Steam condensers in a Vietnam powerplant use large quantities of thin-wall tubing to cool steam leaving the turbine.
The lower the temperature of the steam, the more electricity produced. Unfortunately, the design let fastmoving water in the condenser mix with sandy, brackish river water. This accelerated erosion and caused premature failure of the aluminum brass tubes and necessitated a complete retube of the condenser to restore full capacity.
Two years of material trials and development between the power company and Sandvik Materials Technology Co., Scranton Pa. (smt.sandvik.com), pinpointed a stainless steel, Sandvik SAF 2507, as a suitable material for resisting erosion corrosion and corrosion fatigue. The high-alloy steel outperformed not only aluminum brass but also other austenitic stainless steels and specialty alloys. To retube the entire plant, 250 km of the Sandvik SAF 2507 tubing will be installed into an existing tube plate within the powerplant condenser.