Abstract:
LBW is widely known for its high precision and dilated applications in heaps of areas stretching from simple cooking ware to intricate aeronautical structure. In the existing study, to characterize laser beam welding process an attempt was made to join the 4.5 mm thick sheets of D406 A steel because of its superb amalgamation of strength, toughness particularly in aerospace and military sector. For this purpose, Ytterbium source was used for generating fiber laser containing power of 3.4 kW for optimizing the selected input parameters by varying gap width and focal position at a constant speed of 2600 mm/min in square butt joint configuration. Experimental investigation was carried out by using multilevel factorial design technique for optimizing input parameters. The ultimate tensile strength, distortion and residual stresses were considered as response parameters .The analysis of variance suggested the quadratic models that can sufficiently predict the correct results within the set limits. Significant process parameters and their optimum ranges were also recognized by using ANOVA. The relationship between inputs parameters and responses taken into consideration and found in terms of empirical models. The process parameters were optimized to give maximum ultimate tensile strength (UTS), minimum distortion and minimum residual stresses by validating model in terms of percentage error. Metallographic study of samples extracted from the experiments was carried out to analyze the microstructure and besides this, differential analysis between the base metal, FZ and HAZ was also subsumed using the results of optical microscopy, scan electron microscopy and energy dispersive X-ray spectroscopy.
