Weathering Steel Plate

A588 Gr.B Weathering Steel Plate

ASTM A588 Gr.B atmospheric corrosion resistant steel plate forming a protective patina for bridges, towers and outdoor structures.

A588 Gr.B is the classic American weathering structural steel: with time and weather it grows a dense, adhering oxide patina that slows further corrosion to a crawl - which is why bridges and towers wear it bare, no paint. Yield strength is 345 MPa class, so it is a structural grade that also happens to protect itself.

Grades and Standards

  • ASTM A588/A588M Grade A, B, K
  • Minimum yield 345 MPa (50 ksi) up to 100 mm
  • Charpy impact testing available per your bridge or structure spec

Sizes and Supply

  • Thickness 6-100 mm, widths 2000-2500 mm, lengths to 12000 mm
  • Cut-to-size with drilling for bolted field connections

Quality Documents

EN 10204 3.1 MTC with heat-by-heat chemistry - the patina forms correctly only with the right Cu, Cr, Ni balance, and the certificate proves yours has it.

Where This Plate Goes

  • Bridges and highway structures
  • Transmission and telecom towers
  • Building facades and architectural screens
  • Sculpture and landscape structures

Questions Buyers Ask

Q: Bare or painted? A: Bare works when the structure gets regular wet-dry cycles and is away from heavy chlorides (coastal salt, de-icing salt splash zones). Those conditions need paint or a different grade - we will tell you honestly.
Q: How do I get an even patina? A: Time, cycles and clean drainage. Some owners pre-weather; we can advise on the process.
Send the structure location and exposure with sizes - patina suitability is the first check we run.