Papers by Author: Subhash Chandra Saha

Abstract: In this paper, the Taguchi method coupled with desirability function approach is used for the optimization of response parameters in submerged arc welding (SAW). Desirability function (DF) approach has been introduced to convert the multi- response objective to single objective. Weld quality is greatly influenced by the weld parameters which directly or indirectly affect the response parameters. In the present investigation three process variables viz. Wire feed rate (W_f), stick out (S_o) and traverse speed (T_s) have been considered and the response parameters are hardness (H), tensile strength (TS), toughness (IS). Finally a confirmatory test has been carried out with the optimal process parameters for validation of the experiment.

Abstract: The quality of joining has assumed a greater role in fabrication of metal in recent years, because of the development of new alloys with tremendously increased strength and toughness. Submerged arc welding is a high heat input fusion welding process in which weld is produced by moving localized heat source along the joint. The weld quality in turn affected by thermal cycle that the weldment experiences during the welding. In the present study a simple comprehensive mathematical model has been developed using a moving heat source and analyzing the temperature on one section and then the temperature distribution of other section are correlated with time delay with reference analyzed section.

Abstract: In this paper, a standard CFD code, COMSOL is used to describe the 3-dimensional modeling of friction stir welding using threaded tool and based on fully sticking friction. A standard threaded tool profile is used for the full flow analysis including heat generation and heat flow. Temperature distribution is analyzed for full sticking and sliding condition. The effect of different operating parameters on the temperature distribution was performed.The importance of cell Peclet number is also investigated in the temperature distribution on advancing and retreading side. The results are in reasonable agreement with the predictions.

Abstract: A 3D thermal pseudo mechanical model formulated in an Eulerian frame considering a quassisteady approach to Friction Stir welding modeling of AA6061 Aluminium alloy is proposed and implemented using nonlinear finite element code in Comsol Multiphysics v 4.1. The effect of different operating parameters on the temperature distribution was analyzed. The material flow is found to be enhanced with the increase in traverse speed and angular velocity of the pin with a pronounced swirl on the advancing side. The distribution of equivalent plastic strain and dynamic viscosity was found to correlate with the distribution of the microstructure zones in the weld.