Svensk Kärnbränslehantering AB Swedish Nuclear Fuel and Waste Management Co Box 250, SE-101 24 Stockholm Phone +46 8 459 84 00 R-09-14 Stress strain flow curves for Cu-OFP Rolf Sandström, Josefin Hallgren Materials Science and Engineering Royal Institute of Technology (KTH) Gunnar Burman, Bodycote Materials Testing AB April 2009