Investigation of wear and fatique behavior of 1.2436, 1.2379 and CPOH cold work tool steels after quenching and cryogenic treatment

In this thesis study, an investigation was conducted to examine the hardness, wear resistance, and fatigue behavior of cold work tool steels with high carbon content—specifically 1.2436, 1.2379, and CPOH by applying quenching and sub-zero (cryogenic) treatments. As part of the experimental process, test specimens were first manufactured in accordance with relevant standards. Subsequently, the heat treatment parameters for quenching and tempering were determined, and the quenching processes were carried out. Following quenching, in order to eliminate retained austenite in the steels, sub-zero (cryogenic) treatment at -196°C was applied. The fatigue behavior, wear losses, and hardness values of quenched and tempered, as well as cryogenically treated specimens, were compared. Finally, the microstructural characteristics of the materials were analyzed and interpreted through Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) analyses, contributing to the interpretation of the study results. The experimental findings revealed that the cryogenic treatment had a beneficial effect on increasing both hardness and wear resistance in all the steels examined. Furthermore, it was observed that the fatigue resistance of 1.2379 and CPOH cold work tool steels improved following cryogenic treatment. However, the cryogenic treatment was found to have an adverse effect on the fatigue resistance of the 1.2436 cold work tool steel.