Carbon steel flanges need surface protection from the moment they are machined. The right coating depends on how long the flanges will be stored and where they will be installed.
Anti-rust oil
The standard protection for flanges that will be painted or insulated after installation. It is cheap and easy to remove, but only protects during transport and indoor storage.
Black or yellow paint
A thin primer or varnish gives better protection during storage and is common in European and Middle East orders. Sealing faces are usually left unpainted or masked so that the gasket seats on clean metal.
Hot-dip galvanizing
Flanges are dipped in molten zinc, giving long-term corrosion protection for water, fire protection and outdoor piping. The zinc layer adds thickness, so threaded flanges need their threads re-cut or protected, and sealing faces should be checked for zinc build-up.
Electro-galvanizing
A thinner zinc layer applied electrically. It gives a smooth finish and protects during storage, but offers less outdoor protection than hot-dip galvanizing.
For the RFQ
Name the coating type, colour (for paint), any coating thickness requirement and whether sealing faces and threads must be masked.
About Hyupshin Flanges
Shandong Hyupshin Flanges Co., Ltd has manufactured forged steel flanges since 1988 and exports more than 90% of its production. Monthly output is about 2,000 tons, with a supply range of DN15 to DN3000. Orders are supplied with EN 10204 3.1 material certificates, and third-party inspection can be arranged. Certifications include ISO 9001, Korea KS, CE PED, UKCA, AD 2000, LRQA.
See the flange rust prevention methods, or send your RFQ, drawing or item list. Minimum order is 1 ton or 100 pieces.