1999 Volume 39 Issue 7 Pages 637-648
The processing and mechanical properties of ultrahigh carbon steels (UHCS) have been studied over the past twenty-five years, initially at Stanford University and later at Lawrence Livermore National Laboratory. These studies have shown that such steels ( 1 to 2.1% C) can be made superplastic at elevated temperature, and have high strength and good ductility at room temperature. The metallurgy of UHCSs is now well understood allowing economical procedures to achieve ultra-fine hypereutectoid spheroidite, pearlite and optically-unresolvable martensite. The investigation of these UHCSs brought us, eventually, to study the history and metallurgy of Damascus steel and Japanese swords, and of ancient blacksmiths. These ancient Persian and Japanese weapons, the most famous in the world, were also ultrahigh carbon steels. It is proposed that the iron age may have begun at the same time period as the early bronze age, approximately 7000 BC. The Damascus steel age began at about 2000 BC, the same as the full bronze age.