Analisis Pengaruh Kedalaman Penyayatan Proses Bubut Terhadap Distorsi Sumbu Poros Pada Material Aisi 4340 Pasca Proses Hardening

Abstract

AISI 4340 alloy steel is widely applied in shaft components that demand high mechanical strength and wear resistance. Nevertheless, the hardening process frequently induces shaft axis distortion, leading to dimensional deviations and additional corrective machining. One of the contributing factors that has not been sufficiently addressed is the influence of machining parameters prior to heat treatment, particularly the turning depth of cut . This study experimentally investigates the relationship between turning depth of cut  and shaft axis distortion after hardening in AISI 4340 steel. Cylindrical specimens with dimensions of Ø10 mm × 200 mm were machined using depth of cut  variations of 0.5 mm, 1.0 mm, 1.5 mm, and 2.0 mm, followed by a hardening process in an electric furnace with variations in quenching media and quenching orientation. Distortion was measured using a dial indicator at five axial positions, while hardness was evaluated using the Rockwell C method. Parameter influence was further analyzed using the Taguchi method. The results demonstrate that quenching media is the dominant factor affecting distortion, followed by turning depth of cut . An increase in depth of cut  results in higher post-hardening shaft distortion, whereas vertical oil quenching produces the lowest distortion values. These findings provide practical machining and heat treatment references to minimize shaft distortion and improve manufacturing efficiency.