High-Temperature Gas Extrusion as a Promising Method of Producing Preforms for Tool Steels

Abstract

Results are presented from an investigation of the structure and mechanical properties of tool steels R6M5 and EK-80 after their high-temperature gas extrusion (HTGE). It is shown that this treatment has a significant effect on steels’ phase composition, the structure of the phases that are formed, and, thus, the steels’ mechanical properties (hardness, ultimate strength, and ductility). It was determined that after undergoing HTGE at 1000–1150°C the steels have a hardness of 60–64 HRC and the same ductility as before the treatment. This makes it possible to use them to fabricate small tools by a simplified technology – single or double annealing of extruded semifinished products in the range 500–600°C without additional heating before quenching. Small tools made from such semifinished products last 2–3 times longer than tools made from cold-drawn rolled products.