Method and device for thermal treatment of metallic materials

1. A method for the heat treatment of metal materials in an industrial furnace having a heating chamber having a treatment chamber and a quenching chamber, the method comprising:

utilizing a first treatment medium, having components of carbon dioxide, oxygen, and water vapor in addition to minimum components of carbon monoxide, hydrogen, and nitrogen;

utilizing a second treatment medium utilized for a carburizing process; and

providing a processing chamber in the heating chamber of the industrial furnace for the recycling of protective gas, the processing chamber being structurally or functionally associated with the treatment chamber,

wherein the components carbon dioxide, oxygen, and water vapor catalytically react with fed hydrocarbon as a reaction gas to carbon monoxide and hydrogen, and the reactions are to be accelerated by utilizing a catalyst at a catalyst bed, such that the protective gas then has a controlled C potential in the treatment chamber after said reactions;

wherein the protective gas processed in this manner is then fed to the treatment chamber of the heating chamber in a re-circulating manner.

2. The method according to claim 1 , wherein nickel, platinum, palladium, or rhodium is utilized at the catalyst bed as the catalyst.

3. The method according to claim 1 , wherein only such an amount of carbon is fed in the form of a reaction gas for a gas carburizing process in each active carbon transfer phase, as is required for gas carburizing.

4. The method according to claim 1 , wherein natural gas is utilized as the reaction gas.

5. The method according to claim 1 , wherein the C potential is controlled by means of gas analysis, and a temperature measurement is carried out.

6. The method according to claim 1 , wherein the C potential present in the treatment chamber of the heating chamber is controlled after feeding of the hydrocarbon at the catalyst bed.

7. The method according to claim 1 , wherein the C potential present in the treatment chamber of the heating chamber is controlled by means of feeding the hydrocarbon in the treatment chamber, wherein the hydrocarbon reacts at the catalyst bed in a re-circulating manner.

8. The method according to claim 1 , wherein a working pressure is between 1 to 10 mbars.

9. The method according to claim 1 , wherein in case of a drop in operating pressure, reaction gas and air, or protective gas are fed accordingly.

10. The method according to claim 1 , wherein any excess of H 2 is separated.

11. The method according to claim 1 , wherein a mandatorily recycled gas guidance is carried out without any gas cooling by means of a re-circulating gas removal from the area of the heating chamber.

12. The method according to claim 1 , wherein during the gas carburizing in the treatment chamber the reactions

2CO→C+CO 2

CO+H 2 →C+H 2 O

CO→C+0.5O 2 ,

are carried out, wherein the C potential then drops and the volume-% of CO 2 , H 2 O, and O 2 rises, and a gas enrichment occurs in the processing chamber at the catalyst bed according to the reactions

2CH 4 +O 2 →2CO+4H 2

CH 4 +CO 2 →2CO+2H 2

CH 4 +H 2 O→CO+3H 2

wherein the C potential rises and the volume-% of CO 2 , H 2 O, and O 2 drops.

13. The method according to claim 12 , wherein the processing chamber comprises:

at least one of a first feeding point and a second feeding point for feeding the hydrocarbon.

14. The method according to claim 13 , wherein the processing chamber with catalyst bed is locally separated from the treatment chamber.

15. The method according to claim 1 , wherein the protective gas is guided to a burnout point, ignited, and burned, if an impermissible pressure increase is present, wherein the operating pressure is thus controlled, or if a temporary rinsing process requires the same.

16. The method according to claim 15 , wherein a gas-tight valve for a burnout point having a pressure regulator and the function of a gassing in case of a drop in pressure is used.

17. The method according to claim 1 , wherein a mandatorily recycled gas guidance is carried out from the area of the quenching chamber.

18. The method according to claim 17 , wherein a control cycle carries out at least one of the functions defined by the process steps.

19. The method according to claim 1 , wherein a mandatorily recycled gas guidance is carried out, which is carried out in a largely isothermal manner in order to avoid any undesired reactions, such as the formation of soot.

20. The method according to claim 19 , wherein the mandatorily recycled gas guidance for the cycle of the recirculation is carried out by means of a recycling device.