Residual stresses in compression and tension mandrelling thick-walled cylinders

The paper presents methodology and results of experimental study by Sachs method of residual stresses in thick-walled cylinders of the steel grade 45 (0.45% C) with 5 mm diameter hole, outer diameter of 15 mm, height of 50 mm after compression and tension mandrelling, which is performed with allowances that ensure high accuracy of the mandrelled holes. It was found that the transition from the compression configuration to the tension one increases axial and radial residual strains and reduces hoop residual strains on the surface of the hole and outer surface of the cylinder, and increases the largest in absolute value residual stresses in these areas: hoop stresses - from 285 to 320 MPa; radial stresses - from 105 to 115 MPa; axial stresses - from 20 to 60 MPa. It is shown that the nature of the residual stress distribution in cylinders does not depend on the mandrelling configuration.