THE EFFECT OF MATERIAL REMOVAL ON THE STRENGTH OF AUTOFRETTAGED CYLINDERS.
WATERVLIET ARSENAL N Y
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Autofrettage is a process which increases the ability of a thick-walled cylinder to contain internal pressure without undergoing plastic deformation by means of producing a system of favorable residual stresses in the cylinder. If material is removed from the cylinder after autofrettage, some of these residual stresses will be removed. This report presents the results of an experimental study of the effect of material removal on the elastic strength of autofrettaged cylinders. The test specimens used were one inch bore diameter cylinders, ranging in diameter ratio from 1.4 to 2.4, of a modified 4330 steel with a yield strength of about 160,000 psi. The specimens were autofrettaged by internal hydrostatic pressure to the complete overstrain condition, thermally treated and machined on either the inside or outside surface. They were then pressure tested to determine their re-yield pressure. The results are compared with those predicted by various theories. Significant differences are noted and are explained in terms of material behavioral phenomena such as the Bauschinger effect and strain aging. author
- Manufacturing and Industrial Engineering and Control of Production Systems