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Ф170/Ф750×850 Four-roll Hydraulic AGC Reversible Cold Mill Unit

I. Operating conditions:

Material: SS201, SS304
Material thickness: ≤2.75mm  Material width:
Product thickness: ≤0.25mm  Product width:  
Rolling speed: V≤230m/min
Rolling pressure: P≤1200t

II. Configuration:

Main unit: Ф170/Ф750×850 Four-roll Hydraulic AGC Reversible Cold Mill, one set

1) Description of hydraulic automatic gage control system (AGC)
Hydraulic AGC is a necessary device to improve the rolling precision and guarantees manufacturers to gain the advantage in the severe market competition in the future. To maintain the gage control precision and the good pattern of strip steel, it has many functions such as hydraulic roll gap control (AGC), constant rolling pressure control (AFC), thickness gauge pre-control and monitoring. It works reliably and operates conveniently.  Furthermore, it is equipped with the complete self-protection functions and the rolling recipe database. To make strip steel of various specifications, access the corresponding setting recipe before each rolling. With it, the thickness control precision of strip steel will become 0.25±0.005mm (vertical thickness deviation)

2) Main components

①Hydraulic pump station
A hydraulic pump station mainly consists of main hydraulic pump, accumulator, oil tank, servo valve bank, pressure reducing/maintaining valve bank, circulating filter and others. For hydraulic pump, the maximum design pressure is 31Mpa and the operating pressure is between 20Mpa and 23Mpa. The hydraulic station provides the flow at the rate of 42L/min and the capacity of 1.0m3 and covers an area about 4 to 6㎡.

②Screw-down oil cylinder
The screw-down oil cylinder is made of high-grade casting alloy steel and passes three NDT cycles to prove the quality of cylinder block. Adopt the unique structure design and the imported oil seal. The use of high-resolution displacement sensor, SONY Magnescale can detect the displacement of oil cylinder and provide the measurement as accurate as 0.001mm. The cylinder block is also equipped with the high-precision pressure sensor to detect the rolling pressure and provide the measurement as accurate as 0.2% to 0.3%. The cylinder block operates 15 to 20 cycles per second.

③Control System
It is equipped with the high-performance and reliable PLC control that is particularly applicable for severe working conditions.

④Thickness gauge (provided by user)
Adopt the isotopic ray thickness gauge.
Measurement accuracy: 0.3%; Response time: 30ms

⑤Servo valve
Adopt the best Chinese servo valves that are made by Nanjing No. 609 Institute and Shanghai No. 701 Institute. These valves are regularly used in China F-7 and F-8 aircrafts and feature the high reliability.

3)Technical parameters and requirements

① Hydraulic AGC system
② The designed rolling pressure is 1200t and the output of one cylinder is 600t.
③ Stroke of hydraulic cylinder: 80mm; screw-down speed: 3mm/s
④ Use the screw-down hydraulic cylinder. Its installation is illustrated in the attached figure.
⑤Adopt the medium/high-end configuration for driving system. Otherwise, it may affect the performance of AGC.
⑥ Adopt SONY Magnescale as displacement sensor.
⑦ Use SIEMENS S7-400 to control the AGC and SIMENES S7-200 to control the hydraulic station.
⑧ Rolling speed: 230m/s

4) Main functions of automatic gage control system

① The PLC controls the start, running, stop and other safe operations of hydraulic pump station.
② Functions of hydraulic AGC:
(A) Thickness gage AGC
(B) Monitoring AGC
(C) Pre-control AGC
③ It can realize the quick lifting of roll and automatic calibration of rolling mill.
④ It permits the manual setting of roll gap and displays the rolling pressure, the roll gap and other information.
⑤ It is equipped with various overload protections against over-pressure, over-differential pressure, out-of-tolerance roll gap and other errors and sends alarms.
⑥ It can display rolling parameters.
⑦ It is equipped with rolling recipe database.
⑧Tension AGC and flow AGC are optional upon your request. Nevertheless, you must make sure that the electrical, speed, tension and other systems are accurate and reliable.

(2)、Frame assembling:
1. Two closed gantries (sectional dimension of column: 450x580mm)
2. A pair of back-up rolls: hydraulically balanced; working roll: hydraulic positive bending roll
3. The opening height of working roll gap is 20mm or smaller to accept the strip steel.
4. It is equipped with the front and the rear thickness gauge tables, the hydraulic pressure plate and the carrier roll.
5. QNT-2 thickness gauge:   two sets (purchased by user separately)
6. Unilateral-adjustment roller-type aligner
7. Drive base, set of anchor bolts and frame platform


1. Working roll: diameter x width: Ф170×900㎜   Material: 9Cr2Mo
Composite bearing
2.Back-up roll: diameter x width: Ф750×850㎜   Material: 9Cr2Mo
FCDP88124450E bearing (made by Wafangdian Machinery& Bearing Plant)
3. Method of lubrication: Air-oil lubrication
4. Roll replacement: hydraulic replacement (with rail)

(4)Main drive:

1. Driving method: through back-up rolls
2. Main motor: Z500-4A  N=630KW  n=474/1200r/min  U=440V, two motors connected in parallel
3. Main reduction drive: compound gear box (with lubricant pipe)
4. Crosshead universal coupling: SWC440 (with bracket)

III. There is one Ф500×850mm hydraulic unwinder in the front of unit.

IV. Two sets of solid winder

1. Size of winding drum: Ф550×1450mm (suitable for offset eight-roll unit)   
2. Motor: Z560-2A  N=750KW  n=515/1200r/min  U=440V
3. Reduction drive: ZLY500 (with lubricant pipe)
4. Winding tension: ≤15T; Max. coil weight: 15T; Max. coil diameter: φ1800㎜
5. Gear-driven hydraulic clutch, floating hydraulic pressure device and hydraulic drum positioning
V. Hydraulic station: one 16MPa medium-pressure type and one 21MPa high-pressure type (for AGC)
Condenser, accumulator, pressure gauge, unloading device, overflow valve and segment control of system pressure

VI. Thin-oil lubrication station: one set, 125L/min

(for lubricating tooth surfaces in reduction boxes of rolling mill and winder and Herringbone gear box and bearings)

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