R. Goldstein

Source: Fluxtrol.com

Induction heat treaters know that proper coil design is crucial to increasing longevity, improving production quality, and cutting costs. Among the topics addressed in this paper about induction heat treat coil design and fabrication (presented by R. Goldstein, W. Stuehr, and M. Blackby at ASM International) are these:

• The design and fabrication of induction heating coils over the years
• The Variable of Flow and the Influence of Frequency
• Control and Presentation
• Structure, Quenching, and Cooling

Considerations for Inductor Design

Induction heat treating coils are available in many shapes and sizes and must perform a variety of tasks in a given induction heat treating application. Depending on the application, the induction coil design requirements include:

• Meet heat treatment specifications in desired production rates
• Be robust enough to tolerate manufacturing variations
• Mount into the induction machine
• Have electrical parameters that match the induction power supply
• Deliver quench
• Have a satisfactory lifetime
• Have satisfactory efficiency
• Be repeatable from inductor to inductor

In developing a new induction heat treating coil and process, the first question is whether the component will be produced on an existing system or if a new machine must be built. In many cases, the part producer’s desire is to develop new tooling for an existing machine with spare capacity. This reduces the degree of freedom and can make the induction coil design procedure more complicated because a less-than-optimal frequency or coil style will be necessitated to fit the existing machine (Ref 16).

To determine the ability to use existing equipment, it is necessary to make an analysis of the part to be heat treated. Part material, prior processing, geometry, production rate, and heat treatment specifications all play roles. The part material and prior processing determine what the minimum heat treatment temperature should be, along with how much time is allowed for cooling. The part geometry and heat treatment specifications indicate how much energy is required, what the preferred frequency ranges are, and what type of induction method (i.e., single shot, scanning) is best suited for the application. Finally, the production rate determines how much power and/or how many spindles or stations are required.

Read more: "Design and Fabrication of Inductors for Induction Heat Treating"