Plasma nitriding and deposition in AISI M2 and D2 steel tools used in nail forming and stamping: a viability study

ABSTRACT

The growing need to increase the productivity of the industrial sector, drives the development of new steels and new treatments that can improve the performance and useful life of cutting, forming and stamping tools. Plasma-assisted surface treatments stand out in this context. Previous research has shown that these coatings are efficient in increasing hardness, wear resistance and corrosion resistance of different types of steels. In this sense, samples and tools from AISI M2 and D2 heat-treated steels were subjected to conventional plasma nitriding processes, in cathodic cage and duplex treatment in order to evaluate the effect of these treatments on forming tools seeking the viability of applying the method in the industrial sector with the reduction of the manufacturing cost in the conformation and stamping of nails. Vickers microhardness tests, SEM analysis and X-Ray Diffraction (XRD) made it possible to identify mechanical properties, layer of compounds and the phases present, respectively. The performance of the tools was based on the volume of nails produced in kg. The productive cost was determined in function of productivity, the purchase price of the tool and the nitriding price. The use of plasma nitriding proved to be feasible for both steels, highlighting the fact that the D2 steel tools nitrided at 480ºC for 3 hours, obtained the greatest productivity gains in relation to non-nitrided tool. The application of conventional nitriding in the steel tool M2 at 480ºC for 4 hours made it possible to reduce its cost by 26% and reduce by 3.5% the total cost of producing nails, obtaining the best cost-benefit ratio.

Key-words
Plasma Nitriding; cathodic cage; duplex; AISI M2 and D2 steels