12.9 bolt grades: 1.Spec:DIN,JIS,ASTM,GB,UIC ... Q235,45#,40Cr ASTM DIN GB Standard High strength 12.9 bolt grades with large hexagon ... head for steel structures I. Item:High strength bolts for steel structuresII. Specification: DIN 6914, DIN 6916, DIN 7990, DIN ... 7999, DIN 931, ISO 7412, ISO 4775, ...