The top steel above labeled 1.3505 is 52100 with a small volume of very fine carbides. This steel is optimal for low angle edges that have high sharpness. The wear to the edge is relatively even and chipping is less likely due to its fine carbide distribution. Roman recommends it and similar steels to be used with edge angles of 16-25° for fine cutting. The bottom steel is a conventional ATS-34 with large carbides. The micrograph to the left shows a fracture due to carbides. To have sufficient “edge stability” a more obtuse edge is recommended by Roman, here 40-60°. The middle steel is CPM-440V later named S60V which has a large volume of carbides like ATS-34 but is produced with the powder metallurgy process for smaller carbides that are more evenly distributed and have a more consistent size. That allows lower angle edges than the conventionally cast ATS-34, or 25-40° as recommended by Roman. Those edge angles are recommended to avoid the fine chipping that occurs because of inevitable side loading during cutting. That way the steels are better at maintaining their initial high sharpness and less likely to chip. However, the higher edge angles that are required for high carbide steels to have sufficient edge stability means that their overall cutting ability is lower.