Applicability of angular orientations of gating designs to quality of sand casting components using two-cavity mould set-up.

Abstract

This study aimed to examine the integrity of two-cavity sand casting products in relation to the angular orientation of gating design. Two angular orientations of 60 and 45 were investigated experimentally and numerically and compared with the efficiency of a 90 gating system. The FLOW three-dimensional (3D) simulation was conducted to detect smooth filling and describe the pattern of molten aluminium LM4 (Al–Si5Cu3) alloy flow. From the results obtained, the turbulent flow was observed with vortex, which created a larger surface gap to allow air entrapment in molten metal. For both instances, casting discontinuities such as blow holes, pin holes, sponge shrinkage, sand inclusions, and dross were observed on the cut 2 mm machined surfaces of the moulded components with various degrees of intensity. Visual analysis, optical microscopy, ultrasonic and X-ray measurements were conducted to check the accuracy of the experimental components. All the defect detection methods depicted the fewest manufacturing defects with 45 angular orientation, which was attributed to uninterrupted flow of molten metal and low backflow strain. The component with 90 exhibited significant defects due to turbulent flow, entrapment of air bubbles, lack of mould filling, and uneven solidification. These factors consequently caused irregular cracks in the material. Therefore, practically, 45 angular orientation of gating design with two-cavity mould set-up is hereby recommended for optimum/best quality sand casting of aluminium LM4 (Al–Si5Cu3) alloy components, as required in many manufacturing companies.