Conclusions
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1.
The optimal chromium content in steel 35GSFB is 2.5–2.9%. A high level of strength, plastic, and ductile properties is provided in the steel with this chromium content after quenching and high tempering in the 630–660°C interval: σu⩾900 N/mm2, σ0,2⩾790 N/mm2, δ5; ⩾ 18%; ψ⩾58% J/cm2; also provided for is a high resistance to brittle and ductile failure:a 1⩾140 J/cm2,a −501 ⩾70 J/cm2,a −500.25 ⩾40 J/cm2, andT 50≤40°C.
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2.
M3C and M7C3 carbides of globular form, which are uniformly distributed in the matrix of the steel and which exert a favorable influence on its resistance to ductile and brittle failure, are observed in the steel's structure when it contains 2.5–2.9% Cr.
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3.
An increase in the chromium content to more than 2.9% will effect an increase in the tendency of steel 35GSFB to reversible temper brittleness (ΔT 50≽90°C). Cooling in air or in water after tempering makes it possible to reduce the embrittlement of the steel with 2.5–2.9% of Cr to a level acceptable in practice (ΔT 50⩾30°C).
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Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 18–21, August, 1988.
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Shukyurov, R.I., Zikeev, V.N., Ismailov, V.A. et al. Effect of chromium on the structure and properties of steel 35GSFB for the shafts of turbine drills. Met Sci Heat Treat 30, 580–584 (1988). https://doi.org/10.1007/BF00778261
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DOI: https://doi.org/10.1007/BF00778261