Volume 29, Issue 1 (January 2001)
Small Punch Testing in Creep Conditions
The creep behavior of low-alloy steel was studied using small punch tests under the action of constant force. Disks with a diameter of 8 mm and a thickness of 0.5 mm were pushed against a die with a bore of 4 mm diameter using a ball of 2.5 mm diameter. The time dependence of the central deflection was registered. The resulting dependence has the sigmoidal shape typical of conventional creep tests but with a very significant primary stage. The conventional constant-stress creep tests were performed for comparison. A simple method for the approximate correlation of the force in punch tests with the stress in conventional creep tests of the same duration is suggested.