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Saha, S. C.
- Study the Influence of Heat Input on the Shape Factors and HAZ width during Submerged Arc Welding
Authors
1 Department of Mechanical Engineering, National Institute Technology, Agartala, IN
2 Department of Production Engineering, National Institute Technology, Agartala, IN
Source
Indian Welding Journal, Vol 48, No 1 (2015), Pagination: 51-55Abstract
Welding process variables play a significant role in determining the quality of a weld joint. The joint quality can be defined in terms of properties such as weld- bead geometry, mechanical properties and distortion. In this paper, an experimental study was conducted to investigate the influence of welding parameters in submerged arc welding (SAW) process particularly welding current (I) and traverse speed (Ts) on weld shape factors and heat affected zone (HAZ). These responses have different meaning in joint properties. Penetration shape factor (PSF) defines the deposition and distortion of weldment whereas reinforcement form factor (RFF) means the excess of the deposited material. Width of HAZ indirectly defines the mechanical properties of the weld. It was found that an increase in current PSF has a significant effect and RFF has a little effect. And traverse speed shows a mixed trend over PSF and little change in RFF. Welding current and traverse speed have a positive effect on HAZ.
Keywords
Submerged Arc Welding, Penetration Shape Factor, Reinforcement Form Factor, Width of HAZ.
- Heat Transfer in Welding - A Numerical Approach
Authors
1 Department of Metallurgical Engineering, Institute of Technology, B.H.U., Varanasi 221 005, IN
Source
Indian Welding Journal, Vol 26, No 4 (1993), Pagination: 8-12Abstract
The effectiveness and profitability of welding operation depends upon the efficiency of each individual phases of the process namely, joint configuration, welding parameters, quality of weldments and subsequent repair of defective welds. Out of the four phases, welding process parameters and quality control are the foremost areas where evaluation of data is carried out extensively. These data in turn are used for the selection of the most suitable process of welding along with its parameters, for a particular use. The thermal based problems, e.g. transient heat transfer in weld and base metal, transient thermal stress and strains, transient metal movement during distortion, residual stresses and distortion after welding, etc. may easily be solved by numerical techniques employing computer facilities. This paper first describes the different numerical techniques generally employed in solving these welding problems along with their suitability and applicability. Later, it elaborates a generalised approach of numerical technique for predicting temperature histories in a weld cross section and associated cooling rates. The validity of the model was ascertained through experiments carried out on indigeneously produced HSLA steel plates employing submerged arc and carbon-dioxide welding process. A comperative study with Rosenthal equation confirms a better match of the numerical technique with the experimental values. The cooling rate information thus obtained may then be used to assess the related microstructure and mechanical property changes for a particular steel.- Study of Submerged Arc Weld Metal and Heat-Affected Zone Microstructures of a Plain Carbon Steel
Authors
1 Department of Metallurgical Engineering, Banaras Hindu University, Varanasi, IN
2 Regional Engineering College, Silchar, Assam, IN
Source
Indian Welding Journal, Vol 23, No 3 (1991), Pagination: 151-157Abstract
A detailed study on the microstructure of submerged arc (SA) weld metal and the heat-affected zone of a 1.2- cm (0.5-in.) thick plain carbon steel plate was carried out using transmission electron microscopy. The various subzone microstructure observed in the HAZ of a SA weld are spheroidized, partially transformed, grain-refined and grain-coarsened. The grain-coarsened area exhibits predominantly Widmanstatten ferrite with pearlite, while the other subzones of HAZ reveal polygonal ferrite and pearlite. Depending on the number, size and distribution of inclusions, the weld metal microstructure varies. With a larger number of inclusions, grain boundary ferrite and, in absence of inclusion, either side plate with pearlite or cementite along the boundaries of side plates are observed. It is noticed that a limited number of larger size inclusions favor the formation of acicular ferrite. Because of the prevalence of varying cooling rates in weld metal, a wide range of microsturctures, such as periodic pearlite, grain boundary ferrite with pearlite, and side plate with cementite along the side plate boundaries, are observed.- Challenges In Welding - Indian Context
Authors
1 National Institute of Technology, Agartala, IN
Source
Indian Welding Journal, Vol 42, No 1 (2009), Pagination: 22-24Abstract
The industries related to automobile, railways, ports and ship building, oil gas and refinery, nuclear, power, water supply and sanitation rely heavily on welding for mass production of various types of components. The higher production rates encountered in the mass production have led to very higher degree of automation and mechanization associated with special purpose processes. It is highly essential and important that India becomes a major manufacturing unit to increase the G.D.P. Growth from 9% to 12%. This requires high quality skills in the manufacturing technology which can be ensured with a continued supply of quality manpower. Universally, short supply of welding technologists and welders are being felt. The problem can be minimized through vocational education, training, up gradation of curriculum and public-private partnership. An integrated approach in this line may a good solution to the problem of unemployment and to meet the shortage of manpower in this profession.
Keywords
Welding Education, Training, Automation, Mechanization and Robotics.- Recent Trend in Welding Research
Authors
1 Mechanical Engineering Department, National Institute of Technology, Agartala-799055, IN
2 Production Engineering Department, National Institute of Technology, Agartala 799055, IN
Source
Indian Welding Journal, Vol 42, No 2 (2009), Pagination: 21-23Abstract
The continuous advancement in the design and development of modern equipments for power plant, defense technology coupled with the development of new materials put greater emphasis on welding research. The welding techniques employed in the manufacture of these equipments require high productive processes with suitable power source and consumables. This paper presents the recent developments that have taken place in welding Research and in welding technology. The current trends world over in the development of Technology is also indicated.