Dispersion Strengthening Particles in Vanadium Microalloyed Steels Processed by Simulated Thin Slab Casting and Direct Charging, Part 2
The compositions of sub-15 nm particles in six related vanadium high strength low alloy steels, made by simulated thin slab direct charged casting, have been determined using electron energy loss spectroscopy (EELS). Such particles are considered to be responsible for dispersion hardening. For the first time, particles down to 4 nm in size have had their composition fully determined. In all the steels, the particles were nitrogen and vanadium rich and possibly slightly substoichiometric carbonitrides. Equilibrium thermodynamics predicted much higher carbon to metal atomic ratios than observed in all cases so that kinetics and mechanical deformation clearly control the precipitation process. Thus it is important to formulate the steel with this in mind.
High strength low alloy (HSLA) steel, Analytical electron microscopy, Electron energy loss spectroscopy, Precipitation, Thin slab direct charged process
J. A. Wilson (1), A. J. Craven (1), Y. Li (2,3) and T. N. Baker (3)
(1) Department of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK
(2) Vanitec, Winterton House, High Street Westerham, Kent TN16 1AQ, UK
(3) Metallurgy and Materials Engineering Group, Department of Mechanical Engineering, University of Strathclyde, Glasgow G1 1XJ, Scotland, UK
Materials Science and Technology, Vol. 23 No. 5, 2007, pp.519-527