caa a22 4500 46798221X CHVBK 20180323112521.0 cr unu---uuuuu 170328e19901001xx s 000 0 eng 10.1007/BF00693689 doi (NATIONALLICENCE)springer-10.1007/BF00693689 Heat treatment of large forgings with heating in the intercritical temperature range [Elektronische Daten] [A. Astaf'ev, S. Sal'kova] Conclusions: 1. In large forgings the investigated Mn-Ni-Mo-steels provide with slow cooling rates of 30-50°C/h a mixed ferritic-pearlitic-bainitic structure with a bainite content of not less than 30%. Such steels must have a low carbon content (about 0.1%) to increase the quantity of ferrite in the ferritic-pearlitic mixture and the necessary quantity of alloy elements to obtain the required stability of the supercooled austenite. 2. Heating to intercritical range temperatures and slow cooling leads to a reduction in the temperature of the bainitic transformation and the formation of a significant quantity of lower bainite causing phase strain hardening of the ferritic matrix. Obtaining of a structure of lower bainite in combination with the strain hardened ferritic matrix and also the presence of a fine grain, provide quite high mechanical properties. 3. After heat treatment from the intercritical temperature range with slow cooling it is necessary to temper at 400-450°C. This provides the greatest stability of the structure, preservation of phase strain hardening, and the maximum strength, plasticity, impact strength, and fracture toughness. 4. To obtain guaranteed mechanical properties of large forgings produced from the heterophase steels (σt ≥ 600 N/mm2, σ0.2 ≥ 350 N/mm2, σ5 ≥ 20%, ψ ≥ 60%,a 0.25 +20 ≥ 150 J/cm2,a 0.25 50 ≥ 100 J/cm2) the following heat treatment is recommended: anneal or normalize with heating to 920°C; final heat treatment by heating to 750°C, cooling at a rate of 30-50°C/h, and tempering at 400-500°C. Plenum Publishing Corporation, 1991 Astaf'ev A. aut Sal'kova S. aut Metal Science and Heat Treatment Kluwer Academic Publishers-Plenum Publishers 32/10(1990-10-01), 729-734 0026-0673 32:10<729 1990 32 11041 https://doi.org/10.1007/BF00693689 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00693689 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Astaf'ev A. aut NATIONALLICENCE 700 1- Sal'kova S. aut NATIONALLICENCE 773 0- Metal Science and Heat Treatment Kluwer Academic Publishers-Plenum Publishers 32/10(1990-10-01), 729-734 0026-0673 32:10<729 1990 32 11041 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer