Evaluación de la fuerza de corte, rugosidad y desgaste, como criterio de maquinabilidad en procesos de torneado del acero endurecido aisi 4340 utilizando insertos de carburos recubiertos

• Autor: Lujan Lujan, Elvis Robert
• Formato: tesis de grado
• Fecha de Publicación: 2019
• Institución: Universidad Nacional de Trujillo
• Repositorio: UNITRU-Tesis
• Lenguaje: español
• OAI Identifier: oai:dspace.unitru.edu.pe:20.500.14414/12659
• Enlace del recurso: https://hdl.handle.net/20.500.14414/12659
• Nivel de acceso: acceso abierto
• Materia: Fuerzas de corte

The influence of the cutting parameters on the cutting forces, surface finish and tool wear in hardened steel bars AISI 4340 (45HR), subjected to hard turning in dry, using coated carbide inserts was investigated. From 38 mm diameter bars previously hardened to 45 HRC, specimens of 36 mm (Ø) and 200 mm in length were made, which were marked for a machining time. The turning was carried out in a lathe, following the orthogonal cutting model, using coated carbide inserts. Four cutting parameters were used: speed, advance, depth and machining time in 4 different levels. For the measurement of the cutting forces, an octagonal type dynamometer was used, which incorporates two strain gauges that are connected in ½ Wheatstone bridge, which in turn are connected to a deformation recorder that provides the reading of the cutting force. For the measurement of roughness, a digital Mitutoyo rugosimeter with a diamond probe with a nose radius of 2.5 to 10 μm was used. The wear measurement was done indirectly, using a digital micrometer and at each time stop was measured the reduction of the diameter (μm) of the piece, assuming that this variation of measurement must coincide with the tool wear, largely attributed to wear on the flank. It was found that the cutting force increases with the speed of advance for a given value of depth of cut and with an additional increase in the depth of cut, the cutting force also increases. The combination of low feed speed, low cutting depth and low machining time with high cutting speed is beneficial to minimize the value of the cutting force. The roughness of the surface is sensitive to the variations in the speed of advance to lower values of cutting speed compared to values of higher cutting speed. A better surface quality is observed with a higher cutting speed and with a lower speed of advance. The wear of the cutting tool increases with the increase of the cutting speed for all values of feed rates and is sensitive to the variations of the feed rate for all specified cutting speed values. It is concluded, that the increase of the cutting speed minimizes the cutting force and surface roughness when the other parameters are minimal, and the use of the lower cutting speed and advance speed can reduce the tool wear.