scope:

This Standard specifies micrographic methods of determining the non-metallic inclusions (hereafter referred to as inclusions) in rolled or forged steel products having a reduction ratio of at least 3 through comparison with standard diagrams (hereafter referred to as the standard diagram method), measurement of shape of inclusions (hereafter referred to as direct measurement method) and point counting method.

This Standard also specifies the method for determination of non-metallic inclusions by image analysis technologies (Annex D).

NOTE 1 These methods are widely used to assess the suitability of a steel for a given use. However, since it is difficult to achieve reproducible results owing to the influence of the test operator, even with a large number of test pieces, precautions should be taken when using these methods.

NOTE 2 For certain types of steel (e.g. free cutting steels), the standardized diagrams described in this Standard may not be applicable.

This Standard also provides in Annex JA the method for assessing the cleanliness of steel by determining the type and number of inclusions in steel by means of a microscope.

NOTE 3 The International Standard corresponding to this Standard and the symbol of degree of correspondence are as follows.

ISO 4967 : 2013 Steel - Determination of content of nonmetallic inclusions - Micrographic method using standard diagrams (MOD)

In addition, 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/IEC Guide 21-1.