Prediction of friction stir welding process parameters for joining aluminium alloys AA 7075-T651 and AA 6061-T651 by S Ravikumar, V Seshagiri Rao, D Muruganandam andSushil Lal Das
Abstract:
Aluminium alloys have gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to weight ratio and good corrosion resistance. Modern structural concepts demand reductions in both the weight as well as the cost of the production and fabrication of materials. Therefore welding processes have proven more attractive, and there is an urgency to study their potential. Compared to the fusion welding processes that are routinely used for joining structural aluminium alloys, friction stir welding (FSW) process is an emerging solid state joining process was invented in 1991 by TWI, in which the material that is being welded does not melt and recast. The major advantage in FSW process is that the maximum temperature reached is less than 80% of the melting temperature (TM), i.e. the joint is performed in the solid-state and excessive micro structural degradation of the weld zone is avoided. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters such as tool rotational speed, welding speed, axial force etc., and tool pin profile play a major role in deciding the joint strength. This paper focus on Mechanical properties evaluation and predicting the process parameters in varying rotational and welding speeds of friction-stir welding for the dissimilar precipitation hardenable aluminium alloys ie., between 6xxx (Al-Mg-Si) and 7xxx (Al-Zn-Mg).
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Experimental and theoretical evaluation of hot cracking in the super austenitic stainless steel weld metal during autogeneous welding by K Balasubramanian and V Balusamy
Abstract: The main idea of this work is to compare the dependability of the theoretical and experimental evaluation of the hot cracking susceptibility of super austenitic stainless steel weld metal. In this juncture, the hot cracking susceptibility of super austenitic stainless steel weld metal is explained through a theoretical procedure and an experimental procedure. In a theoretical evaluation, the hot cracking susceptibility of a given super austenitic stainless steel is explained in terms of Creq/Nieq, level of impurities (S+P%), ferrite number FN and microstructure. Another way to measure the hot cracking susceptibility of super austenitic stainless steel is through experimental tests by means of Houldcroft hot cracking test. The results of the theoretical analysis were agreed with results achieved from the Houldcroft test. Therefore, the outcome obtained by theoretical assessment and experimental assessment indicate that the experimental and theoretical evaluation are consistent with one another and are both dependable
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Experimental investigation and multi objective optimization of process parameters in Micro-EDM by N Natarajan and RM Arunachalam
Abstract:
This study investigates the optimization of process parameters of micro Electric Discharge Machining (micro-EDM) for Stainless Steel grade 304 (SS 304) on the machining characteristics using the Grey Relational Analysis (GRA) method. Twenty seven experimental runs based on the Orthogonal Array (OA) of Taguchi method have been carried out. The multi-objective optimization of the process parameters viz. Material Removal Rate (MRR), Tool Wear Rate (TWR), Diametral Overcut (DOC) and Taper (T) has been performed. The current is identified to be the most influential factor of the MRR, TWR and the T, and the pulse-off time has an impact on DOC. Additionally, the analysis of variance (ANOVA) is also carried out to identify the most significant factor in which the current is observed to be the most significant factor. In-depth studies have also been made to examine the influence of various process parameters through SEM micrographs.
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Analysis on the effect of silicon and copper on the mechanical properties of grey cast iron using Taguchi method by PVR Ravindra Reddy, G Chandra Mohan Reddy, Shiva Shankar Reddy and L Suresh Comer
Abstract:
Cast iron can be used to produce varied products ranging from basic components in daily life to complex engine blocks of automobiles. This flexibility is achieved in cast iron by process of alloying, where the properties of cast iron changes tremendously with addition of alloys.In this work the significance and contribution of the effect of copper and silicon on mechanical properties of grey cast iron is studied using taguchi method. An L-4 orthogonal array is selected for design of experiments and ANOVA is carried out to find out relative significance of copper and silicon on mechanical properties.The micro structural examination is also done to support the results obtained from ANOVA.
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