Novel sprue designs to reduce casting defects in nickel?aluminum bronze: A computational study

As 3D Sand-Printing technology becomes more widely available to the casting market, the search for opportunities to take advantage of its freedom of design is critical for its rapid adoption by the casting community. This original research investigates casting design principles towards defect-free alloy Nickel-Aluminum Bronze (NAB). This is an alloy of interest for marine applications due to its corrosion resistance, mechanical strength and good castability. Numerical modeling of flow within a casting is examined, and rigging redesigns are proposed to improve casting quality by controlling flow behavior. It has been demonstrated that turbulence and filling velocity are determining factors that seriously impact casting performance due to the generation of casting defects. Among these are bifilm formations, gas and sand entrapment and cold shut. This work examines the effectiveness of mathematically designed rigging components in controlling mold filling and compares the results to a conventional casting rig. Design solutions are proposed using 3DSP that can be directly applied to casting operations of Nickel-Aluminum Bronze. The results from this study demonstrate the effectiveness of mathematically designed sprues to reduce filling velocity of Nickel-Aluminum Bronze. The procedure followed here can be extended to marine casting production environments. Findings from this study can be seamlessly transferred to castings of any geometry, alloy and pouring conditions.