Machinability the AISI 316 stainless steel after processing by various methods of 3D printing

Abstract

The importance of the 3D metal printing parts still increases in many branches of production not only for prototyping. The metal prints need machining very often to obtain specific shape, accurate dimensions as well as superior surface roughness. Internal structure of 3D metal prints differs from workpiece made by conventional processes like a rolling process. That leads to different mechanical properties and machinability of the same material grade but after different way made metal 3D printed specimen. This paper is focused on the milling of the stainless steel AISI 316L. The relative machinability of the various preparations of specimens from this material were investigated. The default standard was a rolled specimen and it was compared with a Wire Arc Additive Manufacturing (WAAM) specimen and a Laser powder cladding (LPC) process specimen. The cutting forces and roughness of a machined surface were measured. The hardness and material analysis were made to inspect the material properties of the 3D printed specimens and standard. A relative machinability was evaluated and both 3D printed specimens were compared with the rolled standard. The effect of the hardness of tested specimens on cutting forces was investigated and the correlation between them was evaluated. Different chemical composition and material structure manifested itself as the increased variability of force values on the measured length and with small hollows in the surface profile after machining for printed specimens. The different internal structure of printed specimens led to the worse machinability compared to the rolled specimen of AISI 316L in case of surface roughness.