1750mm 6-Roll Reversible Cold Rolling Mill

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1750mm 6-Roll Reversible Cold Rolling Mill

General Information
The production of this unit is to roll hot rolled coils with the thickness of 2.0～4.5mm into high precision cold rolled coils with the thickness of 0.18～1.5mm through several time of rolling. The scale of the cold rolling production line is a production of 225 thousand tons of cold rolled steel coils per year. It adopts the UCM-type single-stand 6-roll reversible cold rolling mill. The work roll of the rolling mill is equipped with positive and negative bending. The intermediate roll is equipped with positive bending and twitch. The uncoiler is equipped. Both front and rear frames are equipped with coiler, thickness gauge, laser velocimeter etc., which can realize large tension rolling and guarantee high-speed and stable production with specified thinness.

Characteristics of the Rolling Mill
1750 6-roll reversible cold rolling unit is the cold rolling production line with designed annual output of 225 thousand tons and adopts UCM-type single-stand mill. Roll pickled hot rolled coils into cold hard coils. The unit is equipped with hydraulic AGC. The work roll is equipped with positive and negative bending and subsection cooling. The intermediate roll is equipped with the positive bending and moving, and the front and rear frames are equipped with double X-ray thickness gauge, double-laser velocimeter, etc. Characteristics:
 

1. Uncoiler is equipped with CPC automatic centering function, which adopts EMG products from Germany, and improves the centering response speed and position control accuracy.
2. Rolling line adjustment equipment adopts stepwise wedge combination adjustment, and the roll diameter can quickly and automatically control the stepwise wedge displacement of the oil cylinder drive to the right position, realizing automatic and quick adjustment of the rolling line (companys utility model patent:  ZL201120139812.6);
3. Positive and negative bending of the work roll; the intermediate roll has transverse moving presetting, locking, and positive bending control measure. The bending roll can be controlled from single side; rollers are equipped with subsection cooling and roll shape adjustment. Multiple-plate-shape control measure is able to better control the plate shape of finished strips.
4. Double-station roll changing carriage is adopted, which realizes the swift changing between the work roll and the intermediate roll.
5. Roll system of the rolling mill, the turning roll, and the oil removal roll bearing adopt air-oil lubrication, which can prolong the bearings life and reduce oil consumption, pollution and maintenance quantity with high lubrication efficiency.
6. ImportedX-ray thickness gauge is adopted, improving the thickness precision of finished strips.
7. Imported laser velocimeter is adopted to realize mass flow AGC control in combination with AGC system, with improved the yield of strips.
8. The rolling mill adopts Simens S7-400 programmable controller, DC drive adopts 6RA70 all-digit speed regulating system, and the electric system takes safety protection measures of overload protection, strip breakage protection, emergency cut-off, etc.; the unit is equipped with functions of strip tail automatic deceleration, accurate stopping and multi-point stopping; coiler is equipped with functions of cycle memory, strip length calculation, and jaw accurate positioning.
9. AGC automatic system adopts S7-400+FM458 structure, which makes the utmost use of the controller and matches the quick response of the high-speed rolling mill.
10. In the second-level automation controlled by AGC, rolling schedule is further improved.
11. All key components and parts of hydaulic system adopt import components and parts, which improves system reliability.
12. Hydaulic AGC system is equipped with advanced functions of constant roll gap control, constant roll force control, constant thickness control, mass flow control, thickness precontrol, tension/speed automatic control, etc.

1. Rolling mill specification:F 1250F 450F 370 1750mm
2. Max rolling pressure: 18000 KN
3. Max rolling torque:115 KN.m
4. Max threading speed: 30m/min
5. Max uncoiling speed: 500m/min
6. Max rolling speed:1200m/min
7. Uncoiling tension: 78~8 KN
8. Coiling tension: 200~20 KN  (I gear V＜760  m/min)

1. Max coiling speed: 1260m/min

1. Drive system of main rolling mill, uncoiler and coiler adopts Simens 6RA80 all-digit DC speed regulation, thyristor power supply and unit PLC control.  
2. The basic automation system of the unit is composed of Simens S7-400 PLC as the master controller and the corresponding remote I/O(ET-200M), which controls the rolling line and the operation of auxiliary equipment.
3. AGC is a FM458+1.5 level automatic thickness control system with full hydaulic screw-up. It is equipped with control functions of total travel mass flow control, constant roll gap control, constant roll force control, adjustment control, automatic prepressing control, thickness precontrol AGC, thickness monitor AGC, tension/speed AGC, acceleration and deceleration AGC compensation control, roller eccentricity compensation, etc., and it is also equipped with process management functions of rolling process database, data presentation and operating control, product quality tracing, automatic recording of high-speed rolling data, automatic report generation, failure warning, and recording etc.
4. The rolling mill has regulating measures of screw-down off tracking, positive/negative bending of the work roll, the positive bending of the intermediate roll etc.; it has plate shape control measures of intermediate roll transverse presetting, roller subsection cooling etc.
5. Upper and lower work rolls are driven separately.
6. Uncoiler is equipped with CPC automatic centering function.
7. Swift roll changing between the work roll and the intermediate roll.
8. The electric system of the rolling mill takes safety protection measures, including overload protection, strip breakage protection, emergency cut-off, etc.; the unit is equipped with functions of strip tail automatic deceleration, accurate stopping, and multi-point stopping; coiler is equipped with functions of cycle memory, strip length calculation, jaw accurate positioning, and work roll spindle accurate positioning.
9. The unit is preset with the process parameter, and detection, presentation, alarming and stored recording for process parameters and equipment key parameters.
10. The master operational console is equipped with human-computer interface, image display of finishing rolling mill state (main parameters like uncoiling, coiling tension value, current value, speed value etc.), manual regulation, rolling process parameter setting, failure warning and report printing.
11. The rolling line elevation adopts stepwise wedge quick regulation.
12. Roll system, turning roll and oil removal roll adopt air-oil lubrication.
13. Strip surface is degreased by the combination of air purge and roller drying and degreasing.
14. Imported X-ray thickness gauge is adopted.
15. Import laser velocimeter is adopted to realize mass flow control, improve strip yield and keep encoder speed.
16. Gears adopt five-level precision 20CrMnMo alloy steel carburizing, quenching gears, and oil injection circulating lubrication.
17. Key parts like the principal axis of the coil mandrel, the fanlike segment and the hollow shaft adopt 34CrNi3Mo alloy forged steel.
18. Components of low-pressure hydaulic system adopt renowned products using imported technologies; key components like the high-pressure AGC system, the bending roll and the CPC system also adopt imported products.