Search

Your search keyword '"Rao, K. Bhanu Sankara"' showing total 211 results
Start Over Author "Rao, K. Bhanu Sankara"
211 results on '"Rao, K. Bhanu Sankara"'

30. Development of SQUID-based system for nondestructive evaluation

Author

Nagendran, R., Janawadkar, M.P., Pattabiraman, M., Baisnab, Dipak Kumar, Jayapandian, J., Baskaran, R., Vaidhyanathan, L.S., Hariharan, Y., Nagesha, A., Valsan, M., Rao, K. Bhanu Sankara, and Raj, Baldev

Subjects
Superconducting quantum interference devices -- Usage, Superconducting quantum interference devices -- Electric properties, Dielectric films -- Electric properties, Thin films -- Electric properties, Niobium -- Electric properties, Business, Electronics, Electronics and electrical industries
Abstract

A superconducting quantum interference device (SQUID) system for nondestructive evaluation is developed using a thin-film-based Nb SQUID. This system is used to detect subsurface defects in artificially engineered aluminum plates and stainless steel weldment specimens.

Published
2007

41. Influence of weld discontinuities on strain controlled fatigue behavior of 308 stainless steel weld metal

Author

Rao, K. Bhanu Sankara, Valsan, M., Sandhya, R., Mannan, S.L., and Rodriguez, P.

Subjects
Steel, Stainless -- Research, Materials -- Fatigue, Science and technology
Abstract

Type 308 stainless steel (SS) defect-free weld metal showed less strain-controlled fatigue resistance than type 304 SS base material. Weld metal discontinuities were found harmful to fatigue resistance. Porosity has been found to be particularly harmful even when compared to slag inclusions. Persistent slip bards at the surface are where crack initiation occur in base and sound weld metal. Irrespective of their location, discontinuities in welds act as crack initiation sites.

Published
1994

43. Temperature and Strain-Rate Effects on Low-Cycle Fatigue Behavior of Alloy 800H

Author

Rao, K. Bhanu Sankara, Schiffers, H, Schuster, H, and Halford, G. R

Subjects
Metallic Materials
Abstract

The effects of strain rate (4 x 10(exp -6) to 4 x 10(exp -3)/s) and temperature on the Low-Cycle Fatigue (LCF) behavior of alloy 800H have been evaluated in the range 750 C to 950 C. Total axial strain controlled LCF tests were conducted in air at a strain amplitude of +/- 0.30 pct. LCF life decreased with decreasing strain rate and increasing temperature. The cyclic stress response behavior showed a marked variation with temperature and strain rate. The time- and temperature- dependent processes which influence the cyclic stress response and life have been identified and their relative importance assessed. Dynamic strain aging, time-dependent deformation, precipitation of parallel platelets of M(23)C6 on grain boundaries and incoherent ledges of twins, and oxidation were found to operate depending on the test conditions. The largest effect on life was shown by oxidation processes.

Published
1996

44. Effect of Processing Route on Strain Controlled Low Cycle Fatigue Behavior of Polycrystalline NiAl

Author

Rao, K. Bhanu Sankara, Lerch, B. A, and Noebe, R. D

Subjects
Metallic Materials
Abstract

The present investigation examines the effects of manufacturing process on the total axial strain controlled low cycle fatigue behavior of polycrystalline NiAl at 1000 K, a temperature above the monotonic Brittle-to-Ductile Transition Temperature (BDTT). The nickel aluminide samples were produced by three different processing routes: hot isostatic pressing of pre- alloyed powders, extrusion of prealloyed powders, and extrusion of vacuum induction melted ingots. The LCF behavior of the cast plus extruded material was also determined at room temperature (below the BD77) for comparison to the high temperature data. The cyclic stress response, cyclic stress-strain behavior, and strain-life relationships were influenced by the alloy preparation technique and the testing temperature. Detailed characterization of the LCF tested samples was conducted by optical and electron microscopy to determine the variations in fracture and deformation modes and to determine any microstructural changes that occurred during LCF testing. The dependence of LCF properties on processing route was rationalized on the basis of starting microstructure, brittle-to-ductile transition temperature, deformation induced changes in the basic microstructure, deformation substructure, and synergistic interaction between the damage modes.

Published
1995

47. Laser Welding of Ultrafine Bainitic Steels.

Author

Ramakrishna, V. S. M., Gautam, Jai Prakash, Reddy, G. Madhusudhan, Masthanaiah, P., and Rao, K. Bhanu Sankara

Subjects
LASER welding, BAINITIC steel, ELECTRON beam welding, SURFACES (Technology), ELECTROMAGNETIC waves, STAINLESS steel welding, LASER beams, STEEL fracture
Abstract

Laser beam welding (LBW) is one of the advanced welding process which results in joining of materials with intense heat. The intense heat is produced using focused light source falling upon the metallic material's surfaces to be welded. The coherent laser beam is a known source of electromagnetic energy or light with single frequency which can be projected without diverging and also can be focused to an exact spot. The current investigation aims at establishing the parameters required for producing sound welds by fibre laser beam welding and identifying the evolution of microstructure in bainitic steel during similar welding of three mm thick plates. Sound welding was accomplished with laser power 3.5kW and at traverse speeds of 2000, 3000 and 4000 mm/min. The weld joints revealed base metal, weld zone and heat affected zones. The widths of weld zone and HAZ varied as a function of welding speed. Weld zone displayed hardness around 750-800 VHN. A sudden drop in hardness was observed across the heat affected zone, reaching a dip in the intercritical region of HAZ. Hardness in ICHAZ reached around 400-450VHN. The ICHAZ was more pronounced at 3000 mm/min. Microstructural changes were explored by optical microscopy techniques. The high hardness in fusion zone and low hardness in the intercritical structure was found to have correlation with prevailing microstructural features in the respective zones. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results