WHAT IS CHROMIZING?

Chromizing is a thermochemical treatment in which chromium atoms are diffused on the surface of the workpiece to form carbides with the base material.

CHARACTERISTICS

High hardness 1300-1700 HV on carbon and alloy steels. Hardness is stable up to an operating temperature of 450°C.
To further improve mechanical properties, the parts can be tempered after Chromizing.
Chromizing increases resistance to acids, especially organic acids and alkalis. A wide variety of ferrous, superalloy and sintered materials can be treated.
Chromizing is uniform regardless of the unevenness of the pieces to be treated.

ADVANTAGES

  • Increases component life
  • Increases the stain resistance of components
  • Provides good abrasive, sliding and adhesive wear resistance
  • Reduces the need for lubrication
  • Chromized surfaces can be sanded with a high finish
  • It has a low coefficient of friction
  • Chromizing reduces the tendency towards cold welding

PROCESS CHARACTERISTICS

The parts to be treated are put in intimate contact with the chromizing product and placed in the oven. The parts are brought to a temperature of 1050°C in a protective atmosphere. The time in temperature depends on the material and on the required Chromizing depth. The time varies between 4 – 12 h.

The pieces are cooled to room temperature and the compound is removed. The increase in volume is generally from 15% to 30% of the Chromized layer; it varies according to the base material, but it is predictable and repeatable for a given geometry and treatment cycle.

RESISTANCE TO ACIDS

Chromizing increases resistance to sulphuric, phosphoric, hydrochloric and organic acids in general. It gives the chromed components high stain-resistance characteristics both to atmospheric agents and to oils and fuels.