Ball-milling properties and sintering behavior of Al-based Gd2O3–W shielding materials used in spent-fuel storage

Effect of activating fluxes on weld mechanical properties in TIG welding

Effect of welding current on the dimensions of bead in tungsten inert gas welding process

Borated stainless steels are being used to control neutron criticality in reactors as control rods, shielding material, spent fuel storage racks and transportation casks. Borated stainless steels fabricated via powder metallurgy (P/M) route (grade A) exhibit superior neutron absorption, enhanced toughness and ductility compared to cast ingot metallurgy (I/M) steels (grade B), due to fine and uniform dispersion of borides. In this study, welds were made using both 304B grade A and grade B materials by gas tungsten arc welding and activated gas tungsten arc welding processes. The effect of the activated flux on the bead geometry, microstructure and mechanical properties was investigated and compared. The heat input required for P/M steel material to produce full penetration welds has been found to be significantly higher compared to I/M steel, while all welds exhibited high joint efficiencies. Metallographic examinations revealed that no porosities and shrinkage cracks have been observed either in ...

Comparison of the welding behavior of P/M borated and I/M borated stainless steel

This paper presents a review on Activated Flux Welding Process. In this paper different types of organizations are striving hard to control costs, maintain high levels of productivity, meet changing expectations of the customers and attain quality of weld. Gas tungsten arc welding has wide variety of application in industries due to advantages like high reliability, low cost, higher production rate. Activating flux is a concept, which is used in different welding process like GTAW, EBW and PAW. The flux ingredient which is inorganic compound (which can be used to produce deep penetration and are constriction). The use of activated flux in conventional GTAW process is one of the most significant advancements for overcoming the shortcomings of TIG welding, which helps in increasing the depth of penetration and depth to width ratio of the weld pool, thereby increasing the productivity of the process and also it helps in achieving better mechanical properties.

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A Review on Activated Gas Tungsten ARC Welding Process

Borated stainless steels (304B) are used in nuclear power plants as control rods, shielding material, spent-fuel storage racks and transportation casks as they have a high capacity to absorb thermal neutrons. In this study, bead-on-plate welds were made on 10-mm-thick 304B plates using gas tungsten arc welding with Ar and Ar+2% nitrogen as the shielding gases, activated-flux GTA and electron-beam welding processes. The effects of the activated flux and nitrogen addition to the weld metal through the shielding gas, on the microstructure, bead geometry and mechanical properties were investigated. Activated-flux GTA welding and electron-beam welding substantially enhanced the depth of penetration and the aspect ratio compared to the other processes. Full-penetration welds were obtained in a single pass using activated-flux GTA and EB welding. The fusion-zone (FZ) microstructure of an activated GTA weld exhibits a columnar dendritic structure with eutectic borides in interdendritic regions, while a fine equiaxed dendritic structure was noticed in EB welds. GTA, nitrogen-added GTA and activated-flux GTA welds exhibited a partially melted zone adjacent to the fusion zone, with the activated-flux GTAW process resulting in a significantly thinner partially melted zone (PMZ). No PMZ was noticed in the EB welds. All the welds exhibited a high joint efficiency and impact toughness equal to those of the base material. It is concluded that the activated-flux GTA and EB welding processes are advantageous due to the use of a low heat input and failure location.

/pdf/effect-of-activated-flux-and-nitrogen-addition-on-the-bead-ol3r74ysmr.pdf

Gabbita Durga Janaki Ram

Papers

Effect of activated flux and nitrogen addition on the bead geometry of borated stainless-steel GTA welds

Comparison of the welding behavior of P/M borated and I/M borated stainless steel