nut bolt: 1Spec:DIN,JIS,ASTM,GB,UIC 2Surface:black 3Grade:8.8,10.9,12.9 4Material:Q235,45#,4Cr Rail fastener high strength structural steel nut bolt I. Item:High strength bolts for steel structuresII. Specification: DIN 6914, DIN 6916, DIN 7990, DIN 7999, DIN 931, ISO 7412, ISO 4775, ISO 7416, JIS B 1186, ASTM A325, ASTM A490, GB/T 1228, GB/T 1229, GB/T 1230 III. Usage:Supply to railway, highway, ...