A709 Gr. 50S is a steel plate for bridge structures under the ASTM standard

A709 Gr. 50S is a structural steel plate for bridges compliant with the ASTM A709/A709M standard; it is primarily used in applications such as steel building structures, bridges, construction machinery, and pressure vessels.
 
Meaning of the grade designation:
"A" indicates an alloy steel conforming to American standards; "709" is the series identifier;
In "Gr50S," "Gr50" is typically associated with yield strength (actual yield strength ≥ 345 MPa),
while "S" may denote special treatment (such as enhanced weather resistance) or a specification distinction, with the specific meaning varying by manufacturer or standard.
 
Delivery conditions for A709 Gr.50S steel plate:
Delivered in various conditions such as normalized, tempered, normalized and tempered, or quenched and tempered (specific delivery condition must be specified).