EFFECTIVENESS OF DEEP CRYOGENIC TREATMENT IN IMPROVING PROPERTIES OF TOOL STEEL

摘要

In the last years deep cryogenic treatment (DCT) is getting increased attention in many tool applications. Numerous investigations concerning cold-work and high-speed steels have shown that deep cryogenic treatment can lead to improved material performance. However, there are some contradictory results, with investigations reporting improved as well as deteriorated wear resistance and toughness properties of cold-work and high-speed steels after deep cryogenic treatment. The aim of this research work was to investigate the effect of deep cryogenic treatment on fracture toughness, wear resistance and load-carrying capacity of cold work tool steel and to determine the effectiveness of deep cryogenic treatment depending on the tool steel type and chemical composition. Results show that the type and chemical composition of the tool steel considerably affect the way how deep cryogenic treatment changes mechanical, tribological and load-carrying capacity of the tool steel. For lower carbon and higher W and Co containing cold work tool steel properties can be improved for up to 70%, but are very limited in the case of high speed steel. However, at high carbon and vanadium contents properties of cold work tool steels can even be deteriorated after deep cryogenic treatment.