A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
Kasiviswanathan, K. V.
- Nondestructive Measurement of Residual Stress in Carbon Steel Weld Joints
Authors
1 Indira Gandhi Centre for Atomic Research, Kalpakkam, IN
Source
Indian Welding Journal, Vol 27, No 4 (1994), Pagination: 34-41Abstract
The knowledge of the nature and magnitudes of residual stress (RS.) in a weld joint is important for avoiding distortions and premature failures. Both analytical and experimental techniques are used for getting information on RS distributions.
- Residual Stress Evaluation In Austenitic Stainless Steel Butt Weld Joints By Ultrasonic Technique
Authors
1 Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, IN
Source
Indian Welding Journal, Vol 25, No 3 (1992), Pagination: 130-136Abstract
This paper discusses the results of measurement of residual stress pattern across butt weld joints by ultrasonic velocity measurements in 15 mm and 47 mm thick AISI type 304 stainless steel plates. These are supplemented by results obtained from hole drilling strain gauge measurements. Pulse echo overlap technique was used to measure the through thickness longitudinal ultrasonic velocities. Acoustoelastic constant was determined to convert the change in ultrasonic velocities to residual stress values. The residual stress pattren obtained by the two techniques showed similar trends. Brief overview of various other residual stress measurement methods, and various techniques for ultrasonic velocity measurements are included in the paper.
Keywords
Residual Stress, Austenitic Stainless Steel, Weld Joint, Ultrasonic Velocity, Acoustoelastic Constant, Strain Guage Technique.- Development of Brazed Joints Using Induction Heating System for High Temperature Nuclear Applications
Authors
1 Group for Remote Handling, Robotics, Irradiation. Experiments and Post Irradiation Examination (GRIP), Metallurgy and Materials Group (MMG), Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam- 603 102, Tamilnadu, IN
Source
Indian Welding Journal, Vol 44, No 2 (2011), Pagination: 43-53Abstract
Fabrication of instrumented capsule for irradiation experiments for evaluating the irradiation performance of fuel and structural materials in a nuclear reactor requires development of thin-walled joints capable of withstanding high temperature and internal pressure. Instrumented capsules are being developed in IGCAR for irradiation of fuel and structural material specimens in Fast Breeder Test Reactor (FBTR). Instrumented capsule for irradiation of fuel pin specimen will have thermocouple of diameter 1 to 1.5 mm passing through the end plug of the fuel pin in a leak tight manner to prevent the release of fission gases generated in the fuel pin that may reach a pressure upto 10 MPa at 550°C during reactor operation. Out of the various joining methods, development of high temperature brazed joint method is found to be beneficial with respect to sealing the thermocouple passing through the end plug of the fuel pin and the intermediate plug of the irradiation capsule. Furnace and induction brazing methods have been tried and induction brazing method is seen to be more suitable for the present application. A procedure has been established to properly orient and braze the thermocouples in stainless steel plugs representing end plug and intermediate plug. Brazing parameters like temperature, time, vacuum level, and the brazing gap width are important factors in achieving good quality brazing joints. The trials carried out and the results obtained are discussed in this paper.
Keywords
Instrumented Fuel Irradiation Capsule, High Temperature Brazing, Induction Heating.- Laser Welding of Precision Engineering Components
Authors
1 Group for Remote Handling, Robotics, Irradiation Experiments and Post Irradiation Examination (GRIP), Metallurgy and Materials Group (MMG), Indira Gandhi Centre for Atomic Research (IGCAR) Kalpakkam- 603 102, IN
Source
Indian Welding Journal, Vol 44, No 2 (2011), Pagination: 54-59Abstract
Laser beam welding (LBW) with its high power density produces narrow and deep welds with a small heat-affected zone. Nd-YAG laser has been used extensively in the fabrication of small precision components at Indira Gandhi Centre for Atomic Research (IGCAR). Some important laser welding works carried out are related to Eddy Current based Position Sensor (ECPS) and Sodium Leak Detector (SLD) in Diverse Safety Rod Drive Mechanism (DSRDM) of Prototype Fast Breeder Reactor (PFBR), and components for Ir-192 High Dose Rate (HDR) source for Board o f Radiation and Isotope Technology (BRIT). ECPS is being designed to incorporate in the DSRDM to provide a measurement on signal which indicates that all the safety rods are dropped in case of a reactor scram signal. Mineral insulated (MI) cable of 1 mm diameter used as the eddy current coil in the ECPS has been terminated with suitable end configuration using laser welding. SLD is housed inside the electromagnet assembly of DSRDM to indicate if there is any leakage of sodium into the electromagnet. The fabrication of SLD requires precision laser welding of a few of its components. For the indigenous development of Ir-192 source assembly for use in HDR Branchy therapy, the feasibility study has been carried out for the fabrication of the miniature source holder by laser welding process. This paper discusses the techniques followed in the successful fabrication of above mentioned variety of intricate components used in critical applications.