Mechanical properties and characteristics of nanometer-sized precipitates in hot-rolled low-carbon ferritic steel
Abstract
The microstructures and properties of hot-rolled low-carbon ferritic steel have been investigated by optical microscopy, field-emission scanning electron microscopy, transmission electron microscopy, and tensile tests after isothermal transformation from 600°C to 700°C for 60 min. It is found that the strength of the steel decreases with the increment of isothermal temperature, whereas the hole expansion ratio and the fraction of high-angle grain boundaries increase. A large amount of nanometer-sized carbides were homogeneously distributed throughout the material, and fine (Ti, Mo)C precipitates have a significant precipitation strengthening effect on the ferrite phase because of their high density. The nanometer-sized carbides have a lattice parameter of 0.411-0.431 nm. After isothermal transformation at 650°C for 60 min, the ferrite phase can be strengthened above 300 MPa by precipitation strengthening according to the Ashby-Orowan mechanism.
- Publication:
-
International Journal of Minerals, Metallurgy, and Materials
- Pub Date:
- March 2014
- DOI:
- 10.1007/s12613-014-0904-y
- Bibcode:
- 2014IJMMM..21..266W
- Keywords:
-
- ferritic steel;
- nanoparticles;
- mechanical properties;
- carbides;
- precipitation;
- strengthening