Integrating cryogenic treatment with nitro-carburizing to improve performance of AISI H-13 tool steel

Deep cryogenic treatment (DCT) and nitro-carburizing, both are additional treatments carried out after regular heat treatment to improve performance of tool steels. Nitro-carburizing is surface treatment which improves surface properties whereas in case of DCT entire mass is treated. This paper investigates possibility of integrating deep cryogenic treatment with nitro-carburizing to take advantages of both treatments to improve surface and core material properties. AISI H-13 tool steel samples were Deep cryogenically treated before (DCT+NC) and after nitro-carburizing (NC+DCT) and performances of these samples in terms of hardness, toughness, wear and case depth were compared with cryogenically treated (DCT only) and nitro-carburized (NC Only) samples. The result shows that samples which were cryogenically treated before nitro-carburizing (DCT+NC) exhibits better performance as compared to other sample treatment conditions. In addition, optical, SEM, EBSD and XRD analysis were also carried out to recognize mechanisms responsible for these improvements.