Study on using Casting Simulation Software for Design and Analysis of Riser Shapes in a Solidifying Casting Component

ABSTRACT
Filling and solidification of molten metals are very complex and difficult to simulate correctly by conservative methods. For a large industrial application, it needs an alternate approach that is fast, reliable and user friendly. In current casting industries, product development paradigm is shifting from traditional trial-and-error in the workshop to computer-aided casting design and simulation package by a computer(s). Computer-aided
casting simulation plays an important role in the paradigm of new product development by way of modeling entire casting processes and reveals a dynamic behavior of casting scheme in working conditions. This study, highlighting is given on using casting simulation software which helps foundry industries to design and analysis the size and shape of the riser. Intended for simulation simplification in this study, grain size of mold green sand, casting material quality, casting process parameters are deliberated identical for all design schemes. Only the
shape and dimensional variances of sprue/risers are taken into considerations for defects analysis. It is found that defects such as micro and shrinkage porosities, and improper solidification, are directly related to gating and risers system. Casting simulation software is used for mold filling and solidification analysis and it is observed that the proposed gating and risers system design will improve casting results with small defects. From this study, the conclusion can be stated that taper sprue design, also acts as a riser, with an additional four
small risers that will produce a small fraction of porosity inside of the casting part. Validation of simulation, in the future, will be proved through experimental trials in the foundry shop.
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INTRODUCTION
Casting, which comprises substantial metallurgical and mechanical phases, is an intricate procedure. The amount of solidification directs the microstructure mainly, which in turn controls the mechanical characteristics related to strength, hardness, machinability, etc. Location, size, and shape of a riser in a casting depend on geometry of casting, mold design and thermal properties of metal, and other process constraints. Riser which is designed wrongly will result either in imperfect casting with shrinkage hole or in lesser yield since directly solidification is not achieved. Therefore, correct design of riser system and process parameters with good control are essential for excellence castings.

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