Pengaruh Waktu Penahanan (Holding Time) pada Proses Heat Treatment terhadap Kinerja Material Baja Pegas Daun

Abstract

Used leaf springs are materials that still retain good mechanical properties and are widely utilized as alternative raw materials for manufacturing agricultural tools, particularly by small and medium enterprises (SMEs). This approach is considered cost-effective without compromising product quality. This study aims to examine the effect of holding time during heat treatment on the hardness and toughness of leaf spring steel. The heat treatment process was conducted at an austenitizing temperature of 900 °C with holding times of 15, 25, and 30 minutes, followed by rapid quenching using water. The results indicate that hardness increases significantly with longer holding times, from 43 HRC in non-reconditioned specimens to 61.5 HRC in specimens held for 30 minutes. Conversely, toughness values decreased drastically, from 2.2 J/mm³ to nearly zero after heat treatment. These findings reveal a trade-off between hardness and toughness, emphasizing the need to select heat treatment parameters based on the intended application of the component. The results are expected to serve as a reference for optimizing the reuse of used leaf spring steel in agricultural tool applications.