Authors: Keshav Prasad D K Dwivedi
Publish Date: 2006/12/12
Volume: 36, Issue: 5-6, Pages: 475-483
Abstract
This paper investigates the influence of the submerged arc welding SAW process parameters welding current and welding speed on the microstructure hardness and toughness of HSLA steel weld joints Attempts have also been made to analyze the results on the basis of the heat input The SAW process was used for the welding of 16 mm thick HSLA steel plates The weld joints were prepared using comparatively high heat input 30 to 63 KJ/mm by varying welding current 500–700 A and welding speed 200–300 mm/min Results showed that the increase in heat input coarsens the grain structure both in the weld metal and heat affected zone HAZ The hardness has been found to vary from the weld centre line to base metal and peak hardness was found in the HAZ The hardness of the weld metal was largely uniform The hardness reduced with the increase in welding current and reduction in welding speed increasing heat input while the toughness showed mixed trend The increase in welding current from 500 A to 600 A at a given welding speed 200 mm/min or 300 mm/min increased toughness and further increase in welding current up to 700 A lowered the toughness Scanning electron microscopy of the fractured surfaces of impact test specimen was carried out to study the fracture modes Electron probe micro analysis EPMA was carried out to investigate the variation in wt of different elements in the weld metal and HAZ
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