Duplex Stainless Steels obtained by means of Powder Metallurgy from recycled sources

Department

Department of Applied Science and Technology (DISAT), Politecnico of Turin

Main research activities/topics/projects

Duplex stainless steels are renowned for their exceptional mechanical strength and corrosion resistance, making them widely used in the oil and gas and chemical industries. Recently, they have also been considered for biomedical prosthetic devices. These steels are composed of both ferrite stabilizers (such as chromium, silicon, and molybdenum) and austenite stabilizers (such as carbon, nickel, and nitrogen), which create a duplex microstructure with roughly equal amounts of ferrite and austenite. This unique structure enhances corrosion resistance, particularly against stress corrosion cracking and pitting in chlorinated environments, while also providing greater strength compared to standard austenitic stainless steels like AISI 304 or AISI 316. Additionally, duplex stainless steels demonstrate outstanding resistance to atmospheric corrosion, reducing the need for painting or extensive maintenance in harsh conditions. Their high strength also allows for reduced material thickness, offering a cost-effective alternative to painted carbon steel over the product’s life cycle.

In the recent decades, traditional powder metallurgy processing of super duplex stainless steel (SDSS) has been explored, including pressing and sintering, as well as hot isostatic pressing. More recently, there has been a growing interest in the additive manufacturing of duplex stainless steels. Metal powders for laser additive manufacturing are typically produced through gas atomization, a process in which the parameters play a crucial role in determining powder properties. The choice of process gas, whether nitrogen or argon, influences the composition of the steel melt and can even lead to the formation of hollow particles due to argon encapsulation. The interplay between powder production process parameters and conditions significantly impacts the properties of the powder, and consequently, the quality of powder metallurgical (P/M) parts.

The research to be carried out at the Politecnico di Torino laboratories, involving the Brazilian post-doc candidate, aims to explore the possibility of producing SDSS powders with an optimized chemical composition for the use in the oil and gas sector starting from scraps and wastes from the conventional metallurgy. The activity will involve producing various batches of powder with different compositions using a gas atomizer. These powders will be thoroughly characterized, assessing their chemical, physical, and processing properties. The following activities will be focused on evaluating the processability of the powders, primarily through Additive Manufacturing techniques, to identify the most effective process for producing demonstrators.

Working language

The working language can indifferently be either Italian or English

Special entry requirements

Skills in the use of a gas atomizer

 Skills in the analysis of metals powders properties 

 Broad knowledge in the field of Material Science 

 Expertise in Industrial Engineering, material processing and fabrication methods

 Leadership and proven ability to conduct his/her own research activities

 Excellent communication and organizational skills

Duration in months (min-max)

Post Doc: 6-12