Induction heating equipment models available from eldec LLC are perfect for induction annealing because all of our generators control the heat easily and precisely via a practical LED display:
- Red means the temperature is too high.
- Blue means it is too low.
- Green is just right.
Operators also benefit from the speed of the annealing process, which is completed in seconds. Since heat is generated directly in the workpiece, using an alternating electromagnetic field, the process can be carried out very precisely, quickly, and with high-energy conversion efficiency.
Induction Annealing Systems and Processes
Process reliability and reproducibility – two good reasons to use induction annealing for stress relief and impurity removal from metal components. The induction annealing process allows precise and reliable control of metal material properties within workpieces, including hardness, toughness and internal stress. Although mainly used for soft and stress-relieving annealing, induction also offers enormous advantages over conventional methods because it can be used to thermally remove impurities during a process called bright annealing.
Unlike conventional methods, induction annealing generates heat directly in the workpiece by using an alternating electromagnetic field. The entire heating process is carried out without contact and in a very short time. Often, the cooling process for the part creates less distortion as well because the temperature of the workpiece can be reduced slowly without coolant rather than quickly through abrupt immersion in water or coolants.
Our power supplies can fine-tune the frequency, power and annealing time, and our experienced technicians can help you find the perfect recipe of settings for your production environment.
Common Applications for Induction Annealing
Induction annealing can be used to control material properties of metals in various manufacturing scenarios. It is often used to stress-relieve parts, increase material toughness and to remove residues from recycled metals. The ability to precisely control where heat is applied as well to control the temperature in that exact location ensures the process can be accurately reproduced, which is especially important in mass production environments.
Although annealing can be adapted to many processes, here are two examples that may help spark your imagination and lead to possibilities within your own plant:
- Soft annealing – is used to reduce the hardness of a metal to increase its toughness. The process makes the metal less brittle and prone to fracture. Pelton, a turbine manufacturer, used eldec LLC’s MF (Medium Frequency) power supplies to stress relieve the welds of turbine blades destined for a hydro-electric power plant.
- Induction tempering – eliminates or minimizes stresses created during machining or forming. The process is like soft annealing, but much lower temperatures are used. It is especially helpful for heat treating workpieces with high internal stresses.
Induction Heating Benefits for Annealing
Manufacturers in industries ranging from automotive to aerospace, oil and gas production and distribution to power generation among others rely on induction annealing to strengthen critical metal parts.
Advantages of induction annealing over furnace tempering include:
- Anneal workpieces only where needed
- Reduce workpiece distortion
- Thermal elimination of surface impurities
- Control temperatures precisely
- Shorter cycle times
- Create reliable, reproducible processes
- Better energy efficiency
- The ability to manufacture a part as an in-line process rather than requiring to “batch” parts through an oven
Discover how induction heating equipment for annealing has been used in various manufacturing situations and environments.
Soft Annealing to Prevent Part Fatigue Fractures in Your Operation
Soft annealing is used to reduce the hardness of a metal to increase its toughness. The process makes the metal less brittle and prone to fracture. There are few mechanical parts that must withstand loads as great as those imposed on turbines in hydroelectric power plants. Water gushes out under high pressure from specially designed nozzles before hitting the individual blades at a high speed. The blade that is hit first drives the wheel a short distance, but is then idle again for a revolution, resulting in high alternating forces in the root area of the blade.
To prevent fatigue fractures in the root area, turbine makers anneal the weld between the turbine wheel and blade. This relatively gentle, heating process improves the durability of the part significantly. However, the heating must be reproducible and carried out with high precision to ensure turbine quality requirements are met.
Annealing water turbine blade welds is just one example of how the process can be used to stress-relieve parts. eldec LLC’s experienced technicians have a thorough understanding of induction annealing. They’ll begin with a design review of your parts as well as a review of your manufacturing processes.
Request a consultation by giving us a call or request a consultation and we’ll contact you to see how we can help you prevent part fatigue fractures in your operation.
Induction Tempering to Obtain Optimal Properties for Shafts, Bars and Joints
Induction tempering can be used to heat treat workpieces with high internal stress points. Induction tempering eliminates or minimizes stresses created during machining or forming and will make metal less brittle.
The process is like soft annealing, but much lower temperatures are used. It is especially helpful for heat treating workpieces with high internal stresses. Since induction tempering can be precisely controlled using a generator’s power, frequency and the inductor’s geometry, deformities in the workpiece can be avoided and the process is more efficient.
Induction tempering can be broken down into two categories:
- Surface hardening and tempering of automotive and aviation parts such as valve seats, gears, transmission and axle shafts
- Thorough hardening and tempering of workpieces such as chain links, structural metal used in construction and seamless, electrical-resistant tubing and pipe necessary for safe oil and gas production and distribution
This process can be used across a wide range of industries, and in some cases, like hardening and tempering a shaft, tempering can be performed right after the hardening process — sometimes using the same coil.
Our experienced application engineers can help you select the right power supply and design specialized inductors for your specific workpiece and manufacturing environment. They will also work with you to optimize your production process for optimum speed and efficiency.
Generators and Inductors for Induction Annealing
We offer a wide array of generators that are appropriate for induction annealing. They range from power supplies to complete heating systems. Units are available in low, medium, high frequencies and dual or simultaneously dual frequencies.
Typically, a true annealing process requires more than lowering the hardness value of the surface by a few points. In this case, a lower frequency power supply, a medium frequency or even low frequency model, depending on the thickness of the material, would work best. When tempering, a high frequency generator would be appropriate because you would only need to lower the hardness value by a couple of points.
De-coating, on the other hand, requires only the surface of the workpiece to get hot to strip the coating. In this case, either a medium frequency or high frequency generator would work well. For barrel de-coating, we recommend using a medium frequency power supply with an outside heating coil.
We can help select the best induction annealing system for your workpiece components and operating environment.
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