Klockner-Humboldt-Deutz of Bochum, West Germany, chose Ferralium® 255 super duplex stainless steel (UNS S32550, Alloy 255, DIN 1.4507, ASTM F61) for 24 K-H-D liquid ring gas pumps supplied to fertiliser plants in the USSR. Some 30 tons of Ferralium® 255 went to the pump manufacturer as castings weighing up to 370lb each and as wrought bar and plate.
Ferralium® 255 has a long-established reputation as a super stainless steel, with considerably better performance in most corrosive environments than normal austenitic stainless steels. One of its speciality applications is handling the extremely corrosive and mechanically aggressive conditions of the "wet" process production of fertiliser grade phosphoric acid.
The pump castings and twelve impellers show the versatility and workability of the alloy: components of a complex design can be fabricated in both cast and wrought material by entirely traditional techniques. The liquid ring gas pump has a wide range of applications, and its design gives reliability, long service life and low maintenance costs, since there is no sliding friction between critical metal parts.
