Induction Heating

Induction heat treatment equipment has greatly improved the speed and ease of the heating of large scale metal pieces for construction, weld preheating/post-heating and the maintenance of industrial equipment.  Red-D-Arc has become known for our expertise in the application of induction heat using induction heat blankets, coils and ovens in a diverse variety of applications.

Preheating Applications in Welding

· Leave a comment · reddarc

Importance of Preheating in Welding – Equipment Options

Preheating pipe for welding

Why preheat?

Preheating reduces the risk of cracking in weld metal and heat-affected zone (HAZ) by:

  • Lowering the cooling rate of the weld – prevents formation of brittle weld metal/HAZ, allows more time for hydrogen to escape the molten weld.
  • Removing moisture (hydrogen source) from the part.
  • Reducing shrinkage by lowering the temperature differential.

Preheat or not?

The requirement and level of preheating for steel is determined by the relevant welding code and is dependent on the weld heat input, chemical composition of steel (carbon equivalent), thicknesses, diffusible hydrogen etc. Non-ferrous materials generally require preheat because of their high thermal conductivity.
Preheating can be carried out using the following methods:

  • Applying direct flame – surface of the part heated and then heat conducted through the part, open flame.
  • Placing the part in a furnace – uniform heating of complete part if sufficient time provided in furnace, limitations of use due to the size of the furnace.
  • Electric blankets – surface of the part heated and then heat conducted through the part.
  • Induction heating using blankets – heat generated by electromagnetic currents within the material.

Out of the above methods, induction heating delivers the most consistent and fastest results and allows for the precise temperature control. It is also the safest and most energy efficient method.

The temperature is measured on the workpiece using thermocouples, temperature crayons or infrared pyrometers. The measuring positions are specified by the relevant welding code and are typically dependent on the thickness and geometry of the joint.

Red-D-Arc’s range of induction heating equipment includes air cooled and water cooled induction heating systems with heat applied via blankets and rolling inductors (for moving parts). These systems feature the ability to accurately monitor, control and record temperature. The required accessories including blankets, cables, thermocouples and recorders are also available for rental.

Visit our induction heating equipment page to find out more.

Induction Heating Speeds up Repair of the World’s Largest Rock Crusher

· Leave a comment · Geoff Campbell

Red-D-Arc staff at the Moncton, New Brunswick branch recently helped a customer save time and money repairing the world’s largest rock crusher through the use of induction heat. The hydraulic cylinder that operates the pressure plates used by the enormous rock crusher needed to be brought to a temperature of 500 °F and that temperature needed to be maintained for 3 full days. This was required in order to allow welders to repair the lifting tabs on the cylinder. Normally 3 workers would have used blow torches to heat the metal which would have taken 2 weeks or longer. Red-D-Arc Induction Heating Equipment allowed them to get the job done in less than half the time. Induction heating has many applications in construction, shipbuilding, hydro dam maintenance and bridge building. Red-D-Arc technicians are recognized in the industry for their innovative application of this technology, ready to meet any variety of customer challenges.

Ask us how induction heating can save you time and money on your next project.

Have a look at our entire selection of weld preheating equipment available for rent.

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Airgas, an Air Liquide company, is the nation's leading single-source supplier of gases, welding and safety products. Known locally nationwide, our distribution network serves more than one million customers of all sizes with a broad offering of top-quality products and unmatched expertise.