Rapid cyclic annealing of high-speed steel

Conclusions

• 1. The methods used for annealing of high-speed steels \3- with continuous and isothermal cooling \3- can be replaced in several instances with rapid stepless cyclic annealing in furnaces or salt baths, which can be used for welded, rolled, and forged blanks and also for hardened tools that require rehardening.

• 2. With stepless cyclic annealing it is simpler to determine the effect of the chemical composition and heating conditions during the preliminary treatment on the annealability of high-speed steels, which in the given case can be characterized by the number of cycles or the total time of the process required to reduce the hardness to the level required by GOST 19265-73.

  The most difficult steels to anneal are those containing 8–10% Co and high-speed steels greatly overheated during quenching.

• 3. Stepless cyclic annealing is most expedient in a well-deoxidized salt bath, which ensures even heating, consistent results, and reliable protection against decarburizing; the possibility of conducting this treatment in furnaces with a protective atmosphere or without it is limited by the requirements.