6-stand 650mm cold tandem rolling mill

1. Equipment Overview
This equipment is a 6-stand 650mm cold tandem rolling mill, a core heavy-duty asset in the metal cold rolling sector. Unlike single-stand reversible mills, a 6-stand tandem mill enables continuous multi-pass rolling—the strip passes through six stands sequentially, undergoing progressive thickness reduction in a single pass from input coil to finished product. This design offers exceptional production efficiency, high yield, and superior shape control. The mill is suitable for continuous cold rolling of low-carbon steel coils such as Q195, Q215, and Q235.

2. Mill Stands and Rolling Force
The mill features 6 stands, each equipped with independent roll systems and screw-down mechanisms for continuous multi-pass thickness reduction. The maximum rolling force reaches 6000 kN (equivalent to 600 metric tons of force), reflecting the equipment's structural strength and rolling capability when handling thick input materials and large reductions. A rolling force of 6000kN is in the mid-to-upper range for 650mm-class tandem mills, more than sufficient for the cumulative large reduction from 3.0mm to 0.3mm.

3. Main Motor System — Total Power 3360kW
Each of the 6 stands is equipped with an independent main drive motor, with the following power distribution:

The total combined power of all 6 main motors is 3360 kW. F1 and F6, as entry and exit stands, handle greater rolling loads and tension control demands, hence their higher power ratings (both 630kW); intermediate stands are configured with 500–600kW, forming a rational power gradient distribution. Each motor is rated at 500/1200 r/min with a voltage of 440V, using DC drive technology, offering high starting torque, wide speed range, and strong overload capacity—advantages particularly suited to the complex speed matching and tension coordination requirements among stands during tandem rolling.

4. Uncoiler and Coiler
The uncoiler and coiler are essential auxiliary equipment for the tandem line, responsible for pay-off of the mother coil and recoiling of the finished product, respectively. The coiler motor is model Z4-315-42, with a power rating of 315kW and speed of 750/1600 r/min. The 315kW high-power coiler ensures tight recoiling of finished coils under high-speed rolling and high-tension conditions, preventing interlayer slippage and coil loosening. The coiling method adopts a collapsible drum, which retracts during coil unloading for easy removal of finished coils, significantly improving unloading efficiency and operational safety.

5. Roll Systems

• Working Roller: Specification Ø185～175×680mm, meaning the roll diameter is replaced when worn from 185mm (new) down to 175mm, with a barrel length of 680mm. Working rollers directly contact the strip and are the direct execution elements of rolling deformation; their surface hardness and roughness directly affect the surface quality of finished strips.

• Backup Roller: Specification Ø580×650mm, with a diameter significantly larger than the working rollers, providing rigid support to the working rollers, reducing bending deflection under immense rolling forces, and ensuring flatness accuracy and thickness consistency.

6. Screw-Down System — AGC Hydraulic Screw-Down
This mill employs an AGC (Automatic Gauge Control) hydraulic screw-down system, rather than traditional electric screw-down. AGC hydraulic screw-down offers significant advantages including fast response, high control precision, and strong dynamic adjustment capability, enabling real-time detection and adjustment of roll gaps during high-speed continuous rolling, ensuring that the thickness tolerance of finished strips is controlled within extremely tight limits across the entire length. AGC is a core configuration of modern cold tandem mills, directly determining product thickness accuracy and quality stability.

7. Designed Rolling Parameters

• Designed rolling materials: Q195, Q215, Q235 low-carbon steels—the most widely used carbon structural steel series, covering construction, structural, stamping, tube-making, and various other applications.

• Maximum designed input thickness (entry): 3.0 mm.

• Minimum designed finished thickness (exit): 0.3 mm. Rolling from 3.0mm down to 0.3mm represents a total reduction of 90%, fully demonstrating the powerful cumulative deformation capability of a 6-stand tandem mill.

• Maximum designed rolling width: 550 mm, with working roll barrel length of 680mm, leaving sufficient margin.

• Designed rolling speed: 240 m/min, a conventional speed configuration for 650mm-class tandem mills, balancing production efficiency and process stability.

