3. Conclusion

This article, devoted to the classification and evolution of tool steels, defines the properties and main areas of use of the different categories of tool steels. Cold-working, hot-working and machining are very specific sectors, each with its own group of steels, with a certain continuity and even interpenetration between the cold-working and high-speed steel sectors. There is also continuity between hot-work steels and the nickel-based superalloys used in the aerospace industry for very severe working conditions, where service temperatures reach or exceed 700°C. Advances in powder metallurgy have also ensured continuity between high-speed steels and sintered carbides for machining under severe conditions.

Cold-work steels are currently evolving in the direction of high-wear steels containing 8-12% Cr (with nitrogen incorporated for some of them) to resist corrosion,...