Online ISSN : 1883-2954
Print ISSN : 0021-1575
Forming Processing and Thermomechanical Treatment
Evaluation of Porosity Closure during Hot Compression of Steel by Synchrotron X-ray Laminography and FEM Analysis
Keisuke WatanabeHirofumi IdeMorihiko NakasakiAkihisa TakeuchiMasatoshi AramakiOsamu Furukimi
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2018 Volume 104 Issue 2 Pages 65-71


The shape change due to hot compression of the porosities formed in center of the steel ingot of carbon steel S25C and stainless steel SUS316L was sequentially, nondestructively and three-dimensionally observed by synchrotron X-ray laminography. As a result, it was revealed that closure of porosities was easier in SUS316L than in S25C. In addition, when the compression ratio increased, originally high aspect ratio porosities (length/width ratio, ℓ/w > 2.5) became decoupled. Larger porosities were more readily closed with smaller compression ratio. As a result of verifying the difference in closure behavior between S25C and SUS316L by Finite Element Method (FEM), it was demonstrated that the hydrostatic integration was larger for SUS 316L of which work hardening coefficient was smaller. This result was consistent with the experiment as results that porosities of SUS 316L tended to close easily.

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© 2018 The Iron and Steel Institute of Japan
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