Image processing tool quantifying auto‐tempered carbides in as‐quenched low carbon martensitic steels

Abstract

As-quenched low-carbon martensitic steels (<0.2 wt.% C) contain auto‐tempered carbides. Auto‐tempering improves the work hardening and upper‐shelf impact energy; however, an efficient characterization method to determine the degree of auto‐tempering has not been available. This paper demonstrates an efficient image processing tool that calculates the relative auto‐tempered carbide fraction by analyzing scanning electron microscope micrographs. By the process of image segmentation, the qualitative volume fraction of auto‐tempered carbides can be determined, and an associated color map produced, which distinguished the levels of auto‐tempering. This image processing tool could become useful for the optimization of new low‐carbon steel’s mechanical properties.