Charpy toughness and microstructure of vibrated weld metal

Abstract

Vibration during welding can be used to obtain certain changes in mechanical properties of weld metal. Research work on the influence of vibration on the secondary microstructure of welds and hence on the Charpy toughness was performed. Vibration during welding exhibits positive effects on the microstructure constituent formation. Multipass welding was simulated with reheating of the original single pass weld in order to obtain similar microstructure to multipass welds. Microstructures were examined with an optical microscope. Additionally, fractographic examination of the rupture of Charpy specimens was performed. Changes in the microstructure according to vibration were observed which affect toughness of the weld metal. Vibration during welding was rated more effective in the case of reheating the weld metal, which is the case in multipass welding.

Welding in Vibration Conditions – Critical Approach

“…It was confirmed that the vibration welding of thick-walled steel cylinders led to an increase in impact energy during an impact strength test (only in the weld material) and to the obtainment of a greater bend angle (during a bend test) [7]. The confirmed vibration welding-triggered increase in impact energy was ascribed to more favourable thermal conditions in the heat affected zone [8]. The process of vibration welding performed at a frequency of 80 Hz led to the refinement of grains in the weld zone, thus improving mechanical properties of the area [9].…”

Vibration assisted welding processes and their influence on quality of welds

“…Charpy toughness and microstructure of weld metal in vibration assisted SAW were further studied, and it was found that vibration during multipass welding helped to improve the weld metal toughness, while vibration during single pass welding did not have any significant effect on toughness. 36 The single pass welds were made on high strength low alloy steel with vibration and without vibration, and there was difference in microstructure of the two.…”