4-high 1150mm cold rolling mill

1. Advantages Summary Table

2. Spare Parts Advantages Detailed Table

3. Detailed Advantages in Bullet Points (English)

3.1 Reliable Equipment Source from Well-Known Manufacturer

• Value: Manufacturer is Wuxi Jingcheng

• Detailed advantages:

  • Wuxi Jingcheng is a well-known domestic manufacturer of metallurgical equipment with extensive experience in 4-Hi cold rolling mills and reversible mills.

  • Their equipment is known for reasonable structure, stable operation, and easy maintenance, with many successful installations in small-to-medium cold rolling enterprises in China.

  • Choosing this brand provides users with mature technology and ample after-sales service resources.

3.2 Excellent Current Condition – Not Long-Idle

• Value: Current status is In operation

• Detailed advantages:

  • Unlike long-idle used equipment, this mill is still in normal production, indicating all systems are functional with no major faults.

  • “In operation” status means:

    • Electrical control system is fully functional

    • Mechanical drive system has no abnormal wear

    • Hydraulic and lubrication systems are in good condition

    • Condition of rolls, bearings, and other key components can be verified

  • Buyer can conduct on-site inspection before shutdown to observe actual operation, reducing procurement risk.

3.3 Well-Balanced Motor Power Configuration

• Detailed advantages:

  • Total installed power of 2900 kW is above average for this specification of 4-Hi mill.

  • Wide speed ranges (main: 350–1000 rpm, recoiler/uncoiler: 400–1200 rpm) allow adaptation to different pass speeds and tension requirements.

  • Recoiler motor power (900 kW) exceeds uncoiler motor power (750 kW), consistent with the physical requirement for higher tension on the recoiling side.

3.4 Simple and Reliable 4-Hi Structure

• Value: Number of mill rolls = 4

• Detailed advantages:

  • 4-Hi mill consists of two work rolls + two backup rolls – a simple, clear structure.

  • Compared to 20-Hi mills, the 4-Hi mill offers:

    • Lower maintenance cost: Simpler roll system, shorter roll change time, fewer spare part types.

    • Lower operator skill requirements: Shorter training period.

    • Lower capital investment: Significantly lower equipment price than 20-Hi mills.

    • Wide application range: Suitable for cold rolling of mild and medium-carbon steel in the 0.2–4.0 mm thickness range.

3.5 Wide Rolling Width for Strong Adaptability

• Value: Max designed width 1050 mm, actual max width 1050 mm

• Detailed advantages:

  • 1050 mm width covers the vast majority of medium-width cold-rolled strip applications, such as:

    • Home appliance panels (refrigerators, washing machines)

    • Construction thin sheets (pre-painted substrate)

    • Hardware stamping parts

    • Automotive interior structural parts

  • Designed and actual values match, confirming stable performance at this width with no specification inflation.

3.6 Wide Input Thickness Range for Strong Material Adaptability

• Value: Actual max input thickness 4.0 mm

• Detailed advantages:

  • 4.0 mm input thickness means the mill can directly roll hot-rolled coils or pickled coils without an additional roughing mill.

  • Common hot-rolled input thicknesses range from 2.5 to 4.0 mm, which this mill fully covers.

  • Compared to mills limited to 2.5 mm input, this mill offers greater upstream material flexibility and wider sourcing options.

3.7 High Finished Thickness Precision

• Detailed advantages:

  • Design minimum 0.02 mm: Demonstrates the mill’s mechanical precision and control system have the potential for ultra-thin rolling.

  • Actual minimum 0.2 mm: This is the stable production thickness achieved by the original owner, sufficient for the vast majority of cold-rolled sheet applications (home appliances, hardware, packaging, etc.).

  • The combination of 0.2 mm thickness and 1050 mm width represents the typical advantageous product range for this 4-Hi mill specification.

  • If thinner finished products (e.g., 0.1 mm) are required, they can be achieved through process parameter adjustments or control system upgrades.

