Grain Refinement Strategies in High Strength Cast Steel


This paper reviews the physical metallurgy of grain refinement produced by standard heat treatment practices. Grain refinement by normalization is shown to be dependent upon the starting microstructure. High alloy steels with as-cast microstructures that are bainitic are shown to be problematic with respect to obtaining grain refinement by standard normalization practices. These as-cast bainitic microstructures contain remnant austenite that is stable during heating, which subsequently grows during austenitization, and upon impingement reproduces the original parent austenite grain. The addition of a tempering heat treatment for these high alloy steels is shown to eliminate the austenite, increase grain multiplication upon heating, and produce grain refinement.

Meeting Name

23rd International Federation of Heat Treatment and Surface Engineering Congress 2016, IFHTSE 2016 (2016: Apr. 18-21, Savannah, GA)


Materials Science and Engineering


This work has been supported under the Steel Founders' Society of America (SFSA) program on Casting and Advanced Steel Technology that has been funded by the Army Research Laboratory under the provisions of cooperative agreement W911NF-12-2-0033.

Keywords and Phrases

Alloy steel; Austenite; Bainite; Grain size and shape; Heat treatment; High strength steel; Metallurgy; Microstructure; Steel castings; Steel metallurgy; Surface treatment, As cast microstructure; Austenite grain; Austenitization; Bainitic microstructures; High-alloy steels; Physical metallurgy; Refinement strategy; Standard heat treatments, Grain refinement

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

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© 2016 ASM International, All rights reserved.

Publication Date

21 Apr 2016

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