Fatigue strength of hot-dip galvanized S960 cut edges and longitudinal welds

Lipiäinen, Kalle; Ahola, Antti; Virolainen, Esa; Hirvi, Ari Mikael; Björk, Timo

doi:10.1016/j.jcsr.2021.107083

Cited by 8 publications

(3 citation statements)

References 8 publications

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“…The fatigue performance of FL N2 cut edges was at expected level based on previous studies. Hotdip galvanized unnotched S960 t = 6 mm specimens with nitrogen assisted laser cut edges were fatigue tested in [14] and FAT 144 MPa m = 3 was obtained with estimated initial crack length of 150 μm, which corresponded for HAZ width, due to liquid metal assisted cracking. Based on polished sections and fractography analyses, enough material should be removed (up to 0.5 mm), if fatigue performance is increasing with grinding, to remove sub-surface crack-like features.…”

Section: Discussionmentioning

confidence: 99%

Fatigue performance of fiber laser fusion cut edges on thick plates

Lipiäinen,

Ahola,

Afkhami

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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Fatigue performance of cut edges is an important factor in structural design, especially when geometrical stress concentration factors (SCFs) are present. High power laser cutting systems have enabled efficient and fast fusion cutting with nitrogen as an assistant gas. The fusion cutting induces recast layer, which features crack-like defects close to cut edge. In this study, plates with thickness 16 ≤ t ≤ 30 mm have been fatigue-tested. A 10 kW fiber laser cutting system was used to cut plates with nitrogen as an assistant gas. High strength steel (HSS) S690 specimens included unnotched coupon specimens and welded T-profile with longitudinal gusset in post-weld treated conditions, where laser cut edge was found critical. Fatigue performance of S690 cut edges were found close to 170 MPa m = 3 when SCFs of welded specimens were included on analysis. Local properties at the cut edge including hardness measurements and scanning electron microscope (SEM) fractography. Fractography obtained local quality use with theory of critical distances -based fatigue strength assessment was demonstrated.

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Section: Discussionmentioning

confidence: 99%

Fatigue performance of fiber laser fusion cut edges on thick plates

Lipiäinen,

Ahola,

Afkhami

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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“…Higher stresses in structures cause increased demands in the quality requirements in design and manufacturing [4]. Fatigue design aspects are especially emphasised in order to effectively utilise the higher material strength of UHSSs in structures [5].…”

Section: Introductionmentioning

confidence: 99%

Fatigue design of stress relief grooves to prevent weld root fatigue in butt-welded cast steel to ultra-high-strength steel joints

Havia,

Lipiäinen,

Ahola

et al. 2024

Weld World

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In the welded joints, fatigue failures typically originate from defects or notch-like geometries under cyclic loading. This study investigates the impact of stress relief grooves (SRG) on the fatigue performance of butt-welded cast steel to ultra-high-strength steel components using experimental fatigue tests and finite element method. The experiments examined the fatigue properties of hybrid joints between G26CrMo4 cast steel (t = 20 mm) and S960 steel plate (t = 6 mm) with and without SRG. Gas metal arc welding process was used to weld the butt joints that had a permanent root backing machined on the cast steel part, causing a crack-like defect to the weld root. Additionally, the top surfaces of the welded parts were aligned, resulting in a significant axial misalignment in the butt joint. The SRG, positioned close to the weld root, was found to have a beneficial influence on the joint’s fatigue performance by a factor of 1.2 when using the nominal stress criterion. However, the fatigue capacity was still roughly 35% lower compared to the symmetrical equivalent due to the secondary bending stress, caused by axial misalignment. The finite element analyses indicated that the SRG reduces the amount of secondary stresses at the weld root leading to lower total structural stress. The study recommends using the FAT80 (m = 3) design curve in the structural stress method, for similar butt-welds having a crack-like defect, parallel to the loading direction, at the weld root. However, for welded joints with crack-like defects, it is advisable to use linear elastic fracture mechanics rather than relying solely on stress-based local approaches.

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“…When steel materials are used in sea water or the atmosphere for a long time, they will fail owing to the electrochemical corrosion caused by sea water in the ocean or water in the atmosphere [1,2]. Hot dip galvanising is widely used for steel protection because of its simple process and low cost [3,4].…”

Section: Introductionmentioning

confidence: 99%

Effect of indium on the microstructure and corrosion resistance of the galvanising coating

Wang

Zhao

et al. 2023

Materials Science and Technology

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The addition of alloying elements to a zinc bath is an effective method to inhibit silicon reactivity while galvanising silicon-containing steel. In this work, the effect of indium on the microstructure and corrosion resistance of galvanising coating on the Q235 steel was investigated. The results show that indium can promote the dense Γ phase to form, 0.79 wt-% Si can be dissolved in the ζ phase with the addition of indium into the zinc bath, which decreased the segregation of silicon at ζ phase boundaries and reduced the liquid phase channel, and inhibited the rapid growth of the ζ phase. Indium can improve the corrosion resistance of the coating. Compared with pure zinc coating, the self-corrosion current of Zn-0.4In coating decreased by 9.59 µA/cm2.

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Fatigue strength of hot-dip galvanized S960 cut edges and longitudinal welds

Cited by 8 publications

References 8 publications

Fatigue performance of fiber laser fusion cut edges on thick plates

Fatigue performance of fiber laser fusion cut edges on thick plates

Fatigue design of stress relief grooves to prevent weld root fatigue in butt-welded cast steel to ultra-high-strength steel joints

Effect of indium on the microstructure and corrosion resistance of the galvanising coating

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