Roll Grinding Method for Matched Pair of Rolls

Abstract

A method of grinding a pair of matching rolls in which the position of a grinding wheel relative to the rolls is computer controlled, and the surface profile of a roll is continuously measured and input to the computer comprising modifying the desired profile of the second roll of the matched pair adjusted by the residual shape error profile of the first roll to establish a uniform gap between the pair of rolls; and grinding the second roll to bring the profile of the second roll within acceptable tolerance based on the modified desirable profile.

Description

BACKGROUND OF THE INVENTIONField of the Invention[0001]This invention is directed to a method of grinding a pair of matching rolls used in a strip rolling mill.Description of Related Art[0002]Steel sheet is made by pressing thick slabs of steel between large rollers. The rollers are referred to as “rolls.” The rolls are generally cylindrical and are journaled on parallel axes. Depending on the process, the rolls used to make steel strip can vary from about 2 inches in diameter to 72 inches in diameter. The space between the rolls through which the slabs pass is referred to as the “nip.” On passing through the nip, the thickness of the slab is reduced. For example, one step in making steel sheet is with the hot strip mill. Thick slabs are heated to about 2,300 degrees Fahrenheit. Typically, the slab will pass through two banks of six mill stands, one rough bank and one finish bank. A mill stand is a vertical group of rolls, typically four or six. The rolls defining the nip are backed...

AI Technical Summary

Benefits of technology

The patent text describes a method for improving the accuracy of a nip (the point where two rolls press together) in a printing machine. The method involves relaxing the tolerance of the first roll to reduce grinding time, while still improving accuracy. In another embodiment, the tolerances of both rolls are relaxed to achieve even better nip accuracy. This method can help to improve the quality and efficiency of printing machines.

Problems solved by technology

In modern mills, roll profiles can be very complicated.

Of course, the surfaces of the rolls must not have surface irregularities that produce undesirable surface quality of the steel strip.

Imperfections in the roll surface will cause imperfections in the surface of the rolled sheet.

An uneven shape of the roll causes unevenness in the rolled product, which at the very least means a waste of rolled material.

Over a period of use, rolls undergo wear and deterioration in surface quality.

There is always a residual error up to the acceptable tolerance level, for example, several microns.

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