HR vs CR Slitting Lines: Understanding the Differences

Material Characteristics

Hot-Rolled (HR) Steel

• Thickness: Typically 1.5mm to 25mm
• Surface: Mill scale, rough texture
• Tolerance: Wider dimensional tolerance
• Applications: Structural, heavy fabrication

Cold-Rolled (CR) Steel

• Thickness: Typically 0.2mm to 3mm
• Surface: Smooth, clean finish
• Tolerance: Tight dimensional control
• Applications: Automotive, appliances, precision parts

Key Differences in Slitting Line Design

Frame and Structure

HR Slitting Lines:

• Heavy-duty fabricated frames
• Massive foundation requirements
• Robust mechanical components
• Higher safety factors

CR Slitting Lines:

• Moderate frame construction
• Standard foundations
• Precision components
• Cleanliness focus

Decoiler Specifications

| Feature | HR Line | CR Line | |---------|---------|---------| | Capacity | Up to 35 tons | Up to 15 tons | | Mandrel | Heavy-duty hydraulic | Standard hydraulic | | Drive | High-torque motor | Standard motor | | Hold-down | Essential | Optional |

Slitter Head Design

HR Slitting Lines:

• Larger knife diameters
• Heavier arbors
• More robust bearings
• Higher horsepower drives

CR Slitting Lines:

• Smaller knife diameters
• Precision arbors
• Premium bearings for accuracy
• Moderate drive power

Knife Specifications

| Aspect | HR Application | CR Application | |--------|----------------|----------------| | Material | High-chrome steel | Carbide or high-speed steel | | Diameter | 200-400mm | 100-200mm | | Clearance | Higher (8-12%) | Lower (3-6%) | | Edge prep | Chamfered | Sharp edge |

Recoiler Requirements

HR Lines:

• Heavy-duty expanding drums
• High-torque drives
• Robust tension systems
• Larger coil OD capacity

CR Lines:

• Precision drums
• Smooth tension control
• Surface protection features
• Moderate OD capacity

Operating Considerations

Line Speed

• HR Lines: 30-60 meters/minute typical
• CR Lines: 100-300 meters/minute typical

Edge Quality

• HR: Fracture-type edge acceptable
• CR: Clean shear edge required

Maintenance Focus

• HR: Wear and structural integrity
• CR: Precision and surface cleanliness

Application Examples

HR Slitting Line Applications

• Structural steel strips
• Pipe and tube skelp
• Heavy equipment parts
• Shipbuilding components

CR Slitting Line Applications

• Automotive body panels
• Appliance components
• Electrical laminations
• Precision parts

Investment Considerations

| Factor | HR Line | CR Line | |--------|---------|---------| | Initial Cost | Higher | Moderate | | Floor Space | Larger | Moderate | | Power Requirements | Higher | Moderate | | Maintenance | Heavy-duty focus | Precision focus |

Choosing the Right Line

Consider:

1. Primary material to be processed
2. Customer quality requirements
3. Production volume needs
4. Available infrastructure
5. Operator skill levels

Combination Lines

Some manufacturers offer combination HR/CR lines that can process both material types with adjustments. These offer flexibility but involve compromise in optimization.

Conclusion

Understanding the differences between HR and CR slitting lines helps in selecting the right equipment for your needs. Friend Engineering Works manufactures both types, customized to your specific requirements and material mix.