Annealing bolt shafts

Objective

To heat 431 Stainless steel bolts to 1,850 ºF (1,010 ºC) and Inconel and 8740 alloy steel bolts to 1,000 ºF (538 ºC) for annealing.

End Product

Bolt shafts

Equipment

Ambrell EASYHEATTM 3 kW, 150-400 kHz solid state induction heating power supply with a workhead and coil specifically designed for this application.

Materials

Various sizes of 431 stainless steel, Inconel and 8740 alloy steel bolts

Temperature

1000 ºF (538 ºC) and 1850 ºF (1010 ºC)

Frequency

264-273 kHz

Testing

A three-turn helical coil was used to heat the shaft of the bolts for 10 to 12 seconds on the large bolts and 18 to 20 seconds on the smaller bolts using the same coil. This met the client’s objectives. 

Benefits

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

• Flameless process

• Pinpoint accuracy and repeatable cycle after cycle

• Rapid heating

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