This British Standard specifies materials and manufacture, dimensions, protective finish and quality assurance requirements for hexagon head bolts with unified threads for aerospace use.
It also caters for the bolts to have additional safety locking wire holes in the heads if so required.
It covers two material types:
corrosion-resisting steel with a minimum tensile strength of 127 600 lbf/in2 (880 MPa); and
high-expansion heat-resisting steel with a minimum tensile strength of 130 500 lbf/in2 (900 MPa).
Bolts made from this material are primarily intended for use for securing components made with aluminium, so to match its similar coefficient of thermal expansion (CTE).
NOTE The values in British units are to be regarded as the standard, with metric SI conversions in parentheses ( ) as required.