International Journal of Minerals, Metallurgy and Materials
Volume 17, Number 5, October 2010, Page 573
DOI: 10.1007/s12613-010-0359-8
Corresponding author: Jun-xian Liu E-mail: ljxian0023@sina.com
© University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg 2010
Test research on sticking mechanism during hot rolling of SUS
430 ferritic stainless steel
Jun-xian Liu, Yong-jun Zhang, and Jing-tao Han
School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
(Received: 11 October 2009; revised: 13 November 2009; accepted: 21 November 2009)
Abstract: The sticking phenomenon during hot rolling of SUS 430 ferritic stainless steel was investigated by means of a two-disc type
high-temperature wear tester. The test results indicate that sticking particles on the surfaces of high chromium steel (HiCr) and high-speed
steel (HSS) rolls undergo nucleation, growth, and saturation stages. Grooves on the roll surface generated by grinding provide nucleation
sites for sticking particles. The number of sticking particles on the HiCr roll surface is greater than that on the HSS roll surface. The average
surface roughnesses (R
a
) of HiCr and HSS rolls change from 0.502 and 0.493 μm at the initial stage to 0.837 and 0.530 μm at the saturation
stage, respectively. The test further proves that the sticking behavior is strongly dependent on roll materials, and the HSS roll is more benefi-
cial to prevent particles sticking compared with the HiCr roll under the same hot-rolling conditions.
Keywords: ferritic steel; stainless steel; hot rolling; sticking; rolls
1. Introduction
SUS 430, a representative ferritic stainless steel, has been
widely used in construction, decoration, food machinery,
electric appliance, and automobile fields, owing to the low
cost, the excellent resistance to chloride stress corrosion and
pitting corrosion, and well cold processing performance.
The high-temperature deformation resistance of SUS 430
ferritic stainless steel is lower than that of austenitic stainless
steels, because SUS 430 is the body-centered cubic (bcc)
microstructure and 300 series austenitic stainless steels are
face-centered cubic (fcc) microstructure. Therefore, the
sticking phenomenon occurs easily during hot rolling of fer-
ritic stainless steels, the surface quality of roll materials and
rolled steel products deteriorates. Previous research [1-5]
reported that the sticking of the bare metal, exposed by the
breakaway of oxidation scale on ferritic stainless steels dur-
ing hot rolling, was influenced by the stainless steel proper-
ties and hot-rolling conditions such as rolling temperature,
contact stress, and relative slip between rolls and rolled ma-
terials. On the other hand, it is well known that there is a
wide variation in sticking resistance among ferritic stainless
steels. In addition, different roll materials for hot rolling
show distinct difference in the sticking behavior, which in-
dicates that the sticking phenomenon is heavily affected by
the wear, scratch resistance, and mechanical properties of
roll materials.
A high-temperature wear tester was used to investigate
the effect of high chromium steel (HiCr) and high-speed
steel (HSS) rolls on the sticking of hot-rolled SUS 430 fer-
ritic stainless steel in this study. The surface roughness
changes of the two rolls were measured by means of a sur-
face roughness tester. The sticking phenomena were ob-
served and analyzed using a portable metallurgical micro-
scope.
2. Experimental
Fig. 1 shows the schematic diagram of the tester for re-
searching the sticking mechanism of hot-rolled SUS 430
ferritic stainless steel. The tester is mainly composed of the
medium-frequency induction heating unit, water-cooling
system, temperature-measuring system, and loading system
between two discs. The upper disc (hereafter “rolled disc”)