ABSTRACT
Among the various manufacturing processes, it is worth mentioning the machining. Among its operations is milling, which confers characteristics to the surface generated that influence the performance of the component or workpiece. One of these characteristics is the process-induced residual stress. Depending on its character, trative or compressive, intensity and depth affected, it can be beneficial or deleterious. This work investigated the effect of the parameters, cutting speed, edge angle and material condition, ABNT 4340 steel, obtained by annealing and normalizing heat treatments on residual stress induced on the surface. For this, a 2x3x2 factorial design with three replicates was performed. The residual stresses were measured by the hole drilling method. The results obtained were organized and analyzed on the qualitative aspects, profile along the depth, and quantitative. The results indicated that the increase of cutting speed caused the residual stress induced on the surface to be compressive or less tractive. The variation of the edge angle exerted a discrete effect on the residual stress. The milled material in the normalized condition showed compressive residual stresses, on the other hand in the annealed condition trative one. In order to evaluate the quantitative aspect, a variance analysis was performed for the residual stress induced in the depth of 17µm beneath surface. The results showed that the data follow a normal distribution and that the cutting speed and heat treatment factors were found to be significant at the 95% confidence level both in isolation and in the second and third order interactions
Keywords
milling; residual stress; edge angle; hole drilling method; 4340
