Grade 8.8 High tensile hexagon head bolts DIN 931 are sometimes referred to as a part threaded bolts. They are easily identified by their 8.8 head markings and usually but not always have metric thread forms. The most common surface finish in use is bright zinc plated. Hot dipped galvanised finishes are becoming ever more popular, particularly in the rail industry sector.
Hexagon headHigh tensile steelPart threadedGrade 8.8Bright zinc platedDIN931p : 2 : Pitch
b : 34 : Thread Length <125mm
b : 40 : Thread Length 125 - 200mm
b : 53 : Thread Length >200mm
k : 8.8 : Head Height
AF : 22 : Width Across Flat