Thermal Fatigue Cycle Shock Effects on Physical and Structural Properties of H13 Tool Steels before and after Heat Treatments

Abstract

Any tool that is subjected to repetitive thermal service will undergo degradation in loss of various properties such as, strength, structures, thermal stability, and so on. These natural changes lead to huge premature failures and unexpected break downs during production by causing uneconomical and undesirable situations. Therefore in this present research, the raw, heat treated, and heat treated and nitrided H13 tool steel specimens were subjected to a thermal shock cycle condition similar to a real industrial application using a unique in-house built thermal shock cyclic fatigue (TSCF) testing machine to impose the thermal gradients. All the TSCF tested samples were then characterized by physical and structural tests, including, hardness, (Rockwell, HRc), X-ray diffraction (XRD), and field emission scanning electron microscope (FESEM). The interesting changes in hardness, distorted crystal structure, and crack initiation due to the imposed cyclic thermal gradients by TSCF process up to 2000 thermal shock cycles were found to be different for differently treated H13 tool steel specimens. Therefore, this present investigation specifically would help in predicting the design parameters and to fabricate the proper mould components of various casting products.