Comparison of advantages between steel shell furnace and aluminum shell furnace

Jul 27, 2022


Compared with aluminum shell furnace, steel shell furnace has the following advantages

Compared with aluminum shell furnace, steel shell furnace has the following advantages:

1) The steel shell furnace is solid and durable, beautiful and generous, especially the large capacity furnace body (generally more than 1.5-2 tons, it is recommended to choose the steel shell furnace body) requires a strong rigid structure. From the perspective of the safety of tilting the furnace, the steel shell furnace should be selected as far as possible.

2) The magnetic yoke made of silicon steel sheet unique to the steel shell furnace shields and emits the magnetic field lines generated by the induction coil, reduces magnetic leakage, improves thermal efficiency, increases output, and saves energy by about 5%-8%.

3) The existence of steel shell furnace cover reduces the heat loss and improves the safety of the equipment.

4) The steel shell furnace has a long service life, and aluminum is oxidized seriously at high temperature, resulting in fatigue of metal toughness. At the site of foundry enterprises, it is often seen that the shell of aluminum shell furnace used for about a year is in bad condition, while the service life of steel shell furnace is much longer than that of aluminum shell furnace due to less magnetic leakage.

5) The safety performance of steel shell furnace is much better than that of aluminum shell furnace. Aluminum shell furnace is easy to deform and has poor safety due to high temperature and heavy pressure during smelting. The steel shell furnace uses hydraulic tilting furnace, which is safe and reliable.

Although the steel shell furnace is superior to the aluminum shell furnace, you should also start from the economic return on investment and decide whether to choose the aluminum shell furnace or the steel shell furnace according to the weight of the melted material. Aluminum shell furnace can be selected, but we must pay attention to the thickness and weight of the furnace shell to ensure safe production.

2、 Why are the prices of products of the same model very different and how to choose the medium frequency smelting furnace?

There are great differences in the price of the same type of medium frequency induction furnace. Taking the widely used 1 ton furnace as an example, the market price sometimes varies several times, which is related to many factors, such as the structure of the furnace, the selection of components, technical content, after-sales service and equipment quality.

1. Different material selection

Furnace shell and yoke: in terms of the choice of the shell of the aluminum shell furnace, the shell weight of the standard 1 ton aluminum shell furnace is 400kg cast aluminum alloy, and the thickness is 40mm. The shell of some manufacturers is often insufficient in weight and thickness; The most important thing for steel shell furnace is the choice of yoke. The choice of yoke for the same type of steel shell furnace is different, and the price difference is very large. Generally, it should be made of brand-new Z11 cold-rolled silicon steel sheet with high permeability. The thickness of the silicon steel sheet is 0.3mm, and the profiling structure is adopted. The inner arc surface and the outer arc of the induction coil are the same, so that the yoke can be close to the outside of the induction coil, and the coil can be restrained to radiate the magnetic line of force outward to the greatest extent, The yoke is clamped by stainless steel plates and stainless steel on both sides, welded and fixed, and cooled by water.

Copper tube and copper bar: as we all know, the core of the smelting furnace is the induction coil. The effect and price of selecting cold extruded copper tube or cast copper tube for the inductor are very different. T2 cold extruded copper pipes with huge cross-section should be used. The surface insulation treatment of copper pipes adopts electrostatic spraying to achieve H-class insulation. In order to protect its insulation strength, mica tape and alkali free glass ribbon are wound and wrapped on the surface respectively once, and then moisture-proof insulating enamel is coated. There is a certain gap between the turns of the coil. When applying the fire-resistant plaster in the coil, the fire-resistant plaster should penetrate into the gap to strengthen the adhesion of the plaster on the coil to the coil. After the fire-resistant plaster is built, the inner surface is smooth, which is convenient for removing the furnace lining to protect the coil. A few turns of stainless steel water-cooling rings are added at the upper and lower ends of the coil to increase the overall rigidity and facilitate heat dissipation. (some manufacturers use cast copper or T3 copper pipes, which have poor conductivity and are easy to crack and leak, so special attention should be paid.)

Silicon controlled rectifier: the quality of silicon controlled rectifier used by various manufacturers is generally uneven. Good quality silicon controlled rectifier has good temperature sensitivity, fast response and low failure rate. Therefore, the SCR from well-known manufacturers is selected with reliable and stable quality. (when selecting, the electric furnace manufacturer is required to indicate the manufacturer of thyristor and show the product certificate of thyristor manufacturer, etc.)

Power cabinet: the sizes and specifications of power cabinets of regular manufacturers are standard. The power cabinets of irregular manufacturers have also shrunk, and the height, width and thickness are not enough. Some even put reactors outside the power cabinets. Regular manufacturers have low-voltage switches inside the medium frequency power supply, so users do not need to configure another voltage switch cabinet. Some irregular manufacturers do not install low-voltage switches inside the power supply, which virtually increases the cost of users.

Capacitance: the capacitance cabinet for reactive power compensation must be equipped with sufficient quantity. Generally, the compensation value of capacitance is 18-20 times of power supply power, that is, capacitance compensation (kvar) = (18-20) × The power of the power supply shall be the capacitor of the regular manufacturer.

Reactor: the main material of the reactor is silicon steel sheet. New products produced by regular manufacturers should be selected, and recycled second-hand silicon steel sheet cannot be used.