Microstructure, mechanical properties, and corrosion resistance of boron-modified stainless steels processed by additive manufacturing

• Grant number: 21/10735-4
• Support type: Scholarships abroad - Research Internship - Doctorate
• Effective date (Start): March 01, 2022
• Effective date (End): January 31, 2023
• Field of knowledge: Engineering - Materials and Metallurgical Engineering
• Principal researcher: Claudemiro Bolfarini
• Grantee: Brenda Juliet Martins Freitas
• Supervisor abroad: Sergio de Traglia Amancio Filho
• Home Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Research place: Graz University of Technology, Austria
• Associated to the scholarship: 19/05885-7 - Microstructure, mechanical properties and corrosion resistance of boron-modified stainless steels processed by additive manufacturing, BP.DR

Abstract

The parts used in the oil and gas industries are often subjected to severe wear and corrosion conditions. Stainless steels exhibit a great combination of mechanical and corrosion resistance; however, they also exhibit a relative low wear resistance. Supported by FAPESP and Petrobrás, recent and pioneer studies performed in the Department of Materials Engineering - UFSCar show that the addition of high boron contents in stainless steels promotes a significant enhancement of the wear resistance due to the formation of hard boride particles. The production of boron-modified duplex stainless steel by selective laser melting (SLM) has earned considerable interest due to the capability to produce and/or repair in a noticeably short time near-net-shape components with complex geometries to the offshore platforms and chemical industries. Therefore, considering the challenges faced so far in producing boron-modified stainless-steel alloys by selective laser melting which are mainly related to the limited access to a SLM machine, the objective of this research internship is to systematically study the influence of the SLM parameters on the microstructure of duplex stainless steel modified with boron to produce entire parts free of defects, such as pores and cracks. This research internship abroad aims to the doctoral student spend a period at the Institute of Materials Science, Joining and Forming of Graz University of Technology under the supervision of Dr. Sergio de Traglia Amancio Filho working on the selective laser melting of duplex stainless steel modified with 1 and 2 wt.% of boron. It can be mentioned that the production by SLM of novel alloys composition, such as boron-modified stainless steels, demands a methodical study of parameters (laser power, scanning speed, hatching distance, layer thickness, scanning strategy, and substrate temperature) to achieve a condition that allows the building of parts free of structural defects. The SLM machines present in the Institute of Materials Science, Joining and Forming of Graz University of Technology are available to perform several tests requested to the alloys of this project. Moreover, during the research internship it will be possible to evaluate the microstructure and corrosion behavior of the SLM alloys.