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Steel Heat Treatment - Metallurgy and Technologies 2nd ed - G. Totten (CRC_ 2007) 7

Tham khảo tài liệu 'steel heat treatment - metallurgy and technologies 2nd ed - g. totten (crc_ 2007) 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | m c ZE 130 70 110 90 0 50 100 150 200 Time h FIGURE 6.78 Hardness of an unalloyed steel with 0.89 C after soft annealing depending on the spheroidization time and temperature. From H.J. Eckstein Ed. Technologic der Warmebehandlung von Stahl 2nd ed. VEB Deutscher Verlag fur Grundstoffindustrie Leipzig 1987. For medium-alloy steels up to 630 C 1166 F with a cooling rate of 15-20 K h furnace cooling For high-alloy steels up to 600 C 1112 F with a cooling rate of 10-15 K h furnace cooling Further cooling below the temperatures indicated is usually performed in air 6.2.5 Recrystallization Annealing Recrystallization annealing is an annealing process at temperatures above the recrystallization temperature of the cold-worked material without phase transformation that aims at regeneration of properties and changes in the structure that exists after a cold-forming process Tensile strength Rm N mm2 FIGURE 6.79 Influence of the ultimate tensile strength and degree of spheroidization on machinability of steels for carburizing and structural steels for hardening and tempering expressed as 1 h turning speed v60 in m min. a Spheroidization degree less than 30 b spheroidization degree between 40 and 60 c spheroidization degree greater than 70 . From G. Spur and T. Stol erle Eds. Handbuch der Fertigungstechnik Vol. 4 2 Warmebehandeln Carl Hanser Munich 1987. 2006 by Taylor Francis Group LLC. m c ZE 130 70 110 90 0 50 100 150 200 Time h FIGURE 6.78 Hardness of an unalloyed steel with 0.89 C after soft annealing depending on the spheroidization time and temperature. From H.J. Eckstein Ed. Technologic der Warmebehandlung von Stahl 2nd ed. VEB Deutscher Verlag fur Grundstoffindustrie Leipzig 1987. For medium-alloy steels up to 630 C 1166 F with a cooling rate of 15-20 K h furnace cooling For high-alloy steels up to 600 C 1112 F with a cooling rate of 10-15 K h furnace cooling Further cooling below the temperatures indicated is usually performed in air 6.2.5 Recrystallization Annealing