Hot Rolled Steel Coil Q195 Q215 St37 S235jr S355jr Ss400 Steel Coil Top Quality Carbon Steel Coil

The production process of hot-rolled steel coil is a key link in steel manufacturing. It mainly forms the steel billet into the required plate shape through high-temperature rolling. The following are its core steps:

Raw Material Preparation
Continuously cast or bloomed slabs are used as raw material, typically with a thickness of 150-300 mm.
The slab surface is cleaned (e.g., flame cleaning or mechanical grinding) to remove scale and defects to ensure rolling quality.
Heating
The slab is fed into a walking beam furnace and heated to 1100-1300°C to reach the austenitizing temperature and improve plasticity.
Heating time and temperature uniformity are controlled to avoid overheating or underheating.
Roughing
The slab is reduced to a thickness of 30-50 mm in a reversing roughing mill (e.g., a two- or four-high mill) to form an intermediate bar.
After each rolling pass, high-pressure water descaling may be performed to remove the surface oxide layer.
Finishing
The intermediate bar enters the finishing mill (usually consisting of six or seven four- or six-high mills) where it is gradually reduced to the target thickness (e.g., 1.2-25 mm) through continuous rolling. Automatic Gauge Control (AGC) and a shape control system are used to ensure dimensional accuracy and flatness.
During the rolling process, the rolls require cooling and lubrication to prevent thermal deformation and wear.
Cooling
A laminar cooling system is used to rapidly cool the steel strip from the final rolling temperature (approximately 800°C) to room temperature by controlling the water volume and cooling rate (e.g., 30-50°C/second).
The cooling process directly affects the microstructure (e.g., the ratio of ferrite to pearlite) and mechanical properties of the steel coil.
Coiling
The steel strip is coiled into a coil using pinch rolls and a coiler. The tension is controlled at 100-500 N/mm² to ensure a tight coil shape and no loose coils.
The coiling temperature is typically controlled between 550-700°C to optimize performance.
Post-Processing
Surface treatment: Pickling to remove oxide scale, or coatings such as galvanizing or aluminizing.
Annealing: Improving material ductility (e.g., recrystallization annealing before cold rolling). Flattening: Through rolling with a low reduction ratio, we eliminate yield flats and improve surface finish.
Quality Inspection and Packaging: We inspect dimensions, mechanical properties, and surface quality, and then coil, bundle, and label the products according to customer specifications.