Effect of Central Segregation on Drawability of High-carbon Steel Wire Rod Manufactured from Continuously Cast Blooms

Abstract

A study has been made on the microstructure of the central segregation zone in wire rod and its fracture process for the purpose of improving the drawability by reducing central segregation in high-carbon steel wire rod manufactured from continuously cast blooms. (1) In the central segregation zone of wire rod, a kind of duplex segregation which consists of segregation plateau and microsegregation peaks was observed. This type of segregation is considered to originate from the macrosegregation in cast blooms. (2) The fracture which occurred during wire drawing was initiated from the martensite stringers or proeutectoid cementite networks on the microsegregation peaks formed on the segregation plateau. The propagation of fracture was governed by the width of the segregation plateau. (3) A dominant factor governing wire drawability is the width of the segregation plateau, that is, the width of the macrosegregation spots in cast blooms.