Induction heating suspension smelting new technology
1. Principle of induction heating suspension smelting
Induction heating suspension smelting is a new melting method of suspending metal materials in crucible and heating melting them. Its basic principle is the current through the induction coil in the water cooled copper crucible and eddy current is generated in metal materials due to the eddy current electromagnetic force between mutually exclusive, make the metal material is suspended, heating and melting.
2. Calculation of suspension force
The metal material is in complete non-contact or partial contact with the water-cooled crucible during melting. How much buoyancy does the metal need to be suspended? Because the alternating magnetic field changes along the metal surface. Let's say the permeability layer is very small compared to the thickness of the metal. The higher the frequency, the lower the suspension force. The lower the frequency, the greater the suspension force.
3. Characteristics of induction heating suspension smelting
Induction heating suspension smelting has the following characteristics:
(1) metal materials capable of melting high melting point;
(2) as there is no impurity from the crucible, ultra-high purity metal materials can be smelted;
(3) because of strong electromagnetic stirring, the alloy with uniform structure can be produced;
(4) shorten the melting time to achieve rapid melting;
(5) the crucible is not damaged and can be reused.
4. Types of induction heating suspension smelting devices
Metal materials in the process of melting and the crucible in the non-contact state, in order to ensure that liquid metal in the non-contact state from within the crucible out smoothly, adopted at the bottom of the crucible and vacuum suction casting export two pouring ways.
4.1 the melting device of the molten metal liquid at the bottom is known from equation (3) that the suspension force of the molten metal liquid is inversely related to the frequency. Rich soil motor adopts different frequencies of two groups of coil, suspending and melting each have emphasize particularly on, the coil is given priority to with melting, a 10 kHz frequency, the coil is given priority to with suspension, a few kHz frequency, two groups of coil control independently, even if the type and quantity of different metal materials can achieve stability, flexible operation. From liquid metal in order to guarantee the smooth inside crucible, designed the export at the bottom of the crucible, change the upper and lower the power of suspending liquid metal coil change shape, reduce the levitation force and the gravity of the liquid metal on the exported from the bottom of the metal liquid flow out. The metal liquid and the crucible are also in non-contact state due to the action of electromagnetic force in the outflow process. According to the above principle, a suspension smelting device with a capacity of 2.3kg and 5.0kg has been developed, and products made of titanium alloy, stainless steel and cast iron have been produced. For example, under the protection of argon gas, the smelting of 50kg of iron takes only 12min and 15s of pure iron solution. In addition, on the basis of the bottom outlet smelting device, a crystallizer (tensile die) was set up to manufacture a continuous casting device. See figure 3. Using the device have produced Φ 6 mm, 1.4 m long without defect lead rod and the length of 1.0 m no defects casting iron bars.
4. 2 levitation melting outside the vacuum suction device in addition to the melting device, and a water cooling at the bottom of the crucible, vacuum casting is not the same material of solid metal melting, the upper metal and crucible wall is still in the state of non-contact planktonic melting equipment. The state of fusion. The heat loss of this device includes two types: thermal radiation and heat conduction. Then, in the molten state, the heat of the molten metal is balanced with the loss of heat radiation and heat conduction. That is, Q supply =Q radiation +Q conduction (4). Therefore, the power satisfying the design requirements can be obtained according to equation (4). In order to ensure the smooth pouring out of metal liquid in non-contact state, vacuum suction casting method is adopted. See figure 5. This device has the following characteristics :(1) suitable for large capacity melting; (2) vacuum suction casting improves the fluidity of metal liquid; (3) simple device and high productivity, suitable for single piece and small batch production. Figure 6 shows the parts cast this way. (a) golf head figure 6 (b) the supercharger impeller casting parts 5 conclusion induction heating levitation melting technology is a new kind of smelting technology, the most suitable for smelting high melting point, high purity and nature lively metal materials. It is called "ideal melting method".