GB/T 6394-2017 Active

1.1 This standard specifies the methods of expressing and determining the average grain size of metal microstructures, including comparison method, area method, and intercept method. It is applicable to single-phase microstructures, but after specific provisions, it is also applicable to the determination of the average grain size of specific types of microstructures in multi-phase or multi-element samples. Non-metallic materials with microstructural morphologies similar to those in comparison rating charts may also be used for reference.
1.2 This standard uses the single-peak distribution (approximately log-normal distribution) of grain area, diameter, or intercept length to determine the average grain size of samples. It is not applicable to grain size with a double-peak distribution. The evaluation of double-peak grain size is described in GB/T 24177. The determination of individual very coarse grains distributed on a fine grain matrix is described in YB/T 4290.
1.3 This standard is only applicable to the measurement of planar grain size and is not applicable to the measurement of three-dimensional grain size, that is, the size of three-dimensional grains.
1.4 This standard is only a recommended test method and cannot determine whether the tested materials are acceptable or suitable for use.