Effect of the Quenching Temperature on the Structure and Mechanical Properties of Martensitic–Ferritic Corrosion-Resistant Nitrogen-Bearing 08Kh17N2AF Steel

• Published in: Russian metallurgy Metally Vol. 2023; no. 6; pp. 629 - 637
• Main Authors: Lukin, E. I., Blinov, V. M., Bannykh, I. O., Blinov, E. V., Antsyferova, M. V., Ashmarin, A. A., Seval’nev, G. S., Demin, K. Yu, Zavodov, A. V., Samoilova, M. A., Chernenok, D. V., Mamykin, N. I., Nerutskaya, A. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.06.2023; Springer Nature B.V
• Subjects: Austenite; Carbon nitride; Chemistry and Materials Science; Chromium; Corrosion resistance; Corrosion resistant steels; Dislocation density; Ferritic stainless steels; Grain size; Heat treating; Impact strength; Manufacture of Ferrous and Nonferrous Metals; Martensite; Materials Science; Mechanical properties; Metallic Materials; Nitrogen; Quenching; Toughness; corrosion-resistant steels; austenite; nitrogen; ferrite; heat treatment; corrosion resistance; mechanical properties; martensite
• ISSN: 0036-0295; 1555-6255; 1531-8648
• DOI: 10.1134/S0036029523060290

The structure and mechanical properties of martensitic–ferritic nitrogen-bearing 08Kh17N2AF steel after quenching in the temperature range 800–1200°C are studied. This steel after quenching from 950°C is found to have a high strength (σ u = 1290 MPa, σ 0.2 = 850 MPa) and impact toughness at +20°C ( KCU = 0.8 MJ/m 2 ) but a low impact toughness at –70°C ( KCU = 0.3 MJ/m 2 ) as a result of the formation of a martensitic–ferritic–austenitic structure containing ∼82% α, ∼17% δ, ∼1% γ, and a small amount of chromium carbonitrides. The 08Kh17N2AF steel is noted to have the best combination of strength (σ u = 950 MPa, σ 0.2  = 800 MPa) and impact toughness at +20 and –70°C ( KCU +20°C = 1.65 MJ/m 2 , KCU –70°C = 0.7 MJ/m 2 ) after quenching from 800°C and cooling in water as a result of the formation of a martensitic–ferritic–austenitic structure containing 75% martensitic with a high dislocation density, 17% ferrite with grain sizes 2–3 μm, and 8% austenite. The increased impact toughness at +20°C and –70°C is shown to be related to a low content of chromium and vanadium carbonitrides and thin-lamellar martensite having formed from fine austenite grains.