BS EN ISO 643:2024 - TC

This standard BS EN ISO 643:2024 - TC Tracked Changes. Steels. Micrographic determination of the apparent grain size is classified in these ICS categories:

• 77.040.99 Other methods of testing of metals
• 77.040.99 Other methods of testing of metals

This document specifies micrographic methods of determining apparent ferritic or austenitic grain size in steels. It describes the methods of revealing grain boundaries and of estimating the mean grain size of specimens with unimodal size distribution. Although grains are three-dimensional in shape, the metallographic sectioning plane can cut through a grain at any point from a grain corner, to the maximum diameter of the grain, thus producing a range of apparent grain sizes on the two-dimensional plane, even in a sample with a perfectly consistent grain size.