Correlation dependences between the mechanical characteristics of corrosion-resistant steels
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CORRELATION DEPENDENCES BETWEEN THE MECHANICAL CHARACTERISTICS OF CORROSION-RESISTANT STEELS V. I. Vytvyts’kyi
UDC 669.017.53
A stability factor of austenite Aγ is proposed for corrosion-resistant steels. By using this factor, the equilibrium phase-structural state of steels can be quantitatively evaluated according to their chemical composition. The factor Aγ is determined by the values of the chromium and nickel equivalents. This factor, together with the generalized Scheffler diagram, enables one to deduce the correlation equations for the mechanical characteristics of steels σu , σ0.2 , δ, and ψ.
Statement of the Problem The development of new materials and the analysis of serviceability of the available materials according to the results of numerical experiments is an extremely costly process. The attempts of making predictions are restricted by the insufficient number of currently established relationships helpful in analyzing the behavior of materials in broad ranges of chemical compositions and structures. The available empirical relations can be split into the following two groups: (i) polynomials relating the characteristics σu , σ 0.2 , δ, and ψ to the concentrations of chemical elements and certain structural components; these correlations are established separately for low-strength ferritic-pearlitic steels with carbon contents below 0.1%, medium-carbon ferritic-pearlitic steels (≤ 0.25% C), and low-carbon austenitic steels; each of these types of steel is characterized its own chemical compositions and structures; (ii) relationships between the fatigue and some static mechanical characteristics used as input parameters; numerous equations of this sort are proposed for low-cycle fatigue [2] and fatigue limit [3]; their extensive application encounters certain restrictions caused by the significant deference between the experimental and numerical data which may sometime differ by an order of magnitude (especially, in the case of structural changes); thus, each of these relations is true in a certain narrow range of structures and properties and, hence, the available approaches fail to establish a general quantitative characteristic reflecting the influence of the chemical composition of the material on its phase and structural state. In the present work, we propose a phase-structural characteristic of the collection of elements of the chemical composition for chrome and chrome-nickel steels (studied as an example) and analyze the possibility of application of this parameter in deducing the relationship between the characteristics of static short-term strength and plasticity. Karpenko Physicomechanical Institute, Ukrainian National Academy of Sciences, Lviv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 1, pp. 54–60, January – February, 2007. Original article submitted May 25, 2005. 1068–820X/07/4301–0053
© 2007
Springer Science+Business Media, Inc.
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V. I. VYTVYTS’KYI
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Fig. 1. Influence of Cr E and NiE on the phase state of chrome and chrome-nickel steels [Sc
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