Structure and properties of vanadium steels after isothermal decomposition of supercooled austenite

Autor: L. P. Potapov, A. G. Rakhstadt, V. I. Kirienko, K. A. Lanskaya, N. M. Suleimanov
Rok vydání: 1979
Předmět:
Zdroj: Metal Science and Heat Treatment. 21:270-273
ISSN: 1573-8973
0026-0673
DOI: 10.1007/bf00775106
Popis: 1. Isothermal decomposition of supercooled austenite in steels of the 27F1B and 27KhMF1B types at 650° for 30 min begins with the formation of highly dispersed particles of vanadium carbide. Field-ion microscopy reveals the precipitation of carbide phases with two morphologies — points 20–50 A in size that are grouped in linear chains with a distance of 10–20 A between particles and needlelike particles 200–400 A long that are oriented in direction [100] of the cubic lattice. 2. In the process of isothermal decomposition of supercooled austenite at 720° for 30 min lamellar vanadium carbide particles with dimensions of (120–200)×(40–60)×(5–10) A are formed, which are located in plane {100} of the matrix. 3. After transformation at 650° the steels investigated tend to undergo brittle fracture, since the ferrite formed in the transformation at 650° has a higher density of defects than after transformation at 720°. 4. After isothermal decomposition at 650° the steels have high strength and low ductility. Subsequent tempering at 720° for 3 h lowers the strength and increases the ductility and toughness.
Databáze: OpenAIRE
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