Microstructures of Heavily-deformed High Carbon Steel Wires

The influence of heavy drawing (true strain4.0) on the structures of pearlitic steel wires containing 0.9mass% of carbon has been investigated. As for ferrite region, typical dislocation structures are observed in the lightly deformed wires and cell structures are observed in the heavily deformed wires. After heavy drawing, cementite has polycrystal structures and are decomposed partially. The diameter of the cementite particles are less than 5 nm and the amount of the decomposition is strongly affected by strain and half of the cementite is decomposed when true strain is 4.0.The free carbon which comes from cementite decomposition is insoluble in ferrite and it might be segregated at dislocations both in ferrite and at cementite/ferrite boundaries.