Preheating in Welding Induction Heating Systems | MillerWelds

Heating Equipment

Induction Heating

The right system for your heating needs

Why Induction Heating?

Induction heating is easy to set up, offers a fast time-to-temperature, and delivers exceptional heating efficiency, accuracy, and uniformity in part temperature. In addition, induction offers safety benefits compared to open flame and resistance heating methods.

Applications

  • Preheating and maintaining weld temperature
  • Hydrogen bake-out
  • Post-weld heat treatment (PWHT) up to 1450° F
  • Shrink-fit processes
  • Various other applications which requires heating

Industries

  • Oil and Gas
  • Structural
  • Power plants
  • Petrochemical/Refineries
  • Process/Power Piping
  • Pressure vessels
  • Shipyards
  • Mining

Plate Induction Heating

Infrared Plate Induction Heating
This highly efficient technology uses non-contact heating to induce heat electromagnetically rather than using a propane torch or resistant heating.  With induction, the part becomes its own heating element, heating from within.  This makes induction very efficient since little heat is lost in the process.
Time to temperature is dramatically faster than flame or resistance heating -- reducing cycle time. Setup and tear down times are quick and unlike flame or resistance, induction allows continuous heating and fabrication.
Induction heating lowers operational costs because reaching target temperatures is dramatically faster, resulting in reduced consumable costs and labor expenses. In addition, it eliminates the expense of fuel gases, fire watch personnel, and heating subcontractors.
Quality IconProvides exceptional joint temperature uniformity.  Induction eliminates the inconsistencies and quality issues associated with flame or resistance heating.
Welders are not exposed to open flame, explosive gases, and hot elements associated with flame and resistance heating.  Induction’s method of heat transfer results in a cooler environment that reduces operator fatigue and improves work conditions.  

Compare Induction, Flame and Resistance Heating Methods

 
INDUCTION HEATING
FLAME HEATING
RESISTANCE HEATING
SETUP/TEARDOWN EASY
20 minutes or less per joint. Teardown time is fast, as induction tools can immediately be moved to the next joint without cooldown time.
EASY
 
COMPLEX
Approximately 3 hours per joint. Teardown times are also lengthy, as crews must first wait for the heating equipment to cool.
TIME TO TEMPERATURE FAST
20 minutes or less per joint
SLOW
Up to 3 hours, depending on part/material size and thickness
SLOW
Up to 3 hours, depending on part/material size and thickness
JOINT TEMPERATURE UNIFORMITY EXCEPTIONAL
Thorough and even heat profile
POOR
Subject to hot and cold spots
MARGINAL
HEATING EFFICIENCY EXCEPTIONAL
90% efficient
POOR
Much heat lost to air; reheating needed after breaks and off hours
GOOD
Marginal heat lost to air
SAFETY EXCEPTIONAL
Tools do not heat up; no toxic byproducts or noise
POOR
      
  • Risks burn injuries, fires and explosions
  •   
  • Excessive noise levels
  •   
  • Toxic, combustible byproducts
MARGINAL
      
  • Ceramic pads are as hot as the work surface, bringing risk of burn injuries
  •   
  • Damaged/incorrectly used heating tools bring risk of electric shock
  •   
  • Inhaling insulation fibers/particles is a health hazard
OPERATING COST LOW
      
  • Delivers strong return on investment
  •   
  • Electricity cost: $5/hr
  •   
  • Induction air-cooled cables and air-cooled quick wraps are ruggedly constructed for repeatable uses
HIGH
      
  • Fuel cost: $50/hr
  •   
  • Fire-watch personnel must often be hired
HIGH
      
  • Preheating contractors can charge up to $2,000 per joint, and final project costs often exceed original bid pricing
  •   
  • Requires installation of electrical infrastructure
  •   
  • Ceramic pads require frequent replacement
  •   
  • Used insulation is considered hazardous waste; proper disposal is costly