GB/T 6394-2017 (English Version) PDF

Scope: This standard specifies the expression and measurement methods of the average grain size of metal structures, including comparison method, area method and cut point method, applicable to single-phase structure, but also applicable to multi-phase or multi-component samples after specific regulations Determination of the average size of grains of a particular type in Non-metallic materials can also be used as a reference if the structure morphology is similar to the metal structure in the comparative rating diagram. This standard uses the unimodal distribution (approximate to the log-normal distribution) of the grain area, diameter or cross-section length to determine the average grain size of the sample, and is not applicable to the grain size of the bimodal distribution. See GB/T 24177 for the evaluation of double grain size. See YB/T 4290 for the determination method of individual very coarse grains distributed on the fine grain matrix. This standard applies only to the measurement of plane grain size, not to the measurement of three-dimensional grain size, that is, the measurement of three-dimensional grain size. This standard is only a recommended test method and cannot determine whether the tested material is acceptable or suitable for use.

GB/T 6394-2017 Referenced Document

GB/T 13298 Inspection methods of microstructure for metals
GB/T 24177 Standard test methods for characterizing duplex grain sizes
GB/T 30067 Standard terminology relating to metallography
GB/T 4335 Determination of ferrite grain size for cold rolled low carbon steel sheets
YB/T 4290 Determination method of the largest grain size grade (ALA grain size) on the metallographic inspection surface