LAUSR

As nitrogen is nonreactive and non-flammable, it can provide a quick and simple medium of cooling and environment protection. One disadvantage of nitrogen cooling is its lower heat transfer coefficient than water. Despite its lower cooling capacity, nitrogen cooling can produce cleaner products, thereby eliminating the need to wash the parts and dispose of the contaminated water. In this study, an innovative nitrogen cooling system was developed for an accelerated and eco-friendly cooling of metallic parts. The dry nitrogen gas, transported via the nozzle of a cryogenic liquid nitrogen tank, is passed into the cooling chamber and exchanges heat with the workpiece. The heated nitrogen gas is forcibly transported to the chiller, where the heat is reduced, and the cooled gas is circulated again. The performance of this nitrogen cooling system has been evaluated with cooling experiments of sintered tungsten heavy alloys. The nitrogen-cooled product shows a clean surface with improved mechanical properties. Furthermore, nitrogen induces less distortion compared to water cooling, thus reducing the post-machining costs.