Speaker
Description
Steels for fusion applications will have stringent chemical requirements due to the activation potential arising from the high energy neutrons – therefore prediction of casting-induced segregation is important to ensure specifications can be met. The NEURONE (NEUtron iRradiatiOn of advaNced stEels) programme is a UKAEA-led consortium looking to develop advanced reduced-activation ferritic-martensitic (A-RAFM) structural steels capable of withstanding this neutron damage and operating at 650°C.
Sheffield Forgemasters has developed thermo-mechanical models for melting and casting of potential fusion alloys as part of the NEURONE programme. Recent work has modelled a 7-tonne ingot from a nominal 35 tonne minimum cast quantity, based on an A-RAFM steel developed within the programme.
Material files with thermal-mechanical properties were generated using specialized software, and the 7-tonne ingot casting models were developed using Thercast commercial software. The combined computational fluid dynamic and finite element simulations included an ingot filling stage, solidification of the ingot with thermal-mechanical behaviour, exothermic powder reactions and micro-segregations development.
Micro-segregations were simulated, and the results of six elements are presented. Carbon, Silicon, Chromium, Manganese, Tungsten and Vanadium predicted concentrations are shown. The highest concentrations of all elements were found at the head of the ingot. Si and Mn concentrations were predicted to have a small spread of segregations. W segregation predictions showed a high concentration at the ingot head peaking at around 10%, with concentrations as low as 1% in the central part of the ingot. Prediction of V segregation behaviour showed very similar results to W.
Further modelling of the thermo-mechanical processing of the ingot will be presented, highlighting the potential effect that segregation would have on such and ingot; with comparisons drawn with existing modelling completed on a pilot-scale procedure undertaken in the NEURONE programme.
| Speaker Company/University | Dr Mikhail Trull |
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