June 27, 2014
Charles Thompson Ltd. (CTL), South Yorkshire, U.K., has successfully produced a zirconium bundle and header for a TEMA AKU type heat exchanger from a Grade 702, 1.57-in.-thick flat plate.
“The challenge was the hot rolling of the zirconium at this thickness, taking into account the procedures, control, and additional requirements like cleanliness, surface finish, and uniform heat specifications,” said Technical Director Peter Coe. “Zirconium, especially of this form, doesn’t like being worked, and the risks of cracking are extremely high. Of course, the part would be useless with one crack, and the smallest scratch or indent could have been disastrous.”
The company heat-treated the zirconium and prebent the ends to form the cylinder. These were machined, and the plate was heat-treated again before final rolling and welding. When complete, the cylinder was 35.8 in. dia. and 47.24 in. long.