Method for producing a retort for a nitriding furnace and retort
A method for producing a retort for a nitriding furnace, in which metallic workpieces are heat-treated in a pre-determined atmosphere, includes pickling at least the surfaces of the retort, which are configured to come into contact with the pre-determined atmosphere while the nitriding furnace is operating, by using a pickling agent. The pickled surfaces may then be electropolished and passivated. A retort may be produced according to this method and the retort may be used in a nitriding furnace.
1. A method for producing a retort for a nitriding furnace, in which metallic workpieces are heat-treated in a pre-determined atmosphere, wherein the retort is produced from a stainless steel, comprising:
pickling at least the surfaces of the retort, which are configured to come into contact with the pre-determined atmosphere while the nitriding furnace is operating, by using a pickling agent; and
after pickling, polishing the surfaces by using an electrolyte in a galvanic bath.
2. The method according to claim 1 , wherein the pickling agent comprises nitric acid and hydrofluoric acid.
3. The method according to claim 1 , wherein the electrolyte comprises phosphoric acid and sulfuric acid.
4. The method according to claim 1 , further comprising passivating the polished surfaces with nitric acid.
5. The method according to claim 1 , wherein the retort is cylindrical shaped, and the retort is made from metal sheet cut-outs, which are welded together.
6. The method according to claim 1 , wherein the retort is made from metal sheet cut-outs, which are welded together.
7. The method according to claim 1 , wherein the retort is cylindrical shaped.
8. The method according to claim 1 , wherein the retort concentrically encompasses a guide cylinder configured to hold the metallic workpieces during operation.
9. The retort method according to claim 8 , wherein:
the retort is made from metal sheet cut-outs, which are welded together; and
the retort is cylindrical shaped.
10. The method according to claim 4 , wherein the pickling agent comprises nitric acid and hydrofluoric acid.
11. The method according to claim 10 , wherein the electrolyte comprises phosphoric acid and sulfuric acid.
12. The method according to claim 11 , wherein the retort is cylindrical shaped and the retort is made from metal sheet cut-outs, which are welded together.
13. The method according to claim 12 , wherein inner surfaces of the retort are pickled, electropolished and passivated.
14. The method according to claim 12 , wherein the pre-determined atmosphere contains ammonia.
15. The method according to claim 1 , wherein the pre-determined atmosphere contains ammonia.