JIS G3114 — Weather-resistant hot-rolled steel for welded structures
Grades
SMA400AW, SMA400BW, SMA400CW, SMA490AW, SMA490BW, SMA490CW, SMA570W, SMA570P
Chemical composition and mechanical properties
| Grade | Chemical composition | Mechanical properties |
|---|---|---|
| SMA400AW | C≤0.18, Mn≤1.40, P≤0.035, S≤0.035, Si 0.15-0.65, Cr 0.30-0.55, Cu 0.25-0.55, Ni≤0.30 | Rm ≥400 MPa, Rp0.2 ≥245 MPa, A≥22%, weather resistance |
| SMA400BW | C≤0.18, Mn≤1.40, P≤0.035, S≤0.035, Si 0.15-0.65, Cr 0.30-0.55, Cu 0.25-0.55, Ni≤0.30 | Rm ≥400 MPa, Rp0.2 ≥245 MPa, A≥22%, 0℃ Akv≥27J, weather resistance |
| SMA400CW | C≤0.18, Mn≤1.40, P≤0.035, S≤0.035, Si 0.15-0.65, Cr 0.30-0.55, Cu 0.25-0.55, Ni≤0.30 | Rm ≥400 MPa, Rp0.2 ≥245 MPa, A≥22%, 0℃ Akv≥47J, weather resistance |
Application scope
JIS G3114 specifies atmospheric corrosion resistant hot-rolled steel for welded structures such as bridges, towers, and buildings, primarily using the SMA series grades. It is suitable for components requiring both welded and bolted connections. The standard classifies steels according to strength and impact absorption energy, achieving exposed weather resistance through the formation of a protective rust layer using alloys such as copper, chromium, and nickel. The products are delivered hot-rolled, exhibiting good weldability and toughness, suitable for long-term exposed, maintenance-free steel structures.
Typical applications
Primarily used in bridge steel structures, power transmission and communication towers, and exposed steel structures of buildings, such as main beams, trusses, tower bodies, and facade components. Also used in railway vehicle bodies and various outdoor facilities. With excellent weldability and resistance to atmospheric corrosion, it is suitable for long-term exposed service in large load-bearing structures where welding is the primary method. It can also be used in situations where maintenance is inconvenient, such as platform canopies, trestle bridges, and landscaping structures.
