
Q/BQB 420-2009 DD51D+Z steel is one kind of galvanized steel. The tensile strength of DD51D+Z steel is 270-500Mpa. The following table is the chemical composition of DD51D+Z steel.
| Grade  | C max. | Si max. | Mn max. | P max. | S max. | Ti max. | 
| DD51D+Z | 0.12 | 0.50 | 0.60 | 0.10 | 0.045 | 0.30 |