Shrink fit a carbon graphite ring insert into an outer steel band

Objective

To heat a steel band to 1000 ºF (538 ºC) and insert a carbon graphite ring into the center of the steel band.

End Product

graphite ring

Equipment

Ambrell EKOHEAT ® 10 kW, 50-150 kHz solid state induction power supply with a workhead and coil specifically designed for this application.

Materials

4340 steel ring 8” (20.3cm) OD x 7.75” (19.7cm) ID, .895” (22.7mm) thick, carbon graphite ring insert

Temperature

1000 ºF (538 ºC)

Frequency

132 kHz

Testing

A four turn, two-over-two helical coil was used for heating the steel ring. 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.

Benefits

• Accurate and repeatable results

• Reduced cycle time, lower consumable expenses

• Even distribution of heating

• Ease of integration into existing production lines

• Energy efficient

• Hands-free heating that involves no operator skill for manufacturing

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