Wear Resistant Duplex Stainless Steels Produced by Spray Forming

Author(s)

Soyama, Juliano ^{[1, 2]} ; Lopes, Thiago Pama ^[1] ; Zepon, Guilherme ^[1] ; Kiminami, Claudio Shyinti ^[1] ; Botta, Walter Jose ^[1] ; Bolfarini, Claudemiro ^[1]

Affiliation

^[1] Univ Fed Sao Carlos UFSCar, Dept Engn Mat DEMa, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Estadual Campinas UNICAMP, Fac Engn Mecan, BR-13565905 Campinas, SP - Brazil

• Document type: Journal article
• Source: METALS AND MATERIALS INTERNATIONAL; v. 25, n. 2, p. 456-464, MAR 2019.
• Web of Science Citations: 3

Abstract

In this work, boron-modified duplex stainless steels were prepared by spray forming using design guidelines provided by thermodynamic calculations. Firstly, an investigation of stable phases and phase formation sequence in duplex steels containing high levels of boron was conducted. The calculation indicated that there was an eutectic point at around 1wt% boron with different primary phase formations upon equilibrium solidification. For hypoeutectic compositions, the primary phase was -Ferrite, whereas for hypereutectic a metallic boride (M2B) should form. Additionally, eutectic reactions for both compositions should lead to the formation of borides M2B and M3B2. Secondly, spray forming experiments were conducted based on the thermodynamic calculations. Sample preparation was carried out using a conventional superduplex steel (2507) as starting material. Two different compositions were selected: one hypoeutectic (0.8wt% B) and one hypereutectic (2.5wt% B). The microstructural investigation revealed the formation of different types of borides embedded in an austenitic-ferritic matrix. Finally, the wear resistance was evaluated with the dry sand/rubber wheel test and a significant improvement was observed for boron-containing steels in comparison with the same steel without boron. This improvement was attributed to the presence of fine and well-distributed boride particles that protected the austenitic-ferritic matrix from material removal. (AU)

• FAPESP's process: 13/05987-8 - Processing and characterization of amorphous, metastable and nano-structured metallic alloys
• Grantee: Claudio Shyinti Kiminami
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 14/27073-0 - Study of stainless steels modified by additions of boron and nitrogen in order to obtain wear resistant materials with low friction coefficient
• Grantee: Juliano Soyama
• Support Opportunities: Scholarships in Brazil - Post-Doctoral