scope:

This Standard specifies the grid method for evaluation of pitting corrosion of anodic oxide coatings (hereafter referred to as "coatings") on the products of aluminium or aluminium alloy products (hereafter referred to as "products").

The grid method evaluates the degree of pitting corrosion on the test pieces subjected to corrosion tests and outdoor exposure tests, and on products subjected to practical service tests based on the grid rating number (GRN) and/or percentage of defective squares (%).

This Standard takes into account only pitting corrosion resulting from penetration of the coating.

NOTE 1 The gird rating system is frequently used for rating the results of shortterm corrosion tests for relatively thin anodic oxidation coating, such as those used in the automotive industry.

NOTE 2 The International Standard corresponding to this Standard and the symbol of degree of correspondence are as follows.

ISO 8994: 2011 Anodizing aluminium and its alloys-Rating system for the evaluation of pitting corrosion-Grid method (MOD)

The symbols which denote the degree of correspondence in the contents between the relevant International Standard and JIS are IDT (identical), MOD (modified), and NEQ (not equivalent) according to ISO/ lEC Guide 21-1.