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@PHDTHESIS{Wans:61302,
author = {Wans, Jochen},
othercontributors = {Senk, Dieter},
title = {{O}berflächenqualität peritektisch erstarrender
{K}ohlenstoffstähle : {V}ergleich zwischen {S}trangguss und
{B}andguss},
address = {Aachen},
publisher = {Publikationsserver der RWTH Aachen University},
reportid = {RWTH-CONV-122978},
pages = {Getr. Zählung : Ill., graph. Darst.},
year = {2006},
note = {Aachen, Techn. Hochsch., Diss., 2006},
abstract = {Peritectic carbon steels, produced by conventional
continuous casting, show slab surface defects as a
consequence of the shrinkage caused by the delta-gamma
transformation. Unsteady heat flux conditions between strand
shell and mould plate leads to an irregular
solidification.By following the hypothesis, that the cooling
rate has an effect to the peritectic reaction, twin roll
strip cast trials were done at a pilot strip caster at RWTH
Aachen University. Local cooling rates of -1000 K/s in
combination with an eightfold higher heat flux compared to
continuous casting are typical for strip casting process.
The indication for effects from the strip casting process to
the peritectic reaction was on the one hand the steady heat
flux and on the other hand the strip surface quality.Trials
were performed in 3 campaigns with the chemical analyses of
peritectic carbon steels known from continuous casting. The
campaigns just distinguish between the casting roll surfaces
structure and the range of carbon content. All other process
parameters were constant. The casting roll surface was
developed from a fine, hexagonal open structure to a coarse
hexagonal structure. The structure is regular and was
produced by knurling. The carbon range was 0.06 to 0.17 wt
$\%.The$ result of the 1st campaign was that nearly all
strips were attack by many cracks. The number of cracks
rises to higher carbon content up to 0.17 wt $\%.$ The
maximum of defects around 0.1 wt $\%$ of carbon, known from
continuous casting, was not found. By proofing the strip
surfaces, it was found out that the steel melt didn’t wet
the roll surface intensive. An unsteady solidification
process was the result.The results of the 2nd campaign were
different. Just very few cracks were remaining at the strip
surfaces. No dependence between carbon content and number of
crack were found. Once again the critical range around 0.1
wt $\%$ carbon wasn’t noticeable by strips produced with
the twin roll casting process.The important different in
comparison to the first campaign was an excellent wetting
behaviour between steel melt and roll surface. An imprint of
the roll surface structure was found at all strip surfaces.
A homogenous heat flux and solidification condition
exists.The results of the 3rd series, performed with a
further regular roll surface structure, confirm the above
explained facts. The geometric shape and adjustment were
again diversifying to coarser values.The work could
demonstrate that the twin roll process is suitable for the
production of peritectic carbon steel grades. The key factor
for solidification and heat flux is the wetting condition at
the roll surface. Steel specific roll surface structures are
required.},
keywords = {Bandgießen (SWD) / Benetzung (SWD) / Erstarrung (SWD) /
Oberflächenriss (SWD) / Schnelle Erstarrung (SWD) /
Strangguss (SWD) / Topographie (SWD) / Wärmestromdichte
(SWD)},
cin = {522310 / 520000},
ddc = {620},
cid = {$I:(DE-82)522310_20140620$ / $I:(DE-82)520000_20140620$},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:hbz:82-opus-15202},
url = {https://publications.rwth-aachen.de/record/61302},
}
Gast ::