| C | SK | SECTION C — CHEMISTRY; METALLURGY |
| C22 | KL | METALLURGY (of iron C21); FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS (general methods or devices for heat treatment of ferrous or non-ferrous metals or alloys C21D; production of metals by electrolysis or electrophoresis C25) |
| C22B | UKL | PRODUCTION OR REFINING OF METALS (making metallic powder or suspensions thereof B22F 9/00; electrolytic C25); PRETREATMENT OF RAW MATERIALS |
| C22C | UKL | ALLOYS (flints C06C 15/00; treatment of alloys C21D, C22F) |
| C22F | UKL | CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS OR NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F 17/00) |