Product Name: DIN6922 M5 M6 M8 Stainless Steel Hex Flange Bolt Material: Stainless steel:SS210,SS304,SS316,SS316L,SS410 Color: Polish, Passication Standard: DIN,ASME,ASNI,ISO Grade: A2-70,A2-80,A4-70,A4-80 Finished: Polish, Passication Thread: Coarse,Fine Used: Building Industry Machinery Usage: Hexagon flange bolts are particularly commonly used as industrial equipment in the industry.Because they have the characteristics of precise decoration and strong endurance, they have been widely used.It is widely used on highways and railway bridges, including industrial and Civil construction, cranes, excavators and other heavy machinery. Surface treatment: .BLACK ☆ Black is a common method for metal heat treatment. The principle is to make an oxide film on the metal surface to isolate the air and achieve rust prevention. Blackening is a common method for metal heat treatment. The principle is to make an oxide film on the metal surface to isolate the air and achieve rust prevention.