Development of IN-RAFM steel and fabrication technologies for Indian TBM

摘要

India has indigenously developed its own Indian Reduced Activation Ferritic Martensitic Steel (IN-RAFM steel) which, it is proposed to use for fabrication of Indian TBM to be installed in ITER. With an objective of qualifying this material for use in ITER, extensive testing of this material to generate the necessary data required to offer this material for Particular Material Appraisal of ITER has been undertaken. Accordingly, data generation on creep, fatigue and physical properties of this steel is in progress. Physical properties like thermal diffusivity, heat capacity and thermal expansion coefficient for this steel at various temperatures have been measured and thermal conductivity estimated from the measured physical properties. Values obtained for these physical properties are comparable with those reported for other RAFM steels. Results of creep tests that are in progress also indicate that creep is comparable to that of other RAFM steels. Low cycle fatigue (LCF) behaviour of this steel has been studied in air with total strain control in the strain amplitude range of +/- 0.25-1% and temperatures range of 300-873 K at a constant strain rate of 3 x 10(-3) s(-1). Results confirm that fatigue life of IN-RAFM steel is at par with that of the European Union grade Eurofer 97 RAFM steel.