Optimization in Spheroidized Annealing of Two AISI 1022 Low Carbon Steels Used in Bolt Industry

Abstract

-The quality of spheroidize annealed steel wire affects the forming quality of screws. Various parameters affect the quality of spheroidized annealing such as spheroidized annealing temperature, prolonged heating time, furnace cooling time and flow rate of nitrogen. The effects of spheroidized annealing parameters affect the quality characteristics of wires, such as tensile strength and hardness. In this study, Taguchi method is used to obtain optimum spheroidized annealing conditions to improve the mechanical properties of two AISI 1022 low carbon steel wires, WA and WB. The main quality characteristic of spheroidized annealing wires is tensile strength with a target value of 39 kgf/mm 2 . It is revealed experimentally that, for wire WA, spheroidized annealing temperature and prolonged heating time are the significant factors, however, for wire WB, spheroidized annealing temperature and furnace cooling time are the significant factors to influence the mechanical properties of steel wires.