pISSN : 1598-706X / eISSN : 2288-8381
한국주조공학회지 (14권1호 52-61)
Effect of Ni on the Mechanical Properties and Fracture Characteristics of Austempered Ductile Iron
오스템퍼드 구상흑연주철의 파괴특성에 미치는 Ni의 영향에 관한 연구
Sang-Ho Baek*, Hong-Beom Kim*, Chang-Kuy Kim**, Chang-Ock Choi*
*Dong-A University, **Pusan National University of Technology
The effect of Ni addition, on the mechanical properties and fracture characteristics of Mo-Cu and Mo-Ni-Cu alloyed ductile iron austenitized at 900℃ and austempering temperatures of 250℃, 300℃ and 350℃. The tensile strength, yield strength and hardness are decreased and elongation and impact value are increased in both Mo-Cu and Mo-Ni-Cu alloyed austempered ductile iron, with increased austempering temperature. According to the austempering temperature are increased, the amount of retained austenite are increased. Maximum value of fracture toughness is obtained at 350℃ austempering temperature at this condition, the amount of retained austenite came to 40% in Mo-Ni-Cu alloyed ADI and 34% in Mo-Cu alloyed ADI. The fracture surface of ADI which had represented high toughness are showed a quasi-cleavage pattern and a dimple pattern with micro void. Comparing the fracture characteristics of Mo-Cu alloyed ADI with that of Mo-Ni-Cu alloyed ADI, the latter was superior to the former.