GB1431801A - Method of producing an article or continuous strip from metallic powder - Google Patents

Abstract

1431801 Production of hot pressed metal articles ARMCO STEEL CORP 1 May 1973 20586/73 Heading C7D Metal or alloy articles such as strip are produced by feeding a binder free metal powder between opposed electrode rolls and simultaneously applying pressure and an electric current to the rolls to form a sintered strip with a density approaching theoretical. The rolls are preferably segmented with each pair of opposing segments being separately supplied with electrical power so that the power to each pair can be regulated and a uniform temperature achieved across the strip. The powder may be precompacted by electrode rolls and the voltage applied to the precompacting rolls is greater than that applied to the final compacting rolls. The powder may be fed between horizontal rolls 12, 12a as shown in Fig. 1 and dry H 2 , dew point -40‹C may be introduced into the roll nip from nozzles 16, 16a. The rolled strip may be cooled at station 18, cold rolled at 20 and heat-treated at 22. Alternatively the powder from a mould 34 may be fed into the opening of a continuous U-shaped mould 32 and rolled between vertical electrode rolls 30, 30a as in Fig. 2. In an alternative embodiment uniformity of density across the strip is achieved by altering the depth of powder feed on a conveyer belt fed to the rolls or by using rolls with a concave rolling surface. Examples are given of rolling low carbon 18Cr- 12Ni-2À5Mo stainless steel and Ti-6Al-4V alloy powders.