Skip Navigation

Products and solutions, 2002-04-15, 02:00 AM

Nickel-base alloy strip for BUBI pipes

Nicrofer 4221 - alloy 825 for acid gas applications

The Strip division of ThyssenKrupp VDM has recently increased production of the nickel-ferro-chromium alloy Nicrofer 4221 - alloy 825 (material No. 2.4858). It is being supplied to BUTTING Edelstahlrohre, a German company based in Wittingen-Knesebeck, to produce pipes for acid gas applications in the oil and gas industry. As part of the "Bintang Field Development Project", BUTTING is manufacturing almost 2,000 metric tons of BUBI pipes and other clad pipes from steel grade X65 + Nicrofer 4221 for its customer "Esso Production Malaysia".

A leading producer of welded pipes, BUTTING Edelstahlrohre is using the ThyssenKrupp VDM material to manufacture so-called BUBI (BUTTING-BIMETAL) pipes, which consist of a ferritic outer pipe and a welded inner pipe. Nicrofer 4221`s high corrosion resistance made it a natural choice for the inner pipes, which are to be used to convey acid gas, although the material can also resist attack from sulfuric, phosphoric and nitric acid, organic acids as well as calcium and magnesium hydroxides. Its 42 percent nickel content also gives Nicrofer 4221 outstanding resistance to stress corrosion cracking.

Conventional clad pipes are normally welded from roll-bonded plates. By contrast, BUBI pipes feature a corrosion-resistant inner pipe which is telescopically aligned inside a low-alloy outer pipe. Inner and outer pipes are then expanded and calibrated to provide a tight mechanical bond. Pipes of this type offer advantages whenever the thin inner pipe (up to 3 mm wall thickness) satisfies corrosion resistance requirements and the outer pipe can be used to handle pressure loads. In such cases, BUBI pipes - especially in longer lengths - offer substantial economic benefits over solid-wall designs of corrosion-resistant material.

For more information:
ThyssenKrupp VDM GmbH
Heinz-Jürgen Möller, Head of Sales Organization and Marketing Services
Tel. +49 (0)2392 55 25 01
Fax +49 (0)2392 55 25 96

To the top