| CARBOFLEX® annealing atmospheres are available in various mixtures of nitrogen as the base constituent with added hydrogen or methanol, respectively. In some cases other hydrocarbons such as natural gas or propane can be used. They are normally used for bright or neutral annealing with strong requirements on control of decarburization of flow of high alloy steels.
For continuos annealing of steel coils we have developed the CARBOFLEX-RHF system.
PURE NITROGEN is preferred for annealing of some steels, cast irons, copper and aluminium. We have the knowledge to optimize nitrogen flow and purity to minimize oxidation and discoloration of aluminum strip coils.
HYDROFLEX is suitable for stainless steel where either 100% hydrogen is used when the maximum surface quality is required or a mixture containing nitrogen or argon to precisely match the quality demands with the most cost effective gas composition. 100% hydrogen is also used to minimize annealing time in bell furnace annealing of strip coils of mild steels or brass.
Bright annealing of mild steels for instance steel tubes is done in HYDROFLEX with low hydrogen concentration, typically 10% (by volume). In decarburization annealing water is added to the mixture of nitrogen /hydrogen.
The different recommended atmospheres for annealing
| Annealing |
| Low carbon steels | Nitrogen, Hydrogen, CARBOFLEX, HYDROFLEX |  |
| Medium carbon steels | CARBOFLEX | |
| High carbon steels | CARBOFLEX | |
| Tool steels | CARBOFLEX | |
| Stainless steels | Hydrogen, HYDROFLEX | |
| Copper | Nitrogen, HYDROLFEX, CARBOFLEX | |
| Brass/bronze | Hydrogen, HYDROFLEX | |
| Aluminum | Nitrogen Nickel HYDROFLEX | |
| Chromium | Hydrogen, HYDROFLEX | |
| Titanium | Hydrogen, HYDROFLEX | |
| Noble metals | HYDROFLEX | |
|
|
|
