6. Conclusion

The data in this document may be modified by the introduction of new grades in the NF-EN-ISO 4957 reference standard dated May 2000. Indeed, since the publication of this standard, new tool steels have been developed by producers, notably in mold steels, with steels whose characteristics are obtained by precipitation of intermetallic phases, and in chromium-alloyed tool steels, with the release of 5%Cr steels with improved hardenability for hot working, and 8%Cr and 1%C steels for cold working. There is also a new family of high-chromium steels for cold working, in which some of the carbon has been replaced by added nitrogen. Within this group of steels, powder metallurgy has also led to the development of grades with high chromium, vanadium and carbon contents. The characteristics of these grades are described in the article