In order to measure the graphite nodule count accurately, we investigated the influence of photographic devices and image analysis conditions on graphite nodule counts, in spheroidal graphite cast iron. The following results were obtained. If the undercut diameter of the graphite nodule was smaller than 7um, the nodule count of low magnification images (for example, observed by 100 magnification) was less than that of high magnification (by 200 magnification). However, the difference in the nodule count between the low nodule count images and the high nodule count images disappeared when the undercut diameter was more than 7um. If the undercut diameter was small, the graphite image size was observed smaller than that of real size. As a result, many graphite nodules were undercut and the nodule count decreased. Therefore, when the undercut graphite size is about 7um, there is a need to carefully measure the nodule count of small size T. P. graphite nodules.
