Chromizing
Chromizing consists of the introduction of chromium into the surface layers of the base metal. The process is not resistricted to ferrous materials and may be applied to nickel, cobalt, molybdenum, and tungsten to improve corrosion resistance and heat resistance.
The chromizing process most widely used employs the principle of transfer of chromium through the gas phase at elevated temperatures. The temperatures used range from 900 to 1090oC. These high temperatures may produce some distortion and grain growth throughout treatment. Chromizing is used on drop forging dies, tools, hydraulic rams, pistons and pump shafts.