The clusters on the both fractures of each tensile specimen
were observed further by SEM in order to obtain the distribution
of clusters. However, there was usually one or two larger clusters
on the fracture. It could be explained that the smaller clusters fell
out of the fractures due to the stress as the specimens fractured
and it was more likely to cause local stress concentration near the
larger clusters. Therefore, the fewer large clusters often appeared
and the distribution of many scattered clusters was hardly found
on the limited area of the fracture. The severe degradation of
mechanical properties in the steel with high Ti content is considerably attributed to the presence of the larger TiN inclusions.