Study on Solidification Behavior of Aluminium alloy ( LM 6 ) Castings by using Computer aided Simulation software
Method layout of a casting is an important aspect of tooling development. It involves decisions regarding part orientation in mould, parting line, cores, cavity layout, feeders, neck and gating system. An improper method layout leads either poor quality or low yield, which affects the productivity. Method design is mostly carried out manually, using 2D drawing of the cast part. Then tooling is fabricated the sample castings are produced to 3-4 trials which involves lot of production cost in the from of wastage of manpower, time and hamper the day to day schedule of the particular production. Computer simulation provides a clear insight regarding the location and extent of internal defects, ensuring casting are right as first time and every time. In the present study plate castings were considered to study the solidification behavior of Aluminium Alloy (LM6) at different sizes of riser and riser neck. The VEM based casting simulation software is used to study the solidification behavior of above castings. The simulated results were compared with the experimental results. It is expected that this work will be of immense importance equally to the academicians as well as to the industrial methoding engineers.
Casting Simulation and Optimisation: Benefits, Bottlenecks, and Best Practices
Casting simulation has become a powerful tool to visualize mould filling, solidification and cooling, and to predict the location of internal defects such as shrinkage porosity, sand inclusions, and cold shuts. It can be used for troubleshooting existing castings, and for developing new castings without shop-floor trials. This paper describes the benefits of casting simulation (both tangible and intangible), bottlenecks (technical and resourcerelated), and some best practices to overcome the bottlenecks. These are based on an annual survey of computer applications in foundries carried out during 2001-2006, which received feedback from about 150 casting engineers, and detailed discussions involving visits to over 100 foundries. While new developments such as automatic optimisation of method design are coming up, a national initiative must ensure that the technology is available to even small and medium foundries in remote areas.
Evolution of carbide precipitates in Hastelloy N joints during welding and post weld heat treatment
Abstract The effects of welding and post weld heat treatment (PWHT) on the morphology, composition and lattice parameter of the precipitates in the welding joints of Hastelloy N alloy have been investigated. Joint samples were prepared using a gas tungsten arc welding process with ERNiMo-2 fillers, and then solid-solution treated at 1100 °C for 20 min. After welding, eutectic M6C carbides can be observed in the heat affected zones (HAZ) and weld zones (WZ). These eutectic M6C carbides become spheroidized during the following PWHT. The concentration of Si decreases during the transformation from the primary ones to eutectic ones, and then increases during the spheroidizing process. The total concentration of Si + Cr in M6C carbides remains stable during welding and PWHT. At the same time, the heat leads to the outward diffusion of Mo from the M6C carbides, which results in a decrease of the lattice parameter.