Role of bainitic microstructures with M-A constituent on the toughness of an HSLA steel for seismic resistant structural applications

Ramachandran, Dileep Chandran; Moon, Joonoh; Lee, Chang‐Hoon; Kim, Sung Dae; Chung, Jihoon; Biro, E.; Park, Yeong-Do

doi:10.1016/j.msea.2020.140390

Cited by 53 publications

(17 citation statements)

References 31 publications

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“…The high CVN energies are attributed to the maintenance of the ferritic microstructure in all cases. Figures 8 and 12 show that in both the CGHAZ and ICCGHAZ, M-A-C was formed with slender and massive morphologies [34,43]. Several studies have investigated the in uence of the M-A-C morphology on the toughness.…”

Section: Mechanical Testingmentioning

confidence: 99%

Effect of the Interpass Temperature on Simulated Heat-Affected Zone of Gas Metal Arc Welded API 5L X70 Pipe Joint

Dornelas

Filho

Oliveira

et al. 2021

Preprint

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Welding costs associated with the laying of pipes for deepwater oil and gas extraction can be reduced using high interpass temperatures (ITs). However, a high IT can decrease the mechanical properties of the heat-affected zone (HAZ) of welded joints. With the use of high strength-toughness stees, this decrease may be an acceptable trade-off. Therefore, it is necessary to evaluate the influence of high ITs on the HAZ. The influence of the IT on the coarse grain HAZ (CGHAZ) and intercritically reheated coarse-grain HAZ (ICCGHAZ) of an API 5L X70 pipe joint welded by gas metal arc welding was investigated. The welding was numerically simulated using finite element method software. The microstructure of the HAZ was predicted using thermodynamic simulation software. The CGHAZ and ICCGHAZ were also physically simulated and evaluated via optical microscopy and scanning electron microscopy, dilatometry, and Vickers microhardness and Charpy V-notch (CVN) impact tests. The increase in IT led to a decrease in CGHAZ microhardness, but did not affect the ICCGHAZ. The CVN energies obtained for all ITs (CGHAZ and ICCGHAZ) were higher than that set by the DNVGL-ST-F101 standard (50 J). These results show that increasing the IT is an interesting and effective method to reduce welding costs. In addition, thermodynamic simulation proved to be a valid method for predicting the phases in the HAZ of API 5L X70 pipe welded joints.

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Section: Mechanical Testingmentioning

confidence: 99%

Effect of the Interpass Temperature on Simulated Heat-Affected Zone of Gas Metal Arc Welded API 5L X70 Pipe Joint

Dornelas

Filho

Oliveira

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…The high CVN energies are attributed to the maintenance of the ferritic microstructure in all cases. Figures 8 and 12 show that in both the CGHAZ and ICCGHAZ, M-A-C was formed with slender and massive morphologies [34,43]. Several studies have investigated the influence of the M-A-C morphology on the toughness.…”

Section: Mechanical Testingmentioning

confidence: 99%

Effect of the interpass temperature on simulated heat-affected zone of gas metal arc welded API 5L X70 pipe joint

Dornelas

Filho

Oliveira

et al. 2021

Int J Adv Manuf Technol

View full text Add to dashboard Cite

Welding costs associated with the laying of pipes for deepwater oil and gas extraction can be reduced using high interpass temperatures (ITs). However, a high IT can decrease the mechanical properties of the heat-affected zone (HAZ) of welded joints. With the use of high strength-toughness steels, this decrease may be an acceptable trade-off. Therefore, it is necessary to evaluate the influence of high ITs on the HAZ. The influence of the IT on the coarse-grain HAZ (CGHAZ) and intercritically reheated coarse-grain HAZ (ICCGHAZ) of an API 5L X70 pipe joint welded by gas metal arc welding was investigated. The welding was numerically simulated using finite element method software. The microstructure of the HAZ was predicted using thermodynamic simulation software. The CGHAZ and ICCGHAZ were also physically simulated and evaluated via optical microscopy and scanning electron microscopy, dilatometry, and Vickers microhardness and Charpy V-notch (CVN) impact tests. The increase in IT led to a decrease in CGHAZ microhardness but did not affect the ICCGHAZ. The CVN energies obtained for all ITs (CGHAZ and ICCGHAZ) were higher than that set by the DNVGL-ST-F101 standard (50 J). These results show that increasing the IT is an interesting and effective method to reduce welding costs. In addition, thermodynamic simulation proved to be a valid method for predicting the phases in the HAZ of API 5L X70 pipe welded joints.

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“…Amount of studies indicated that the impact toughness of CGHAZ decreases with the increase of heat input [2][3][4]. At high heat input, the prior austenite grain (PAG) was coarsened in the CGHAZ of micro-alloyed steel [5].…”

Section: Introductionmentioning

confidence: 99%

Improvement of impact toughness by microstructure refinement of simulated CGHAZ through enhancing welding heat input of low carbon Mo-V-Ti-N-B steel

Fan¹,

Shi²,

Wang³

et al. 2022

Mater. Res. Express

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Welding heat input greatly influences the microstructure and impacts the affected zone's toughness. To interpret the relationships between the welding heat input, microstructure, and low-temperature toughness of the coarse-grained heat-affected zone (CGHAZ) of Mo-V-Ti-N-B steels, welding heat cycles with different heat inputs (25–75 kJ/cm) were performed on a Gleeble 3500 simulator. Intragranular ferrite in the simulated samples subjected to different thermal cycles was characterized and quantified, and the impact energies of simulated samples were evaluated at -20 °C. Upon increasing the heat input, the intragranular ferrite content rose sharply from 4.3% to 76.0%. The V(C,N) enrichment on the precipitate surface increased the size of precipitates, providing favourable nucleation conditions for intragranular ferrite. The prior austenite grain (PAG) and martensite/austenite (M/A) constituents became rough, and the content of the M/A constituent increased while the impact energy of the CGHAZ increased. This behaviour occurred due to the formation of intragranular acicular ferrite (IGAF), which refined the microstructure of the CGHAZ. Grain refinement eliminated the negative influence of higher M/A content on the impact toughness of the CGHAZ.

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Role of bainitic microstructures with M-A constituent on the toughness of an HSLA steel for seismic resistant structural applications

Cited by 53 publications

References 31 publications

Effect of the Interpass Temperature on Simulated Heat-Affected Zone of Gas Metal Arc Welded API 5L X70 Pipe Joint

Effect of the Interpass Temperature on Simulated Heat-Affected Zone of Gas Metal Arc Welded API 5L X70 Pipe Joint

Effect of the interpass temperature on simulated heat-affected zone of gas metal arc welded API 5L X70 pipe joint

Improvement of impact toughness by microstructure refinement of simulated CGHAZ through enhancing welding heat input of low carbon Mo-V-Ti-N-B steel

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