Conclusions
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1.
Use of the relative length of a stable crackl c/b, where b is specimen width, is proposed for evaluation of the fracture resistance of a steel and determination of the critical defect size.
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2.
09G2S steel has higher impact strength and crack resistance and a lower ductile-to-brittle transition temperature but a greater anisotropy of properties than 20 steel.
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3.
In fractures of specimens of 20 and 09G2S steels at temperatures of the ductile-to-brittle transition in impact bend and static tensile tests zones of drawing out (Θ 1) and of shear (Θ 2) and separation (Θ 3) fracture were observed. Their total is the zone of stable crack growth (l c). The ductile-to-brittle transition temperature of 20 steel determined from the fibrous constituent in the fracture (F=50%) is practically independent of notch sharpness of the specimens used.
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A. A. Baikov Institute of Metallurgy. All-Union Petroleum and Gas Scientific-Research Institute, Samara. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 9–14, October, 1992.
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Botvina, L.R., Tetyueva, T.V., Geikhman, T.D. et al. Features of the fracture of specimens of low-carbon steels under impact and static loading conditions. Met Sci Heat Treat 34, 614–621 (1992). https://doi.org/10.1007/BF00776899
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DOI: https://doi.org/10.1007/BF00776899