2016年9月21日星期三

Vacuum heat treatment furnace to enhance the convection heat transfer

Vacuum heat treatment furnace to enhance the convection heat transfer
Vacuum heat treatment furnace of the resistance furnace industry generally by the electric heating element, masonry, metal shell, oven door and oven with mechanical and electrical control system, etc. Heating power from less than a kilowatt to thousands of kilowatts. Working temperature below 650 ℃ low temperature furnace; 650 ~ 1000 ℃ temperature in the furnace; More than 1000 ℃ high temperature furnace. In the high temperature and the temperature in furnace mainly by way of radiation heating. In low temperature furnace to heat convection heat transfer, conceal electric heating element is installed inside the air duct, by forced circulation flow of gas in the fan and to enhance the convection heat transfer. Has room type resistance furnace, pit type, car type, push rod type, step type, muff type and tunnel type. Controlled atmosphere furnace, vacuum furnace, fluid particles, etc are also resistance furnace.
Vacuum furnace masters know starting power vacuum furnace, set the switch control cabinet in the automatic control location. Input the parameters of the vacuum furnace process planning into the computer. Then the workpiece with charging car smoothly away in furnace, oven door closed and locked (cover), to ensure the seal. According to the technological requirements to choose good vacuum furnace and the cooling way of cooling medium and pressure. Press the cycle start button, equipment execution procedures: vacuum heating _ _ cooling automatically. Remember to check whether the system is running normal, if there is any abnormal timely report the captain. In before, we should restore the normal pressure in the furnace, the light is normal after open the oven door (cover). When discharging, should careful operation, workpiece and tooling shall glory hole collision.
Difficult control mainly has two aspects, first, how to take off carbon to the lowest in 15 minutes; Second, according to 15 minutes after the decarburization of the residual oxygen content in liquid steel, aluminum one-time add in position, aluminum DNA can be ensured and the aluminum alloy and can guarantee. In this way, the smelting time can control between 25 to 30 minutes. Otherwise, the vacuum processing time was significantly longer. Smelting in the process of production of ultra-low carbon steel, as the extension of time, the contact between refractory material and steel liquid will lead to carbon steel back, in addition, the amount of ultra-low carbon steel because of the addition of aluminum is larger, a lot of Al2O3 inclusions produce, so the aluminum to join the sooner, the more conducive to Al2O3 inclusions floatation, the more conducive to the process after the operation and improve the quality of our products.

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