Induction Annealing Stainless Steel Tubes With High Frequency Heating Equipment
Objective To anneal a ¼” area around an oval cutout on a stainless steel tube prior to extrusion
Material .75” (19mm), 1.5” (38.1mm) and 4” (101.6mm) diameter steel tubes
Temperature 1900 ºF ( 1038 ºC)
Frequency 300 kHz
Equipment • DW-UHF-20kW induction heating system, equipped with a remote workhead containing one 1.0μF capacitor.
• An induction heating coil designed and developed specifically for this application.
Process A single turn helical coil is used on the 4” (101.6mm) diameter tubes and a two turn helical coil is used on the smaller diameters. The coil is placed over the oval cutout and power is
supplied for 15 seconds to anneal a .25 (6.35mm) diameter around the cutout.
Results/Benefits Induction heating provides:
• Precise and controllable placement of heat to anneal only the required area
• Faster process than flame
• Repeatable results
• Hands-free heating that involves no operator skill for manufacturing
