Probing Pulsed Current Gas Metal Arc Welding for Modified 9Cr-1Mo Steel

Krishnan, S.; Kulkarni, D. V.; De, A.

doi:10.1007/s11665-015-1430-4

Cited by 9 publications

(5 citation statements)

References 11 publications

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“…Figure 7 shows the distribution of spherical micro-inclusions with Al, Si, Mn and Fe respectively around 5.96%, 5.77%, 7.86% and 79.59% as obtained from an SEM–energy dispersive spectroscopy analysis. An inclusion rating analysis as per ASTM E-45:2013 38 has shown that the size of these inclusions is lesser than 2 μm that is significantly lower than those obtained in FCAW 11 and single-pass GMAW-P. 32 The smaller size of inclusions in multipass GMAW-P of P91 welds is attributed to the remelting of the underneath weld beads during multiple weld passes and resulting disintegration of the coarser micro-inclusions and formation of numerous finer particles.…”

Section: Resultsmentioning

confidence: 90%

“…30,31 A recent study on single-pass GMAW-P of P91 steel showed a fair improvement of the weld chemistry and mechanical properties over the similar joints prepared using conventional GMAW. 32 A detailed investigation on multipass GMAW-P of 12 mm thick P91 steel is undertaken in the present work. The effects of welding current, speed and groove geometry on the bead profile, weld chemistry and oxygen content, weld toughness and tensile strengths and susceptibility to the formation of delta ferrite and nonmetallic inclusions are examined.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Multipass pulsed current gas metal arc welding of P91 steel

Krishnan

Kulkarni

2016

Science and Technology of Welding and Joining

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Conventional gas metal arc welding of modified 9Cr-1Mo steels referred to as P91 steels is considered difficult due to loss of alloying elements and degradation of weld joint properties. In comparison to the conventional process, pulsed current gas metal arc welding allows more accurate control of heat input per unit length and electrode deposition and, thus, can be more suitable for the joining of P91 steel. A detailed experimental study is therefore undertaken to examine the roles of welding current, speed and groove angle in the weld bead profiles and joint properties in multipass pulsed current gas metal arc welding of 12 mm thick P91 steel. The results show that the joint properties are strongly influenced by the heat input per unit length and the groove angle. A groove angle of 758 and an appropriate choice of process conditions resulted in fairly acceptable bead profiles and joint properties.

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Section: Resultsmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

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Multipass pulsed current gas metal arc welding of P91 steel

Krishnan

Kulkarni

2016

Science and Technology of Welding and Joining

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“…MSAW and FCAW are two distinct processes, although they have many similarities in equipment and application. Both processes utilize a continuous wire-feed as the filler metal, and both employ gas and a flux to shield the arc and Weld Metal (WM) as well as preventing the molten metal from oxidation [ 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

Post-Weld Heat Treatment of API 5L X70 High Strength Low Alloy Steel Welds

et al. 2020

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High Strength Low Alloy (HSLA) steels are the materials of choice in pipeline construction with the API X70 grade as the steel for the majority of pipeline networks constructed during the late 20th and early this century. This paper reports on the influence of Post-Weld Heat Treatment (PWHT) on the reduction of residual stresses, resulting changes in the microstructure, and mechanical properties of a multi-pass, X70 HSLA steel, weld joints made by a combined Modified Short Arc Welding (MSAW) and Flux Cored Arc Welding (FCAW) processes. Neutron diffraction results highlighted high magnitude of tensile residual stresses, in excess of yield strength of both parent and weld metal, in the as-welded specimen (~650 MPa), which were decreased substantially as a result of applying PWHT (~144 MPa). Detailed microstructural studies are reported to confirm the phase transformation during PWHT and its interrelationship with mechanical properties. Transmission Electron Microscopy (TEM) analysis showed polygonization and formation of sub-grains in the PWHT specimen which justifies the reduction of residual stress in the heat-treated weld joints. Furthermore, microstructural changes due to PWHT justify the improvement in ductility (increase in the elongations) with a slight reduction in yield and tensile strength for the PWHT weld joint.

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“…Uma corrente sucientemente baixa, denominada Corrente de Base, que tem como nalidade manter o arco e que não gera a transferência, mas produz o início da fusão; o outro é um nível alto, denominado Corrente de Pico, que gera energia suciente para fundir o arame e destacar a gota da sua extremidade, dando boa penetração ao cordão de solda. Este processo de soldagem produz cordões de solda com uma alta qualidade e livre de defeitos [23]. Adicionalmente, resulta em menor nível de distorções e maior controle da poça de fusão, o que possibilita a soldagem fora de posição [24].…”

Section: Transferência Pulsadaunclassified

Água como tema CTS no ensino médio : uma proposição

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This work presents a study on the bead deposition planning strategy in order to allow the use of robotic welding on the task of lling the crack removal cavity. Therefore, when thinking about dening the necessary sequence and the distribution of weld beads to ll the cavity with metal, such that the deposition process can be robotized, some problems arise related to the bead section geometry dependence on the welding parameters and on the welding position. Such geometry will strongly inuence the number of layers of weld beads needed, considering that the lling process is carried out in layers. In this case, the rst problem to be faced is the denition of the distance between parallel beads necessary for the deposition of a at weld layer. The second problem is the layer thickness that results from the selected distance between parallel beads within a layer. This work, therefore, addresses the two previously cited problems by developing statistical models that can map the bead section geometry variations due to changes in welding parameters for the pulsed GMAW process. Then this methodology denes the strategy to determine the trajectory of weld beads of each layer in order to perform the geometric evaluation of the recovery and quality of the lling. Practical results of geometric point of view of the strategy of lling, applied to a cavity such as the one resulting from the removal of a crack are presented in order to validate the proposed methodology.

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Probing Pulsed Current Gas Metal Arc Welding for Modified 9Cr-1Mo Steel

Cited by 9 publications

References 11 publications

Multipass pulsed current gas metal arc welding of P91 steel

Multipass pulsed current gas metal arc welding of P91 steel

Post-Weld Heat Treatment of API 5L X70 High Strength Low Alloy Steel Welds

Água como tema CTS no ensino médio : uma proposição

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