On the Intergranular Corrosion Properties of Thin Ferritic Stainless Steel Sheets Welded by Fiber-Laser

Sommer, Niklas; Kryukov, Igor; Wolf, Christian; Wiegand, Michael; Kahlmeyer, Martin; Böhm, Stefan

doi:10.3390/met10081088

Cited by 8 publications

(19 citation statements)

References 19 publications

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“…After welding, the values of uniform tensibility and tensibility decreased. In the case of the study performed by Sommer et al [37], the differences in tensibility were not as significant as in our case. It should be noted that in our research, the samples of AISI 430 material were not thermomechanically processed before or after welding.…”

Section: Resultscontrasting

confidence: 74%

“…The comparison of the mechanical properties given in Table 4 shows that the laser-welded samples of AISI 430 LW produced higher values of yield strength, lower values of tensile strength, uniform tensibility and tensibility, and no significant changes in the normal anisotropy ratio and strain-hardening exponent compared to the values found in the base samples of AISI 430 BM. Sommer et al [37] observed a similar trend for AISI 430. After welding, the values of uniform tensibility and tensibility decreased.…”

Section: Resultsmentioning

confidence: 62%

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Formability Prediction of Laser-Welded Stainless Steel AISI 304 and AISI 430

Evin

Tomáš

2021

Metals

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The effect of laser welding on the mechanical properties and the prediction of formability for austenitic stainless steel AISI 304 and ferritic steel AISI 430 when welded by a YLS-5000 fiber laser, were studied in the paper. The microstructure of the welded joint was analyzed using light microscopy. The mechanical properties were determined by static tensile testing. The forming limit diagrams were produced from notched samples at R5, R17, and R25 mm. The hardness values of the welded joint and the base material were determined using the Vickers method. Samples made of AISI 430 showed that the formability suffered due to laser welding. Longitudinal coarse ferrite grains were observed in the microstructure of the AISI 430 weld metal. The coarse-grained structure of the welded joint and the continuous interface along the centerline caused the failure of the AISI 430 laser-welded samples at significantly lower actual stress and strain values than were required to break the base material. No significant changes in the formability were observed in the AISI 304 samples after laser welding. The growth of dendrites was observed in the microstructure of the AISI 304 welded joint in a direction towards the centerline of the welded joint. A comparison of the experimentally determined FLD0 values and the values calculated from predictive equations showed that a better agreement was achieved for uniform elongation than for the strain hardening exponent. The manufacturability and economic efficiency of selected parts of an exhaust system by hydromechanical drawing were evaluated on the basis of the process capability index Cpk.

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Section: Resultscontrasting

confidence: 74%

Section: Resultsmentioning

confidence: 62%

Formability Prediction of Laser-Welded Stainless Steel AISI 304 and AISI 430

Evin

Tomáš

2021

Metals

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“…Moreover, titanium carbides (TiC) or nitrides (TiN) act as inclusions within the surrounding matrix and therefore, again, promote selective corrosion phenomena [14,15]. Along with these observations, intergranular corrosion can also be identified in unstabilized and Ti-stabilized FSS when welded with a fiber-laser under the utilization of very low energy inputs [31]. Based on transmission electron microscopy studies on the precipitation behavior, chromium depletion is the governing factor for intergranular corrosion propagation within welds of unstabilized FSS [32].…”

Section: Introductionmentioning

confidence: 91%

“…Table 1. (a) Chemical composition of AISI 430 and AISI 430Ti sheet material used in the investigation, adopted from [31]. Copyright 2020 Niklas Sommer; (b) Chemical composition of AISI 316L austenitic stainless steel powder, partially adopted from [37] Nominal distribution 20-53 µm, partially adopted with permission from ref.…”

Section: Sheet and Powder Materialsmentioning

confidence: 99%

A Novel Approach to Inhibit Intergranular Corrosion in Ferritic Stainless Steel Welds Using High-Speed Laser Cladding

Sommer

Grimm

Wolf

et al. 2021

Metals

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Ferritic stainless steels are prone to localized corrosion phenomena such as pitting corrosion or intergranular corrosion, in particular when jointed by fusion welding processes. State-of-the-art techniques to avoid intergranular corrosion mainly consist of alternating alloy concepts or post-weld heat-treatments—all of which are associated with increased production costs. Hence, the present investigation seeks to introduce a novel approach for the inhibition of intergranular corrosion in ferritic stainless steel welds through the use of high-speed laser cladding. Here, vulnerable sites prone to intergranular corrosion along the weld seam area are coated with a chemically resistant alloy, whereby an overlap is achieved. Optical and electron microscopy as well as computer tomography and tensile tests reveal that the detrimental effects of intergranular corrosion in both stabilized and unstabilized ferritic stainless steel are substantially reduced. In addition to that, the effects of varying overlap widths on the identified corrosion phenomena are studied. Moreover, the resulting dilution and precipiation phenomena at the clad–sheet interface are thoroughly characterized by electron backscatter diffraction and energy dispersive X-ray spectroscopy, whereby interrelationships to corrosion resistance can be drawn. As a result of this investigation, the number of techniques for the inhibition of intergranular corrosion is enlarged, and substantial cost-saving potentials in the manufacturing industry are unlocked.

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“…The sheets were laser-cladded in cold-rolled and blank-annealed surface condition. For additional information about the used substrates and clamping devices, the reader may be referred to [25]. AISI 316L austenitic stainless steel with nominal powder size distributions of 20-53 µm (GTV Verschleißschutz GmbH, Luckenbach, Germany), as well as 50-150 µm (DEW Specialty Steel GmbH and Co. KG, Krefeld, Germany) were employed as feedstock.…”

Section: Materials and Process Setupmentioning

confidence: 99%

High-Speed Laser Cladding on Thin-Sheet-Substrates—Influence of Process Parameters on Clad Geometry and Dilution

2021

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Laser-based Directed Energy Deposition (DED-LB) represents a production method of growing importance for cladding and additive manufacturing through the use of metal powders. Yet, most studies utilize substrate materials with thicknesses of multiple millimeters, for which laser cladding of thin-sheet substrates with thicknesses less than 1 mm have only been scarcely studied in the literature. Most studies cover the use of pulsed laser sources, since sheet distortion due to excess energy input is a key problem in laser cladding of thin-sheet substrates. Hence, the authors of the present investigation seek to expand the boundaries of cladding thin-sheet substrates through the use of a high-speed laser cladding approach which utilizes a continuous-wave, ytterbium fiber laser and traverse speeds of 90 mms−1 to clad stainless steel sheets with a thickness of 0.8mm. Furthermore, fundamental process–property relationships for the target values of clad width, clad height, and dilution depth are studied and thoroughly discussed. Additionally, process maps for the target values are established based on manifold experiments, and the significance of process parameters on target values is studied using analysis of variance. The results demonstrate that clad widths as high as 1413 μm and dilution depths as low as 144 μm can be obtained by high-speed laser cladding of thin-sheet substrates. Thus, pathways toward thin-sheet substrates with enhanced performance are opened.

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On the Intergranular Corrosion Properties of Thin Ferritic Stainless Steel Sheets Welded by Fiber-Laser

Cited by 8 publications

References 19 publications

Formability Prediction of Laser-Welded Stainless Steel AISI 304 and AISI 430

Formability Prediction of Laser-Welded Stainless Steel AISI 304 and AISI 430

A Novel Approach to Inhibit Intergranular Corrosion in Ferritic Stainless Steel Welds Using High-Speed Laser Cladding

High-Speed Laser Cladding on Thin-Sheet-Substrates—Influence of Process Parameters on Clad Geometry and Dilution

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