AbstractA homogeneous set of Cr–3·5Ni low alloy steel samples has been made to enable laboratories studying grain boundary segregation by Auger electron spectroscopy to interrelate their studies. This steel has P, Sn, and Ni segregated at the grain boundaries. Data are provided of the effect of variation of signal intensities across a grain, on one grain as a function of the electron emission angle, on many grains, etc. for both unidirectional (concentric hemispherical) and multidirectional (cylindrical mirror) spectrometers. Reference spectra recorded from the sample allow the spectrometer transmission function to be calibrated so that data from all instruments may be interrelated. After correction for the transmission function, the Auger electron peak-to-peak height ratios, for a 5 eV Savitzky and Golay differentiation, are found to be P120/Fe703=0·33±0·06 and Sn430/Fe703=0·12±0·02. Calibrations from the literature show these signals can be attributed to 33 and 31% of a monolayer of P and Sn, respectively.MST/1684a