Influence of Microstructure on the Temper Embrittlement of Some Low-Alloy Steels
Influence of Microstructure on the Temper Embrittlement of Some Low-Alloy Steels

Author: R. Viswanathan

Publisher:

Published: 1979

Total Pages: 17

ISBN-13:

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The effect of microstructural variations produced by varying the transformation product and the tensile strength level on the temper embrittlement susceptibility of steels has been the subject of some recent studies. A review of the results pertaining to chromium molybdenum (Cr-Mo), chromium-molybdenum-vanadium (Cr-Mo-V), and nickel-chromium-molybdenum-vanadium (Ni-Cr-Mo-V) steels has been completed. Based on the review, it appears that in 2.25Cr-1Mo steels embrittled by step-cooling the transformation product does not appreciably affect the temper embrittlement susceptibility. In Cr-Mo-V and Ni-Cr-Mo steels, susceptibility to embrittlement increases in the order ferrite-pearlite, bainite, and martensite. Results on the effect of strength levels are inconclusive. In general, those structures that cause the steel to have low toughness initially also result in reduced susceptibility for further embrittlement. The limited amount of Auger data available suggest that the effect of microstructure is explainable, at least in part, by differences in grain boundary segregation of impurity elements caused by differences in microstructure.

Temper Embrittlement of Low Alloy Steels
Temper Embrittlement of Low Alloy Steels

Author: A. Joshi

Publisher:

Published: 1972

Total Pages: 31

ISBN-13:

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In an effort to understand the role various elements play on the temper embrittlement of low alloy steels, chemical analyses of fracture surfaces of nonembrittled and embrittled steels are conducted using Auger electron spectroscopy. The alloying elements, nickel and chromium, and trace elements antimony and tin segregated to grain boundaries during the embrittling treatment. No segregation was detected in nonembrittled steels. An attempt is made to relate the segregation of various elements and the observed embrittlement. The nature and extent of segregation is determined by ion sputtering experiments followed by Auger spectroscopic analysis. The segregation of impurity and alloying elements is examined considering both the Gibbsian and nonequilibrium models for segregation. A model is proposed to explain the observed concentration profiles. The effect of solute segregation on the grain boundary embrittlement is discussed in terms of true surface energy and plastic strain energy criteria.