Autofrettage: From Development of Guns to Strengthening of Pressure Vessels

Abstract

Autofrettage is a popular metal forming process generally incorporated for strengthening thick cylindrical and spherical pressure vessels. It is based on the principle of pre stressing a vessel due to an applied load to achieve a partial or complete plastic deformation followed by unloading. The process induces compressive residual stresses in the vicinity of the inner wall that is beneficial to the vessel. The process has its roots to the nineteenth century during which military engineers invented techniques to enhance the performance of gun barrels by increasing the range and accuracy of the gun along with the reduction of weight. As these efforts and techniques progressed with the advancement of material science and metallurgy, the concept of autofrettage was born. This chapter presents a history of autofrettage. The events of the military engineers in seeking methods to overcome the shortcomings in the early design of the gun barrels to the eventual invention of autofrettage are presented. The further evolution of autofrettage into various types in the following years is also presented.