Efeito dos parâmetros de torneamento e do roleteamento sobre a integridade superficial do aço ABNT 4140

• Ano de defesa: 2019
• Autor(a) principal: Augusto Moura Martins
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Rugosidade; Aço ABNT 4140; Torneamento; Vida em fadiga; Roleteamento; Qualidade superficial; Fadiga; Processos de fabricação; Engenharia mecânica; Aspereza de superficie
• Link de acesso: http://hdl.handle.net/1843/RAOA-BCGFAS

Machine components are usually subjected to cyclic loads, which may induce failures, even when the component is only subjected to elastic deformations. The failure that happens in this situation is known as fatigue failure. Manufacturing processes are capable of plastically deforming and inducing residual stresses in different ways, being able to affect the components capacity to withstand cyclic loads. Besides the nature of the process, the parameters used on each process are also capable of influencing the fatigue strength of a material. This work, investigates the influence of turning and deep rolling on the fatigue life and surface roughness of hardened AISI 4140 steel (40 HRC), as well as the influence of turning on residual stresses. The material was machined varying cutting speed, feed and depth of cut. The material was also subjected to deep rolling using constant conditions. The fatigue life was evaluated under rotating bending fatigue tests. Regarding the turned samples, it was noticed that the cutting parameters did affect the residual stress profile, the residual stresses were tensile and of higher intensity for higher cutting speeds and tensile on higher depths for lower cutting depth and higher turning feed. It was possible to notice the influence of the turning parameters on the fatigue strength of the of the turned samples and also for the turned and deep rolled specimens. With regard to the fatigue life, there was a combined influence of feed and depth of cut, as the behavior for an increase in depth of cut has a different influence for each feed value. The influence of turning feed on the fatigue life of deep rolled specimens was also noticed and was higher for higher feed values. Deep rolling was capable of influencing all the studied roughness parameters, reducing the amplitude of the roughness parameters and increasing the fatigue life.