High Precision HI Reversing Cold Rolling Mill | China Suppliers & Factory for Steel Strips
The Theory of Four Roll Rolling Mill
Four roll rolling mill system is composed of two pcs of support rolls and two pcs working rolls. During mill, 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 rolled piece. The work piece 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
The four-high reversing cold rolling mill is an important metal pressure processing equipment, widely used in metallurgy, mechanical manufacturing, non-ferrous metal processing and other industries. It performs cold rolling on metal materials through the coordinated action of four rolls, achieving material thinning, surface quality improvement and mechanical property enhancement.
⚙️
Technical Design: The four-high reversing cold rolling mill consists of work rolls and backup rolls. The work rolls directly contact the rolled piece to perform rolling deformation, while the backup rolls support the work rolls to reduce their deflection and ensure the stability and accuracy of the rolling process. The reversible design enables the rolling mill to roll in both forward and reverse directions without frequent adjustments, significantly improving production efficiency.
🏭
Application Scenarios: Mainly used for rolling various metal strips and plates, such as stainless steel, carbon steel, alloy steel, copper, and aluminum. For example, in automotive manufacturing, rolled plates are used for body panels requiring high strength, good formability, and corrosion resistance; in the electronic and electrical industry, rolled strips are used for precision components requiring high surface finish and dimensional accuracy.
📋
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, ensuring stable and reliable operation and the safety of operators.
🔧
Operation & Maintenance: Operators need professional training to be familiar with the structure, performance, and operating procedures. Regular maintenance — including roll replacement, lubrication system inspection, and electrical system maintenance — is key to ensuring long-term stable operation of the rolling mill.
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)
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 working rolls and two backup rolls. The working rolls directly contact and deform the metal strip, while the backup rolls support the working rolls to prevent deflection. A pressing cylinder or mechanical pressing device applies force through the backup rolls onto the working rolls, reducing the material's thickness and extending its length. The reversing feature allows the mill to roll in both forward and reverse directions, increasing efficiency without repositioning the workpiece.
Q
What materials can be processed by the four-high reversing cold rolling mill?
The four-high reversing cold rolling mill is suitable for processing a wide range of metal strips and plates, including carbon steel, low alloy steel, stainless steel, alloy steel, copper, and aluminum. It can meet diverse industry requirements for thickness, width, surface quality, and mechanical properties.
Q
What are the available mill models and what are their key differences?
Three standard models are available: 650, 750, and 850. The main differences lie in their rolling capacity — including material width range (400–550mm, 500–650mm, and 600–750mm respectively), pressing force (5,000 KN, 6,000 KN, and 7,500 KN), and rolling speed (360, 450, and 540 m/min). All models can be customized to meet specific production requirements.
Q
What control systems are used in these rolling mills?
All three models are equipped with Siemens 6RA70 DC speed regulators and Siemens PLC electric control systems. The pressing method uses Hydraulic AGC (Automatic Gauge Control), ensuring precise and consistent thickness control throughout the rolling process.
Q
Why do rollers need convexity grinding in a four-roll rolling mill?
During rolling, the high pressing forces cause the rollers to bend slightly, which can result in the edges of the workpiece becoming thinner than the center. To compensate for this deflection and ensure uniform thickness across the entire width of the rolled material, the rollers are ground with a specific convexity (crown) profile based on practical rolling conditions.
Q
Can the four-high reversing cold rolling mill be customized for specific production needs?
Yes. The standard models and parameters listed in the technical table are provided for reference only. The rolling mill can be fully tailor-made in terms of design and production configuration to meet the specific requirements of individual users, including adjustments to roll dimensions, rolling speed, pressing force, material compatibility, and automation level.