Investigation of the effect of casting process parameters on the properties of titanium alloyed hi̇gh manganese steel

ASTM A128 Gr. E-1 (1.0C-13Mn) steel is a strongly preferred alloy in the impact and wear-resistant pallet systems of earthmoving equipment used in the mining industry. The need for higher performance alloys has increased with the aggravation of working conditions. Accordingly, higher wear resistance, toughness, and tensile properties can be achieved with alloy development, heat treatment optimization, and microstructural design of the alloy. Within the scope of this thesis, the effects of carbon, manganese, titanium elements in the composition of high-manganese steels as well as the effects of different heat treatment and pouring temperatures on microstructure and mechanical properties were examined and consequently it was aimed to improve tensile strength, impact resistance and abrasion properties under appropriate microstructure conditions. Firstly, it was aimed to determine the optimum solution annealing temperature with the optimum carbon and manganese rate by using casting samples produced in different chemical compositions at constant casting temperature (1450 °C). In comparison with reference alloy (1.0C-13Mn), the optimum results with an improvement of 5% in yield strength, 19% in elongation and 21% in impact strength were obtained with 1.0C-17Mn sample that solution annealed at 1100 ° C. Secondly, the effect of the Ti addition at different rates was examined. It was observed that a stable Ti (CN) phase was formed in the microstructure with the addition of titanium and accordingly, there was a 45-52% reduction in the grain size. Although reduction of 22 % in impact resistance due to differences in Ti (CN) distribution and morphology, the most ideal results were obtained with 1.0C-17Mn-0.05Ti sample with an improvement of 7% in tensile strength, 9% in elongation and 40% in wear resistance. In the last stage of the thesis, real track shoe (3.5 tons) was cast with 1.0C-17Mn (Ti free) alloy. The effects of different pouring temperatures on microstructure and mechanical properties were investigated. Significant differences in the mechanical and microstructural properties are noticeable between the results obtained in the sample blocks and the thick section casting part. Despite the increase in casting mass and thickness, the desired mechanical properties obtained in the cast part produced at lower pouring temperatures (1420 °C). As a result, the production of cast parts used in industry with suitable casting parameters increased the service life of the parts by 30%.