The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 21, 1981
Filed:
Nov. 03, 1978
Frank Weber, Sulzbach-Rosenberg, DE;
Erwin Jericho, Sulzbach-Rosenberg, DE;
Werner Friedrichs, Amberg, DE;
Eisenwerk-Gesellschaft Maximilianshutte, Sulzbach-Rosenberg, DE;
Abstract
A pierced metal blank having an annular cross-section with one end closed and the other end open for use in the manufacture of seamless tubes has a bore with portions of different diameters, the portion of larger diameter, which is adjacent the open end of the blank has a wall thickness which is less than that of the portion of smaller diameter which is adjacent the closed end of the blank. Preferably there is a conical transition between the two portions of different diameters. The blank is preferably made from a metal billet of square cross-section in a substantially cylindrical piercing mould by piercing the billet within the mould by means of a stepped mandrel which presses the material of the square billet outwards into contact with the cylindrical wall of the mould.