There are a large number of steel making processes in which great demands a
re made on the surface behavior of several components that come into direct
contact with steel under various conditions. Continuous casting is mainly
a heat-extraction process. The mold must rapidly transfer heat from the ste
el to the cooling water. In continuous casting, steel solidification starts
when it comes in contact with the mold liner's interior surface. The key j
ob of every mold consists in cooling the molten steel in a controlled way.
The mold is a major element in the overall economics of a continuous castin
g plant which explains the number of innovative approaches to increase the
working life (length of time during which the mold shows acceptable dimensi
onal stability to meet the quality standards) or to satisfy the new demands
to be met by the mold liners. Coating the mold inner is a firmly establish
ed practice, in particular with electrolytic surface modification treatment
s, to cope with the various operating needs including low wettability, high
hardness, good wear resistance and low cost. Several pin-on-disk tests wer
e carried out to determine the friction and wear behavior of different coat
ings. The friction partner for all coatings was a K30 (WC-Co 9%) chip, the
sliding speed was 10 cm/s at a temperature of 250 degreesC and a load of 5
N. The sliding time was 200 h (720 000 revolutions for a radius of friction
16 mm). Additional tests for shorter times allowed verification of the mor
phological evolution of the wear track. All coatings were also evaluated us
ing a scratch test. This test introduces stresses at the interface between
the coating and the substrate as the sample is displaced at constant speed.
The critical load (L-c) recorded from the scratch test translates the comp
lex intrinsic properties of a specific coating into a very reproducible fig
ure of great practical significance. This paper presents a tribological cha
racterization of conventional electrolytic coatings, bare copper alloys and
some new surface solutions for continuous steel casting molds. (C) 2001 El
sevier Science B.V. All rights reserved.