Conclusions
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1.
Mathematical treatment of experimental data on establishing relationships between σs and ɛ with the use of the “Nairi” computer confirmed the usefulness of the equation σs = mɛn for describing experimental hardening curves and indicates the very close relationship between σs and; the correlation coefficient is 0.935–0.993, However, for many of the investigated materials the exponential hardening rule has a somewhat approximate character, which is the result of a change in n with an increase in ɛ. This rule is best fulfilled with the use of the coefficient m and the strain-hardening exponent n determined with ɛ ≥ 1.0.
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2.
For many metals and alloys the value of n is not a constant but changes with an increase in the degree of strain. For alloys the deformation of which is not complicated by structure and phase transformations the value of n decreases with an increase in ɛ basically up to ɛ ≈ 0.6–0.8 or remains unchanged. Of the investigated materials the value of n is constant over the whole range of considered values of ɛ for technical grade iron and 40Kh and 45Kh steels while for 35 and 18KhGT steels there is an insignificant decrease in n with an increase in ɛ. For alloys having structure and phase transformations during plastic deformation the value of n first increases with an increase in ɛ and then starts to drop.
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Translated from Problemy Prochnosti, No. 8, pp. 72–77, August, 1981.
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Krokha, V.A. Relationship of the strain-hardening exponent to the degree of strain and fulfillment of the exponential rule of hardening. Strength Mater 13, 1022–1027 (1981). https://doi.org/10.1007/BF00762176
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DOI: https://doi.org/10.1007/BF00762176