چكيده به لاتين
In this research, the improvement of the efficiency of the HTR hot-work tool steel by optimizing the Heat treatment parameters was investigated. In order to design the heat treatment experiments, after the initial investigations, the three parameters of the austenitic temperature, the time of austenite and the temperature of the tempering, among the most effective parameters and variation of hardness, impact energy and high temperature tensile properties of the studied steel were selected. Also, a one-stage and two-stage stamping was selected with an optimal time of two hours. The lower and upper limits were selected for the austenitic temperature of 1040 and 1100 ° C, for the time of austenite, 10,30 and 60 minutes, and for the tempering Temperatures were selected at 560 ° C and 650 ° C. The obtained results included the impact energy, the hardness, and the strength of the ambient temperature and the high temperature tensile, and the goal was to achieve the highest high-temperature strength with an optimum level of hardness and impact energy. an evaluation of the effect of thermal cycles was performed using scanning electron microscopy, X-ray spectrometer analysis, X-ray diffraction and micro-tensile test. Measurement of volumetric volumes of carbides in different cycles of thermal treatment was done using image analysis software. The results indicated an increase in the mean diameter of the primary austenite grains and reduced hardness by increasing the temperature and time of austenite. The 1040 ℃ temperature was selected as the temperature and time of 30 minutes as the optimal time of austenitizing. . At constant Austenitizing Temperature, the effect of temperature changes on the hardness, impact energy and temperature of the ambient temperature Tensile and high temperature Tensile at 400 and 600 ° C on the HTR hot work tool Steel was investigated. The results from these experiments indicated an increase in hardness at 590 ℃ to 510 V; due to the secondary hardnening phenomenon, and then the hardness temperature up to 440 V, at a tempering temperature of 650 ℃, was reduced. The results obtained from the tensile test The ambient temperature indicated an increase in yield strength and ultimate tensile strength at 590 ° C compared to other tempering temperatures. This increase in strength is probably dependent on the secondary hardening phenomenon. The results obtained from the impact test on the tempered steel samples also indicate a brittle fracture in all specimens, but the impact energy in the heated sample at a temperature of 590 ° C, which had the least amount of impact energy compared to other tempered specimens. Finally, according to the results of the high temperature tensile experiment and the microstructural studies on the distribution of Precipitated particles and the size of the austenite grains, the temperature of 590 ° C was selected as the optimum temperature for the tempering operation for 4 hours.
