Annealing Services


About Heat treatment -

All heat treatment cycles consists of three basic steps.

  1. Heating the charge,
  2. Holding at high temperature(Soaking)
  3. Controlled cooling.

Soaking or holding at high temperature helps in purifying the charge and forming magnetically permeable microscopic structure. During controlled cooling this microscopic structure is fixed and increase in magnetic permeability is locked in. Depending on the soaking and cooling time the entire process typically takes about 20 to 35 hrs.

In order to produce components with desired magnetic performance PML has developed distinct heat treatment cycles for each material. These treatments are generally performed after all manufacturing/fabrication processes are completed.

PML uses pure dry Hydrogen and/or Nitrogen (as and when relevant) atmosphere furnaces in order to achieve best magnetic properties.

End applications for heat treatment cycles:-

  • Heat treatment of Nickel Iron alloy: Purpose to reduce the impurities like carbon and increase in material permeability by grain growth. The components are been used as flux concentrators, Magnetic shields and cores in various industries like Energy meter, Automobile, Aviation, Healthcare etc.

    Before Annealing           After Annealing
    before-annealing         After-annealing
  • Heat treatment of Silicon Iron (Low loss): Purpose to reduce the impurities like carbon and increase in material permeability by grain growth. The components are been used as flux concentrators in industries like Energy meter, Automobile etc.
  • Material Softening: Purpose to reduce the material hardness without material oxidation and carbon pickup.
  • Component Demagnetizing: Purpose to remove the residual magnetic field in the component, which gets induced in the component during sheet metal working in mass qty. The components are been used in various industries like Energy meter, Automobile, Aviation, Healthcare etc, which needs to be in demagnetized state for operating.

At PML -

  1. PML facility has 9 fully controlled furnaces capable of heat treating a range of sizes of components.
  2. All our furnaces are equipped with well maintained and calibrated controlling and monitoring devices.
  3. Thermocouples, PID, Thyristor and Programmable controllers are used to program and control the heat treatment profile.
  4. Data logger device records continuous data of the heat treatment and aids in monitoring the entire cycle. Complete heat treatment profiles are stored on dedicated computer and can be generated as and when required.
  5. Every heat treatment cycle is certified by ensuring the magnetic properties of test samples using Hysteresis Loop plotter.
  6. PML’s class 2 type (+/-6 deg. C) furnaces enables us to offer a first class subcontract heat treatment service for Nickel Iron, Silicon Steel, Cobalt Iron, low carbon steel, etc.
  7. Specially designed annealing furniture enables optimum usage of available capacity.
  8. Exclusive facilities for cleaning/de greasing/pre heating for the parts going for annealing.
  9. Heat treatment cycles are based on unique experience and backed by recommendations by PML’s team of technical experts and metallurgists.

If you are looking for stress relieving, hydrogen annealing, Oxidation processes etc…PML will be able to help you.

For a quote PML requests the following information:

  1. Drawing and material specification of the part
  2. Heat treatment specification
  3. Quantity
  4. Calibration needs…if any
  5. Any special handling requirements