Carburizing  [ Return towards  Applications  ]

Such operations can be carried out in a wide range of continuous or batch furnaces.

The AIR LIQUIDE ALNAT™ C (CN) solution is based on cracked methanol as the carbon agent, which is sprayed with nitrogen in the hot zone of the furnace around 950 °C for carburizing and 890°C for carbonitriding.


CH3OH => CO + 2H2

CO2 et H2O produced during methanol cracking are in lower concentration than those produced by an endothermic generator, leading to a higher carbon activity atmosphere.

Nitrogen / cracked methanol ratios are normally regulated between 20/80 and 40/60 in volume to achieve a good quality treatment.

Carbon potential, which represents the carburizing atmosphere activity, can be continuously calculated through residual O2 ( or CO/CO2 ) and temperature measurements in the hot zone, and regulated with small injections of hydrocarbon or air.

In many cases, Nitrogen can also be delivered by non-cryogenic FLOXAL™ generator.

AIR LIQUIDE is able to supply complete installations including methanol storage and pumping equipment, flow control panels and safety monitoring equipment. A supervision offer, associated with a remote management of gas storage tanks will enhance the traceability of your process.

.Advantages of ALNAT™ C (CN)

Quality and reproducibility of the carburizing atmosphere
Flexibility of the atmosphere by simple flowrate adjustment
Complete security monitoring with automatic nitrogen purge