Paprican is skilled at working together with teams of researchers from different companies and universities. Within the corrosion control field, collaborations have been established with scientists and engineers working for such diverse organizations as Oak Ridge National Laboratory, Natural Resources Canada, VTT (Technical Research Centre of Finland), Industeel (Cruesot Loire Industries), Outokumpu, Sandvik, and many universities, including the University of British Columbia, University of Toronto, University of Manchester Institute of Science and Technology, Abo Akademi, and IPST @ Georgia Tech.

Composite Tubes in Kraft Recovery Boilers

	Corrosion and cracking of co-extruded boiler tubes jeopardize safe boiler operation. A multi-year collaborative research program with Oak Ridge National Laboratory and other partners was required to understand the root causes of the problems, and to find both process and metallurgical solutions.

Cross-sections of composite tubes showing cracks produced in-service.(photographs courtesy ORNL)

	Laboratory tests found 304L – the standard material used in composite tubes – to be very susceptible to stress corrosion cracking. Surprisingly, both A825 and A625 were nearly as susceptible to cracking in the cold-worked state as 304L. Subsequent field experience with A625 composite tubes confirmed their susceptibility to cracking when they were bent to form air port opening tubes.

Alloy 625 weld overlay tubes with localized corrosion at corners of air port openings

The environment at the corners of air port openings was also simulated in laboratory tests. The results closely matched experience in the field. These data have been used to develop recommendations for alloys that are more resistant to corrosion in these areas of the boiler.