Structure and mechanical properties of the nitrogen-containing austenitic plate steel 04Kh20N6G11AM2BF

Abstract

Structure and mechanical properties of the nitrogen-containing austenitic plate steel 04Kh20N6G11AM2BF with a thickness of 20 and 40 mm after hot rolling, quenching from different temperatures, and final strengthening by cold or warm deformation have been studied. For these large-section plates, sufficiently high mechanical properties were obtained, namely, the yield stress σ0.2 ≥ 690 MPa, the relative elongation δ ≥ 20%, the relative reduction ϕ ≥ 50%, and the impact toughness KCV +20 ≥ 100 J/cm2. This complex of strength and plastic properties of hot-rolled steel was produced after the quenching of the plates from 1150°C and subsequent strengthening warm (600°C) or cold (20°C) rolling with a reduction of up to 15%. These properties of steel were due to several causes, namely, the presence of nitrogen in the fcc solid solution, an increased density of dislocations (≈ 1010 cm−2), the precipitation of nanocrystalline vanadium nitrides with sizes of 2–4 nm, and the absence of large amounts of coarse near-boundary particles.