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FEATURE A D V A N C E D M A T E R I A L S & P R O C E S S E S | N O V E M B E R / D E C E M B E R 2 0 1 9 6 7 peratures are adequate to achieve a fully martensitic microstructure dur- ing quenching. SUMMARY Attaining higher fracture strengths by means of induction hardening materi- al withmuch smaller grain sizes likeASTM 12 requires careful discipline on the part of induction hardening-equipment oper- ators. It is necessary to start with steels having a uniform microstructure, and then closely control induction-hardening thermal cycles to prevent grain growth. However, the improved resistance to fracture can be well worth the effort. Note: Gleeble is a registered trademark of Dynamic Systems Inc., Poestenkill, N.Y. Acknowledgment: The author acknowl- edges the support of corporate sponsors of the Advanced Steel Processing and Products Research Center, and thanks TimkenSteel Corp. for providing the test steels. ~HTPro For more information: Robert Cryder- man, research associate professor, Ad- vanced Steel Processing and Products Research Center, George S. Ansell De- partment of Metallurgical and Materials Engineering, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401, 734.735.3093, rcryderm@mines.edu. References 1. J.D. Wong, “A Comparison of Con- ventional and Induction Tempered Steels,” Master of Science Thesis, Colo-rado School of Mines, Golden, Colorado, 2001. 2. T. Hayashi, N. Kurosawa, and K. Yamada, “Method of Prior Austenite Grain Refining Using Induction Hardening,” JFE Technical Report, No. 15, May 2010, www.jfesteel.co.jp/en/research/report/015/pdf/015- 03-2.pdf. 3. R.S. Hyde, D.K. Matlock, and G. Krauss, Quench Em- brittlement: Inter-granular Fracture Due to Cementite and Phosphorous in Quenched Carbon and Alloy Steels, Proc. 40th Mechan. Working and Steel Process. Conf., p 921-928. 4. B.M. Whitley, J.G. Speer, R. Cryderman, and J. Klemm-Toole, Understanding Microstructural Evolution during Rapid Heat Treatment of Microalloyed Steels Through Computational Modeling, Advanced Physical Simulation, and Multiscale Charac-terization Techniques, J. Matls. Engrg. and Perform., Feb 2019. 5. R. Cryderman, Austenite Grain Nucleation and Growth after Re-Austenitizing Pre-Quenched 0.56% C Steels, Proc. Therm. Process. in Motion, ASM Intl., June 2018, p 152-157. 6. R. Cryderman and J. Speer, Microstructure andNotched Fracture Resistance of 0.56% C Steels After Simulated In- duction Hardening, Proc. 29th ASM Heat Treating Society Conf., Oct 2017, p 226-233. 18 17