Heavy Hex Bolts ASTM A193 B7China Products/Suppliers. ASTM F3125 Gr A325 A490 Type Heavy Hex Structural Bolt, Find details about China Bolts, Carbon Steel Bolts from Heavy Hex Bolts ASTM A193 B7China Products/Suppliers. ASTM F3125 Gr A325 A490 Type Heavy Hex Structural Bolt