3.8 Moderate Rolling Speed Balancing Efficiency and Quality

• Value: Rolling speed 260 m/min

• Detailed advantages:

  • 260 m/min is in the medium-speed cold rolling range. Compared to high-speed mills (600–800 m/min), it offers:

    • Easier shape control: Lower speed results in more uniform rolling force distribution, reducing shape defects (edge wave, center wave).

    • More stable thickness tolerances: AGC system responds more quickly at lower speeds, improving thickness control precision.

    • Less equipment wear: Bearings, rolls, gearboxes, and other components have longer service life at lower speeds.

    • Higher operational safety: Threading, coil unloading, and other operations are safer at lower speeds.

  • For 0.2–2.0 mm thick cold-rolled strips, 260 m/min is fully sufficient and delivers reasonable daily output.

3.9 High Rolling Force for Strong Deformation Capability

• Value: Maximum rolling force 1500 tons

• Detailed advantages:

  • 1500 tons (approx. 15,000 kN) is a larger-than-average configuration for a 1150mm 4-Hi mill.

  • Benefits of high rolling force:

    • Can reduce 4.0 mm hot-rolled coils to 0.2 mm in 3–5 passes.

    • Can roll higher-strength materials (e.g., Q345, 510L low-alloy high-strength steel).

    • Allows higher reduction per pass, reducing total passes and improving production efficiency.

  • Combined with large-diameter backup rolls (Φ1060 mm), the mill has high overall stiffness with uniform rolling force transmission.

3.10 Well-Designed Roll Specifications

• Detailed advantages:

  • Working roll Φ172 mm:

    • Compared to small-diameter work rolls (e.g., Φ60 mm), Φ172 mm work rolls offer better bending stiffness, suitable for medium-thickness strip rolling.

    • Larger work roll diameter means lower roll change frequency and lower roll consumption costs.

  • Backup roll Φ1060 mm:

    • The large diameter (1060 mm) provides extremely high rigidity, effectively supporting the work rolls and reducing their elastic deflection.

    • Lower contact stress on large-diameter backup rolls results in longer roll surface life.

3.11 AGC Automatic Gauge Control for High Precision

• Value: Screw-down type is AGC (Automatic Gauge Control)

• Detailed advantages:

  • AGC is the core technology of modern cold rolling mills, using real-time entry and exit thickness detection to automatically adjust rolling force or roll gap, ensuring finished thickness tolerances.

  • When combined with thickness gauges (X-ray or isotope), thickness tolerances can be controlled within ±0.005 mm.

  • The presence of AGC means this mill has high-precision rolling capability, meeting strict thickness requirements for home appliances, automotive, electronics, and other industries.

3.12 Reasonable Mill Housing Window Size for Good Rigidity

• Value: Mill housing window size 530 × 600 mm

• Detailed advantages:

  • The mill housing is the most critical load-bearing component. Its window size determines overall mill rigidity.

  • The 530 mm × 600 mm window size is compact and reasonable for a 1150mm 4-Hi mill, ensuring:

    • Sufficient space for roll chocks

    • Good rigidity, reducing mill弹跳 (spring) during rolling

    • Convenient roll change operations

3.13 High-Quality Gearbox Configuration for Reliable Transmission

• Detailed advantages:

  • Tailong is a well-known brand in the Chinese gearbox industry, widely used in metallurgy, mining, and building materials.

  • Advantages of herringbone gearboxes compared to spur gearboxes:

    • Smoother engagement, lower noise

    • Higher load capacity

    • No axial thrust, longer bearing life

3.14 Extremely Rich Spare Parts Inventory Significantly Reduces Operating Costs

• Detailed advantages:

  • The spare parts included with this equipment is exceptionally rich, rarely seen in used equipment transactions:

• Operating cost advantages:

  • 93 work rolls mean the buyer will not need to purchase new work rolls for at least 5 years, saving hundreds of thousands of RMB.

  • 2 pairs of new backup rolls can be used immediately; 2 pairs of used backup rolls can serve as backups or be reground for future use.

  • High-value items like chocks and bearings are included, reducing downtime due to spare parts shortages.