Induction Heater: Specialized Equipment for Pre-Bending Heating of Metal Materials
In the field of metal processing, bending forming is a common process. For hard-to-bend materials such as high-strength steel, thick-walled pipes, and special-shaped profiles, pre-bending heating is a key link to ensure forming quality. Induction heaters, with their efficient, precise, and controllable heating characteristics, have become an ideal choice for pre-bending heating of metal materials. They can significantly reduce the bending resistance of materials, reduce the risk of cracking, and ensure the dimensional accuracy and mechanical properties after bending forming.
| Model |
60KW Induction Preheating PWHT Machine |
| Input Voltage |
3 Phase 380V, 50HZ |
| Output Frequency |
5KHZ ~ 30KHZ |
| Output Power |
60 KW |
| Input Current |
0-90A |
| Cooling Type |
Air cooling |
| Heating Temperature |
Preheat 0 - 350 C |
| Temperature Control |
1 Channel or 4 Channel |
| Heating Pipe size |
Dia: 50 -1000 mm |
| Heating Coil |
Induction Coil, Heating Blanket, Clamp Induction Coil |
| Extend cable |
1-20 meter |
| Heating Blanket |
Induction heating blanket, High temperature tube |
| Alarm |
Over Voltage, Over Current, Over Temperature and so on |
Core Functions: Creating Ideal Conditions for Metal Bending Forming
Before bending, metal materials need to be heated to a specific temperature (usually 0.6-0.8 times the recrystallization temperature of the material) to reduce yield strength and improve plasticity. Induction heaters meet the pre-bending heating needs through the following functions:
- Precise temperature control for different materials: For different materials such as low-carbon steel, high-carbon steel, alloy steel, aluminum alloy, and titanium alloy, the heating temperature can be precisely controlled (e.g., low-carbon steel is heated to 600-800°C before bending, and aluminum alloy to 200-400°C), ensuring that the material is bent in the best plastic state. For example, when pre-bending and heating a 10mm thick 45# steel plate, the temperature can be stably controlled at 700°C ± 10°C, avoiding grain coarsening due to excessive temperature or bending cracking due to too low temperature.
- Local heating focusing on the bending area: Through customized induction coils (such as arc coils, strip coils), only the bending deformation area of the metal material (such as the outer tensile area and inner compression area of pipe bending) is directionally heated. The heating range can be precisely controlled within 50-200mm on both sides of the bending center line, reducing the thermal impact on non-bending areas and lowering the risk of overall deformation.
- Collaboration between rapid heating and heat preservation: Induction heating uses the electromagnetic eddy current effect to make the material heat itself, with a heating speed 3-5 times faster than traditional flame heating (e.g., a φ100mm alloy steel pipe can be heated from room temperature to 650°C in only 3-5 minutes). It also supports constant temperature preservation function, ensuring that the material is always in a suitable temperature range during the bending process, especially suitable for continuous batch bending operations.
Technical Advantages: Adapting to Special Requirements of Metal Bending Processes
The technical advantages of induction heaters in pre-bending heating of metals make them significantly superior to other heating methods:
- Heating uniformity ensures bending accuracy: Through multi-frequency adjustment (usually medium-high frequency, 1-50kHz) and optimized coil design, the temperature gradient in the heating area can be controlled within ±5°C, avoiding uneven deformation during bending caused by local temperature differences of materials (such as excessive ovality during pipe bending). For example, when heating channel steel for U-bending, the temperature deviation between the flanges on both sides and the web can be controlled within 3°C, ensuring consistent angles on both sides after bending.
- Reducing material oxidation and decarburization: Induction heating is fast and can be equipped with an inert gas protection device, which can effectively reduce oxidation and decarburization of metal materials at high temperatures. Compared with the thickness of surface oxide scale caused by flame heating (usually 50-100μm), the oxide layer thickness of induction heating can be controlled within 10μm, which is especially suitable for precision bending parts with high surface quality requirements (such as special-shaped parts of automobile chassis).
- Linkage with bending equipment to realize automation: Induction heaters can be integrated into the bending production line, and through sensors linked with bending equipment, the fully automatic process of "heating - transfer - bending" can be realized. For example, in the CNC pipe bending machine production line, the heater can automatically call the preset heating parameters according to the pipe specifications and bending angle, and immediately transfer to the bending station after heating is completed to avoid temperature drop affecting the forming effect.
Application Scenarios: Covering Various Metal Bending Needs
The flexibility of induction heaters makes them widely used in pre-bending heating scenarios of various metal materials:
- Pipe and profile bending: Pre-bending heating is performed on oil pipelines, scaffolding steel pipes, high-speed rail track support profiles, etc., especially suitable for heating thick-walled pipes with large diameters (such as seamless steel pipes above φ200mm) before cold bending, reducing the load of bending equipment and avoiding wrinkling on the inner side and cracking on the outer side of pipes.
- Plate and plate part bending: In processes such as pressure vessel head bending, automobile panel flanging, and steel structure node bending, heating is performed on thick plates (thickness > 10mm) or high-strength steel plates (such as HSLA steel) to ensure no springback or controllable springback (springback angle ≤ 1°) after bending.
- Bending of special-shaped parts and complex structures: For complex forming needs such as titanium alloy special-shaped frames in the aerospace field and wear-resistant steel bucket bending in engineering machinery, precise temperature control is achieved through local induction heating to ensure the forming accuracy of complex curved surfaces.
Equipment Features: Balancing Efficient Production and Operational Convenience
- Customized coils for various workpieces: According to the shape (circular, square, special-shaped) and bending radius of the workpiece, detachable and replaceable induction coils are designed. For example, for S-bent pipes, segmented flexible coils can be used to fit the pipe surface for uniform heating.
- Intelligent control system to ensure process stability: Equipped with a touch screen operation interface, it can store more than 50 kinds of pre-bending heating process parameters (temperature curve, heating time, power output, etc.), support encryption and calling of process parameters, and ensure the heating consistency of workpieces in different batches. At the same time, it has real-time temperature monitoring and abnormal alarm functions to avoid improper heating caused by equipment failure.
- Outstanding energy-saving and safety performance: The heat conversion efficiency is over 80%, saving 40% energy compared with resistance heating; it adopts a fully enclosed cabinet design, equipped with overheating, overcurrent, and leakage protection devices; the coil and workpiece are heated without contact, and there is no open flame risk, which meets industrial safety standards.
Through precise control of pre-bending heating of metal materials, induction heaters not only solve the forming problems of hard-to-bend materials but also improve bending efficiency and product qualification rate. They are key equipment for achieving high-quality and efficient production in modern metal forming processes. Whether it is small-batch customized parts or large-batch assembly line production, they can be flexibly adapted to provide reliable heating support for metal bending processes.
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