Dispersion strengthening in vanadium microalloyed steels processed by simulated thin slab casting and direct charging Part 2 – Chemical characterisation of dispersion strengthening precipitates

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.

[1]  T. N. Baker,et al.  The effects of vanadium, niobium, titanium and zirconium on the microstructure and mechanical properties of thin slab cast steels , 2004 .

[2]  T. N. Baker,et al.  Evolution of precipitates, in particular cruciform and cuboid particles, during simulated direct charging of thin slab cast vanadium microalloyed steels , 2004 .

[3]  J. Wilson,et al.  Improving the analysis of small precipitates in HSLA steels using a plasma cleaner and ELNES. , 2003, Ultramicroscopy.

[4]  C. Scott,et al.  Quantitative analysis of complex carbo-nitride precipitates in steels , 2002 .

[5]  A. Craven,et al.  A fast beam switch for controlling the intensity in electron energy loss spectrometry. , 2002, Ultramicroscopy.

[6]  T. N. Baker,et al.  The Evolution of Microstructure during Thin Slab Direct Rolling Processing in Vanadium Microalloyed Steels , 2002 .

[7]  M. G. Burke,et al.  Quantitative Microanalysis with high Spatial Resolution: Application of FEG-DTEM XEDS Microanalysis to the Characterization of Complex Microstructures in Irradiated Low Alloy Steet , 2001 .

[8]  O'Keefe,et al.  Plasma Cleaning and Its Applications for Electron Microscopy , 1999, Microscopy and Microanalysis.

[9]  Ray F. Egerton,et al.  Electron Energy-Loss Spectroscopy , 1997, Microscopy and Microanalysis.

[10]  Y. Ishiguro,et al.  Determination of non-stoichiometric composition of complex carbon-nitrides in steel by measuring plasmon energy , 1996 .

[11]  R. Egerton,et al.  Electron Energy-Loss Spectroscopy in the Electron Microscope , 1995, Springer US.

[12]  A. Craven.  The electron energy‐loss near‐edge structure (ELNES) on the N K‐edges from the transition metal mononitrides with the rock‐salt structure and its comparison with that on the C K‐edges from the corresponding transition metal monocarbides , 1995 .

[13]  L. Garvie,et al.  Electron Energy Loss Near Edge Structure (ELNES) on the Carbon K-Edge in Transition Metal Carbides with the Rock Salt Structure , 1995 .

[14]  R. Kašpar,et al.  Direct charging of thin slabs of a Ti-microalloyed low carbon steel for cold forming , 1994 .

[15]  R. Honeycombe,et al.  Ageing characteristics of VC, TiC, and (V, Ti)C dispersions in ferrite , 1978 .

[16]  G. Dunlop,et al.  Atom-Probe Field-Ion Microscopy of Mixed Vanadium–Titanium Carbides in a Low-Alloy Steel , 1975 .

[17]  T. N. Baker.  Controlled-rolled low-carbon, nitrogen–vanadium iron alloys , 1974 .

[18]  M. Mackenzie,et al.  Nanoanalysis of very fine VN precipitates in steel , 2006 .

[19]  M. Korchynsky,et al.  New steels for new mills , 1999 .

[20]  S. Zając,et al.  The Role Of Vanadium In Microalloyed Steels , 1999 .

[21]  and as an in , 2022 .

[22]  I. Miyazaki,et al.  AND T , 2022 .