A307 Hex Bolts Zinc: A low carbon steel, externally threaded mechanical fastener, with a trimmed hex head. A hex bolt does NOT have a washer face on its bearing surface, nor does it have a machined point. The low carbon steel fastener ASTM A307 is a special bolt used in piping and flange work. Economical for use in non-critical applications.

A307 Hex Bolts Zinc: A low carbon steel, externally threaded mechanical fastener, with a trimmed hex head. A hex bolt does NOT have a washer face on its bearing surface, nor does it have a machined point. The low carbon steel fastener ASTM A307 is a special bolt used in piping and flange work. Economical for use in non-critical applications.