Heat treatment helps refine the microstructure, resulting in excellent elasticity and a high yield-strength ratio of the steel strip. It improves the overall strength and toughness, reduces surface oxidation during heating, and gives the steel strip a good blue finish.

The production line adopts a lead-free process, eliminating environmental pollution and health hazards to workers caused by heavy metal lead. Products comply with the lead restriction requirements of the EU RoHS Directive, are environmentally friendly, and can be safely exported.

It employs a DCS system with multi-CPU distributed control and centralized management, featuring dual closed-loop control of temperature and speed. The steel strip runs with uniform tension and stable operation, with even and consistent heating temperature. The system has a user-friendly HMI and full-line program control.

Production Flow

Uncoiling → Pay-off → Head and tail shearing → Head and tail welding → Looper → S1 roller drawing →

Slitting → Edge trimming → Annealing heating → Annealing cooling → Painting → Paint drying → Wax coating →

Wax film drying → S2 roller drawing → Looper → Winding tension control → Single strip shearing → Coiling →

Unloading → Bundling → Stacking → Measuring → Packaging → Warehousing

II. General Provisions

2.1 Raw Material Coil: Cold-rolled steel strip coil

Steel strip thickness: 0.9 mm;

Steel strip width: 265 mm;

Coil inner diameter: φ508

Coil outer diameter: ≤φ1200 mm

Total coil weight: ≤6 tons;

2.2 Steel Grade Composition

Low-carbon steel, medium-carbon steel or low-alloy steel

The chemical composition, tolerance requirements, edge and surface quality of the steel coil must conform to relevant national standards.

2.3 Production Technical Parameters

2.3.1 Annual output: 5000 tons

2.3.2 Number of steel strips produced: 6

2.3.3 Line speed

Maximum speed: 30 m/min

Normal production speed: 15–25 m/min

2.4 Finished Steel Strip

Steel strip thickness: 0.9 mm

Steel strip width: 31.75 mm

Coil weight: Single coil 50 kg, double coil 300 kg

Winding inner diameter: φ406 mm

Winding outer diameter: φ600–φ750 mm

Winding mode: Single spool winding or rewinding winding, optional

Product coil width: Single coil: 31.75 mm, double coil: 190 mm

Surface treatment: Blueing, painting and wax coating

Product strength: Medium to high strength

2.5 Mechanical Properties of Steel Strip

Item

Grade Strength (MPa) Elongation (%)

1 Medium strength ≥830 ≥10

2 Medium strength ≥880 ≥10

3 High strength ≥930 ≥10

4 High strength ≥980 ≥12

2.6 Dimensions and Surface Conditions

Width tolerance: ±0.04

Camber: 40 mm/2000 mm

Curve: 10 mm/2000 mm

Twist: 20 degrees/2000 mm

Surface condition: Blueed or painted and waxed with clean edges

2.7 Minimum Number of Repeated Bends

0.9 mm steel strip: 5 times

2.8 Environmental Conditions

Production line length: 50 m

Compressed air: 2.5 Nm³/h (6 kg/cm²)

Cooling water: 60 m³/h (3 kg/cm²)

Power: 800 kVA, 3-phase 5-wire, 380 V, 50 Hz

2.9 Reference Consumption Rate (per ton of output, for reference only)

Electric power: 180 kWh (blueing process)

Paint: 3 L

Water: 10 L