Ss400 - Japanese Industrial Standard JIS G 3101 - "Rolled steel for general structure"
American ASTM A36 - "Carbon Structural Steel"
Difference is that Ss 400 has no chemical composition assigned, while A36 is allowed for max. 0.25% C and 0.40% Si.
In case when thickness is over 3/4'' to 1 1/2'' [20 to 40], incl., max. 0.80-1.20% Mn is also assigned for A36.
Japanese standard JIS G 3101 recognizes 4 grades of steel:
Ss 330, Ss 400, Ss 490 and Ss 540.
Ss stands for structural steel, and numbers correspond to tensile strength in N/mm^2.
First three types have no assigned chemical composition, while Ss540 is allowed for max. 0.30%C and 1.60%Mn
Just like you, 70% customers choose long-term cooperation with BBN steel not only for our good product and service quality, good reputation in the international market, but also for our experienced one-stop raw material supply and further steel processing!