Electric heater of low-pressure casting machine

Abstract

An electric heater of a low-pressure casting machine comprises an radiant tube, an electric element and an insulating frame; the electric element which is made of a flat-belt-shaped electrothermal alloy material and spirally wound around the insulating frame is reasonable in design, compact in structure, large in superficial area, high in heating power, uniform in heat radiation, reliable in operation, convenient to maintain and long in service life; the electric element which is made of an iron-chromium-aluminum-alloy material is high in electrical resistivity, small in resistance temperature coefficient, high in oxidization and corrosion resistance, long in high-temperature-resistant service life, light in weight and low in price, the material is saved, the size specification of the electric element is enlarged, surface load is reduced, and therefore the service life can be prolonged. A silicon carbide high-temperature refractory material is used for manufacturing the radiant tube, the radiant tube is high in heat conductivity, high in high-temperature intensity, resistant to abrasion, thermal shock and erosion and high in molten aluminum corrosion resistance and has satisfactory service life.

Description

technical field [0001] The invention belongs to the technical field of metal casting equipment, and relates to a low-pressure casting machine, in particular to a low-pressure casting electromechanical heater. Background technique [0002] With the rapid development of my country's automobile industry, the manufacturing requirements for wheels are getting higher and higher. In order to meet the requirements of lightweight auto parts and the changing structure of wheels, it has become the current development trend to use a large number of low-pressure casting technology to produce aluminum alloy wheels. ; In other fields, such as aviation, textile machinery, etc., low-pressure castings are gradually being used to improve product quality, reduce cutting processing, and reduce equipment weight. as attached figure 1 As shown, the existing domestic and imported low-pressure casting machines, the electric heater used in the airtight holding furnace (crucible), its electric heatin...

AI Technical Summary

Problems solved by technology

as attached figure 1 As shown, the existing domestic and imported low-pressure casting machines, the electric heater used in the airtight holding furnace (crucible), its electric heating element 2 adopts Ni80Cr20 and other grades of wire-shaped nickel-chromium alloy resistance wire, and in order to achieve a certain The use of power, adopt the winding method of axial arrangement, and its outer circumference is generally covered with stainless steel radiant tube 1, otherwise, the molten metal is easy to splash on the resistance wire, resulting in uneven local resistance of the resistance wire and overheating, making it premature damage

Because the heating element 2 of this kind of electric heater has a circular cross-section and adopts an axially arranged winding method, its surface load is large, and the heat dissipation of the inner and outer resistance wires is very uneven. The maximum operating temperature generally does not exceed 1100 ° C, and the service life is relatively short. , while the price of nickel-chromium alloy heating elements is higher

In addition, the stainless steel radiant tube 1 used in the electric heater is easy to bend and deform at high temperature, which is not convenient for disassembly and maintenance, and may even cause corrosion, slag drop, and perforation, which not only affects the actual function of the radiant tube 1, but also affects Components of liquid metals such as aluminum alloys

Existing low-pressure casting machines also have electric heaters that use silicon carbide rods as electric heating elements, but they still cannot solve the problems of high price, short service life of heating elements, and easy corrosion and deformation of radiant tubes. The outlet form is not conducive to the maintenance and repair of electric heaters

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