For the structure part with high requirement of mechanical Property and welding performance in building, bridge, ship, automobile, pertroleum container and construction vehicles.

Grades	Nominal thickness (mm)
Welding structural steel
SM400A, SM400, BSM490A, SM570	≤16.0
SM400, CSM490B, SM490C SM490YA, SM490YB, SM520B,SM520C	≤12.7
BSM590	≤16.0
StE255,StE285	≤10.0
StE355	≤16.0