Also, they are tool steels created for special purposes. And Like the water-hardened tool steel, these ones are water quenched. Tool steels in this category contain high-iron steels, while other alloying elements are either absent or present in minute quantities. Adding other alloying elements sparingly helps improve the mechanical properties of this tool steel while ensuring it is not as expensive as other tool steels.

An instance of special-purpose tool steels is the low-carbon mold steels used in thermoplastic molding. This specially crafted mold steel does not require high impact resistance but excellent wear resistance and heat tolerance. In common, the P20 is the most popular used tool steel in this category.