Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4869470 | Vacuum furnace for heat treatment of metallic workpieces | Fritz Kalbfleisch, Friedrich Preisser, Rolf Schuster | 1989-09-26 |
| 4867808 | Heat treating a metallic workpiece by quenching under cooling gas under above atmospheric pressure and specified circulation rate | Friedrich Preisser, Rolf Schuster | 1989-09-19 |