[en] Austenitic and martensitic stainless steels find various applications in Indian nuclear reactors. Material properties such as tensile properties, creep deformation and stress-rupture behaviours, fatigue-fracture properties of several austenitic and martensitic stainless steels, used in Indian NPPs have been evaluated by RSD, BARC over a period of time for various requirements. These are compiled in the present volume that covers the following materials: (i) SS304L - High temperature tensile and creep-stress rupture properties of both base and weld material; fracture properties of base material; (ii) SS304LN - Tensile, fatigue, fracture and Fatigue Crack Growth Rate (FCGR) properties of both base and weld materials; (iii) SS403 - Tensile, fatigue, fracture, FCGR and impact properties; (iv) SS316LN - Tensile properties. (author)

[en] A series of Bor60 fast-reactor irradiations have been completed on commercial and laboratory heats of 304LSS and 316SS irradiated at 320^oC to doses from 5 to 25 dpa. Dose-dependent grain boundary composition changes are assessed for the 5 heats mapping radiation-induced segregation (RIS) of alloying and impurity elements. The strongest RIS response was observed in a high-purity, Si-doped, 304LSS laboratory heat, while a cold-worked 316SS commercial heat exhibited the lowest level of RIS response at a high dose. Results for the fast-reactor-irradiated materials were consistent at low doses with that measured in similar materials irradiated in light-water-reactor (LWR) environments. Stronger RIS was indicated for LWR versus fast-reactor irradiations at high doses, but more data is needed. In general, heat-to-heat differences revealed larger variations in RIS than differences between the two irradiation environments. (author)

[en] The microstructures of six material/fluence combinations of stainless steels retrieved from BWR components (top guide and control rods) have been examined by atom probe tomography; the irradiated microstructure had been already characterized by transmission electron microscopy (TEM). The fracture toughness of two material/fluence combinations had been previously measured. The aggregate results strongly suggest that radiation-induced clusters play a significant role in the degradation of fracture toughness that occurs at fluences below ∼ 13 dpa. Because TEM has not been able to consistently identify and quantify the nano-sized clusters in this fluence range, it has not highlighted the potential role of radiation-induced clusters. (authors)

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[en] The rotating bending fatigue tests were carried out at room temperature, 200degC, 400degC, 600degC and 800degC with a frequency of 1200 cycles/min. using SUS 304 solution treatment material and SUS 304-1/2H 10% cold working material, and were carried out at room temperature, 300degC and 600degC using SUS 430 and SUS 403. The cold working material showed higher strength at finite life and fatigue limit in every temperature than the other materials did, although the difference of fatigue limit above 400degC between the cold working material and the other materials were a little. The relationships between the fatigue limit σ_W and the tensile strength σ_B were obtained as σ_W=0.44σ_B for SUS 304 at every temperature and SUS 304-1/2 H over 200degC, and σ_W=0.58σ_B for SUS 430, SUS 403 at every temperature and SUS 304-1/2 H below 200degC. Besides, the relationship between the stress ratio σ_a/σ_ωR.T. and the parameter P=(10 - log N_f)/T was proposed to estimate the fatigue strength at finite life, where σ_a is the bending stress amplitude, σ_ωR.T. is the fatigue limit at room temperature, N_f is the cycles to failure and T is the absolute temperature. (author)

[en] Electron microscopy has provided immense scope to utilize the versatility of this technique for identification of various microstructural changes that occurs due to effect of high strain rates in austenitic steels. Thus, an attempt has been made using these techniques to understand the subtle microstructural changes that happen in the austenitic steels e.g., SS304L and SS316LN due to high strain rate compression effect which are very relevant to the various field applications e.g., defence, nuclear, aerospace etc. (author)

[en] Data on the influence of low dose 400--550 C irradiation on the mechanical properties of structural steels (Types 304, 316, 316L, 316H and 316L(N) and associated weld metals) at temperatures from 20 C to 750 C, have been compiled from published literature and the results of British, Dutch, French and German laboratories. Properties evaluated include tensile, impact, creep, fatigue, and creep-fatigue. The preliminary results, which cover the dose range from 0 to 5 displacements per atom (and/or up to 9 appm helium) are presented as comparisons between irradiated and unirradiated control data, covering a range of strength and cyclic properties. The results show that low dose irradiation can have a significant influence on the properties, i.e.: (1) increases in tensile proof strength; (2) reductions in tensile ductility; (3) decreases in impact energy; (4) reductions in creep-rupture strength and ductility; and (5) reductions in creep-fatigue endurance. By considering the influence of irradiation temperature and dose level, the results are rationalized in terms of irradiation hardening and grain boundary embrittlement mechanisms

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