Thermal fatigue testing with repeatable temperature cycles on thermomechanical simulator

This paper presents two thermal fatigue tests developed to simulate the typical thermal fatigue behavior of hot-work tools and rolls. The tests are carried out on a Gleeble 1500D thermomechanical simulator with computer-controlled heating and cooling of the test specimens. In the first test, internal cooling of the specimens is performed, and in the second test, external cooling is performed. This allows constant test conditions and the collection of reliable experimental data on the thermal fatigue behavior. The internally cooled test rig is used for testing the thermal fatigue properties of bulk materials. Indefinite chill double-poured cast iron is used to present the basic capabilities of the test. At the material, the cracks take flattened graphite–cementite pathways. The external cooling test rig, on the other hand, is designed for comparative testing of four surfaces simultaneously. Thus, the capabilities of the second test are presented in the comparative testing of three different laser-welded functionally graded material surface layers and the basic H13 tool steel, simultaneously. The highest thermal fatigue resistance is shown by the weld with the lowest silicon (Si) content. Quantitative evaluation of thermal fatigue resistance as well as following of degradation processes in both tests is enabled.