On the formation of M /SUB a/ C /SUB b/ carbide during tempering of a tungsten steel

Journal Article · Sat Dec 01 04:00:00 EST 1984 · Scr. Metall.; (United States)

DOI:https://doi.org/10.1016/0036-9748(84)90361-2· OSTI ID:5112801

Sarma, D S

The nature of carbide precipitation reactions during the tempering of Mo and W steels was first systematically investigated by Kuo who reported the formation of several isomorphous carbides in the two types of steels. These are the orthorhombic M/sub 3/C, hexagonal M/sub 2/C, complex cubic carbides with face centered symmetry M/sub 23/C/sub 6/ and M/sub 6/C (where the letter M denotes metal atom Fe, Mo or W) and also the hexagonal carbide MoC or WC. The sequence of the carbide formation was found to depend on the Mo (or W) to carbon ratio in the steel. There has, however, been one carbide with orthorhombic symmetry, M /SUB a/ C /SUB b/ , that was found to form only in the Mo steels but not in the W steels. Subsequent investigators confirmed the formation of M /SUB a/ C /SUB b/ carbide in the Mo steels and Dyson and Andrews analyzed this carbide by x-ray fluorescence method and found it to be of composition Fe/sub 2/MoC. The unit cell of this carbide (a = 1.6276 nm, b = 1.034 nm and c = 1.132 nm) is about 12 times larger than that of the orthohombic cementite (a = 0.4524 nm, b = 0.5524 nm and c = 0.6741 nm) which enables an easy distinction between the two carbides in x-ray or electron diffraction patterns. Subsequent investigations also failed to detect the formation of this carbide on tempering tungsten steels and there does not seem to exist any information regarding its morphology even in the Mo steels.

• Research Organization: Department of Metallurgical Engineering, Banaras Hindu University, Varanasi
• OSTI ID: 5112801
• Journal Information: Scr. Metall.; (United States), Journal Name: Scr. Metall.; (United States) Vol. 18:12; ISSN SCRMB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
360102 -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
CARBIDES
CARBON COMPOUNDS
CEMENTITE
CHEMICAL ANALYSIS
CHEMICAL REACTION YIELD
COHERENT SCATTERING
DIFFRACTION
ELECTRON DIFFRACTION
HEAT TREATMENTS
INTERMETALLIC COMPOUNDS
IRON ALLOYS
IRON BASE ALLOYS
IRON CARBIDES
IRON COMPOUNDS
MOLYBDENUM ALLOYS
MOLYBDENUM CARBIDES
MOLYBDENUM COMPOUNDS
MORPHOLOGY
NONDESTRUCTIVE ANALYSIS
PRECIPITATION
QUANTITY RATIO
REFRACTORY METAL COMPOUNDS
SCATTERING
SEPARATION PROCESSES
STEELS
TEMPERING
TITANIUM CARBIDES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN ALLOYS
X-RAY EMISSION ANALYSIS
X-RAY FLUORESCENCE ANALYSIS
YIELDS