The highest strength steel material now in practical use is named Superfine Metal in the form of ultra-fine wire having about ten times the strength of general-purpose ordinary carbon steel (SS400), as shown in the figure. This improved material contains 0.15% carbon, 0.8% silicon, and 1.5% manganese, and is vacuum-melted to reduce the content of such impurities as phosphorus, sulfur, oxygen, and nitrogen. It is then hot rolled to produce wire rod and heat-treated to form a structure in which martensitic-phase particles are dispersed in a ferrite matrix. Wire rod with this structure is reduced to ultra fine wire by cold-drawing through a die, the cross-sectional area being reduced by 99.99%, from 3mm to 30μm in diameter. Such heavy reduction is possible because the hard martensitic phase is made fine and surrounded by the soft ferritic phase. Ferrite work-hardens as a result of heavy processing and, at the same time, becomes a fibrous structure elongated in the working direction. The intervals between fibers are extremely narrow at 50 nanometers. This refinement effect endows the material with characteristically high ductility despite its super-high strength. The good formability of this material can be clearly seen in the photograph.