Astia Ariani, "Analysis of the Effect of Temperature Variation on the Mechanical Properties of ST 60 Steel Using the Jominy Test Method" (Supervised by Muhammad Balfas and Akhiruddin Pasdah).

Abstract

This study aims to analyze the effect of heating temperature variations on the hardenability, hardness, and microstructure of ST 60 steel using the Jominy End-Quench Test method. ST 60 steel specimens were heated at temperatures of 700°C, 800°C, and 900°C for 30 minutes, followed by rapid cooling at one end using water as the quenching medium. The specimens were then subjected to Rockwell C (HRC) hardness testing and microstructural examination. The results indicate that increasing the heating temperature enhances both the hardness and the hardenability depth of ST 60 steel. The specimen heated to 900°C exhibited the highest hardness value of 63 HRC at the point closest to the quenched end, with an average hardness of 56.9 HRC, which was attributed to the dominant formation of the martensitic phase. In contrast, the hardness gradually decreased with increasing distance from the quenched end due to the formation of ferrite and pearlite phases. Therefore, a heating temperature of 900°C was determined to be the optimum condition for improving the mechanical properties of ST 60 steel.