PENGARUH VARIASI HOLDING TIME PADA PROSES PEMANASAN TERHADAP KEKERASAN DAN STRUKTUR MIKRO BAJA S45C

Abstract

This study aims to analyze the effect of holding time variation in the heating process on the hardness value and microstructure of S45C steel. S45C steel is a medium carbon steel with a carbon content of 0.42-0.48%, which is widely used in the manufacturing industry for machine components such as shafts and gears. The heat treatment process was carried out at 900°C with variations without holding time and with holding times of 5, 10, 15, and 20 minutes, followed by rapid cooling using water as a cooling medium. The results showed that holding time had a significant effect on the hardness and microstructure of the steel. The highest hardness value was achieved at a holding time of 10 minutes with an average of 565.3 HB, while the microstructure was dominated by the martensite phase (87.5%) formed due to rapid cooling. These results show that holding time optimization can improve the mechanical properties of S45C steel, especially hardness, making it useful for industrial applications that require materials with high wear resistance.