A test method for performing uniaxial low cycle thermal fatigue tests on ductile metals is described. The test method is built around the Instron testing machine. Both temperature and crosshead extension are programmed and the test cycle can be designed for either tensile or compressive loading at the maximum temperature.

The test method is described for hollow, tubular, threaded-end specimens, resistance heating and compressed air cooling, linear heating and cooling rates, and air environment. The stress dependence of the thermal coefficient of expansion causes no special problem in the determination of the strain values.

A strain measuring system is described that eliminates the thermal component of strain from strain record. Employment of such a system allows a direct recording of load versus mechanical deformation. From these hysteresis loops the pertinent information of the cycle can be determined.