Parameter Control Of Autofrettage & Re-Autofrettage Of Steel Made Hydraulic Cylinder For Single & Multiple Re-Autofrettage

Abstract

Thick cylinders are widely used in High pressure application like Hydraulic power cylinders, canon barrels, Diesel engine pump etc where high pressure is the key criteria. The Autofrettage process is an important part of the material optimization process for thick-walled cylinders. In Autofrettage, intentional residual stresses are generated by the plastic deformation of the inner wall of the cylinder so that some of the stresses can be relieved during the compression loading phase, since the working stresses and residual stresses are of opposite nature. In this article, the problem of deciding the correct initial pressure for Autofrettage was solved for a manufacturer in India. The process involves proper analysis of the material and its properties, followed by determination of the pressure range based on an analytical method, which is then validated by finite element analysis. The Re-Autofrettage process was also carried out for multiple times for same  hydraulic cylinder.