The use of ceran-dcs has been studied to obtain rolling performance levels which cannot be gotten by
conventional steel rolls. Sialon was selected as the most suitable roll material for cold rolling. An excellent
capability of strip rolling with sialon rolls was demonstrated during experimental rolling. Owing to the high
Young's modulus, the rolling loads, the edge drops and the minimum thicknesses were smaller for sialon rolls than
for steel rolls. 'Me roll coating on the sialon rolls was negligible because of the low adhesivity to metal which was
evaluated quantitatively using pin-on-disk abrasive wear test. Strips had a glossy surface and rolling conditions
were stable. Sialon had lower mechanical properties, especially flexural strength, than steel rolls. Sialon rolls,
however, were found to be sufficiently durable for industrial applicafions, and they were superior in wear resistance
to steel rolls. Spalling had occurred in original sialon rolls during rolling under high rolling pressure. The
appearance of the spelling was similar to that of steel roils. SpaHing has not occurred after decreasing the number of
pores in sialon rolls. In commercial roiling, several advantages over conventional rolls, including fewer roiling
passes, fewer roll changes, flexible strip width change, and longer re-grinding intervals, were demonstrated.
Keywords: roiling, cold rolling, ceran-dc rolls, sialon, deformation-load property, minimum thickness, edge@drop, tribology, roll coating.
An On-Line Calculation Model for Transverse Thickness Profile of Hot-Rolled Strips
(Received on July 20, 1995)
Masanori KITAHARA, Ikuo YARITA,
Souichirou ONDA and Kenjirou NARITA
A numerical model for estimating the transverse thickness profile of hot-rolled strips has been developed.
First, the thermal and wear profiles are calculated to obtain the unloaded profile of the work rolls. Next, the
deformation of the work rolls, i.e., deflection and flattening, caused by the uniform roll separating force and work
roll bending force is calculated. The contact force between the work roll and the back-up roll is assumed to distribute
in the fourth-order polynomial form in order to derive an analytical solution for roll deflection. The effects of the
unloaded roll profile on deflection are also taken into consideration. By taking the suni of the unloaded roll profile
and deformation of the rolls, the roll gap profile under uniform load is obtained. Finally, the profile of the rolled
strip is obtained by the linear combination of the ingoing strip profile and the roll gap profile under uniform load.
High accuracy of the model is confirmed by using a strict roll deformation model and the operational data obtained
from No. I and No.2 Hot Strip Mills at the Chiba Works of Kawasaki Steel Corporation. The CPU time required for
the calculation is so short that the model can be used for the calculation of on-line crown setup.
Keywords:hot rolling, crown, strip rolling, numerical model, roll deformatio,,i, tliennal crown, roll wear