Application of Hybrid Laser arc Welding for the Joining of Large Offshore Steel Foundations

Kristiansen, Morten; Farrokhi, Farhang; Kristiansen, Ewa; Villumsen, Sigurd

doi:10.1016/j.phpro.2017.08.018

Cited by 9 publications

(3 citation statements)

References 5 publications

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“…Laser welding is a flexible welding process capable of joining and manufacturing components in a variety of different materials, from polymers, steels, aluminium alloys, titanium alloys, copper alloys, to nickel-based superalloys, for a wide range of industries, such as medical, electronics, aerospace, automotive, and offshore industries [1][2][3][4][5][6]. The demand for welding applications capable of joining thick section structural steels in the shipbuilding, oil and gas, and offshore wind industries has led to significant research into laser welding and hybrid laser welding processes [5][6][7][8]. The high energy density of laser and hybrid laser welding processes can achieve deep penetration, high aspect-ratio welds at high welding speeds due to material vaporisation, and the formation of a laser keyhole, increasing weld productivity.…”

Section: Introductionmentioning

confidence: 99%

Study of the effect of inter-pass temperature on weld overlap start-stop defects and mitigation by application of laser defocusing

Lai

Ganguly

Suder

2021

Int J Adv Manuf Technol

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Laser keyhole initiation and termination-related defects, such as cracking and keyhole cavities due to keyhole collapse, are a well-known issue in laser keyhole welding of thick section steels. In longitudinal welding, run-on and run-off plates are used to avoid this problem. However, such an approach is not applicable in circumferential welding where start/stop defects remain within the workpiece. These issues can hinder industry from applying laser keyhole welding for circumferential welding applications. In this paper, the effect of inter-pass temperature on laser keyhole initiation and termination at the weld overlap start-stop region was investigated. This study has identified that defects occurring within this region were due to laser termination rather than laser initiation because of keyhole instabilities regardless of the thermal cycle. The laser termination defects were mitigated by applying a laser defocusing termination regime to reduce the keyhole depth gradually and control the closure of the keyhole.

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Section: Introductionmentioning

confidence: 99%

Study of the effect of inter-pass temperature on weld overlap start-stop defects and mitigation by application of laser defocusing

Lai

Ganguly

Suder

2021

Int J Adv Manuf Technol

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“…Many studies concerning hybrid welding technology have been conducted so far [6,7,8,9]. Zhang et al [6] have succeeded in achieving a full penetration welded joint without visible flaws on the 40-mm thick plates of 316L austenitic stainless-steel by optimizing the laser-arc hybrid welding process.…”

Section: Introductionmentioning

confidence: 99%

“…Zhang et al [6] have succeeded in achieving a full penetration welded joint without visible flaws on the 40-mm thick plates of 316L austenitic stainless-steel by optimizing the laser-arc hybrid welding process. Kristiansen et al [7] produced steady joints with adequate penetration for the flat position of the butt joint on the offshore steel by investigating the performance of different weldment types and welding positions in the hybrid laser-arc welding process. Son et al [8] found that the hardness values of the heat-affected and fusion zones are higher than that of the base metal zone in laser-arc hybrid-welded boron steel.…”

Section: Introductionmentioning

confidence: 99%

Effect of Quenching Tempering-Post Weld Heat Treatment on the Microstructure and Mechanical Properties of Laser-Arc Hybrid-Welded Boron Steel

et al. 2019

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In the present study, we have investigated the effect of post-welding heat treatment (PWHT) of quenching and tempering (QT) on the microstructure and mechanical properties of welded boron steel joints processed using laser-arc hybrid welding on two commercial filler materials, SM80 (Type-I) and ZH120 (Type-II). The microstructure and mechanical properties of the weld joints were characterized via optical microscopy, Vickers microhardness, and the uniaxial tensile test. The macrostructure of the weld joint was composed of a fusion zone (FZ), heat-affected zone (HAZ), and base metal zone (BMZ). After the QT-PWHT, the QT specimens revealed the V-shape hardness distribution across the weld joint, while the as-welded specimen exhibited the M-shape hardness distribution. As a result, the QT specimens revealed the premature fracture with little reduction in the area at the interface between the HAZ and FZ, while the as-welded specimen exhibited the local necking and rupture in the BMZ. In addition, the Type-II filler material with a greater value of equivalent carbon content was rarely influenced by the tempering, maintaining its hardness in the as-quenched status, while the Type-I filler material showed a gradual decrease in hardness with the tempering time. The results demonstrate that the Type-II weld joint outperformed the Type-I weld joint in terms of the structural integrity of welded parts.

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Physical mechanism of laser-excited acoustic wave and its application in recognition of incomplete-penetration welding defect

Cai

Luo

Wang

et al. 2022

Int J Adv Manuf Technol

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Incomplete penetration is a type of welding defect that severely impacts the quality of weldments. In order to identify penetration levels in pulsed laser and plasma transferred arc (laser-PTA) hybrid welding, this paper uses structure-borne acoustic sensors to detect acoustic signals. Their characteristics are then analyzed with respect to the time and frequency domains. Acoustic signals characteristic of incompletepenetration defects were extracted using a Butterworth band-pass lter. Physical mechanisms of laser excited acoustic wave were then studied by analyzing the correlation between incomplete-penetration defects and their characteristic acoustic signals. The results showed that acoustic signals correlating to incomplete-penetration defects have characteristic frequencies ranging from 0 to 10 kHz, which are generated by interaction between the pulsed laser beam and molten pool. An incomplete-penetration defect constitutes an acoustic cavity, which is an acoustic transmission structure. The structure of phonation sources and the acoustic cavity are affected by levels of penetration, giving rise to acoustic signals with different characteristics. In general, the study of physical mechanisms of laser excited acoustic wave lays a foundation for on-line identi cation of incomplete-penetration defects in laser-PTA hybrid welding.

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Application of Hybrid Laser arc Welding for the Joining of Large Offshore Steel Foundations

Cited by 9 publications

References 5 publications

Study of the effect of inter-pass temperature on weld overlap start-stop defects and mitigation by application of laser defocusing

Study of the effect of inter-pass temperature on weld overlap start-stop defects and mitigation by application of laser defocusing

Effect of Quenching Tempering-Post Weld Heat Treatment on the Microstructure and Mechanical Properties of Laser-Arc Hybrid-Welded Boron Steel

Physical mechanism of laser-excited acoustic wave and its application in recognition of incomplete-penetration welding defect

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