Role of the atmosphere

Heat treatment atmospheres

Figure 1 - Diagram of the state of a pure body [1].

Figure 2 - Permanent gas conditioning [1]

Figure 3 - Conditioning of gases with critical temperatures above ambient Ta.[1]

Figure 4 - Fe-FeO-Fe3O4 equilibrium diagram in the presence of a CO &#43; CO2 atmosphere as a function of temperature.

Figure 5 - Fe-FeO-Fe3O4 equilibrium diagram in the presence of a H2 &#43; H2O atmosphere as a function of temperature

Figure 6 - Redox curves for common metals as a function of the ratio

Figure 7 - Redox curves for common metals as a function of the ratio

Figure 8 - Oxidation-reduction of an 18% chromium steel in a continuous furnace in H2 &#43; H2O atmosphere as a function of temperature.

Figure 9 - Behavior of metals during cooling in a H2 &#43; H2O atmosphere

Figure 10 - Carbon potential as a function of the ratio  and temperature

Figure 11 - Case hardening kinetics of a 16NC6 steel at 900 ˚C for different treatment times in an atmosphere containing, by volume, 20% CO, 40% H2 and 40% N2.

Figure 12 - Flammability limits and auto-ignition temperature [22]

Figure 13 - Schematic diagram of an endothermic generator

Figure 14 - Schematic diagram of an exothermic generator [2]

Figure 15 - Operating principle of the self-contained protective gas generator

Figure 16 - Gas supply trends over the 20th century

Figure 17 - Air separation by cryogenic distillation

Figure 18 - Non-cryogenic nitrogen production system

Figure 19 - Supply methods according to purity and quantity required (limits given for guidance only)

Figure 20 - Iron redox curve as a function of the ratio

Figure 21 - 100% H2 cloche furnace annealing: thermal profile and gas injections

Figure 22 - Hydrogen explosive diagram

Figure 23 - Flammability limits of hydrogen in oxygen

Figure 24 - Flammability limits of hydrogen in air