Nickel alloy 625 is widely used in submarine equipment for the oil and gas industry, which operate in an extremely adverse environment. In order to reduce the costs of these components, weld overlay cladding is employed. The surface generated by this process presents some irregularities that represent an additional difficulty to the machining process. The present work investigates the use of whiskers-reinforced ceramic tools and SiAlON in turning of alloy 625 clad on AISI 4130 steel by an automatic tungsten inert gas (TIG) cladding system. The results indicate the feasibility of the industrial application of the SiAlON inserts in rough turning of the alloy 625 clad, as well as the impossibility of using whiskers-reinforced ceramic tools (Al2O3 + SiCw) in the same conditions. The highest flank and notch wear of the SiAlON inserts were observed for the lowest cutting speed (140 m/min), which induced the formation of burrs in the workpiece at the depth of cut. Adhesion occurred more intensively at this condition. The least flank and notch wear were achieved by using cutting speed of 160 m/min and feed-rate of 0.25 mm/rev. Prolonged turning with worn tools resulted in microstructural alterations of the workpiece material and surface damages.

AISI D6 hardened steel is a difficult to cut material that it is employed in mould and die manufacturing where long ball-end mills are frequently required to machine deep cavities. This condition can lead to excessive vibration between tool and workpiece resulting in a poor surface finishing and reduced tool life. This work analyses the dynamic stability of ball-end milling of AISI D6 hardened steel for different tool path orientations at inclined workpiece angles of 15º and 75º. The evaluation of stability is based on the surface texture and spectrum analysis of the vibration signals. The results showed that for workpiece inclination angle of 15º chatter occurred in vertical upward down-milling and vertical downward up-milling. Best surface texture with tool marks consistent with pick feed and feed directions were generated by applying horizontal downward tool paths that produced the least vibration. Only forced vibrations occurred for the workpiece inclination angle of 75º. The highest peaks of the spectra corresponded to the harmonics of the tooth passing frequency closer to the natural frequency of the system. High magnitudes in the spectrum were found for vertical upward down-milling that generated a less uniform surface texture.

In order to improve the performance of a twist drill, one must understand some aspects involved in drilling process that are not commonly addressed, such as the micro geometry employed in the tool’s tip sharpening and the protection of the main cutting edge. The edge of the twist drill can be protected by rounding, chamfering or the combination of both. This paper analyzes the influence of edge preparation by two different methods, honing and chamfering on a solid cemented carbide twist drill Ø11 mm, used in the machining and processing of SAE 4144M hardened and tempered steel (hardness: 380HV1), with a 100% martensitic structure, employed in injection pumps for diesel engines. The hole’s diameter, position deviation, roughness and roundness revealed significant differences in results. The tool with the honed edge presented lower wear values, when compared to the tool with the chamfered edge.