Analysis of Quenching Parameters in AISI 4340 Steel by Using Design of Experiments

This paper aims to investigate the effects of quenching parameters (temperature and time of austenitizing and cooling rate) on the microstructure, hardness and distortion of AISI 4340 steel by Design of Experiments (DoE). The factorial design was used to determine the influence of the factors on the response variable. After quench samples were characterized by optical and scanning electron microscopy, hardness test and dimensional analysis. Navy C-rings samples are used to determine the distortions after quenching due to development of residual stresses caused by non-uniform cooling. Results show that the cooling rate has a significant effect on the steel after quenching, however, the suitability of all factors is important to achieve the desired properties.