Аналіз якості нагрівання металу при різних способах опалення нагрівальних колодязів

This research was done to analyze the heating efficiency of alloy steel ingots in recuperative heating wells with heating from the hearth center using continuous and pulsed fuel supply methods. It was revealed that the peculiarity of the thermal operation of wells with heating from the hearth center is the vertical location of the torch and uneven heat release along the height of the working chamber of the furnace that results in the nonuniform heating of metal ingots. An analysis of literature sources showed that the heating of highly alloyed and special steels is characterized by long holding times and increased fuel consumption; therefore information on the temperature distribution in ingots is very important for the development of rational temperature modes for their heating. The results of thermometering of an experimental ingot heated within the volume of high-alloy steels have been given. The final temperature differences in the ingot and the pattern of a change during the metal holding process have been established. The final temperature difference in the test ingot is determined by the nonuniformity of the temperature field of the heating well and it is in the range of 80 °C to 120 °C. It has been established that the temperature of air heating in a ceramic recuperator during the heating of a metal volume using a continuous method varies on average from 400 °C to 600 °C, which is significantly lower than the passport data. The use of the obtained research data makes it possible to develop heating modes for stainless steel grades with a shortened holding period. Significant design flaws of wells that affect the uniformity of metal heating, specific fuel consumption and the level of operating costs have been identified. The effectiveness of introducing pulsed fuel supply for heating wells with heating from the hearth center has been studied. It has been proven that the use of a pulsed method of fuel supply during the holding period will intensify heat exchange processes and increase the ingot heating uniformity.