An evaluation of multipass narrow gap laser welding as a candidate process for the manufacture of nuclear pressure vessels

Feng, Jia; Rathod, Dinesh W.; Roy, Matthew; Francis, J. A.; Guo, Wei; Irvine, Neil; Vasileiou, Anastasia; Sun, Yongle; Smith, Marcus; Li, Lin

doi:10.1016/j.ijpvp.2017.08.004

Cited by 30 publications

(9 citation statements)

References 14 publications

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“…It consists of the application of additional beads inside an existing weld or on its face layer. The area of application of this technique mainly involves air repair welding using the MMA, TIG and FCAW processes in the power [22] and pressure equipment industry [23]. TBW provides local heat treatment to prior weld layers and their HAZ.…”

Section: Introductionmentioning

confidence: 99%

Advantages of the Application of the Temper Bead Welding Technique During Wet Welding

2019

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Thermo-mechanically rolled S460ML steel was chosen for welding in underwater wet welding conditions by covered electrodes. The main aim of this study was to check the weldability for fillet welds in a water environment by controlled thermal severity (CTS) tests and to check the influence of temper bead welding (TBW) on the weldability of the investigated steel. Non-destructive and destructive tests showed that S460ML steel has a high susceptibility to cold cracking. In all joints, hardness in the heat-affected zone (HAZ) was extended to the 400 HV10 values. Microscopic testing showed the presence of microcracks in the HAZ of all welded joints. TBW was chosen as the method to improve the weldability of the investigated steel. This technique allows for the reduction of the maximum hardness in the HAZ below the critical value of 380 HV10, as stated by the EN-ISO 15614-1:2017. It was determined that for S460ML steel, from the point of view of weldability, the pitch between two beads should be in the range 75%–100%. Also, if the pitch between two beads increases, the hardness, grain size, and number of cracks decreases. In all specimens where the hardness of the HAZ was below 380 HV10, there were no microcracks.

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Section: Introductionmentioning

confidence: 99%

Advantages of the Application of the Temper Bead Welding Technique During Wet Welding

2019

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“…= M M + B B + F/P F/P ( F + P ) + A A + b0 b0 (6) where Hv, Hv M , Hv B , Hv F/P , Hv A and Hv b0 are the Vickers micro-hardness of the whole mixture, martensite, bainite, ferrite (or pearlite), austenite and base material, respectively; X M , X B , X F , X P , X A and X b0 are the fractions of martensite, bainite, ferrite, pearlite, austenite and base material, respectively. For each ferritic phase, empirical hardness equations in terms of chemical composition and cooling rate are used [22].…”

Section: Accepted Manuscript N O T C O P Y E D I T E Dmentioning

confidence: 99%

“…The predicted sensitivity of microstructure to dilution (Figs. [6][7][8] shows that increasing dilution leads to higher fractions of martensite in both as-deposited and reheated weld metals. Accordingly, high dilution suppresses the tendency of the formation of bainite and ferrite in weld metal.…”

Section: Accepted Manuscript N O T C O P Y E D I T E Dmentioning

confidence: 99%

“…Welding is extensively used in the fabrication of pressure vessels, among other engineering applications, and weldments usually play a critical role in determining the performance and life of these structures [1][2][3]. Currently, the joining of thick-section components, such as those used in nuclear reactor pressure vessels, relies on multi-pass arc welding [4][5][6][7]. It is almost always the case…”

Section: Introductionmentioning

confidence: 99%

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Prediction of Dilution and Its Impact on the Metallurgical and Mechanical Behavior of a Multipass Steel Weldment

Sun

Hamelin

Flint

et al. 2019

Journal of Pressure Vessel Technology

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A three-pass groove weld made by gas-tungsten arc welding in a 20-mm thick SA508 steel plate is modeled to predict the thermal, metallurgical, and mechanical behavior. The dilution for each pass is estimated as the proportion of base material in the weld metal, based on the predicted cross-sectional areas for the fusion zone (FZ) associated with each individual pass. The temperature predictions are consistent with the thermocouple measurement data and cross-weld macrographs. The predicted microstructures are qualitatively compared with the observed microstructures in cross-weld optical micrographs. The measured hardness is then used to quantitatively validate the predictions for postweld microconstituents (e.g., the ferrite, bainite, and martensite fractions), based on a hardness-microstructure correlation. The predicted residual stresses are compared with those measured by neutron diffraction. The results show that the dilution significantly affects the metallurgical and mechanical properties of weld metal (either as-deposited or reheated), and its consideration notably improves the predictions for microstructure and residual stress in the multipass steel weldment. Furthermore, the increase in dilution promotes the formation of martensite, which enhances the hardness, and leads to lower tensile stresses (or higher compressive stresses) in the weld metal. Such behavior arises due to the higher hardenability of the base material employed in this study, coupled with delayed austenite decomposition on cooling.

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“…The local mechanical properties at the BM, HAZ and inhomogeneous weld should be considered in order to consider the structural integrity for designing the weld structures. In the past, detailed experimental investigations were carried out for multi pass welds to analyse the local mechanical performance inside the weld and HAZ [ 21 , 22 , 23 , 24 , 25 ] in the SENB specimen. It is known that mechanical properties such as spatial yield stresses vary within the hardener and softer zones (HAZs) and the weld region.…”

Section: Introductionmentioning

confidence: 99%

The Numerical Modelling Approach with a Random Distribution of Mechanical Properties for a Mismatched Weld

2021

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The aim of this work was to include a local variation in material properties to simulate the fracture behaviour in a multi-pass mis-matched X-weld joint. The base material was welded with an over and under-match strength material. The local variation was represented in a finite element model with five material groups in the weld and three layers in the heat-affected zone. The groups were assigned randomly to the elements within a region. A three-point single edge notch bending (SENB) fracture mechanics specimen was analysed for two different configurations where either the initial crack is in the over or under-matched material side to simulate experimentally obtained results. The used modelling approach shows comparable crack propagation and stiffness behaviour, as well as the expected, scatter and instabilities of measured fracture behaviour in inhomogeneous welds.

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An evaluation of multipass narrow gap laser welding as a candidate process for the manufacture of nuclear pressure vessels

Cited by 30 publications

References 14 publications

Advantages of the Application of the Temper Bead Welding Technique During Wet Welding

Advantages of the Application of the Temper Bead Welding Technique During Wet Welding

Prediction of Dilution and Its Impact on the Metallurgical and Mechanical Behavior of a Multipass Steel Weldment

The Numerical Modelling Approach with a Random Distribution of Mechanical Properties for a Mismatched Weld

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