Induction Preheating Welding Steel Pipe

Induction Preheating Welding Steel Pipe With High Frequency Heating System Objective To preheat a steel pipe to 500ºF (260ºC) before welding. Material Steel shaft assembly 5” to 8” OD (127-203.2mm) with a 2” (50.8mm) heat zone. Temperature 500ºF (260ºC), if higher temperatures are required, heat time can be increased. Frequency 60 kHz Equipment • DW-HF-60kW induction heating system, equipped with a remote workhead containing eight 1.0 μF capacitors for a total of 8 μF. • An induction heating coil designed and developed specifically for this application. Process A multi-turn two position channel “C” coil, adjustable on a busbar is used to heat the desired heat zone. The coil is adjustable to fit various diameter pipes. The shaft is rotated in a fixture and heated for 3 minutes to achieve a temperature of 500ºF (260ºC). Results/Benefits Induction heating provides: • Preheating prevents shock to shaft which eliminates cracking in the welding phase. • Hands-free heating that involves no operator skill for manufacturing. • Even distribution of heating between the shank and the  sleeve.