850mm tension leveler

1. Equipment Overview
This equipment is an 850mm tension leveler (also known as a tension leveller or stretch-bend leveler), manufactured by Wuxi Wanyu. Tension leveling is a core process in the finishing of cold-rolled strip steel. Its working principle involves applying tension to the strip to cause tensile deformation while simultaneously passing the strip over small-diameter bending rolls for repeated bending. Through the combined effect of tension and bending, internal residual stresses are eliminated and strip flatness is improved. Compared to conventional levelers, tension levelers have a significantly superior effect on shape defects such as"waves,""buckles,"and"edge waves,"making them particularly suitable for high-quality cold-rolled strip products with stringent flatness requirements.

2. Equipment Specifications

• Thickness range: 0.2-1.2mm, covering the typical thickness range for thin-gauge cold-rolled strip;

• Width range: 485-750mm, highly compatible with the finished widths of the previously described 5-stand 600mm tandem line (max width 520mm) and 6-stand 650mm tandem line (max width 550mm)—this tension leveler is perfectly positioned to undertake downstream finishing requirements from both tandem lines.

3. Uncoiler System
The uncoiler is equipped with a Z4-250-21 DC motor with a power rating of 81kW and a speed range of 680/2250 r/min, paired with a gearbox of Ø515×850mm and a reduction ratio of 15.75. The uncoiler is responsible for smoothly paying off the cold-rolled mother coil, providing stable strip input for the subsequent tension leveling process.

4. S-Roll Drive System — Core Tension Control Unit
The core of the tension leveler lies in its 4 sets of S-roll drive systems, which achieve strip leveling through the synergistic action of multiple bending passes and applied tension. Each of the 4 S-roll sets is equipped with independent motor drives, configured as follows:

The 4 S-roll sets comprise a total of 8 motors with a combined power of 526kW (22+37+132+75+75+132+31+22 = 526kW). Different S-roll sets generate strip tension through speed differentials, achieving the tension leveling effect. The 2# and 3# S-roll sets, as the core tension units, are equipped with the largest 132kW motors, ensuring stable operation under high-tension conditions.

5. Recoiler System
The recoiler is equipped with a Z4-280-32 DC motor with a power rating of 144kW and a speed range of 675/1700 r/min, paired with a gearbox of Ø508×850mm and a reduction ratio of 15.75. The recoiler is responsible for rewinding the leveled finished strip into neat coils. The 144kW high-power configuration ensures stable tension retention under leveling tension and high-speed recoiling conditions, preventing coil loosening and interlayer slippage.

6. All-DC Drive System
The entire tension leveler—uncoiler, 4 sets of S-rolls (8 motors), and recoiler—is powered entirely by DC motors. DC drives offer special advantages in tension leveling applications:

• High tension control precision: DC motors enable precise torque control, ensuring stable and consistent tension during the leveling process;

• Excellent speed coordination: Multiple S-roll sets require precise speed matching to generate controlled tension differentials, and DC drive systems excel in speed closed-loop control;

• Fast dynamic response: Rapid adjustment to tension fluctuations and speed changes ensures stable leveling quality;

• Strong overload capacity: Short-term overload capability accommodates the passage of strip splices, welds, and other special conditions.

7. Total Drive Power Summary
Summarizing all drive motors:

The total drive power of the entire line reaches 751kW, far exceeding the conventional configuration level of comparable narrow-width tension levelers, indicating that this equipment possesses extremely strong tension leveling capability, capable of handling the demanding process requirements of high-strength steels and difficult-to-level materials.

8. Working Principle and Process Value
The tension leveler applies tensile stress to the strip through speed differentials between S-roll sets, causing a small amount of plastic elongation (typically 0.5-2%) of the strip. In this tensioned state, the strip passes over small-diameter bending rolls to undergo repeated bending deformation, redistributing and eliminating internal residual stresses. Compared to conventional levelers that rely solely on bending, the core advantages of tension leveling are:

• Elimination of residual stress: Not merely improving apparent flatness, but fundamentally eliminating uneven internal stress distribution;

• Cure for shape defects: Significantly improves"center wave,""edge wave,""buckle,""curl,"and other shape issues;

• Improved downstream processing performance: Leveled strips exhibit more stable behavior in subsequent stamping, bending, tube-making, and other processes, with higher yields.

9. Integration with Upstream and Downstream Processes
This 850mm tension leveler occupies a critical position in the cold-rolled strip production process—after the tandem mill and before final product delivery:

• Upstream: Can accept finished coils from the 5-stand 600mm tandem line or the 6-stand 650mm tandem line (0.3mm thickness, 485-520mm width), further improving shape and eliminating stress through tension leveling;

• Downstream: Leveled finished strip can be delivered directly to customers or proceed to subsequent processes such as galvanizing, prepainting, annealing, or slitting.

10. Applicable Materials
This equipment is suitable for:

• Low-carbon steel: Q195, Q235, and other cold-rolled strip steels;

• High-strength steel: High-strength steel grades requiring greater leveling tension;

• Stainless steel: Stainless steel strips with extremely high flatness requirements and greater leveling difficulty;

• Aluminum strip, copper strip, and other non-ferrous metal strips (tension settings to be adjusted according to specific process parameters).

11. Equipment Condition and Second-Hand Value Analysis
Although the technical data sheet does not separately list the manufacturing year and shutdown date, as a Wuxi Wanyu brand equipment, its manufacturing quality and design standards are fully guaranteed. Tension levelers, as high-value-added finishing equipment, represent a scarce category in the second-hand market—they have high technological content, stable market demand, and long equipment service life. This equipment features all-DC drive, ample power, and complete S-roll set configuration, making it a high-reliability finishing asset that can be directly integrated into cold rolling production lines.

12. Equipment Dimensions and Weight Estimate (Based on Industry Experience)
Based on industry standard design references for 850mm-class tension levelers, a reference range can be provided:

• Total equipment weight: Typically in the 60-120 ton range, depending on base dimensions, S-roll set weight, motor specifications, and auxiliary equipment configuration;

• Single S-roll set weight: Each set contains multiple bending rolls and tension rolls, approximately 8-15 tons, with 4 sets totaling 32-60 tons;

• Uncoiler + Recoiler: Approximately 10-20 tons;

• Total motor weight: 10 DC motors combined approximately 10-20 tons;

• Structural components (bases, rails, platforms, etc.): Approximately 10-30 tons.

The above are estimates; actual weights should be based on the physical equipment.

13. Conclusion
In summary, this 850mm tension leveler is an ample-powered (751kW total line power), fully configured (4 S-roll sets + 10 DC motors), specification-matched (0.2-1.2mm × 485-750mm) second-hand finishing core asset. Its powerful tension leveling capability effectively eliminates residual stress and shape defects in cold-rolled strips, significantly enhancing product quality and added value. For steel processing enterprises that already have or plan to configure cold tandem rolling lines, this equipment is an indispensable downstream finishing supporting asset, enabling significant improvements in product quality, customer satisfaction, and market competitiveness.