A comprehensive study on the microstructure and mechanical properties of arc girth welded joints of spiral welded high strength API X70 steel pipe

Węglowski, M. S.; Dymek, S.; Kopyściański, Mateusz; Niagaj, J.; Rykała, Janusz; Waele, Wim De; Hertelé, Stijn

doi:10.1007/s43452-020-00018-0

Cited by 18 publications

(5 citation statements)

References 26 publications

(43 reference statements)

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“…In addition, traces of Widmanstätten ferrite (αw) were also observed. Finally, the fusion zone is similar to a typical fusion zone as seen in many welded steels [15], as it is formed of elongated ferritic grains as indicated by the yellow circle and Widmanstätten ferrite (αw). As mentionned by Fajt et al [16] the microstructure in fusion zone which has been heated above the liquidus temperature is characterized by a typical casting structure.…”

Section: Microstructuresupporting

confidence: 57%

Thermal Cycle Simulation of Heat Affected Zone in the Welded Mild Steel

Hamdi,

Boumerzoug,

Bedjaoui

et al. 2024

KEM

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The aim of this work was to study the microstructure evolution of simulated heat affected zone in mild steel using thermal cycle simulation and it was compared to the heat affected zone in the real welded joint. The optical microscopy, micro-hardness measurements, X-ray diffraction were used as characterization techniques. The microstructures and mechanical properties of the simulated heat affected zone were also determined. The use of the thermal cycle simulation technique revealed in detail the different microstructures in the heat affected zone (HAZ) of the welded joint. Some similarities were observed between the heat affected zone obtained by the thermal cycle simulation technique and the heat affected zone observed in the real welded joint. The thermal cycle simulation technique revealed more details about the microstructure and mechanical behavior of the heat-affected zone. The HAZ microhardness values were lowest hardness in the welded joint. Moreover, the lowest hardness value is obtained for the HAZ simulated at 850°C.

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Section: Microstructuresupporting

confidence: 57%

Thermal Cycle Simulation of Heat Affected Zone in the Welded Mild Steel

Hamdi,

Boumerzoug,

Bedjaoui

et al. 2024

KEM

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“…The HAZ width variation observed by optical microscopy was supported by the measurements of hardness profiles from the cut edge towards the base metal (Figure 2). The hardness profile shape varied with the cutting method and steel composition, although the presence of a hardness minimum at a certain distance from the cut edge was observed previously in welded steels with acicular ferrite and bainite microstructure [33]. In Steel L both oxy-fuel and plasma cutting methods decreased hardness by a maximum of 100 HV from its original hardness of 400 HV (Figure 2a,b); and in Steel H this decrease was slightly higher, by about 130 HV from its original hardness of 500 HV (Figure 2d,e).…”

Section: Hardness Profilesupporting

confidence: 51%

Edge Microstructure and Strength Gradient in Thermally Cut Ti-Alloyed Martensitic Steels

Kostryzhev

Rizwan

Killmore³

et al. 2021

Metals

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Recently developed Ti-alloyed martensitic steels are believed to exhibit higher wear resistance than traditionally quenched and tempered medium carbon steels. However, their properties may deteriorate during thermal cutting and welding as a result of microstructure tempering. This would present significant challenges for the metal fabrication industries. A decrease in strength and wear resistance associated with tempering should vary with steel composition, initial steel microstructure and properties, and cutting method. In this work, we investigated the effect of thermal cutting on the edge microstructure and properties in two alloyed plate steels containing 0.27C-0.40Ti and 0.39C-0.60Ti (wt.%) commercially rolled to 12 mm thickness. Three cutting methods were applied to each of the two plates: oxy-fuel, plasma and water-jet. Microstructure characterisation was carried out using optical and scanning electron microscopy. With an increase in thermal effect, from water-jet to plasma to oxy-fuel, the heat affected zone width increased and hardness decreased in both steels. However, the hardness profile from the cut edge to the base metal significantly varied with steel composition, particularly C and Ti contents. The dependence of grain structure and precipitation kinetics on steel composition, and cutting method, were thoroughly investigated and linked to the hardness profile variation. The obtained results will be used to optimise the technological parameters for cutting and welding of Ti-alloyed martensitic steels.

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“…The F was also observed in the root pass of X70 girth weld from other researchers. [ 35 ] The lower strength and hardness of root welding zone are mainly induced by the welding wire materials of lower strength for root passes for X70 and X80 girth welds. The PF in the root welding zone mainly formed from the original welding wire material.…”

Section: Resultsmentioning

confidence: 99%

Multiscale Characterizations of Local Properties for Girth Welds of X70 and X80

Cao

Zhao³

et al. 2022

Adv Eng Mater

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As pipeline design standards require the parameters of mechanical properties, it is crucial to characterize local properties of grith weld. Consequently, the multiscale characterizations based on indentations are performed to study the local properties of these typical zones: weld metal, heat affected zone (HAZ), fusion zone, and base material. The microhardness is measured for entire girth welds of X70 and X80, and the nanohardness is also obtained to analyze the differences in typical zones of girth welds. Subsequently, the yield strength and ultimate tensile strength in the typical zones of girth welds are characterized by spherical indentation method to analyze the distributions of strength and local hardening capacity. Furthermore, the microstructures of girth welds for X70 and X80 in terms of typical zones are studied to analyze the responses of local properties. Results show that the hardness of cap, filler, and root layers for X70 follows the sequence of cap>filler>root, while that of X80 follows the sequence of filler>cap>root. The softening effect of HAZ is existed in the girth weld of X70. The low hardness and strength in root layer are attributed to polygonal ferrite.

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A comprehensive study on the microstructure and mechanical properties of arc girth welded joints of spiral welded high strength API X70 steel pipe

Cited by 18 publications

References 26 publications

Thermal Cycle Simulation of Heat Affected Zone in the Welded Mild Steel

Thermal Cycle Simulation of Heat Affected Zone in the Welded Mild Steel

Edge Microstructure and Strength Gradient in Thermally Cut Ti-Alloyed Martensitic Steels

Multiscale Characterizations of Local Properties for Girth Welds of X70 and X80

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