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Molybdenum is key to future of steel industry, seminar told
Improving the performance of steels through the use of molybdenum was the topic of a seminar in Beijing, the first of its kind ever held in China.
Organised by the Beijing Antaike Information Development Co Ltd and hosted by the Central Iron and Steel Research Institute of China(CISRI) and the International Molybdenum Association (IMOA), the seminar was addressed by a range of experts who identified current applications and future use while focussing on the specific effects of molybdenum in steel.
They explained how using molybdenum could bring about more performance with less material and energy use; more value at lower production costs and less pollution.
China’s steel industry is by far the biggest in the World. In March 2010 the production was 55 million tonnes, representing 46 per cent of the total world production and a year-on-year growth of 22.5 per cent.
But Professor Han Dong, Vice-President of the Central Iron and Steel Research Institute, told delegates: “Continuous large production of steels has burdened our society by causing resource shortages, energy consumption and environmental pollution. To solve the problems, high performance steels are increasingly demanded since the life span of steel components can be extended, and steel consumption can be reduced, if higher performance steels are used instead.”
He added that a key element in improving the performance of steel under high stress, high or low temperatures and severe corrosion risk was to alloy it with molybdenum, which played a “multifunctional role.”
Prof Han continued: “Molybdenum has many well known beneficial effects in steels such as hardenability promotion, grain boundary cleaning, heat and corrosion resistance and it is widely used in high strength low alloy (HSLA) steels and alloy steels, including structural alloy steels, bearing steels, tool steels, hot work die steels, heat resistant steels, duplex phase stainless steels and ultra high strength steels.”
Professor Zhiyong Yang, Deputy Director of the Institute for Structural Materials at CISRI, told delegates that molybdenum improved corrosion resistance in austenitic and ferritic stainless steels, an effect that became more evident with a higher Mo content. In high strength stainless steels, molybdenum plays a more important role in improving strength than it does in corrosion resistance.
He said: “Molybdenum has promoted the development of high performance, super austenitic stainless steels which have comparable corrosion resistance with Ni-based superalloys. Corrosion resistance of ferritic stainless steel used for muffle is evidently improved with the addition of a small amount of Mo. The ferritic stainless steel 444, when alloyed with a Mo content of 1%, has better corrosion resistance than the SUS 304 stainless steel and when it is alloyed with a Mo content of 2% it has comparable corrosion resistance with SUS 316 stainless steel.
“Mo can increase tempering resistance and has a secondary hardening effect and can thus improve the strength and cracking resistance in high strength martensitic stainless steels. This strengthening effect is due to the precipitation of fine and dispersed Fe2Mo Laves phases.”
Dr George Krauss, Emeritus Professor at the Colorado School of Mines in the USA, said that molybdenum was an extremely important alloying element in low-alloy steels that were heat treated to excellent combinations of high strength, fatigue resistance, fracture resistance and wear resistance.
He said: “Applications of Mo-containing bar and forging steels include parts such as gears, bearings, shafts, oil country tubular, fasteners, aircraft landing gear and tools.
“The Mo combines with steel carbon content and other alloying elements to enhance hardenability and properties of microstructures produced by quenching and tempering heat treatments.”
The seminar was held at the Beijing Friendship Hotel on 27 & 28 June and was sponsored by: IMOA; Beijing Antaike; Jinduicheng Molybdenum Co Ltd; China Molybdenum Co Ltd; Jinzhou New China Dragon Molybdenum Co Ltd and CoMoTech, Chile.
The proceedings of the seminar, with all papers, are available free of charge for download in Chinese and English from www.imoa.info.
For further informations contact:
T: +44 (0)1925 267557
M: +44 (0)7860 272754
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