The Friction Hydro-Pillar Process (FHPP) is an innovative process that has been recently studied regarding its possible in situ repair applications. There is still no literature about usage of the FHPP on duplex stainless steel (DSS) base materials to smaller forces than 25 kN. The investigation on DSS processing is crucial due his wide variety of critical uses in pipes and storage structures applied in chemical industry plants, where usual welding processes may lead to safety concerns. The aim of this study is to qualify the processing of SAF 2205 (UNS 31803) duplex stainless steel welded joints using FHPP as feasible repair procedure. For this, the studied samples were welded applying a range of axial forces. The welded joints were characterized by, α/γ phase ratio, intermetallic quantification, austenite spacing measurement, microhardness profile and microstructural qualitative studies. The results showed the efficiency in repair of the FHPP process on the production of DSS joints according with the material recommendations from the standard DNV-RP-F112.

No abstract

This work presents friction hydro-pillar processing (FHPP) and tungsten inert gas (TIG) welding of SAF2205 duplex stainless steel. Weld microstructural and mechanical characterisation were carried out based on the standards (DNV-RP-F112 and DNV-OS-F101). Therefore, optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction were used. In addition, mechanical properties were evaluated by microhardness measurements. Furthermore, the joining processes were thermodynamically simulated for confirmation of the expected phases in each welding method. It was possible to verify the phases developed after the experimental welding (FHPP and TIG) as well as the ones obtained in the thermodynamic analyses. Finally, it was noted that FHPP promoted mechanical and metallurgical features requested by the standards.

No abstract

A presente investigação demonstra a utilização do processo de Soldagem por Fricção com Pino Consumível (SFPC), ou Friction Hydro Pillar Processing (FHPP), para reparar estruturas que contenham o aço inoxidável duplex SAF 2205 (AID UNS S31803) como material base. Para tanto, foi realizado um estudo preliminar relativo ao mesmo material reparado com o processo Tungsten Inert Gas (TIG). Após a obtenção das juntas reparadas em ambos os processos, estas passaram por rigorosa análise microestrutural e ensaios mecânicos para, dessa forma, qualificá-las através de critérios usuais recomendados em normas que regulamentam a utilização deste material no reparo de estruturas. Foram investigadas as propriedades metalúrgicas através de microscopia ótica e eletrônica de varredura, fractografia e EDS (energy dispersive x-ray), além de ensaios de corrosão. Já as propriedades mecânicas foram averiguadas através de ensaios de impacto, de dobramento e perfis de microdureza. Com o intuito de garantir a qualidade da junta soldada e, por sua vez, a segurança da estrutura reparada, o processo FHPP atendeu aos requisitos recomendados pelas normas DNV-RP-F112 e DNV-OS-F101. Palavras-chave: Reparo de estruturas; Aço inoxidável duplex; FHPP; Fases intermetálicas.