This standard describes a spectrophotometric method for the determination of nitrogen in unalloyed steels and low-alloy steels. The general method is applicable to unalloyed steels and low-alloy steels in the presence of less than 0.6% silicon and, in a particular case (see appendix) to effervescent unalloyed steels, of general use, with a presumed lower nitrogen content of 0.002 %, Note — This method allows you to determine the nitrogen convertible into ammonium salt.
UNI 7336-1974 history
1974UNI 7336-1974 Chemical analysis of ferrous materials. Determination of nitrogen in steel. Spectrophotometric method.