Deep cryogenic treatment in AISI D2 tool steel punches to enhance tool life

New materials and heat treatment are being developed worldwide to improve tool life. Tool steels are expensive due to the alloying elements and fabrication costs. Therefore, the maximization of tool life keeping good surface finishing is especially important to keep the processes attractiveness. The application of cryogenic treatment is promising to enhance mechanical and metallurgical properties of cold work tool steel parts. The possibility of increasing the finer secondary carbides content and decreasing amount of retained austenite during deep cryogenic treatment (DCT) is also an important matter for industry. The aim of this work is to improve tool life by applying DCT in AISI D2 cutting punches and compare these results with punches treated by conventional heat treatment (CHT), vacuum furnace quenching plus triple tempering. The tests used for analyses were: metallography, X-ray diffraction, carbides fraction, hardness and number of parts produced by each punch (practical test). The results indicate that the DCT punches have an enhancement of approximately 50% in its useful life. (author)