An induction heating furnace is a device that uses the principle of electromagnetic induction to heat conductive materials, typically metals. It works by placing an induction coil, carrying a high-frequency alternating current, near the workpiece. This generates a time-varying magnetic field. When a conductive material is placed within this magnetic field, กระแสน้ำวน are induced in it. Due to the material’s inherent electrical resistance, these eddy currents are converted into heat, achieving non-contact heating of the material.
How an Induction Heating Furnace Works
- Electromagnetic Induction: When high-frequency alternating current flows through the induction coil, it generates a fluctuating magnetic field around it.
- Eddy Currents: When a conductive material (workpiece) to be heated is placed in this alternating magnetic field, induced currents, รู้จักกันในชื่อ Eddy Currents, are generated within the workpiece in a swirling pattern, according to Faraday’s Law of Electromagnetic Induction.
- Joule Heating: As eddy currents flow within the workpiece, they generate heat due to the material’s electrical resistance (Joule effect), causing the workpiece’s temperature to rise.
- Hysteresis Loss (for Magnetic Materials): For magnetic materials like iron and steel, in addition to the heat generated by eddy currents, the alternating magnetic field also causes rapid flipping of magnetic domains within the material, leading to hysteresis loss, which further increases the heat.
- Skin Effect: As the frequency of the alternating current increases, the eddy currents tend to flow more concentratedly near the surface of the workpiece. This phenomenon is called the skin effect. This allows induction heating to achieve rapid, localized heating of the workpiece surface.
Uses of Induction Heating Furnaces
Induction heating furnaces are widely used in industrial production due to their efficiency, ความแม่นยำ, cleanliness, and ease of control. Their main applications include:
- Metal Melting: Used for melting various metals and their alloys, เช่นเหล็ก, เหล็ก, สแตนเลส, ทองแดง, อลูมิเนียม, และโลหะมีค่า. Induction melting furnaces achieve fast and efficient melting, and the stirring effect produced by the magnetic field helps ensure uniform alloy composition.
- Heat Treatment:
- Hardening (การดับ): Rapid heating and cooling to increase the hardness and wear resistance of metal materials. Induction hardening allows for localized heating of specific areas of the workpiece, reducing overall deformation.
- การหลอม: Used to relieve internal stresses in metals, improving their ductility and toughness.
- การแบ่งเบาบรรเทา: After hardening, the workpiece is reheated to a lower temperature to adjust its hardness and toughness.
- Carburizing: Surface treatment of metals to increase surface hardness by introducing carbon.
- Pre-heating for Forging: Rapidly heating metal billets before forging to improve their plasticity, reduce deformation, and minimize subsequent straightening work.
- Brazing and Welding:
- Brazing: Joining two or more metal parts using a filler metal with a lower melting point than the workpieces. Induction brazing offers energy efficiency, high productivity, and good repeatability.
- การเชื่อม: ตัวอย่างเช่น, tube welding, where induction heating brings the tube edges to welding temperature before they are pressure-welded.
- Shrink Fitting / Disassembly: Utilizing the thermal expansion and contraction of metals, components are heated to expand them for assembly or disassembled after heating.
- Sintering: In powder metallurgy, used for sintering metal powders to solidify them into a desired shape.
- Extrusion: Heating metal billets for extrusion forming.
- Specialized การใช้งาน:
- In the semiconductor industry, for heating silicon or other semiconductor materials.
- Heating liquid conductors (like molten metals) and plasma.
- Heating non-conductive materials (เช่น, graphite crucibles containing other materials).
- Improving energy efficiency in plastic injection molding machines.
ที่ เตาทำความร้อนเหนี่ยวนำ is a modern heating technology that plays an indispensable role in many industrial fields due to its unique non-contact heating method and excellent performance.
