HOT LINE: +86-510-80628100HOT LINE: +86-510-80628100For the case that the electric resistance furnace and gas furnace are used to heat the blank, the blank with temperature gradient distribution is obtained by heating control. A feasible method is to form a temperature gradient in the length direction of the blank when the water jet is controlled by the water spray cooling and the uniform heating. There are two ways to realize the cooling of water.
One is the use of a single annular nozzle to spray, the blank in the annular nozzle movement, through the control of the speed of the billet and the flow of the nozzle, to achieve the temperature of the billet temperature cooling.
The two is a temperature cooling device of a ladder consisting of multiple annular nozzles. The temperature control is realized by controlling the opening time of each nozzle. The temperature control can be realized by adjusting the distance between the nozzles to open a number or adjust the nozzle.
The advantages of the first method is that the cooling device is relatively simple, but the difficulty of the process control, the second method of the cooling device is more complex than the previous one, the main is to increase the number of ring nozzle, but it has the advantages of more easy to process control, process stability, etc..
Water-cooling device and application in the actual production of billet in water cooling effect and in the blank of 120mm in diameter, length of 500mm. The head and tail temperature difference reached 60 degrees.
After spraying water cooling of the blank, the air cooling of a certain period of time is needed to be put into the extrusion cylinder, so that the radial temperature is uniform. As shown in Figure 9-14, water cooling (about 7S), the temperature of the billet near the surface of the rapid decline, then gradually rise; the central part of the billet temperature in the initial spray cooling, and then began to decline. Mainly because the water spray cooling, high temperature aluminum billet so that the water is boiling heat exchange, take away a lot of heat, and the core part of the heat is not too late to spread, so the surface temperature drop, while the core temperature of the basic constant, and then gradually decreased. When the water cooling, air cooling heat dissipation is small, due to the existence of internal and external temperature gradient, the core of the heat gradually from the internal and external transmission, surface temperature rise, until the internal and external temperature tends to be consistent.
The advantage is that the heating furnace with ordinary electric resistance furnace, gas furnace can be used to reduce the cost of billet heating (resistance furnace and gas turbine and gas turbine and gas turbine and gas turbine and gas turbine and gas turbine). The high temperature gradient can be obtained by using the method of temperature gradient, and it may be used to reduce the energy consumption.
Billet temperature gradient pressing (including gradient temperature heating and temperature gradient cooling in two ways) is a kind of method is simple and obvious effect of the isothermal extrusion process, but the method also exist certain limitations in prior to extrusion given blank along the length direction of the temperature gradient, increase the complexity of the process and control difficulty. Due to the result gradient temperature heat or temperature gradient cooled metal blank internal heat transfer and end of radiative cooling, resulting in changes along the axial billet temperature distribution, billet temperature difference between the head and tail size in presence of bounded.
