Technical Manager, Firth Rixson Superalloys Ltd, Glossop, Derbyshire
Reader in Medical Engineering, University of Bradford, West Yorkshire
Metallurgist, Firth Rixson Superalloys Ltd, Glossop,
International Exchange Student, California Polytechnic State University, College of Engineering, San Luis Obispo, CA
Pages: 21 Published: Jan 1999
The medical implant market's requirement for a forged version of the normally cast only, high carbon (approximately 0.2%) variant of the Co-Cr-Mo alloy, which would combine increased wear resistance with the mechanical properties of the low carbon (approximately 0.05%) variant of Co-Cr-Mo, initiated an investigation to establish a viable manufacturing route for the high carbon variant. Initially, a single melted (vacuum induction melted) cast and forged route, and a metal spraying process were examined. Subsequently a vacuum induction melted, electroslag remelted and hot working route was developed using a number of compositional and thermo mechanical processing variants. The mechanical properties obtained on rolled and forged high carbon Co-Cr-Mo bar from 20mm to 50mm diameter were similar to those of the low carbon variant and also met the requirement of ASTM F1537-94 (warm worked). The wear resistance of the high carbon variant, measured using a pin on disc method, indicated some advantage over the low carbon variant at high applied loads.
cobalt alloys (for surgical implants), mechanical properties, high carbon cobalt-chromium-molybdenum, implants, medical, forged, wear resistance
Paper ID: STP14260S