Corrosion-Resistant, Highly Machinable Tool Steel

Deutsche Edelstahlwerke (DEW), a plastic mold steel producer and member of Swiss Steel Group, highlights Opticut, a tool steel that combines improved machinability with optimized corrosion resistance. DEW says these features are paramount, as corrosion-resistant stainless steel is not only required for molds, but is also essential for mold frames, which are typically produced in large machining volumes.

Material machinability, DEW notes, is typically enhanced by the addition of sulfur. The forming process — hot rolling or forging — often leads to elongated sulfides in the matrix, which can deteriorate mechanical properties and resistance to corrosion in the steel. However, through DEW’s new approach — a special treatment applied to the liquid steel during secondary metallurgy — the morphology and chemical composition of the sulfides are said to be modified and improved, leading to enhanced machinability without any detrimental effect on the corrosion resistance of the mold steel.

Opticut steels show significant improvements of the homogeneity of the microstructure and distribution of the sulfide inclusions, DEW says. Milling tests revealed an increased productivity compared to conventionally manufactured material, which means improved lifetime of milling inserts even at highest cutting speeds. At the same time, mechanical properties, in particular toughness, were improved, while corrosion resistance was not affected. The new Opticut materials are now available as Formadur 2085 Opticut and Corroplast Opticut through Swiss Steel USA.