Studium degradačních procesů pláště termočlánků ze slitiny Inconel 600

Abstract

This thesis deals with the study of degradation processes of thermocouple shells made of Inconel 600 alloy. The observed degradation processes were microstructural changes after high-temperature exploitation and their influence on corrosion resistance. The specimens were exposed to 760 °C for 1 h, 3 h and 7 h. The microstructure and corrosion resistance of these specimens were compared with the specimen in the initial state. The corrosion resistance was determined using the Streicher test and the DL-EPR test. Microstructural studies revealed that heat treatment led to a gradual precipitation of Cr carbides along grain boundaries, which leads to a desensitization of the material and thus an increase in susceptibility to intergranular corrosion. However, this assumption was not fully confirmed by the results of the Streicher test. As it turned out, the results were influenced by the oxide layer that formed on the surface of the tested samples during heat treatment. The sensitisation of the samples after heat treatment was subsequently demonstrated by the DL-EPR test.