Impact of Low Frequency Vibration During Welding and Annealing on Microstructure of Mild Steel Butt-Welded Joints

Volume 3 - Issue 3

Abere Dare Victor¹*, Oyatogun Grace Modupe², Oluwasegun Kunle Micheal², Ojo Sammy Alaba³ and Adeosun Adebayo Samuel²

Received: September 18, 2020;   Published: October 09, 2020

DOI: 10.32474/MAMS.2020.03.000162

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Abstract

This work examined the Impact of Low Frequency Vibration during Welding and Annealing on Microstructure of low carbon steel Butt-welded Joints with a view to establishing vibration regimes and the resultant microstructures that may improve the condition of service performance as well as increasing life span of welded joints. Commercially available mild steel plates were butt-welded employing vibration and non-vibration welding conditions and subjected to heat treatment before carrying out metallographic analysis. Vibration frequencies were varied from 0 to 14.32Hz in three different steps.The mechanical performance of the weldment with reference to strength and toughness depend upon the type of microstructure of weld metal and heat affected zone. The post weld heat treatment of annealing and stress relieving tend to significantly reduce the incidences of the conditions highlighted above. Also, rearrangements and realignments of the grains especially at the weld zones are obvious and have greatly influenced the quality and properties of the welded joints. It was observed from the vibrated frequencies 7.96Hz and 14.32Hz that the grain size diameters are coarser in the non-heated samples than the annealed samples in all the investigated zones. Hence, the vibration treatment during welding and casting greatly influence microstructures and improves grain refinement and service performance of the butt-welded joints.Results of microstructure analysis indicates fine-grained sizes at weld zones; but coarse at the heat affected and base metal zones, respectively. Therefore, microstructures having finer grain sizes are known to possess good mechanical properties with consequential effect on fracture toughness.

Keywords: Butt-Welded; Grains; Microstructure; Coarse; Weldment; Annealing; Vibration

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