Issues »  Volume 44, Issue 6

Influence of Ductility on Structural Reliability of Metal Alloys

Yu. Ya. Meshkov, G. P. Zimina

G. V. Kurdyumov Institute for Metal Physics, NAS of Ukraine, 36 Academician Vernadsky Blvd., UA-03142 Kyiv, Ukraine

Received: 12.04.2022; final version - 02.06,2022. Download: PDF

Based on the temperature dependences of mechanical properties of steels for standard specimens and specimens with stress raisers (SR) of different sharpness the effect of ductility $\psi_{K}$ (reduction in area) on the critical temperature of brittleness is analysed under the various stress-strain state (SSS)—for thin plates (biaxial stress state—BSS), for specimens with circular notches (triaxial stress state—TSS) at tension and for prismatic pre-cracked specimens at three-point bending. As ascertained, embrittlement of steel due to SR is caused by the local ductility near SR via the strain hardening of metal, which is characterized by the parameter of break resistance $B_{\textrm{r}}$. Critical value of break resistance $B_{\textrm{rc}}$ at temperature $T_{\textrm{C}}$ depends on SR sharpness, SSS mode, and on ductility characterizing by the coefficient of break resistance, i.e., accounting for the influence of strain hardening. The effect of ductility is most vividly manifests itself for BSS, so, the sharpest SR (cracks) embrittle metal to maximum extent in thin plates, not in bars (plates of moderate thickness). As shown, structural reliability of steel products with SR ($k_{\textrm{s}}$) is governed by ductility (via $B_{\textrm{r}}$) by a different way for various SSS.

Key words: strength, ductility, break resistance, brittleness, strength stability of steels, structural reliability, stress raiser, crack.

URL: https://mfint.imp.kiev.ua/en/abstract/v44/i06/0807.html

DOI: https://doi.org/10.15407/mfint.44.06.0807

PACS: 62.20.fk, 62.20.fq, 62.20.mj, 62.20.mm, 62.20.mt, 81.40.Np

Citation: Yu. Ya. Meshkov and G. P. Zimina, Influence of Ductility on Structural Reliability of Metal Alloys, Metallofiz. Noveishie Tekhnol., 44, No. 6: 807—821 (2022) (in Ukrainian)

REFERENCES
  1. P. F. Koshelev and S. E. Belyaev, Prochnost' i Plastichnost' Konstruktsionnykh Materialov pri Nizkikh Temperaturakh [Strength and Plasticity of Structural Materials at Low Temperatures] (Moscow: Mashinostroenie: 1967) (in Russian).
  2. G. S. Pisarenko and A. A. Lebedev, Deformirovanie i Prochnost' Materialov pri Slozhnom Napryazhennom Sostoyanii [Deformation and Strength of Materials under Complex Stress State] (Kyiv: Naukova Dumka: 1976) (in Russian).
  3. R. Peterson, Koeffitsienty Kontsentratsii Napryazheniy [Stress Concentration Coefficients] (Moscow: Mir: 1977) (in Russian).
  4. V. P. Kogaev, N. A. Makhutov, and A. P. Gusenkov, Raschety Detaley Mashin i Konstruktsiy na Prochnost' i Dolgovechnost' [Calculations of Machine Parts and Constructions for Strength and Durability] (Moscow: Mashinostroenie: 1985) (in Russian).
  5. A. A. Shmykov, Spravochnik Termista [Thermist's Handbook] (Moscow: Mashgiz: 1961) (in Russian).
  6. G. V. Uzhik, Soprotivleniyu Otryvu i Prochnost' Materialov [Detachment Resistance and Strength of Materials] (Moscow: Izdatel'stvo Akademii Nauk SSSR: 1950) (in Russian).
  7. V. N. Grishchenko, Yu. Ya. Meshkov, Yu. A. Polushkin, and A. V. Shiyan, Metallofiz. Noveishie Tekhnol., 37, No. 7: 961 (2015) (in Russian). Crossref
  8. Yu. Ya. Meshkov, A. V. Shiyan, and V. N. Grishchenko, Stroitel'stvo, Materialovedenie, Mashinostroenie, 89: 112 (2016) (in Russian).
  9. J. H. Hollomon, Trans. AIME Iron Steel Div., 162: 268 (1945).
  10. A. V. Shiyan, Fizicheskaya Priroda Lokal'nogo Napryazheniya Khrupkogo Razrusheniya Staley i Svarnykh Shvov [Physical Nature of Local Stress of Brittle Fracture of Steels and Joint Welds] (Thesis of Disser. for PhD Phys.-Math. Sci.) (Kyiv: Institut metallofiziki AN USSR: 1990) (in Russian).
  11. GOST 25.506-85 Raschety i Ispytaniya na Prochnost'. Metody Mekhanicheskikh Ispytaniy Metallov. Opredelenie Kharakteristik Treshchinostoykosti (Vyazkosti Razrusheniya) pri Staticheskom Nagruzhenii [GOST 25.506-85 Calculations and Strength Tests. Methods of Mechanical Testing of Metals. Determination of Characteristics of Crack Resistance (Fracture Toughness) under Static Loading] (Moscow: Izdatel'stvo Standartov: 1985) (in Russian).
  12. GOST 9454-78 Metally. Metod Ispytaniya na Udarnyy Izgib pri Ponizhennykh Komnatnoy i Povyshennykh Temperaturakh [GOST 9454-78 Metals. Test Method for Impact Bending at Low Room and Elevated Temperatures] (Moscow: Izdatel'stvo Standartov: 1978) (in Russian).
  13. ASTM E1921. Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range.
  14. G. G. Kurdyumova, Yu. V. Mil'man, and V. N. Trefilov, Metallofizika, 1, No. 2: 55 (1979) (in Russian).
  15. Yu. Ya. Meshkov and H. P. Zimina, Metallofiz. Noveishie Tekhnol., 44, No. 2: 273 (2022) (in Ukrainian). Crossref
  16. Yu. Ya. Meshkov and K. F. Soroka, Metallofiz. Noveishie Tekhnol., 43, No. 6: 781 (2021) (in Ukrainian). Crossref

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