Accession Number:

ADA113210

Title:

Thermal Relaxation in Autofrettaged Cylinders

Descriptive Note:

Final rept.

Corporate Author:

ARMY ARMAMENT RESEARCH AND DEVELOPMENT CENTER WATERVLIET NY LARGE CALIBER WEAPON SYSTEMS LAB

Report Date:

1982-03-01

Pagination or Media Count:

45.0

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

Subject Categories:

  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE