Redefining the strain aged state of unalloyed mild steels

The unalloyed mild steels suitable for deep-drawing have a wide range of applications in the manufacturing industry. They are characterised by a high degree of cold formability, which is greatly reduced by the so-called “strain-aging” phenomenon. This leads to increased scrap formation, which is extremely detrimental to the metalworking industries. Strain-aging of steels is a complex subject with a very rich literature, although most of the research on unalloyed steels dates back to the 1970s and 1980s. Since then, steel making technology has developed intensively, which has also had an impact on the strain-aging process of unalloyed mild steels in practice. Our article describes the nature of the strain-aging phenomenon as it is experienced today. The degree of strain-aging described earlier in the literature is no longer fully present in mild steel products produced with today’s technology.