| Title |
Fracture Properties on the Austempering control times of Mo - Cu Ductile Cast Iron |
| Authors |
박현구(Hyun Ku Park); 백승호(Seung Ho Park); 이원식(Won Sik Lee); 강인찬(In Chan Kang) |
| Abstract |
In this study we were examined the effects of austempering time on the fracture properties of Mo-Cu alloyed ADI(austempered ductile iron). All the specimens were austenitized at 900℃for 1.5hr and austempered at 320∼380℃ for various holding time of 0.25∼4hrs. In the microstructure of this specimens austempered for 0.25hr and 0.5hr at all austempering temperatures was shown untransformed austenite volume partially and it was embrittled by martensite transformation. The strenth of these ADI decreases with the increases of austempering temperature, but the fracture toughness increases. When austempering time at various austempering temperatures is 2∼3hr, the strength and fracture toughness was had best value. Also, it`s ductility and fracture tohghness have been proportion with retained austenite volume and SEM fractography of high toughness ADI was showed the dimple and fibrous pattern. |