Microstructural changes associated with vibratory prepared weldments

Abstract

The solidification of grey cast irol~L [1] under imposed vibration shows a varying microstructure. Kou and Le [2] showed experimentally that under lowfrequency vibration there is improvement in the microstructure and mechanical properties of aluminium weldments. Researchers [3-6] have proved that solidification of castings under vibratory conditions shows a refinement in grain size, metaUographic refinement and reduction in various casting defects. This letter pertains to the microstructure of the weldments prepared under stationary and vibratory conditions. Micrographs show an appreciable improvement in the grain refinement of the weldments prepared under vibratory conditions. Two mild steel workpieces were clamped with the help of C-clamps and angle iron pieces on a vibrating table (Fig. 1). The vibrating table rested on shafts which were supported on bearings. This table was rigidly coupled to an electrodynamic vibrator. A three-phase a.c. transformer and futile-coated mild steel electrodes were used for welding. A oscillator/ power amplifier and vibration meter were used for