Process of producing corrosion-resistant tubular connection pieces

US4454977A · kind A · utility

Assignee

• W. C. Heraeus GmbH · DE

Inventors

• Fritz Aldinger · Rodenbach, DE
• Harry Heinke · Niederrodenbach, DE
• Franz Schreiber · Tauberbischofsheim, DE
• Waltraud Werdecker · Hanau, DE

Key dates

• Filing date: Apr 13, 1982
• Grant date: Jun 19, 1984
• Expiry date: Apr 13, 2002

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B23K20/14
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

In order to connect a tube of a more common material, such as stainless steel, to a tube of a highly corrosion-resistant metal such as tantalum, where the two tubes cannot be welded together by fussion technology, a connection piece is made of two closely fitting layers of the two materials telescoped into each other, which are exposed to hot compressed noble gas, such as argon, in a pressure vessel, with precautions against oxidation from residual oxygen in the noble gas. Then the ends are machined to remove any hard soldered portion used to make a gas-tight seal of the blank before pressure treatment, after which a longer ring-shaped section of the stainless part of the connection piece is removed at one end and likewise a section of the tantalum part of the connection piece at the other end, so that the projecting ends can be welded to the pipes to be joined. One method of protection against oxidation is to use a blank in which a tantalum tube is fitted between two stainless steel tubes, one of which is completely removed by machining after the pressure treatment.