Working principle:
This equipment uses medium frequency induction heating to melt the material, and then pours the molten material into a crucible mold of a specific shape for crystallization. This product is mainly suitable for the production of alloy material smelting ingots, etc.
Structural performance and features:
The main structure of the 1100kg vacuum induction melting directional solidification furnace: furnace body, furnace cover, lifting mechanism, rotating shaft power supply, coil, argon gas Miyazaki system, vacuum system, hydraulic system, pneumatic system, window mechanism, temperature control system, etc. Furnace body and furnace cover: They are the vacuum containers that make up this type of electric furnace. All other mechanisms are attached to the furnace body and furnace cover. The diameter of the furnace body is 1200mm vertical structure. The furnace cover can be lifted and rotated. Both adopt water-cooled sandwich structure, and the furnace cover adopts a three-arc structure.
Lifting mechanism:
The lifting mechanism is the connecting mechanism of the furnace body and the furnace cover. Through the lifting mechanism, the furnace cover can be lifted and rotated. The furnace cover is hydraulically driven and electrically controlled. Rotating shaft power supply system and tilting furnace mechanism:
The rotating shaft adopts water-cooled coaxial power supply mode and can be disassembled. The power supply system is composed of 0.1mm single wires with a cross-section of 50mm2, a total of 80 wires, which are used to make the connection between the busbar and the rotating shaft. The efficiency is improved by more than 5% compared with the original water-cooled cable wires. The line voltage drop is not more than 5V. This structure not only improves efficiency, but also rotates flexibly and reliably. The casting tilting furnace is hydraulically rotated and manually operated. The tilting speed can be adjusted. The control console is equipped with a tilting operating lever.
Induction coil:
The induction coil is made of a copper tube with a gap of 3-4mm between turns. The position is fixed by the outer insulating plate. The induction coil and the inlet and outlet electrodes are connected by nuts, which are easy to disassemble. It can ensure good conductivity and reliable vacuum sealing. Since this equipment adopts the induction graphite heating method, there should be 20~30mm of thermal insulation material between the coil and the graphite heating element to prevent the coil from short-circuiting and directly radiating heat. From the test results, the maximum coil voltage should not be greater than 250V to avoid discharge.
Ingot support mechanism:
The ingot support mechanism consists of two parts, the steel-out mechanism and the ingot mold lifting.
Ingot mold lifting mechanism:
This mechanism uses a torque speed measuring unit plus a micro-cycloid reducer to drive a D-level ball screw to raise and lower the crucible (the crucible is placed on the lifting support rod of the cooling water). The water-cooled lifting support rod is equipped with a water-cooled jacket containing liquid alloy at room temperature on the furnace body, which effectively blocks the deposition of volatiles on the water-cooled lifting support rod, thereby reducing the transmission resistance and preventing the torque motor from stalling and interrupting crystal growth due to excessive sediments and excessive resistance. The crucible’s descending speed is 0.1-10mm/min, which is continuously adjustable, with smooth transmission, no noise, and no creeping. The power supply of the torque speed measuring unit has a computer interface, which can remotely control the growth rate of the crystal.
Vacuum system:
In order to have a good working vacuum degree during the entire smelting process, the vacuum unit of this equipment is configured with a KT-400 oil diffusion pump, a ZJ-250 Roots pump, and a 2X-90 mechanical pump. The vacuum system is controlled by pneumatic valves, which are composed of ￠300mm pneumatic flap valve, ￠90mm pneumatic butterfly valve, ￠100mm pneumatic butterfly valve, and ￠80mm electromagnetic air release valve. All valves are driven by compressed air, operated by electrical switches, and can also be operated manually, which is convenient and fast, and the valves have a long service life.
Hydraulic system:
It mainly meets the power drive of furnace cover lifting, crucible tilting, ingot support mechanism rising and falling, etc. The furnace cover lifting and ingot support mechanism lifting are adjustable in speed, and hydraulic locks are also provided to ensure their safe and reliable operation. The furnace tilting adopts the manual hydraulic proportional valve designed and developed by our institute to control the pouring speed.
Pneumatic system:
All valves are pneumatically driven, and the operation is electric or manual.
Window mechanism:
There is a window mechanism on the furnace cover, three observation holes, all of which are double-layer quartz glass, and a set of heat insulation screens with copper brushes on them, which are driven by a micro motor. When the motor rotates, the situation in the furnace can be observed, and it can effectively prevent metal vapor from contaminating the glass. At the same time, the copper brush can be used to remove dirt attached to the glass at any time. If the glass is damaged, it can also be easily replaced. One of the observation holes is made into a water-cooled observation hole to protect the camera when the user configures a TV camera. One is for users to use when they are equipped with infrared temperature measuring devices, and the other allows the operator to observe directly.
Temperature measuring device:
There is one set of temperature measuring devices on the furnace body and three sets of temperature measuring devices on the furnace bottom. WRE5/26 thermocouples and protective tubes are installed to realize continuous online temperature measurement of the smelting furnace and the insulation furnace respectively. The temperature value can be directly read by the ordinary temperature meter.
Three sets of WRE5/26 thermocouples are installed on the insulation furnace, and three SR53 intelligent temperature control meters are equipped to realize online continuous temperature measurement and control. It is equipped with a computer interface, with temperature-power closed-loop control, automatic control of heating and constant temperature, and online storage of process temperature.
There is a pneumatic charging and discharging valve on the furnace body to meet the user’s requirements for deflation and charging of protective gas on the furnace body. A pair of spare interfaces are also provided on the furnace body.