Ceramic Tool Concepts for the Semi-Solid Processing of Steel Alloys

✍ Scribed by S. Münstermann; R. Telle

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 241 KB
• Volume: 37
• Category: Article
• ISSN: 0933-5137
• DOI: 10.1002/mawe.200600997

✦ Synopsis

Two different ceramic tool concepts for the semi-solid processing (Thixoforming) of steel alloys are presented. Materials selection is adapted to forming technology (Thixoforging, Thixoextrusion), preset die temperature, and resulting process conditions. Gas-pressure sintered silicon nitride (Si 3 N 4 ) is chosen as die material in low tool temperature (300...400 C) thixoforging experiments due to its high strength and outstanding thermal shock resistance. High purity dense alumina (Al 2 O 3 ) is applied as die material for high temperature (1200 C) thixoextrusion tests.

Thixoforging results using Si 3 N 4 dies pre-heated to 300 C show sufficient thermal shock and corrosion resistance of Si 3 N 4 and con-firm the applicability of this tool concept. The high temperature tool concept developed at the Institute of Mineral Engineering (GHI) effectively reduced thermal shock impacts on extrusion dies. As expected, corrosion resistance of Al 2 O 3 proved to be excellent. Further research will be carried out concerning long-term behaviour of Si 3 N 4 thixoforging dies as well as on the influence of extrusion speed and tool temperature on the quality of products extruded through Al 2 O 3 dies at high temperature.