Experimental and numerical investigation of residual stress distribution in Al-6061 tubes under using tubular channel angular pressing process by new trapezoidal channel

Tubular channel angular pressing (TCAP) method is an appropriate severe plastic deformation (SPD) techniques for the generation of ultra-fine grained (UFG) and nanostructured (NS) tubes. In forming methods, the measurement of residual stresses is very important due to their significant effects on the processed samples. Therefore, determining the residual stresses created by the TCAP method in metals is of great importance. In this research, the distribution of residual stresses in Al-6061 tubes under the TCAP process, was studied experimentally and numerically. For this purpose, first the TCAP process was applied on Al-6061 tubes and after that the residual stresses generated in the TCAPed tubes were measured. Sachs method was used experimentally to measure the residual stresses. Sachs method is one of the destructive, convenient and efficient methods for measuring the residual stresses of axisymmetric cylindrical samples. Residual stresses measured by Sachs method in the processed samples showed that the tensile and compressive residual stresses were created on the external and internal tube surfaces, respectively. In addition, a good agreement was existed between the results of the numerical simulation and experimental methods for measuring the residual stress distribution.