Analysis of Solidification Cracks in Welds of Al-Mg-Si A6351 Type Alloy Welded by High Frequency Pulsed TIG Process

The First Report-Evaluation of Solidification Crack Susceptibility by means of Houdcroft Test

Abstract

A study was carried out on solidification crack in Al-Mg-Si alloys type A6351 by means of Houldcroft test with GTAW process without filler metal and high pulsation frequency. Three test series were carried out taking into account the variation of heat input. The obtained crack lengths were measured and the effect of pulsation frequency, fraction of pulse time and welding speed were analyzed. The effect of grain structures on the susceptibility of solidification crack was evaluated as well as the welding pool geometry in which these structures developed. The "quasi-stationary" state was studied for the specimen geometry used and the process efficiencies were estimated using welding pool width method. An estimation of the necessary force to close the crack was made using ROGERSON's physical-mathematical model. The obtained results were compared with those presented in surveyed references.