Inclusion Rating (ASTM)
Inclusions - Foreign material held mechanically, usually referring to non-metallic particles, such as oxides, sulfides, silicates etc are considered as inclusion.
Inclusion Count - Determination of the number, kind, size and distribution of non-metallic such inclusions.
As per E-45 of ASTM "Determining the inclusion content of steel", determination of nonmetallic inclusion content of steel is accomplished by Macroscopic methods include macroetch, fracture, step down and magnetic particle tests, and Microscopical methods include four generally accepted systems of examinations.
Inclusion rating engine of the Microstructure Characterizer Software is based only on microscopical method. In Microscopical method, inclusions are assigned to a category based on similarities in morphology, and not necessarily on their chemical identity. Inclusions such as carbides, nitrides, carbonitrides, borides and intermetallic phases may not be rated using this method.
Inclusion Rating (IS)
Inclusion Rating as per Indian Standard IS 4163 1982 can be done from the comparison chart given below. All the frames are as per the standard but at lower magnification.
Microstructure Characterizer Software ships with standard IS rating frames with inclusion type, subtype and ratings, which is to be compared with image whose rating is to be done. Matching frame is the rating number and type and subtype.
Use of this method is recommended for imprecise but rapid and bulk approach for Inclusion Rating.
Live image may be floated on screen by selecting ´stay on top´ option from the frame grabber card window. MiC version 2.0 provides ´on screen´ rulers which are useful to find distance between two cursor locations. These distances are provided considering magnification / objective factor and are true to the scale in the unit of micrometers.
Inclusion Rating (JIS)
The Japanese International Standard specifies the test mehod to measure the types of and the quantity of non-metallic inclusions in steel with a microscope and judge its cleanliness.
For terms and definitions on this standard, refer to G0555 and G0202 of JIS.
This method works on the principle of Point Counting. A grid of 20 x 20 lines is virtually drawn on the frame. Each point occupying any kind of inclusion is determined based on Thershold Setting. Threshold by default is set to an adequate value near to 85. However, operator is responsible for suitable thresholding of image. Type of inclusion is determined in accordance to JIS guidelines given in G0555 and three different types of cleanliness. Rating is automatically found out by MiC. The result of JIS would, typically look like:
dA60 x 400 = 0.15%
dB60 x 400 = 0.02%
dC60 x 400 = 0.09%
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