Development of a New Aluminum Extrusion Hot Work Tool Steel
José Britti Bacalhau and Celso Antonio Barbosa,Villares Metals S.A., Sumaré-SP, Brazil,
Patricia Miller, Böhler-Uddeholm Corporation, Elgin, Illinois, USA
Track: EXTRUSION/DIE PRACTICAL - Tooling and Performance
ABSTRACT—Aluminum extrusion dies are an important segment of tool steels, which are
manufactured in steels based on AISI H13. The main properties of steels applied to extrusion dies are:
wear resistance, hot hardness, toughness, and tempering resistance. The present work discusses the
development of a new hot work tool steel to be used on aluminum extrusion dies and their components.
This hot work tool steel exhibits superior wear and tempering resistance over traditionally used steels.
The effects of chromium (Cr) and molybdenum (Mo) contents have been evaluated with respect to
tempering resistance, as well as the effect of aluminum (Al) additions on the nitriding response. From
forged steel bars, tests on tempering resistance, toughness, nitriding response, and characterization via
EPMA have been conducted. The right balance of Cr, Mo, and Al contents has attributed to VEX steel
more than 2.5 times the tempering resistance of conventional H13, as well as a deeper and harder
nitrided layer. Due to the unique characteristics of VEX, this new development will provide an
interesting alternative to the materials already used by aluminum extrusion companies to increase their
competitiveness. Key words: aluminum extrusion, extrusion dies, hot work tool steel; nitriding.
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