A Method for Measuring the Hardness of the Surface Layer on Hot Forging Dies Using a Nanoindenter

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Abstract

The properties and characteristics of the surface layer of forging dies are critical for understanding and controlling wear. However, the surface layer is very thin, and appropriate property measurements are difficult to obtain. The objective of the present study is to determine if nanoindenter testing provides a reliable method, which could be used to measure the surface hardness in forging die steels. To test the reliability of nanoindenter testing, nanoindenter values for two quenched and tempered steels (FX and H13) are compared to microhardness and macrohardness values. These steels were heat treated for various times to produce specimens with different values of hardness. The heat-treated specimens were tested using three different instruments—a Rockwell hardness tester for macrohardness, a Vickers hardness tester for microhardness, and a nanoindenter tester for fine scale evaluation of hardness. The results of this study indicate that nanoindenter values obtained using a Nanoindenter XP Machine with a Berkovich indenter reliably correlate with Rockwell C macrohardness values, and with Vickers HV microhardness values. Consequently, nanoindenter testing can provide reliable results for analyzing the surface layer of hot forging dies.

Keywords

forging mechanical testing tool steels 
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Notes

Acknowledgments

The work was performed with the support from a Finkl Challenge Grant administered by Forging Industry Education and Research Foundation (FIERF). The authors appreciate FIERF for awarding the grant. The authors also thank C. Ericksen of A. Finkl and Sons, Co. for supplying the steel used in this study.

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Copyright information

© ASM International 2009

Authors and Affiliations

  1. 1.Department of Metallurgical and Materials EngineeringColorado School of MinesGoldenUSA
  2. 2.B.S. Levy Consultants LtdChicagoUSA

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