Test Method of Permanent Set Strength of ZTC4 Titanium Alloy

In order to accurately detect the permanent set strength of incoming titanium alloy raw materials and realize programmed automation control test, the permanent set strength of ZTC4 titanium alloy was tested by unloading method according to the relevant regulations from GB/T 228-2002. Affecting factors such as cycle numbers and duration time on the test results were studied and appropriate test parameters for titanium alloy were gained. The results show that selecting the ratio of cycle numbers and duration time that was the cycle numbers in unit time as parameter to characterize the permanent set strength of titanium alloy was reasonable, and the appropriate duration time was 10-12 s and the appropriate cycle numbers was 4-6 times that was corresponded to the regulations of GB/T 228-2002. When the cycle numbers in unit time were in the range of 0.33-0.60, the tested permanent set strength of ZTC4 titanium alloy was minimum, and it can be regarded as the maximum allowable stress. If the working stress exceeded this limit, the work piece would failure.