For years, induction heating has been used successfully in the pipe and tubing industry, primarily for normalization, bending, and strengthening. Induction heating is still the choice for curving the larger, thicker-walled pipes that transmit chemicals and electricity. For the bend of larger thick-walled pipes, induction heating is ideal because it offers concentrated heat with a tight beam, producing a higher quality bend with lower wall thickness and ovality than other bend technologies.

It is a heating process that is flexible enough to be used in many custom applications. Induction heating technologies are perfect for hot-bending, welding, plating, heat treatment, and welding stress relief.

Fast vs. Slow Induction Heating

Induction heating uses a high-frequency current to heat an electrically conductive material through an intense, rotating magnetic field. To develop a faster induction heating system, engineers will choose higher frequency magnetic fields, which results in the induction wires (coils) heating faster. However, higher frequencies are prohibited in some induction heating systems because of potential damage caused to wire insulation and connections, as well as the safety of workers.

The first choice is to use a low-frequency induction system, where the copper in the coil is heated up very slowly, and thus excess heat can dissipate. The second option is to use a higher frequency heat so that faster heat-up times are possible, but safety measures must be in place to deal with the excessive heat released by the induction coil.

Manufacturers of pipes and tube channels use induction heat to seam together a lengthwise diameter of pipes passing through a high-speed conveyor. Because of these benefits, several large pipe companies specify induction heating to preheat applications that include pipe segments or valves. In addition, as today’s oil and gas pipelines use thinner-walled alloy steel pipes, manufacturers and installers are looking for induction heating systems that deliver fast, precise, and uniform heat.

Induction heating is highly effective because it is contactless. As a result, the metal surfaces are heated from the inside out, with no thermal inertia and no conductivity loss. As a result, the electrically conductive workpiece becomes a heat source, warming it from the inside out, making induction highly efficient as there is very little heat lost during the process. Among induction’s many advantages, induction provides greater uniformity of heating and faster part temperature while also eliminating a potential source of hydrogen, a byproduct of heating using an open flame. The main advantages of induction heat are a dramatically higher power, greater material efficiencies, and better safety than other heating methods.

Pipe and Tube Industry Induction Heating Applications

Induction Tempering: steel pipe, copper pipe

Induction Heating: Preheating for Upsetting, Heat Rod Upsetting, Rubber De-Bonding, Preheating Tool Joints, OCTG pipe ends

Induction Hardening: Curing Coatings, PWHT of Oil and Gas Pipes

Induction Annealing: Longitudinal Tube Welds, Magnetic, and Non-Magnetic Tubes

Induction Brazing: Heat Transfer Tubing for Boilers, Refrigerators, HVAC, copper pipe