8. Actual Production Parameters from the Original User
According to the technical data sheet records, the original user's actual production parameters are highly consistent with the design parameters:

• Actual maximum rolled width: 550 mm

• Actual maximum input thickness: 3.0 mm

• Actual minimum finished thickness: 0.3 mm

This confirms that the equipment has fully realized its design capability in actual production, meeting all design targets, with equipment performance fully verified—there is no issue of"design overstatement, actual underperformance."For second-hand buyers, this is an important confidence indicator—the equipment has proven its capability under real working conditions.

9. Electrical Control System
The mill's electrical control system is supplied by Eurotherm, a globally renowned provider of industrial automation and process control solutions with deep expertise in metallurgical rolling drive control. Eurotherm's DC drives and automation control systems are known for their stability, reliability, high precision, and strong anti-interference capability—a"bonus point"for second-hand equipment, indicating that the electrical control system's technical maturity and maintainability are both at a high level. According to the technical data sheet, the electrical control system is in good condition (Yes) with no missing components.

10. Equipment Status and Ancillary Services
The technical data sheet clearly records:

• Electrical control system intact, no missing components;

• Disassembly services available (Yes);

• Equipment refurbishment and maintenance services available (Yes);

• Spare parts list available upon request (Yes, details to be confirmed).

This information indicates that the equipment is not only functionally complete but that the seller possesses full technical service capabilities, able to provide buyers with end-to-end support from dismantling and refurbishment to installation and commissioning, significantly reducing procurement risks associated with large second-hand metallurgical equipment.

11. Equipment Dimensions and Weight Estimate (Based on Industry Experience)
Although the technical data sheet does not separately list dimensions and total weight for each component, based on industry standard design references for 650mm-class 6-stand tandem mills, a reference range can be provided:

• Total equipment weight: Typically in the 350–500 ton range, depending on base thickness, housing dimensions, motor specifications, and auxiliary equipment configuration;

• Single stand housing weight: Approximately 25–35 tons per housing, totaling 150–210 tons for 6 stands;

• Total main motor weight: Approximately 30–50 tons for 6 DC motors combined;

• Coiler + Uncoiler: Approximately 20–30 tons;

• Rolls (including working and backup rolls, with spares): Approximately 20–30 tons;

• Structural components (bases, rails, platforms, etc.): Approximately 80–120 tons.

The above are estimates; actual weights should be based on the physical equipment or detailed lists provided by the seller. It is recommended to request a detailed equipment weight breakdown and component list prior to procurement to facilitate assessment of foundation requirements, lifting, and transportation planning.

12. Application Scope and Downstream Uses
The 0.3mm thin strip produced by this 6-stand tandem mill can be widely used in:

• Cold-rolled strip: As feedstock for subsequent galvanizing, prepainting, and annealing processes;

• Tube manufacturing: Blank material for high-frequency welded pipes and precision tubes;

• Stamping parts: Stamping raw materials for automotive components, home appliance panels, and hardware parts;

• Packaging materials: Thin-gauge packaging steel strips;

• Electrical products: Motor housings, transformer strip, etc.

13. Summary of Comprehensive Advantages

• 6-stand tandem rolling: Completes 90% total reduction (3.0mm→0.3mm) in a single pass, with production efficiency far higher than single-stand reversible mills;

• Total power 3360kW: Ample power with rational power distribution across stands;

• AGC hydraulic screw-down: High thickness control accuracy and excellent dimensional consistency;

• 6000kN maximum rolling force: Sufficient capability for materials with high deformation resistance;

• Eurotherm electrical control: Reliable brand, intact condition, mature technology;

• Actual production matches design: Equipment performance fully verified;

• Complete support services: Full-chain support from dismantling, refurbishment, spares, to commissioning.

14. Conclusion
In summary, this 6-stand 650mm cold tandem rolling mill is a powerful, fully equipped, performance-verified, and brand-reliable second-hand cold rolling core asset. Its 6-stand continuous rolling capability enables the large reduction from 3.0mm to 0.3mm to be completed in a single pass, delivering exceptional production efficiency. For steel processing enterprises, tube manufacturers, or stamping raw material suppliers looking to establish or expand cold-rolled strip production capacity, this represents a strategically valuable heavy equipment choice.