Practicing Hydraulic Autofrettage for Strengthening a Gun Barrel: Critical Issues and Challenges

Abstract

AbstractHydraulic autofrettage is a sophisticated metal forming approach adopted to strengthen the large caliber gun barrel in defense industries. During the process, the barrel bore is pressurized by hydraulic fluid causing plastic deformation at the bore surface and some portion in its neighborhood. The subsequent depressurization induces compressive residual stresses at the inner bore layer enabling the barrel to sustain increased service pressure and fatigue life. The residual compressive stresses at the inner side of the monobloc barrel also increase the stress corrosion cracking resistance. The performance of hydraulic autofrettage depends on several factors, which need to be taken care of during its operation. The primary focus of this chapter is to discuss the practical procedure of the process performed for a real gun barrel. The critical issues associated with practicing the process and the challenges are also addressed.KeywordsHydraulic autofrettageResidual stressMonobloc barrelMinimum autofrettage pressureLow-temperature treatment