On Predicting Quenched and Tempered Hardness of Mixed Microstructures using Steel Chemistry


A method of predicting tempered hardness of mixed microstructures has been formulated, which uses the quenched hardness and steel chemistry as independent variables. This calculation is based upon a method first proposed in 1947 by Crafts and Lamont for mixed microstructures and modified using the 1977 chemistry-based, tempered martenstte hardness calculation of Grange, Hribal, and Porter. Tempered hardness predictions were examined using Jominy end-quench bars tempered between 204°C (400°F) and 649°C (1200°F). The measured Jominy hardness after tempering was used to make adjustments to the Crafts and Lamont parameters used in the hybrid model. Both plain carbon (SAE 1045) and low alloy (SAE grades 8620, 4130, 4142, and 5160) were used to evaluate the chemistry-based hardness prediction. In combination with a ASTM A255 Jominy hardenability calculation, the proposed calculation can be used to predict the quenched and tempered hardness profile of a round bar based upon chemistry, quench severity, and tempering temperature.

Meeting Name

ASM International - 29th Heat Treating Society Conference, HEAT TREAT 2017 (2017: Oct. 24-26, Columbus, OH)


Materials Science and Engineering

Keywords and Phrases

Forecasting; Microstructure; Tempering, Hardenability; Hardness prediction; Hardness profiles; Independent variables; Mixed microstructures; Quench severity; Steel chemistry; Tempering temperature, Hardness

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


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© 2017 ASM International, All rights reserved.

Publication Date

01 Oct 2017

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