EP 0375083 A3 19910703 - METALLIC COATING ON STEEL PIPES
Title (en)
METALLIC COATING ON STEEL PIPES
Publication
Application
Priority
DE 3844160 A 19881223
Abstract (en)
[origin: EP0375083A2] The invention relates to a process for applying a metallic coating to metallic sealing regions and/or thread regions, subject to a high surface pressure of steel pipes, by means of a pretreatment, consisting of cleaning and degreasing, of the surface to be coated and an electrolytic deposition of a tin layer, by a first heat treatment at a temperature between 150 and 200 DEG C and a second brief heat treatment above the melting point of tin with subsequent cooling. To indicate a process for applying a metallic coating to the sealing region and/or thread region of steel pipes for crude oil and natural gas production, by means of which seizing is reliably prevented in a grease-free screwed union even in the case of repeated screwing and whose sealing effect is optimised, it is proposed first to apply a base layer consisting of or containing tin to the sealing and/or thread regions and then electrolytically to deposit thereon an element or an alloy from the group of the ductile non-ferrous metals to form a top layer and subsequently to heat the zone thus treated for 1-10 seconds at a temperature up to 50 K above the melting point of tin.
IPC 1-7
IPC 8 full level
C25D 5/26 (2006.01); C25D 5/10 (2006.01); C25D 5/50 (2006.01)
CPC (source: EP US)
C25D 5/50 (2013.01 - EP US)
Citation (search report)
- [AD] DE 3147967 A1 19830714 - MANNESMANN AG [DE]
- [AD] EP 0246387 A1 19871125 - MANNESMANN AG [DE]
Designated contracting state (EPC)
AT DE FR GB IT SE
DOCDB simple family (publication)
EP 0375083 A2 19900627; EP 0375083 A3 19910703; DE 3844160 A1 19900628; DE 3844160 C2 19910425; JP H02221393 A 19900904; US 5094730 A 19920310
DOCDB simple family (application)
EP 89250097 A 19891127; DE 3844160 A 19881223; JP 33459989 A 19891222; US 45595989 A 19891222