Effect of Tempering on Microstructure and Mechanical Properties of Boron Containing 10%Cr Steel

Published on Nov 15, 2011in Isij International1.405
· DOI :10.2355/ISIJINTERNATIONAL.51.1912
Nadezhda Dudova13
Estimated H-index: 13
(Belgorod State University),
R. Mishnev10
Estimated H-index: 10
(Belgorod State University),
Rustam Kaibyshev58
Estimated H-index: 58
(Belgorod State University)
The effect of heat treatment on the microstructure and the mechanical properties of a 10%Cr steel with 0.008% boron was examined. The microstructure and the mechanical properties of this steel subjected to the normalizing were studied after tempering under different conditions. The layers of retained austenite are located along the lath boundaries. The formation of M23(B·C)6 phase having film-like shape takes place on interface boundaries of retained austenite/martensite during tempering at 525°C. As a result, the steel exhibits brittle fracture with a low value of Charpy V-notch impact toughness of 6 J/cm2. Particles of the M23(B·C)6 phase are highly resistant against the spheroidizing. The tempering at 770°C only leads to the coagulation of these particles; when the fraction of M23(B·C)6 phase significantly decreases while the fraction of M23C6 carbides increases. The tempered at 770°C steel exhibits a high value of Charpy V-notch impact toughness of 260 J/cm2. The effect of boron additives on the phase composition and the brittleness of high-chromium steels is discussed.
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