Shrink Fitting a Carbon Graphite Ring Insert Into an Outer Steel Band

A client contacted THE LAB at Ambrell needing to heat a steel band to 1000 ºF (538 ºC) and insert a carbon graphite ring into the center of the steel band. THE LAB determined that an Ambrell EKOHEAT^® 10 kW, 50-150 kHz induction heating system with a four turn, two-over-two helical coil would be optimal for this induction shrink fitting application. The frequency for this application was 132 kHz. 

More Shrink Fitting Application Notes

Initial testing was conducted to optimize the power delivered to the part. System power was applied for 14 seconds to reach the target temperature of 1000 ºF (538 ºC). The carbon graphite ring was then inserted and the assembly was allowed to cool which created a strong joint between the two pieces. This achieved the client's time and quality objectives. 

For this shrink fitting application, induction heating offered several advantages. It delivered rapid heating which saved power and time. It's also a clean source of heat. Induction delivers less heat into the work environment than a torch and takes up less space than an oven. Induction is also a highly repeatable heating process, ideal for high volume applications such as this one. Finally, induction can be easily integrated into existing production lines thanks to its size and movable workheads that can be placed a distance from the power supply.

THE LAB at Ambrell has a significant amount of experience with induction shrink fitting applications like this one. To learn more about free application testing, visit our page with more information about THE LAB or contact us today to get the process started.