1. Hot-Rolled (HR)
This is the most common and standard delivery form for Corten A plates, sheets, and structural sections.
Process: The steel is shaped and formed at high temperatures (above its recrystallization temperature).
Characteristics:
Surface has a blue-grey oxide layer (mill scale).
Retains a slightly scaly, rough surface finish.
Dimensional tolerances are wider than cold-rolled products.
Typical Applications: Structural sections (I-beams, channels, angles), thick plates for construction, shipping containers, railroad cars, and large sculptures where surface finish is not the primary concern.
2. Normalized (N)
This is a very common and important condition, especially for thicker plates.
Process: After hot-rolling, the steel is reheated to a specific high temperature and then allowed to cool in still air. This refines the grain structure, making it more uniform.
Characteristics:
Improved toughness and impact strength.
More consistent mechanical properties throughout the thickness.
Enhanced weldability by reducing internal stresses and softening the steel.
Typical Applications: Critical structural applications like bridges, high-rise buildings, and offshore platforms where welding and low-temperature performance are important.
3. Cold-Rolled (CR) / Cold-Drawn (CD)
Less common for Corten A's traditional uses, but available.
Process: Hot-rolled pickled coil is further processed at room temperature to achieve the desired thickness and surface finish.
Characteristics:
Smoother, more precise surface finish.
Tighter dimensional tolerances.
Higher strength and hardness due to work hardening (but reduced ductility).
Typical Applications: Primarily used for thinner sheets and strips where formability and a better surface appearance are required before the patina forms.
1. Hot-Rolled (HR)
This is the most common and standard delivery form for Corten A plates, sheets, and structural sections.
Process: The steel is shaped and formed at high temperatures (above its recrystallization temperature).
Characteristics:
Surface has a blue-grey oxide layer (mill scale).
Retains a slightly scaly, rough surface finish.
Dimensional tolerances are wider than cold-rolled products.
Typical Applications: Structural sections (I-beams, channels, angles), thick plates for construction, shipping containers, railroad cars, and large sculptures where surface finish is not the primary concern.
2. Normalized (N)
This is a very common and important condition, especially for thicker plates.
Process: After hot-rolling, the steel is reheated to a specific high temperature and then allowed to cool in still air. This refines the grain structure, making it more uniform.
Characteristics:
Improved toughness and impact strength.
More consistent mechanical properties throughout the thickness.
Enhanced weldability by reducing internal stresses and softening the steel.
Typical Applications: Critical structural applications like bridges, high-rise buildings, and offshore platforms where welding and low-temperature performance are important.
3. Cold-Rolled (CR) / Cold-Drawn (CD)
Less common for Corten A's traditional uses, but available.
Process: Hot-rolled pickled coil is further processed at room temperature to achieve the desired thickness and surface finish.
Characteristics:
Smoother, more precise surface finish.
Tighter dimensional tolerances.
Higher strength and hardness due to work hardening (but reduced ductility).
Typical Applications: Primarily used for thinner sheets and strips where formability and a better surface appearance are required before the patina forms.
