The Cast Metals Federation (CMF) has urged engineering designers to take advantage of a new guide that highlights the potential and environmental sustainability of cast iron, the ‘original composite material’.
‘Cast Irons – Part 1: Materials and Properties for Design’, which has been published by the International Standards Organisation as a technical report, ISO/TR 10809-1:2023, provides a comprehensive overview of the design considerations and potential of this hugely versatile family of metals. The newly updated report includes tables to assist designers with the selection of the correct type of cast iron for the job at hand and then choose the correct grade, depending upon the component criteria required.
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There’s also information about typical compositions, mechanical properties and section sensitivity aspects (needed because of the effect of variations in cooling rates due to section thickness), along with a series of useful tables, images and diagrams.
The CMF hopes that the guide will act as a bible for key design considerations, principles, limitations and opportunities associated with the use of cast irons.
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‘The metallurgical aspects of cast irons are often not well understood and cast iron is, after all, the original composite material, said Pam Murrell, CHE of the CMF and chair of ISO TC 25, under which committee the work was organised. ‘So, while this revised guide is not a textbook of cast iron metallurgy, I am confident that designers and engineers will find it enormously helpful in discussions with their cast-component suppliers, while materials scientists and students of ferrous metallurgy should also find it hugely informative. We want people designing the next generation of products and applications to do so by making informed material choices and then hopefully they can leverage the huge versatility and power of cast irons.’
The family of cast irons offers a huge range of mechanical properties to the engineering designer, yet many are unaware of the full range of iron grades available to them and the opportunities that they provide in terms of castability and applicability. In most modern economies, cast irons are readily produced using recycled metal (using steel scrap or cast-iron parts at end of life) making them ideal for companies looking to reduce the carbon footprint of their supply chain.
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‘When most people say cast iron, more often than not they mean grey cast iron, which is a relatively low cost and easily castable material, but with excellent machineability and good vibration damping and heat transfer properties – this makes it highly versatile. But this is to ignore the wider family of cast irons,’ Murrell said. ‘They believe cast iron is a material that does not offer much in terms of strength and ductility – but to only consider grey cast irons is to ignore all the other types of cast iron that are available, many of which do offer ductility, wear resistance and corrosion resistance, as well as strength and castability.’
The report can be purchased here.