A method of calculating a quantitative criterion that characterizes the service conditions of rolling-mill
rolls is proposed for use in substantiating the choice of material for the rolls.
Key words: roll wear, mechanical parameters of the rolling operation, metal–roll contact area, heat exchange
The finishing and leader blocks of modern high-speed light-section mills are equipped with rolls made of hard
alloys based on tungsten carbide. The chemical and structural characteristics of the roll material (the granulometric com-
position of the carbide phase, the amount of binder in the material, the chemical composition of the binder) are chosen in
relation to the service conditions of the roll in the specific stand on which it will be used. Information on these conditions
is obtained from data compiled earlier regarding the fitness of different materials for use under the given conditions.
However, such recommendations cannot always be used for other mills or for new roll materials. In light of this, it is nec-
essary to develop a quantitative criterion that can characterize the service conditions of rolls. Having such a criterion will
make it possible to compare experimental data obtained on different mills and devise principles for choosing a roll materi-
al for specific operating conditions.
It was proposed in  that the main quantitative characteristic of roll service conditions be the rolling speed in the
specific stand. The recommendation made here was that the grade of material used to fabricate the roll be selected on the basis
of this characteristic. However, such an approach is obviously usable only for mills with relatively similar characteristics. Thus,
it is necessary to develop a general criterion that accounts for the physical phenomena which determine the wear of rolls.
We propose to use the following approach to find this criterion. Let us assume that the wear of the surface of the pass in a
roll is the result of two processes: the abrasive removal of material from the surface of the pass; the formation of a damaged
layer (due to thermal fatigue). We will suppose that the first process is determined by the mechanical parameters of the rolling
operation ad that the second process is governed by thermal parameters. The rate at which each type of wear takes place
depends on the unit energy – mechanical and thermal.
During the plastic deformation of metal in a pass, energy is exchanged over the interface between the metal being
rolled and the pass – over the so-called true area of contact between the metal and the roll. The nature of the energy exchange
processes that occur in the deformation zone is complex: heat exchange takes place; friction work is done on the interface;
energy is expended on plastic deformation of the metal and elastic deformation of the roll and parts of the drive. Although
analyzing all these processes is a fairly complicated undertaking, from the standpoint of the energy balance in the rolling
operation the energy in the deformation zone can be said to come from two main sources: the heat from hot deformation of
the metal; the mechanical power applied to the drive shaft of the stand. Some of the mechanical energy is converted into ther-
mal energy during plastic deformation, which leads to heating of the metal and the surface of the roll. However, to simplify
our calculations, we will assume that the amount of heat transmitted to the roll due to its contact with the hot metal is sig-
Metallurgist, Vol. 52, Nos. 11–12, 2008
DEVELOPING AN ENERGY CRITERION
FOR THE SERVICE CONDITIONS OF ROLLS
V. V. Pashinskii UDC 621.771.251:621.771.07
Donetsk National Technical University, 58 Artema St., 83001 Donetsk, Ukraine; e-mail: firstname.lastname@example.org.
Translated from Metallurg, No. 11, pp. 49–50, November, 2008. Original article submitted July 30, 2008.
2008 Springer Science+Business Media, Inc.