ISO 945-1:2019 pdf download.Microstructure of cast irons Part 1 Graphite classification by visual analysis.
Microstructure designation is a useful feature that provides a means of classifying the graphite form, distribution and size in cast irons.
Graphite classification by visual analysis is a well-established method which is well recognized within the foundry industry as a means of quickly determining the overall graphite microstructure of a cast iron casting.
ISO 945-1 specifies a method of classifying the microstructure of graphite in cast irons by comparative visual analysis.
The purpose of ISO 945-1 is to provide information about the method of graphite classification. It is not intended to give information on the suitability of cast-iron types and grades for any particular application.
The particular material grades are specified mainly by mechanical properties and, in the case of austenitic and abrasion resistant cast irons, by their chemical composition. The interpretation of graphite form and size does not allow a statistically valid statement on the fulfilment of the requirements specified in the relevant material standard.
2 Normative references
There are no normative references in ISO 945-1.
4.1 Designation system for classifying graphite in cast irons
When cast iron materials are examined under a microscope in accordance with ISO 945-1 the graphite shall be classified by the following:
a) its form, designated by Roman numbers I to VI see Figure 1 and Annex A
b) its distribution, designated by capital letters A to E see Figure 2 and Annex B the graphite distribution designation is only specified for grey cast irons form 1;
c) its size, designated by numbers 1 to 8 see Figures 3,4 and and Table 1.
NOTE jj,gures 1 to show only the outlines and not the structure of the graphite.
The reference images given in Figures 1, 2 3. 4 and provide a basis for classifying graphite forms, distribution and size. The characteristic features of the graphite which occur are designated by letters and numbers. For this purpose, microstructures of graphite are arranged in a series of reference images consisting of schematic microstructures of cast irons. The form, distribution and size of the graphite observed are determined by comparison with the reference images. The classification is allocated as the same as that of the images that resemble them most closely at the same magnification.
NOTE The comparison of actual microstructures with schematic images or photomicrographs depends on the subjective impression of the metallographer.
The polished samples shall be scanned under a microscope in such a manner that a representative area is examined. To examine the graphite form and distribution, a x 100 magnification should preferably be chosen. If necessary, the magnification may be adapted in relation with the wall thickness so that the form and distribution of graphite can be determined by using the reference images given in Figures 1 and .2. see also Annexes A. fl and. Adjust the microscope magnification to match as closely as possible the corresponding images in Figures 1 and 2 before classifying the graphite form and its distribution, if appropriate. The graphite size is determined by reference to Figures 3, 4 and 5 and Table 1, preferably at x 100 magnification. Other magnifications are permitted see Table 1. Notes 1 and 2, as well as Z4.
Examination under the microscope is carried out by direct observation in the microscope or by projection on the ground glass of the microscope or on a visual display screen. The area of view should preferably have approximately the same size as the reference images about 120 mm diameter. The measurement of the graphite particles can be facilitated by the use of suitably calibrated eye-pieces.ISO-945-1-2019