: 1.

Claims (2)

Claims 1.) Process for the production of conical or truncated pyramids Depressions in metal sheets, in particular those made of aluminum #erkstoffe, through Pressing, drawing or similar forming process, characterized in that it is not heated sheet either in the naturally hard or cold-hardened state in two successive stages Stages is deformed, with continuous in the first deformation stage as a preference a spherical cap and in the second stage the final shape is produced. 2.) The method according to claim 1, characterized in that the entire, Material expansion caused by the hump shape already through the spherical cap-shaped Preference is introduced into the material.