Vacuum Induction Melting Furnace
Tension springs and Rotary sealing bearing
Crucible effective volume
Crucible effective capacity (Steel)
Max melting vacuum
Induction copper coil
● 70L/s Double stage Rotary vane mechanical pump
Vacuum furnace shell
● Furnace Shell is a vertical cylinder with double layer water-cooling, 304 stainless steel inner was mirror polished; the outer rolled by carbon steel.
● Double layer water-cooling arched furnace cover. Equipped with two tension springs, used to balance the weight. You can open the cover easily. When it's locking, two tension springs can also provide furnace cover airtight pressure to ensure good sealing.
● The electrode is located in the left side of the furnace shell. It can work as a power supply for induction heating electrodes, and as a fulcrum of induction heater and Crucible.
● Electrodes mounted on Sealed bearing, when needed tilting crucible, worker can operate the handle to pour the liquid steel.
● Alloy feeder is located in the center of the cover. Inside the feeder is divided into six cubicles (material of one cubicle is placed in the tipping bucket), the material can be fed into the crucible in the vacuum or protective gas.
● When turning the feeder hand wheel every 60 degrees, there is one cubicle material fall into the tipping bucket inside the furnace cover.
● Feeding tipping bucket is equipped with damping plate to prevent materials falls too quickly. When in use, gently shake the joystick (outside the furnace cover), you can control the speed and quantity of the material fall into the crucible
● The furnace cover is equipped with an observation window, easy to observe the performance of the furnace.
● Active shutter is installed on the observation window, preventing glass from burning broken and getting dirty by steam accumulation of metal.
● Shutter moves away shortly only when observing, controlled by the handle outside the furnace cover.
● Induction heater consists of a rectangular copper tube, through the two mating nut fixed on the electrode, easy to disassemble.
● Pre-sintering moulding crucible can be placed inside.
● In front of the sensor, at the bottom of the furnace shell (where place the ingot mould), there is a circular pipe. On the pipe, there is a circular shelf to place ingot mould. Normally, ingot mould is placed on this shelf. When you need to cast the slender ingot, the ingot mould will be high, you can remove the shelf and put the ingot mould into the circular pipe, place it on the water-cooling cover. If you have some special needs, you can replace the water-cooling cover into a suitable water-cooling ingot mould room.
On right side of the furnace exhaust pipe fitted with a temperature measuring device. When you need to measure temperature, just pull up the spring latch, turn the handle, the thermocouple tip will insert in the liquid metal. Quartz protecting tube for thermocouple prepared by the user.
Medium frequency power supply and Water-cooling
● Medium frequency power supply is a 1500-2500Hz, 50KW thyristor medium frequency equipment. To compensate for low power factor, the system is equipped capacitor.
● Vacuum system directly connect to exhaust port on the furnace shell. The system includes oil vapor diffusion pump, two stage rotary pump, valve, pipeline, etc.
Step 1. Feeding
● The materials must be carefully cleaned, removed surface contamination, oil, etc. and baked to remove moisture.
Step 2. Vacuum pumping
Firstly, open the 2-stage rotary pump to vacuum the furnace. At the same time, open the diffusion pump power supply, start heating the diffusion pump oil. When the vacuum of 2-stage rotary pump is 15Pa and diffusion pump have been heated for about 50 minutes, now you can close 2-stage rotary pump valve, open diffusion pump valve, vacuum the furnace to the required high vacuum.
Step 3. Melting
● Firstly, open the thyristor medium frequency power supply, increase working voltage sensors gradually. Normally, start with the small power to avoid sudden sharp rise in temperature and vacuum dropped significantly. So the general rate of power increase should not make the vacuum dropped significantly.
● The max power of furnace is subject to the medium frequency voltage and max current.
Step 4. Refining
● After all materials melting, when need to add alloy, you can turn the handwheel, then the alloy will drop into the feeding tipping bucket. Gently turn the operation handle, the alloy will drop into the crucible at the speed you need.
● It's easy to cause sputtering when some alloy drop into the crucible. You need to pay attention to the speed of alloy's adding. It can't be too fast. Sometimes, you need to lower the power, make the liquid surface a bit harder, then adding the alloy to reduce sputtering.
Step 5. Casting
When refining complete, no need to cut off the power, tilt crucible to pour metallic liquid into ingot mould. Notice, do not pour it out of the ingot mould.
● When melting, you should pay attention to cooling condition of each part. The temperature of cooling water should not over 50℃. If the water pressure is inadequate or some part over temperature, you should cut off the power, find the reason and fix it, then restart. The hardness of water should not be too high, should be clean. Cooling water pressure: 0.2Mpa, water consumption: 3000kg/h.
● When stop using the furnace for a while, you need to use compressed air to blow out the remained water to prevent corrosion and extent service life.
● Replace the oil of diffusion pump and 2-stage rotary pump regularly. Add diffusion pump oil as lubricating oil to the seal parts regularly.
● When stop using the furnace, you should clean the furnace inside and outside and vacuum it.