Continuous-Cooling-Transformation Behavior, Microstructure, and Properties of 0.02C-3.5Ni-3.6Mo High-Strength Steels
COLORADO SCHOOL OF MINES GOLDEN DEPT OF METALLURGICAL ENGINEERING
Pagination or Media Count:
The continuous-cooling-transformation CCT behavior, microstructures, and properties of 0.02 C, 3.6 Mo, and 3.5 Ni steels with manganese contents ranging from 1 to 1.76 were investigated. The effects of cooling rate and prior austenite grain size were examined as part of the CCT work for the steel with 1.5 Mn. The CCT diagram for this steel is flat-topped, with almost no variation in the transformation start and finish temperatures as a function of cooling rate. A fully martensitic microstructure forms in response to cooling rates faster than about 37 deg Cs for a prior austenite grain size of about 7 micrometer. At cooling rates faster than 25 deg Cs, martensite forms for the 1.5 Mn steel with a prior austenite grain size of about 34 micrometer. At cooling rates slower than 25 deg Cs and 7 deg Cs for the prior austenite grain sizes of about 7 micrometer and 34 micrometer, respectively, the microstructure consists of acicular ferrite with micronsized islands of martensite and austenite.
- Properties of Metals and Alloys
- Air Conditioning, Heating, Lighting and Ventilating