ASTM E112 Test Using Grain Reticles

ASTM E112 has standard test methods for average grain sizing. The comparison method does not require the tester to count grains, but rather comparing of the grain structure to a series of graded images, either in the form of a wall chart, clear plastic overlays, or a grain counting eyepiece reticle. There appears to be a general bias in that comparison grain size ratings claim that the grain size is somewhat coarser than it actually is.

Grain Sizing Reticle

Test Method E 112, one of the most widely cited ASTM standards, is concerned with the measurement of grain size when the grains are equiaxed in shape (non-deformed), although it does contain some information about measurement of grain size when the grains have been elongated by processing. There are other situations where Test Method E 112 is not helpful and other standards have been developed. For example, certain alloys may not exhibit a uniform distribution of grain sizes. Learn more about ASTM E112 Standard test methods here.

Microscope World offers four different untwinned grain sizing reticles that meet the methods for determining the average grain size ASTM Methods E 112 PCN 12-501120-10. Each of these grain reticles was created for use with a 10x microscope objective.