The Institute of Materials, Minerals and Mining (IOM3) recently honoured Dr B A Szost, R H Vegter and Dr P E J Rivera-Díaz-del-Castillo for their award-winning research paper - Developing Bearing Steels Combining Hydrogen Resistance and Improved Hardness. The team was presented with the Vanadium Award 2012, sponsored by Vanitec, at the annual awards ceremony held onboard the HQS Wellington on the Thames in central London on 8 July 2013.
Their work was carried out at the SKF University Technology Centre, Department of Materials Science and Metallurgy, University of Cambridge, UK, with technical support provided by SKF Engineering & Research Centre, Nieuwegein, Netherlands and financed by SKF AB.
The project has demonstrated that the conflicting objectives of ultra-hardness and hydrogen resistance can be achieved in bearing steels, with excellent rolling contact fatigue (RCF) resistance, by carefully balanced alloy design and novel heat treatment.
In their paper, the authors have given details of the development of a hydrogen embrittlement resistant bearing steel (100Cr6+V) with ultra-high hardness, which is achieved by addition of 0.5 wt% of vanadium to steel 100Cr6 (baseline) with a novel heat treatment consisting of austenitisation (and a temperature spike to dissolve coarse vanadium carbides), followed by tempering at 600C where fine vanadium carbides particles form (and a subsequent temperature spike to dissolve coarse cementite), followed by quench and tempering at 215C, where fine cementite strengthening particles form.
Steel 100Cr6+V was found to have improved hardness, compared to the baseline steel 100Cr6, thought to be due to the strengthening contribution of the fine vanadium carbides formed during the novel heat treatment.
Thermal desorption analysis was conducted to investigate the type of hydrogen traps present in the microstructure of the steels, and steel 100Cr6+V displayed a very high trapping capacity compared to the baseline steel, 100Cr6.
The Vanadium Award recognizes the most outstanding paper in the metallurgy and technology of vanadium and its alloys. Since the Award’s inception in 1982, 29 publications from 11 countries have received the prestigious award.
“The work is sure to benefit the steelmaking and bearing industries.” said David Milbourn, CEO of Vanitec. “Vanitec is pleased to sponsor this Award and will continue to support the research that underscores the role and value of vanadium in modern steelmaking.”