Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5156035 | Method and apparatus for manufacturing seamless tubes | Gheorghe Arnatu, Hermann Josef Frentzen | 1992-10-20 |
| 4404832 | Operating a rolling mill working on seamless tubing | Gerd Pfeiffer, Horst Biller, Manfred Bellmann, Karl Oberem, Hermann Josef Frentzen | 1983-09-20 |