Thermal Relaxation in Autofrettaged Cylinders
Abstract
This report presents an experimental study on the loss of bore expansion and change of residual stresses in autofrettaged cylinders, resulting from internal heating combined with external cooling. It provides information useful in the design of pressure vessels operating at high temperature. Two foot long cylinders were heated internally to bore temperatures up to 950 deg F and simultaneously cooled externally to produce a temperature difference of as much as 725 deg F from bore to outside surface. Reduction of the autofrettage bore expansion and reduction of residual stresses resulted, because the thermal stresses added to the residual stresses and exceeded the lowered yield strength at elevated temperature, permitting relaxation to occur. The data reveal that under certain temperature conditions a considerable portion of the autofrettage induced bore expansion and the associated residual stresses can be lost in a few minutes when external cooling occurs. The experimental results indicate that partial overstrain in autofrettage may be preferable to full overstrain in order to minimize the loss in residual stress. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1982
- Accession Number
- ADA113210
Entities
People
- Gregory S. Leger
- John H. Underwood
- Joseph F. Throop
Organizations
- United States Army Armament Research, Development and Engineering Center