Yüksek Silisli Lamel Grafit Dökme Demir Kamyon Fren Disklerinin Sürtünme ve Aşınma Davranışı

Abstract

In this study, the chemical compositions of high-silicon lamellar graphite cast irons commonly used in truck brake discs and the effects of applied heat treatments on their friction and wear behaviors were investigated. For this purpose, samples with two different chemical compositions (first with 2.43 C and 4.5 Si; second with 2.5 C and 4.2 Si) were produced, and homogenization annealing was applied at 900°C for 30, 45, and 60 minutes followed by air cooling. Hardness, tensile testing, and wear testing were performed on the heat-treated samples. Wear tests were conducted at room temperature and dry sliding conditions (20 N load, 250 mm sliding distance, and 200 mm/min sliding speed) using a ball-on-disk wear apparatus against 52100 bearing steel. The increase in homogenization heat treatment time resulted in an increase in hardness and tensile strength values for both lamellar graphite cast iron grades. The wear test results indicated that both the chemical composition and the duration of applied heat treatment influenced the friction coefficient and wear volume losses. Since high friction coefficient and low wear volume losses are desired in brake discs, it was determined that the best result among the compared samples was achieved in the sample produced with a chemical composition of 2.5 C and 4.2 Si, and then homogenized at 900°C for 30 minutes.