High Precision Reversing Cold Rolling Mill - China Suppliers and Factory for Steel Strips
The Theory of Four Roll Rolling Mill
During milling, through pressing cylinder or mechanical pressing device, the pressing force will transmit to support roll bearing stand, support roll, working roll, and finally act on the rolled piece. The workpiece height will be reduced (become thinner), length extended (become longer), then to meet the expected specifications.
Due to the impact of pressing force, rollers will become bending, the workpiece edges will become thinner. Rollers need grinding its convexity according to practical situation.
Product Introduction
It performs cold rolling on metal materials through the coordinated action of four rolls, achieving material thinning, surface quality improvement and mechanical property enhancement.
In terms of industry standards, the design, manufacture, and acceptance of four-high reversing cold rolling mills follow strict standards and regulations, covering structure, performance, safety, and environmental protection to ensure stable and reliable operation.
Operation and maintenance are also critical. Operators must undergo professional training, understand rolling parameters, and perform regular maintenance including roll replacement, lubrication system inspection, and electrical system upkeep.
Technical Parameter Table
| MILL MODEL / TECHNICAL PARAMETER | 650 | 750 | 850 |
|---|---|---|---|
| Material | Carbon steel and low alloy steel | Carbon steel and low alloy steel | Carbon steel and low alloy steel |
| Material thickness (mm) | 2.0~3.0 | 2.0~3.0 | 2.0~3.5 |
| Material width (mm) | 400~550 | 500~650 | 600~750 |
| Finish thickness (mm) | 0.5~0.15 | 0.5~0.16 | 0.5~0.18 |
| Pressing force (KN) | 5000 | 6000 | 7500 |
| Support roll Specification (mm) | Φ550×600 | ¢650×700 | ¢700×820 |
| Middle roll Specification (mm) | ———— | ———— | Φ300/Φ280×820 |
| Working roll Specification (mm) | Φ185/Φ165×650 | ¢205/Φ190×750 | Φ225/Φ205×850 |
| Driving method | Working roll driving | Working roll driving | Working roll driving |
| Main motor | DC motor | DC motor | DC motor |
| Speed reducer | Joint gear box | Joint gear box | Joint gear box |
| Uncoiler (specifications) | ¢610×650 | ¢610×750 | ¢610×850 |
| Recoiler (specifications) | ¢508×650 | ¢508×750 | ¢508×850 |
| Rolling speed (m/min) | 360 | 450 | 540 |
| Uncoiler tension (KN) | 30 | 35 | 45 |
| Recoiler tension (KN) | 10~70 | 10~80 | 10~90 |
| Pressing method | Hydraulic AGC | Hydraulic AGC | Hydraulic AGC |
| DC speed regulator | Siemens 6RA70 | Siemens 6RA70 | Siemens 6RA70 |
| Electric control | Siemens PLC | Siemens PLC | Siemens PLC |
ⓘ Remark: The model and parameters shown in this table are for reference only. The design and production can be tailor-made according to user's requirements.
Frequently Asked Questions (FAQ)
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Q What is a four-high reversing cold rolling mill and how does it work?A four-high reversing cold rolling mill consists of two work rolls and two backup rolls. The work rolls directly contact and deform the metal strip, while the backup rolls provide structural support to minimize deflection. The reversing function allows the mill to roll material in both forward and reverse directions, improving production efficiency without repositioning the workpiece.
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Q What materials can be processed by a four-high reversing cold rolling mill?The four-high reversing cold rolling mill is capable of processing a wide range of metal materials, including carbon steel, low alloy steel, stainless steel, alloy steel, copper, and aluminum. It is suitable for producing strips and plates used in automotive, electronics, construction, and general manufacturing industries.
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Q What are the available models and their key differences?Three standard models are available: Model 650, 750, and 850. The primary differences lie in material width capacity (400–550 mm, 500–650 mm, and 600–750 mm respectively), pressing force (5000 KN, 6000 KN, 7500 KN), and rolling speed (360, 450, and 540 m/min). All models can be customized to meet specific production requirements.
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Q What control systems are used in these rolling mills?The rolling mills are equipped with Siemens 6RA70 DC speed regulators and Siemens PLC electric control systems, ensuring precise and reliable automated operation. The pressing method uses Hydraulic AGC (Automatic Gauge Control) for consistent and accurate thickness control throughout the rolling process.
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Q Why do rollers need convexity grinding and how often should it be done?Due to the high pressing forces during rolling, work rolls experience elastic bending, which causes the edges of the rolled material to become thinner. Convexity grinding compensates for this deflection by giving the rolls a slightly curved profile. The frequency of grinding depends on production volume, material type, and observed product quality, and should be assessed regularly during maintenance cycles.
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Q Can the four-high reversing cold rolling mill be customized for specific production needs?Yes. All models and parameters listed in the technical table are provided for reference only. The design and manufacture of the rolling mill can be fully tailored to the customer's specific requirements, including material type, strip dimensions, rolling speed, pressing force, and automation level. Please contact us directly to discuss your custom project needs.