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Flatness control system of cold rolling process with pneumatic bearing type shape roll

Submitted bySarda sindeME 4th year

1216140088

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Introduction Need Pneumatic bearing type shape roll Automatic control system used in rolling

3 Introduction

• Use of automatic control system in cold rolling process• Flatness control in rolling processes is widely used for steel and

nonferrous metals, such as aluminum and copper. • The roll shape is developed by applying the principle of pneumatic

bearing

4 Need

Thinner and stronger rolls Higher quality of rolls Shape control Analysis of all the factors involved in cold rolling processes

5Pneumatic bearing type shape roll

Pneumatic bearing or air bearing uses a thin film of pressurized air to provide an exceedingly low friction load-bearing interface between surfaces

• The shape is made by the relation between the cross-sectional profile (also referred to as the crown) of the material and the profile of the gap between mill rolls

• If the material is rolled uniformly and elongated evenly over the strip width, it has a flat shape

6Shape of roll if material has not evenly elongated

1. Wavy edges2. Centre buckles

(b) Wavy edgesges

( a ) Flat shape

(c) Centre buckles

7 Features of pneumatic bearing type shape rolls Simple structure eliminating the need to use auxiliary drives Low rotation resistance owing to rotors supported by the pneumatic bearing High sensitivity (able to detect a change in load smaller than .1 n) Capability to continuously detect the shape.

8 Configuration….

Sectional view of pneumatic bearing type rolls

Rotor Rolled material

Nozzle

Upper pressure port

Lower pressure port Air film

Arbor

Automatic shape control

During rolling, mill profile is subjected to changes because of deflection and thermal expansion and thereby the shape of material is determined by Fourier series expansion

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10 Configuration of automatic control systema.Shape controlb.Control equipment

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Strip shape is controlled by operating the shape control actuators of the rolling mills based on the analysis result

Shape control

Control equipment

In a cold rolling process, materials are processed at a maximum speed higher than 30 m/s, and changes in strip shape are steadily determined and controlled by making calculations every 0.05 second from shape detection to control output.

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