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.
Tämän julkaisun valmistelusta Suomessa vastaa Metalliteollisuuden Standardisointiyhdistys ry, puh. 09 19 231 (vaihde).
Sisällysluettelo
Foreword
1 Scope
2 Normative references
3 Terms and definitions
3.1 Grains
3.2 General
4 Symbols
5 Principle
6 Selection and preparation of the specimen
6.1 Test location
6.2 Revealing ferritic grain boundaries
6.3 Revealing austenitic and prior-austenitic grain boundaries
7 Characterization of grain size
7.1 General
7.2 Comparison method
7.3 Planimetric method
7.4 Intercept method
7.5 Other methods
8 Test report
Annex A Methods for revealing austenitic or prior-austenitic grain boundaries in steels (informative)
Annex B Determination of grain size with standard comparison charts (normative)
Annex C Evaluation method (informative)
Annex D Calculation of grain size and confidence interval (informative)
Annex E Grains of different size indices (informative)