The microstructure and mechanical properties of fine-grained Inconel 718 ring forging were investigated in this paper. The results indicated that the fine-grained ring forgings can be obtained by forging the fine-grained Inconel 718 bars. The grain size can be as fine as ASTM 10 and the precipitated phase are spherical. Heat treated at 980°C/1h/water cooling + 620°C /12h/air cooling, the ring forgings possessed very good mechanical properties. The impact toughness can be over 100J. In the fatigue test with the stress ratio -1, when the theoretical stress concentration factor is 1 and 2.7, the maximum stress for 107 fatigue cycles is over 620 MPa and 260 MPa, respectively. (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.
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