Process for the after-treatment of powder-metallurgically produced extruded tubes
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Dec 21, 1982
Grant Date -
N/A
app pub date -
Sep 6, 1979
filing date -
Sep 6, 1978
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A process for the after-treatment of powder-metallurgically produced extruded tubes of stainless steel or highly alloyed nickel steels, pressings initially being produced by introducing into a capsule of thin sheet steel a powder consisting predominantly of spherical particles which have been produced from the required starting material by sputtering and, after the capsule has been closed, the density of the powder is increased to at least about 80% to about 93% of the theoretical density by cold isostatic pressing and the pressings obtained are then extruded into tubes at temperatures around 1200.degree. C. using glass as the lubricant and the extruded tubes still surrounded by the capsule are initially treated with aqueous sulphuric acid to remove the glass still present on their surface, subsequently cold-worked by drawing or reciprocating rolling and, after cold-working, are annealed in an oxidising atmosphere until the capsule has been converted into scale to such an extent that a surface free from capsule residues is obtained after pickling with mild pickles.
First Claim
Family
International Classification(s)
Cited Art Landscape
Patent Citation Ranking
Recipient Email Address
Recipient Email Address
Comment
Recipient Email Address
Add to Portfolio(s)
To add this patent to one, or more, of your portfolios, simply click the add button.
This Patent is in these Portfolios:
Add to additional portfolios:
Last Refreshed On:
Changes done successfully