Abstract
The effects of tempering on the Charpy impact toughness and tensile properties of upper and lower bainite in a 4150 steel have been studied. The results correlate with quantitative measurements taken from both the fracture surfaces and the microstructures of Charpy test specimens. The fracture surfaces from impact specimens having a lower bainitic microstructure were characterized by quasicleavage fracture, whereas those having an upper bainitic microstructure exhibited only cleavage fracture. The quasicleavage facet size and cleavage facet size correlate with bainite packet size and bainite block size. After tempering at high temperatures, the impact toughness is greatly improved for both the upper and lower bainitic microstructures. Changes in toughness correlate with the microstructural change in carbide shape and distribution resulting from the different tempering operations.
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References
R.F. Hehemann, V.J. Luhan, and A.R. Troiano, The Influence of Bainite on Mechanical Properties,Trans. ASM, Vol 49, 1957, p 409–426
Y. Tomita and K. Okabayashi, Effect of Microstructure on Strength and Toughness of Heat Treated Low Alloy Structural Steels,Metall. Trans. A, Vol 17, 1986, p 1203–1209
A.R. Marder and G. Krauss, The Morphology of Martensite Iron-Carbon Alloys,Trans. ASM, Vol 60, 1967, p 651–660
J.M. Marder and A.R. Marder, The Morphology of Iron-Nickel Massive Martensite,Trans. ASM, Vol 62, 1969, p 1–10
Y. Ohmori, H. Ohtani, and T. Kunitake, Tempering of the Bainite and the Bainite/Martensite Duplex Structure in Low Carbon Low-Alloy Steel,Met. Sci, Vol 8, 1974, p 357–366
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Johnson, D.R., Becker, W.T. Toughness of tempered upper and lower bainitic microstructures in a 4150 steel. JMEP 2, 255–263 (1993). https://doi.org/10.1007/BF02660294
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DOI: https://doi.org/10.1007/BF02660294