AC4A 합금의 충격특성 및 피로특성에 미치는 스크랩 함량의 영향

• Published in: 한국주조공학회지 (주조) Vol. 36; no. 6; pp. 9 - 16
• Main Authors: 김헌주, Heon-joo Kim
• Format: Journal Article
• Language: Korean
• Published: 한국주조공학회 31.12.2016
• Subjects: AC4A alloy; Fatigue property; Impact property; Scrap content
• ISSN: 1598-706X

The effects of scrap content on the impact and fatigue properties were investigated in AC4A alloy. The impact absorbed energy of as-cast specimens were 3.61, 3.56, 3.47, and 3.08 Joules, respectively, when scrap contents of the specimens were 0, 20, 35, and 50%. And, the corresponding energy levels of the T6 heat-treated condition were 3.66, 3.48, 3.25, and 2.96 Joule. In the same way, the fatigue strength values of the as-cast specimens were 53.2, 52.0, 48.4, and 43.8MPa, respectively, and the corresponding fatigue strengths of the T6 heat-treatment specimens were 85.4, 75.7, 60.6, and 51.2 MPa. Impact absorbed energy and fatigue strength decreased as scrap content of the specimen increased. It is assumed that impact absorbed energy decreased owing to the presence of oxide films, which act as branches of 2nd cracks; fatigue strength also decreased with decreased deflection of the fatigue crack path as the scrap content of the specimens increased.