ÖNORM EN ISO 2624

This International Standard specifies three procedures for estimating, and rules for expressing, the average grain size of topper and topper alloys consisting principally of a Single Phase. The respective procedures are termed the comparison procedure, the intercept procedure and the planimetric procedure. The comparison procedure (comparing the specimen with a Standard Chart) is most convenient and is sufficiently accurate for most commercial purposes. Higher degreees of accuracy in estimating grain size are obtainable by using the intercept (Heyn) or planimetric (Jeffries) procedures. In cases of dispute, it is recommended that the use of one of these procedures be agreed between the Parties. For material with non-equiaxial structures it is recommended that the intercept procedure be used.