Pulsed Nd: YAG laser welding and subsequent post-weld heat treatment on super duplex stainless steel

Saravanan, S.; Raghukandan, K.; Sivagurumanikandan, N.

doi:10.1016/j.jmapro.2016.12.015

Cited by 56 publications

(20 citation statements)

References 22 publications

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“…High heat input and small spot size of the laser combined with the fast welding process translates in narrow melted region (approximately 0.8 mm according to Figure 2) which limits the width of the HAZ thanks to the base material acting as a heat sink. In accordance with previous studies [8,9,32,33], it can be seen that the amount of ferrite in the weld zone (~60%) is remarkably higher compared to the base material (46,9%) due to the high cooling rate typical of the laser welding. The precise ferrite content in the HAZ could not be measured because the dimension of the eddy current probe was significantly bigger (~1 mm) than the extension of the zone (~50 µm).…”

Section: Eddy Currentssupporting

confidence: 91%

Microstructural and Corrosion Properties of Cold Rolled Laser Welded UNS S32750 Duplex Stainless Steel

Gennari

Lago

Bögre

et al. 2018

Metals

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The main goal of this work was to study the effect of plastic deformation on weldability of duplex stainless steel (DSS). It is well known that plastic deformation prior to thermal cycles can enhance secondary phase precipitation in DSS which can lead to significant change of the ferrite-austenite phase ratio. From this point of view one of the most important phase transformation in DSS is the eutectoid decomposition of ferrite. Duplex stainless steels (DSSs) are a category of stainless steels which are employed in all kinds of applications where high strength and excellent corrosion resistance are both required. This favorable combination of properties is provided by their biphasic microstructure, consisting of ferrite and austenite in approximately equal volume fractions. Nevertheless, these materials may suffer from several microstructural transformations if they undergo heat treatments, welding processes or thermal cycles. These transformations modify the balanced phase ratio, compromising the corrosion and mechanical properties of the material. In this paper, the microstructural stability as a consequence of heat history due to welding processes has been investigated for a super duplex stainless steel (SDSS) UNS S32750. During this work, the effects of laser beam welding on cold rolled UNS S32750 SDSS have been investigated. Samples have been cold rolled at different thickness reduction (ε = 9.6%, 21.1%, 29.6%, 39.4%, 49.5%, and 60.3%) and then welded using Nd:YAG laser. Optical and electronical microscopy, eddy’s current tests, microhardness tests, and critical pitting temperature tests have been performed on the welded samples to analyze the microstructure, ferrite content, hardness, and corrosion resistance. Results show that laser welded joints had a strongly unbalanced microstructure, mostly consisting of ferritic phase (~60%). Ferrite content decreases with increasing distance from the middle of the joint. The heat-affected zone (HAZ) was almost undetectable and no defects or secondary phases have been observed. Both hardness and corrosion susceptibility of the joints increase. Plastic deformation had no effects on microstructure, hardness or corrosion resistance of the joints, but resulted in higher hardness of the base material. Cold rolling process instead, influences the corrosion resistance of the base material.

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Section: Eddy Currentssupporting

confidence: 91%

Microstructural and Corrosion Properties of Cold Rolled Laser Welded UNS S32750 Duplex Stainless Steel

Gennari

Lago

Bögre

et al. 2018

Metals

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“…Besides the chemical composition of steels and welded joints [40,41], various technological factors and technical operations, such as heat treatment [42,43,44], nitrogen content in shielding gas [45,46,47,48], welding regimes [49], and repeated welding heat [50] etc., also significantly affect the corrosion resistance of welded joints metal. On the other hand, heat treatment can lead to the appearance or removal of welding deformations [51,52,53], and an undesirable change in the phase composition [54]. Studies of the influence of two types of heat treatment on the properties of a welded joint have been conducted because the literature does not provide experimental data on the effect of heat treatment on the corrosion resistance of welded joints obtained by the defocused laser beam.…”

Section: Introductionmentioning

confidence: 99%

Effect of Heat Treatment on the Phase Composition and Corrosion Resistance of 321 SS Welded Joints Produced by a Defocused Laser Beam

Kuryntsev

2019

Materials

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The effect of heat treatment of welded joints made of steel 321 on corrosion resistance, phase composition, residual stresses, and distribution of alloying elements was studied using optical microscope (OM) and scanning electron microscope (SEM), electron dispersive spectroscopy (EDS), X-ray diffraction (XRD), and intergranular corrosion testing (IGC). Samples previously obtained by the authors using defocused laser beam, which led to the formation of directionally crystallized austenite with lathy and skeletal δ-ferrite, were investigated. Based on X-ray diffraction studies in the base metal, the maximum number of peaks of various phases was presented, which decreased after exposure to the heating effect of the welding process and subsequent heat treatment. The distribution of alloying elements, in particular, Ti and Si, was significantly affected by heat treatment depending on the regimes. A spot chemical analysis showed that the nickel content differs in δ-ferrite and austenite by 1.5%–2% whereas the chromium content in these phases is not significantly different. Tests have shown that all samples have high resistance to intergranular corrosion, which can be explained by the insufficient dissolution of titanium carbides in austenite and the absence of chromium carbides formation along austenite grain boundaries, due to high cooling rates when welding by a defocused laser beam, and as a result, the high δ-ferrite content in which chromium dissolves.

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“…Employing the pulsed laser in UNS S32750 alloy created an epitaxial microstructure without any detrimental secondary phases, with a maximum of 80% of ferrite concentration in the FZ (Figure 9P,Q) [61]. In order to restore the equal microstructural balance and guarantee corrosion resistance, the researchers applied the PWHT, and the ferrite was reduced to 64% in this zone [62]. The exposition of 1050 • C for 2 h transformed the excess of columnar ferrite grains into Widmanstätten austenite (Figure 9R).…”

Section: Stainless Steelmentioning

confidence: 99%

Pulsed Laser Welding Applied to Metallic Materials—A Material Approach

Chludzinski

Santos

Churiaque

et al. 2021

Metals

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Joining metallic alloys can be an intricate task, being necessary to take into account the material characteristics and the application in order to select the appropriate welding process. Among the variety of welding methods, pulsed laser technology is being successfully used in the industrial sector due to its beneficial aspects, for which most of them are related to the energy involved. Since the laser beam is focused in a concentrated area, a narrow and precise weld bead is created, with a reduced heat affected zone. This characteristic stands out for thinner material applications. As a non-contact process, the technique delivers flexibility and precision with high joining quality. In this sense, the present review addresses the most representative investigations developed in this welding process. A summary of these technological achievements in metallic metals, including steel, titanium, aluminium, and superalloys, is reported. Special attention is paid to the microstructural formation in the weld zone. Particular emphasis is given to the mechanical behaviour of the joints reported in terms of microhardness and strength performance. The main purpose of this work was to provide an overview of the results obtained with pulsed laser welding technology in diverse materials, including similar and dissimilar joints. In addition, outlook and remarks are addressed regarding the process characteristics and the state of knowledge.

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Pulsed Nd: YAG laser welding and subsequent post-weld heat treatment on super duplex stainless steel

Cited by 56 publications

References 22 publications

Microstructural and Corrosion Properties of Cold Rolled Laser Welded UNS S32750 Duplex Stainless Steel

Microstructural and Corrosion Properties of Cold Rolled Laser Welded UNS S32750 Duplex Stainless Steel

Effect of Heat Treatment on the Phase Composition and Corrosion Resistance of 321 SS Welded Joints Produced by a Defocused Laser Beam

Pulsed Laser Welding Applied to Metallic Materials—A Material Approach

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