CFI High Frequency Welder - Thermatool Corporation

CFI High Frequency Welder

The Thermatool CFI High Frequency Welder is the most reliable Solid State tube and pipe welder on the market. With thousands of CFI HF Welders installed worldwide at fixed frequencies between 150 and 800 kHz, CFI Welders are field proven to be the most successful choice for tube and pipe production. Every Thermatool HF Welder is backed by world leading weld process and materials knowledge, providing each customer the best approach to meeting challenging, every day welding application needs.

As the only global induction heating and welding manufacturer specializing in tube and pipe welders, Thermatool provides the widest range of HF Welders available.

All of our welders are based on the High Frequency or “HF” welding process that we developed almost 60 years ago and have led the way ever since. With its Current-Fed Inverter (CFI) design, our welding equipment range gives you the capability to successfully weld almost any metal you want – efficiently and economically.

We supply equipment needed to weld carbon and stainless steel, brass, copper, and aluminum, as well as exotic alloys, such as boron steel and HSLA, AHSS, and Trip Steels.



Plot No. SM-6, Road No.11 Sanand-II, Industrial Estate, BOL Village, Sanand Ahmedabad- 382170


  • Patented full range Thermatool AutoMatch™ ensures full power output over a wide range of product sizes. The AutoMatch™ also provides stable welding frequency even with changes in weld area set up, tube OD and wall thickness, and impeder material.
  • Power set-point maintained within 0.5%.
  • Fixed frequency maintained within 1.0%.
  • Excellent low weld power output stability (inherent to current fed inverters) and regulation for welding at mill jog speeds (as low as 1% power). This reduces scrap and sends less open seam to the cutoff reducing damage to the cutoff.
  • Short-circuit tolerant CFI technology ensuring reliable operation through coil arc-overs.
  • Available as a traditional contact welder output and with dual induction/contact output to meet your specialized application standard.
  • DC Ripple less than 0.5%. Excellent ID weld bead. This is key to extended ID scarfing tool life.
  • Low harmonic distortion rectifier.  Interference with other mill electronic components and inspection equipment is eliminated.
  • Has standard speed/power control which simplifies operation and significantly reduces scrap through accurate control of weld power in relation to mill speed at start-up and ramp down.
  • Stabilized HF weld frequency is a proven key process parameter that must be controlled. (Weld Process Parameter data logging is available using ThermaView.)
  • Simple, modular design and packaging which reduces spare parts stocking requirements.
  • Power supply is completely sealed with high quality gaskets, thus eliminating contamination from the mill environment.

Tech Specs

Power Range Up to 1200 kW
Output Frequency 400 kHz + 1% stabilized frequency per load requirements
Diameter Range Unlimited
Induction Coils Standard
HF Contact Welding Yes
Dual Induction Contact Yes
Weld Tables Single, 2, 3, VeeAxisTM
AutoMatch™ Yes
Speed Power Control Yes
Tachometer Yes
Efficiency > 85%
Power Factor 0.95
Ripple ~1
WeldScan Yes
ThermaView Yes
ThermaSure Yes


Induction Coils
Thermatool offers a comprehensive range of induction coils, designed specifically for use with Thermatool solid-state HF induction welders. Manufactured from high conductivity copper, quality inspected and coated for long life, there are numerous types and sizes available to satisfy every application. Many of these models are available for immediate delivery from stock.

Whether you are producing carbon steel, stainless steel, copper, brass, aluminum or galvanized tubing, Thermatool has the induction coil to meet your specific needs. Our comprehensive range of induction coils fully supports the entire range of Thermatool welders with power ratings from 50 kW to 2 MW and operating frequencies ranging from 150 kHz to 800 kHz and variable frequency.

For special coil requirements, Thermatool engineers are pleased to review the possibility of a custom coil design/build.

Thermatool offers an extensive range of impeders to satisfy a very diverse range of tube and pipe welding applications. Whether your mill produces small diameter/thin wall tubing or large diameter/heavy wall API line pipe, Thermatool supplies a complete selection for you. The proper choice of impeder, correctly installed, will play a major part in achieving maximum welding efficiency. It should also be noted that as the performance of all ferromagnetic materials is a function of temperature, it is critically important that the ferrite core is kept as cool as possible during the tube welding process. Ideally, the temperature of the coolant flowing through an impeder should not exceed 25°C. Thermatool also supplies booster pumps for these demanding applications.

Modern tube mills that operate at higher line speeds have created demand for impeders that deliver superior performance. Such enhanced performance can only be achieved by using the very best ferrites available. A growing number of tube and pipe producers worldwide choose Thermatool ferrites in order to optimize the performance of their mills. Thermatool offers four different types of ferrites which can be cut to length, if required. Contact us today to learn more!