· Production Process
Hot-Rolled Steel: Softened at temperatures above 1000°C, then rough-rolled and finished-rolled.
Cold-Rolled Steel: Hot-rolled coils are pickled and then processed through multiple cold-rolling passes at room temperature.
· Performance Comparison
Strength: Cold-rolled steel has higher strength but lower toughness; hot-rolled steel offers better ductility and impact resistance.
Surface: Cold-rolled steel has a smooth, mirror-like finish; hot-rolled steel has an oxide layer giving it a sandpaper-like texture.
Thickness: Cold-rolled steel mainly covers thin gauges (0.2–2.0 mm), while hot-rolled steel is used for thicker sections (above 4.0 mm).
· Application Scenarios
Automotive Manufacturing: DC03 cold-rolled steel achieves 0.1 mm-level stamping precision. Jin Steel Holdings’ cold-rolled steel replaces imported materials, improving utilization by 25%.
Construction Engineering: Q345B hot-rolled steel for stadiums has stood the test of 15 years without tearing. X80 hot-rolled pipes for cross-sea bridges withstand pressures at 50 meters below sea level.
Home Appliances: Refrigerator outer panels use 0.6 mm cold-rolled steel passing 1,000-hour salt spray tests, while internal brackets use 4.0 mm hot-rolled steel supporting 300 kg.
· Cost Analysis
The price difference mainly arises from additional processes such as pickling and annealing.