Grinding Recommendations for Tool Steels

Many tool steels are specifically designed to resist wear in service. The presence of vanadium, molybdenum, tungsten and chromium promotes the formation of hard carbide particles throughout the matrix. Because they contain hard carbides, such wear-resistant tool steels often prove to be difficult to grind. The CPM process does minimize this difficulty by keeping the carbide particle size small. However, because many of the CPM grades are intentionally designed for very high wear resistance, the volume of small carbide particles, particularly vanadium carbides, can be quite high. Thus, despite the benefits of the CPM process, these grades may still present some difficulty in grinding.

Certain modifications to standard grinding practices can improve the grindability of these grades. The use of cubic boronitride (CBN) or other types of wheels designed to retain sharp cutting grains are recommended where practical. Within standard wheel types (aluminum oxide, etc.) moving to slightly coarser, softer, or more open wheels, or SG type wheels, can improve grindability, by helping to ensure a clean cutting surface, although wheel wear rates will increase. If possible, slower grinding speeds may also be beneficial. Refer to the following table of wheel recommendations for specific suggestions.