ISO 8434-1 2018 Tube Nut to be used with carbon steel bodies shall be made of carbon steel, and those for use with stainless steel bodies shall be made of stainless steel, unless otherwise specified. Nuts to be used with copper alloy bodies shall be made of a material similar to the bodies.
Tube nut (N)
a Internal chamfer angle.
b Permitted for cold-formed nuts.
c Alternative full chamfer.
d For optional machining of shoulders
e Width across flats.