This is the grade of weather resistant cold-rolled steel plate (coil) in Japanese standards

SPA-C Brand analysis
S:   steel
P:   plate
A:   atmospheric
C:   cold rolled

SPA-C  Chemical element composition  (wt%)

C: 0~0.12
S :0~0.035
Cr:0.3~1.25
Si:0.2-0.75
Cu:0.25~0.55
B:0~0.0008
Mn:0-0.6
Ni:0~0.65
P:0.07~0.15

SPA-C mechanical properties

Bending strength (MPa): 315~999
Tensile strength (MPa):  450-999

Material characteristics and typical applications
Material characteristics: weathering steel, low-alloy high-strength steel Typical applications: structural steel, buildings and bridges, railway vehicles, automobiles,Coal and dust removal equipment for Vitality Power Plant.

Corresponding to ASTM standards   A606/A606M

Type 2: Standard Weather Resistant Type
Characteristics: The most common type of weathering steel. By adding alloying elements such as copper, chromium, nickel, and phosphorus, it provides 4-6 times higher atmospheric corrosion resistance than carbon steel. Its corrosion resistance comes from the dense and stable protective rust layer formed on the surface after exposure.
Usage: Widely used in building curtain walls, outdoor sculptures, uncoated structural components, etc., utilizing its natural rust appearance and maintenance free characteristics.
Type 4: High strength weather resistant type, characterized by ensuring resistance to atmospheric corrosion while having a higher minimum yield strength. Its alloy system is similar to Type 2, but higher strength is achieved through microalloying or process control.
Purpose: Suitable for structural applications that require high strength and corrosion resistance, such as bridge components, heavy transportation equipment, high load outdoor frames, etc.
Type 5: Excellent formability and weather resistance, features: specially designed for parts that require complex cold forming (such as deep drawing and stretching). It optimizes its chemical composition and process while maintaining sufficient weather resistance, with excellent ductility and formability.
Usage: Used for manufacturing weather resistant steel parts with complex shapes, such as electrical cabinet shells, ventilation ducts, and stamping parts for certain automobiles or machinery.