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AssigneeSnecma
InventorsJean-Pierre Bergue, Gilbert Leconte
Estimating the term…
Upsetting method of the invention for working a metal slug of cylindrical shape and provided with a coating, is characterized in that the slug is placed, lengthwise, in a sleeve the internal wall of which leaves a space with respect to the lateral surface of the slug, the slug and sleeve assembly is placed in an upsetting container, and upsetting force is exerted on the slug on at least one of its transverse surfaces until a determined slenderness ratio has been obtained, and the slug is separated from the sleeve. By virtue of the invention, the slug is upset continuously but only the slug is upset, this being permitted because of the space formed by the internal wall of the sleeve. The material of the sleeve, for example made of steel, is not welded or seized to the slug, which means that it need not be machined in order to separate the two after the operation.
1- Upsetting method for working a metal slug of cylindrical shape and provided with a coating, wherein the slug is placed, lengthwise, in a sleeve the internal wall of which leaves a space with respect to the lateral surface of the slug, the slug and sleeve assembly is placed in an upsetting container, and upsetting force is exerted on the slug on at least one of its transverse surfaces until a determined slenderness ratio has been obtained, and the slug is separated from the sleeve.
2- Method according to claim 1 in which the slug is of cylindrical shape.
3- Method according to claim 1, in which the slug has an initial slenderness ratio in excess of 2.8.
4- Method according to claim 1 in which the slug is coated with an enamel, forming a pasty state during upsetting.
5- Method according to claim 1 in which, with the sleeve comprising an end wall, prior to placing the assembly in the container, a lid is placed in the sleeve, over the free end of the slug.
6- Method according to claim 5, in which the lid is welded to the sleeve by a weld that will hold it in position and can be broken by the upsetting operation.
7- Method according to claim 5, in which the end wall and the lid each comprise an imprint for centring and preforming the slug.
8- Method according to claim 1, in which the operation of separating the slug from the sleeve involves an operation of milling at least one slot in one of the walls of the sleeve.
9- Method according to claim 1, in which, prior to being placed in the upsetting container, the assembly is heated.
10- Method according to claim 1, in which the upsetting force is exerted by a punch of a hydraulic press on which the upsetting container is mounted.
11- Method according to claim 10 in which the speed of the punch follows a law in which its values are of the order of 10 mm/sec and, at the end of the method, the punch sustains pressure on the slug.
12- Method according to claim 1 in which the material of the sleeve comprises a mild steel.
13- Method according to claim 1, in which the slug originates from powder metallurgy.
14- Use of a sleeve for implementing the method of claim 1, of cylindrical shape, intended to accommodate a metal slug, comprising an end wall from which there rises a cylindrical side wall, the end wall comprising an imprint for centring and preforming a slug.
15- Sleeve and lid assembly comprising a sleeve according to the sleeve used in claim 14 and a lid in the form of a plate of circular shape, the cross section of which is more or less equal to the internal cross section of the sleeve, very slightly smaller.