Heat Treatment

Rainbow provides various heat treatment services that meet the highest international standards.The heat treatment furnace capacities allow for hardening, normalizing, tempering, and stress relieving for components that weigh up to 4 tons. Shafts of up to 2.2 meters can be accommodated for induction hardening.

While the highlight of the heat treatment shop is the CNC induction hardening machine, Rainbow is able to provide the following heat treatment processes in PID controlled furnaces:

  • Stress Relieving
  • Annealing
  • Hardening
  • Normalizing
  • Tempering
  • Gas carburizing
  • Solutionizing
  • Liquid nitriding
  • Gas nitriding
  • Quench polish quench (QPQ)

Heat treatment provides an efficient way to manipulate the properties of metals by controlling the rates and temperature of heating & cooling to which the component is subject.

Rainbow carries out many complex heat treating schedules to optimize an alloy's mechanical properties such as increasing the strength, increasing the machinability and improving toughness. In the case of steels, enriching the surface of the steel with carbon and/or nitrogen, a surface with extreme wear resistance can be obtained.

Selective Induction Hardening

With the help of a CNC controlled progressive scanner and tailor made mounting equipment (as per job requirements), Rainbow is able to provide selective hardening for various components. In the induction hardening process, heat is provided by magnetically induced eddy-currents. Induction hardening provides a hard surface on top of a tough core structure that has been previously toughened. Induction hardening provides wear resistance on the surface of components manufactured from steel, alloy steel or alloyed ductile iron.

Components regularly hardened include:

  • Down-hole drilling tools
  • Crankshafts
  • Wire-sheaves (including crown sheaves)
  • Crane-wheels
  • Gears
  • Mandrels and shafts

Surface Technologies