The influence of non-metallic inclusions on the prediction of 50% FATT using the miniaturised disk bend test

Abstract

The size and distribution of non-metallic inclusions was studied in detail for a ferritic 2.25Cr1Mo steel using detailed metallographic examination. The results of this were then used to explain the differing amounts of data variation produced in a series of miniaturised disk tests at three temperatures in the ductile, mixed mode and brittle fracture regimes, respectively. The maximum amount of variation was observed in the mixed mode fracture region and was linked to the inhomogeneous nature of large inclusions in the material. The effect of this data variation on the 50%DBTT temperature produced from the disk test was reported. The subsequent effect on 50%FATT prediction for structural integrity purposes of critical component material was then outlined.