X-ray Diffraction
in U. S. Steel Košice Research Laboratories for Phase
Analysis, Texture and Residual Stress Estimation
M. Černík1, I. Kohútek2,
A. Leško3
Výskum a
vývoj, U. S. Steel Košice/ U. S. Steel
1mcernik@sk.uss.com, 2ikohutek@sk.uss.com,
3alesko@sk.uss.com
Keywords: X-ray analyze, goniometer, texture, residual stress, phase
The
X-ray laboratory has been established as part of the Metallography Department
in the Research and Testing Institute VSŽ (East Slovak Steekworks) since 1971. The
first X-ray diffraction equipment was Siemens Kristaloflex IV with two
Bragg-Brentano and Schultz texture goniometers. The originally manual equipment
was step by step fully automated in the early nineties. The detector was
connected through interface to computer for data collection and the analog motors
were replaced by step motion. Special
gear was added to textural goniometer for theta motion; other gear units were
functional and could be used for fully automated regime. The original special
analog recorder drawing pole pictures was replaced by a computer programs. Evaluation
procedure of measured data was changed from paper record to software mode. From
information provided by Prof. Jaroslav Fiala, VSŽ was the first to used PDF2
diffraction database in
After
the plant acquisition by U. S. Steel, the laboratory was refurbished by new
Seifert XRD 3003 PTS equipment with 3D goniometer in the late 2003. The
equipment allows measuring and analyzing also the texture and residual stresses
in rolled steel sheets. The equipment was
upgraded by XY positional stage and highly sensitive PSD Meteor1D type detector,
which reduced the measurement time from about 10 hours to 25 minutes. The point
focus is used for textural and residual stresses analyses and line focus for
phase analysis. X-ray analyzer is equipped by Rayflex software, which does not
cover all analyzed areas. MulTex and LaboTex systems were purchased for
orientation distribution function (ODF) calculations. The popLA mode is still used for the textural
analysis, since 2006 the EBSD analyzer is in operation too. Rayflex – residual
stress program is sufficient for residual stress analyses by use of sin 2 Psi
method. The ZDS search match software with PDF2 2004 diffraction database is
used for qualitative and quantitative phase analysis. Refinement of diffraction
records is performed by AutoQuant program, which uses the Rietveld method. For
more complex analyses, which are solved in cooperation with Institutes of SAS,
TU and
Measured and evaluated diffraction records are systemically processed in the database which provides a great amount of valuable information. According to the keywords, it can be easily identified which analyses are most often required and resolved. Besides to rolled steel sheets also coatings, ceramics, sediments, dusts, sludges, different slags, casting powders, entry ores, etc. are analyzed. The database, which is the enlarged electronic diary, contains approximately 1300 samples records with approximately 260 identified minerals. The stored solutions data are valuable information used with new analyses.
Examples of selected phase analysis, residual stress and texture determinations performed in metallurgical operation laboratory are included to this contribution.
References
1. D.
K. Smith, S. Gorter, J.Appl. Cryst., 24 (1991) 369-402
2. http://www.ncnr.nist.gov/programs/crystallography/software/downloads.html
3. http://www.ill.eu/sites/fullprof/php/downloads.html
4. http://www.ing.unitn.it/~maud/index.html
5. http://www.crystallography.net
6. http://rruff.geo.arizona.edu/AMS/amcsd.php