Machinability of the 18Ni300 Additively Manufactured Maraging Steel Based on Orthogonal Cutting Tests

Metallic additive manufacturing is a trending topic of manufacturing, being nowadays intensively investigated due to its innumerous advantages, such as design freedom. Some challenges remain, namely the need to perform post-processing operations of the parts towards improved surface finishing, which in some cases may involve machining operations. In addition, in some industries, the compatibility of additively manufactured inserts is assured by machining operations. Therefore, understanding the machinability of additively manufactured materials leads to timely research. This paper presents research on metal cutting supported by orthogonal cutting operations, aiming at investigating the machinability of the additively manufactured 18Ni300 maraging steel. Material build direction and tool rake angle were investigated. In addition, conventional material was tested for comparison purposes. Cutting loads, specific cutting pressure, shear angle, friction and chip geometry are evaluated according to Merchant theory. Despite the higher flow stress and anisotropic behaviour of the additively manufactured steel, their specific cutting pressure is lesser influenced by the metallurgical condition than the geometric effect of the cutting tool (rake angle).