Martensitic transformation induced by cold deformation of lean duplex stainless steel UNS S32304

Abstract

Lean duplex UNS S32304 is an austenitic ferritic stainless steel with pitting resistance equivalent number around 24-25. Its corrosion resistance is similar to AISI 316L steel, but with the advantage of a yield limit two times superior to conventional austenitic grades. Deformation induced martensitic transformations (γ→ε and γ→ α') have been extensively studied in austenitic steels, but few works were published about these reactions in austenitic ferritic grades. In the present work, deformation induced martensitic transformation in lean duplex UNS S32304 was investigated by means of magnetic measurements and X-ray diffraction. The curves of α' martensite volume fraction against true deformation by cold rolling were constructed and compared to duplex and austenitic grades. It was found that lean duplex UNS S32304 is much more susceptible to martensitic transformation than duplex UNS S31803, which can be explained by its lower Mo and Ni contents.

Influence of Microstructure on the Corrosion Resistance of AISI 317L (UNS S31703)

“…Many authors studied the deformation induced martensites in austenitic [15][16][17][18][19][20][21][22] , duplex and lean duplex stainless steels [23][24] . Both ε-and α'-martensites can be observed by transmission electron microcopy (TEM) and quantified by X-ray diffraction (XRD).…”

“…Both ε-and α'-martensites can be observed by transmission electron microcopy (TEM) and quantified by X-ray diffraction (XRD). Additionally, α'-martensite is ferromagnetic and, thus, can also be quantified by magnetic measurements [20][21][22][23][24] .…”

“…It is worth noting that the Cr-rich precipitate produced by spinodal decomposition and the magnetic martensite produced by cold working are usually cited with the same symbol (α') [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] , but these are phases completely distinct. For this reason, in this paper, the Cr-rich precipitate produced by spinodal decomposition was called α 1 .…”

Microestrutura E Propriedade Mecânica Dos Aços Inoxidáveis Duplex Uns S31803 E Uns S32304 Após Laminação a Frio E Recozimento

“…A partir da análise via microscopia óptica observou-se uma fase sobreposta a fase austenítica, indicado pela seta vermelha na figura 1b,c,d onde foi possível relatar o aumento da fração da mesma com o aumento da deformação a frio. Estudos realizados por Tavares et al [7], concluiu ser a martensita induzida por deformação (α'). A martensita α' foi estudada no aço inoxidável duplex S32304 por meio do método de saturação magnética, os autores observaram que com o aumento da deformação a frio houve maior formação da martensita induzida por deformação (→ α').…”

Effects of mean strain and tensile pre-strain on torsional fatigue behaviours of duplex stainless steel SAF2205

“…Substantial references have been published focusing on the mechanisms of cold work/pre-straining on the LCF behaviours of ASS, aluminium and magnesium alloy [13][14][15][16][17], among which CL Zhou et al [18,19] investigate the effects of prior tensile plastic deformation on the torsional fatigue properties of a structural steel. As for the DSS, however, the researchers are mainly concerned with the effects of pre-straining/cold-work on the basic mechanical properties, microstructural evolution during monotonic loadings [20][21][22][23][24]. Much more efforts should be made to explore how it works on the subsequent LCF behaviours and reveals the corresponding mechanisms.…”