The carbon content of SM400 steel plate varies with the thickness

Introduction to SM400 steel plate grade
SM400 steel plate is a Japanese steel grade. It is a carbon structural steel plate for engineering structure and also used for welding engineering. SM400 steel grades cover SM400A and SM400B.

The chemical composition of SM400 steel plate is different under different thicknesses:
Chemical composition (mass fraction)/% when thickness ≤ 20 mm
C≤0.23； Si~； Mn≤2.5*C； P≤0.035； S≤0.035
When the thickness is between 50-200 mm, the chemical composition (mass fraction)/%
C≤0.25； Si~； Mn≤2.5*C； P≤0.035； S≤0.035
To be exact, the carbon content varies with the thickness.

SM400 steel plate is widely used in aerospace, electric power, petrochemical, shipbuilding, machinery, electronics, environmental protection and other industries.