Microstructure evolution and hardness of S30C carbon steel produced by powder bed fusion using an electron beam and subsequent heat treatments

Abstract

• S30C carbon steel was first fabricated by PBF-EB additive manufacturing. • PBF-EB-processed S30C carbon steel consists of ferrite and pearlite. • PBF-EB-processed S30C carbon steel had a height-dependent effect. • Quenched sample was needle-like slatted martensite with the maximum hardness. The microstructure and hardness of S30C carbon steel fabricated via powder bed fusion using an electron beam (PBF-EB) and the influence of subsequent heat treatments were firstly investigated. The microstructure of as-built S30C, comprising ferrite and pearlite with an amount of dislocations. The microstructure and hardness showed a height-dependent relationship along building direction. The quenched sample showed lath martensite with maximum hardness (HV 643 ± 18), which transformed to tempered martensite after further tempering. This study provides a research basis for the application of PBF-EB technology in the development of high-performance carbon steel.