Economical and ecological cryogenic machining of AISI 304 austenitic stainless steel

Abstract

 While it is a clean alternative to conventional machining using environmentally polluting cutting oils and emulsions, cryogenic machining using liquid nitrogen has been reported to increase cutting forces and shorten tool life when cutting AISI 304 austenitic stainless steel. This paper presents improved results by using an economical cryogenic cooling approach designed after studying the cryogenic properties of the stainless steel material. By injecting a small amount of liquid nitrogen to the chip–tool interface, but not to the workpiece, this approach yielded a 67% tool-life improvement at 3.82 m/s and a 43% improvement at the medium speed of 3.40 m/s when compared with conventional emulsion cooling. It improved machining productivity and reduced production cost. In this study, different cryogenic machining approaches were compared in the machining test using commercial carbide inserts. The results show the cooling approach is crucial in attaining the benefits of cryogenic machining in cutting stainless steel.