Metallurgical analysis of ASME SA213 T12 boiler vertical water-wall tubes failure

Khedr, Mahmoud; Abd‐Elaziem, Walaa; Newishy, M.; Abdel-Aleem, H.

doi:10.1016/j.engfailanal.2022.107016

Cited by 11 publications

(5 citation statements)

References 34 publications

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“…While the whole steam boiler is made of 20 steel and the steam pipeline is composed of 316L stainless steel, the safe-end feedwater line is welded with both kinds of steel [ 4 , 5 , 6 ]. In the field investigation, under abnormal working conditions, leakage caused by corrosion at the weld of the safe-end feedwater lines often leads to equipment failure, as shown in Figure 1 .…”

Section: Introductionmentioning

confidence: 99%

Investigation of Multi-Factor Stress Corrosion Cracking Failure of Safe-End Feedwater Lines of Submarine Power System

Ji,

Zheng,

Qin

et al. 2024

Materials

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The corrosion process under the complex safe-end feedwater line conditions was investigated via experimental lab testing and numerical simulation. The corrosion of safe-end feedwater lines was controlled through the combination of galvanic corrosion, residual stress, and flow velocity. Firstly, galvanic corrosion occurred once the 20 steel was welded with 316L stainless steel. The pitting corrosion could be observed on the 20 steel side of the weld joint. Secondly, a vortex flow was detected around the welding bump and within the pits. The growth of the pits was accelerated in both the vertical and horizontal directions. Finally, under the residual stress condition, the stress intensity factor (K) at the bottom of the pits was easier to reach than the critical stress intensity factor (KISCC). Then, pitting was transformed into stress corrosion cracking which then propagated along the weld line. Therefore, the critical factor inducing the failure of safe-end feedwater lines was the combined action of galvanic corrosion, residual stress, and flow velocity.

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Section: Introductionmentioning

confidence: 99%

Investigation of Multi-Factor Stress Corrosion Cracking Failure of Safe-End Feedwater Lines of Submarine Power System

Ji,

Zheng,

Qin

et al. 2024

Materials

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“…The leakage factors of the water wall pipe are more complex than other "three pipes". The types of induced failures are more comprehensive, such as overheating explosion [1], corrosion failure [2][3][4][5], wear thinning, fatigue cracking [6][7], etc. This depends on the particularity of the operating environment of the water wall tubes, mainly located in the combustion zone inside the boiler.…”

Section: Introductionmentioning

confidence: 99%

Failure Analysis of Cracking on the Outer Pipe of 12Cr1MoV Water Wall in Thermal Power Plants

Yang,

Wang,

et al. 2023

J. Phys.: Conf. Ser.

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In order to identify the main causes of cracking and leakage of 12Cr1MoV water wall tubes outside the furnace in thermal power plants, this paper uses macroscopic morphology observation, stereomicroscope observation, alloy composition analysis, Brinell hardness test, metallographic structure inspection, and other means to detect and analyze the failed water wall tube. The alloy composition content of the water wall tubes submitted for inspection is within the standard requirements, and the Brinell hardness value of the water wall tubes also meets the requirements of relevant standards, The matrix metallographic structure of the water wall tube is normal. The initial leakage point is the cracking of the fillet weld at the end of the water wall tube fin, while other leakage points are caused by the blowing of the medium leaked from the initial leakage point. The initial leakage point is formed by the fatigue crack initiated at the fillet weld of the fin end and the corrosion crack on the inner wall extending towards each other. It is recommended to further inspect whether there is still cracking at the end of adjacent water wall tube fins to prevent similar cracking from happening again. Due to the frequent changes in the “peak shaving” period and amplitude in recent years, it is necessary to design the peak shaving period or amplitude reasonably to ensure the safe operation of the boiler.

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“…These conditions play the primary role in boiler components damages such as tension-compression, corrosion fatigue, creep damage, hydrogen embrittlement, and erosion, in addition to short-term or long-term overheating and welding defects are among the most frequent reasons for the failure of boiler components. The occurrence of stress concentration areas, such as notches, welding toes, sharp corners, keyways, dents, gouges, laps, folds, flakes, and tensile residual stresses from punched holes, heat treatment, and welding, among others, can trigger fatigue fractures [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Failure Analysis of Welded Steam Boiler Flange

Abdel-Aleem

Khodir

Newishy

2023

International Journal of Materials Technology and Innovation

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Steam boiler flange, made of steel ASTM A105 welded to spool pipe, experienced a failure near the welding area after six years of service. The operator company has reported that a sudden increase in operating pressure and temperature exceeded the normal operation conditions. As a result, the failed flange and welded spool pipe segments were received for further investigation using root cause analysis to determine the reason for the failure. The failed parts were visually inspected (VT) and tested for subsurface defects with a fluorescent wet magnetic particle test (MT). Chemical analysis, microstructure observations, and hardness tests are conducted for the failed flange and pipe. It is noticed that there were no abnormalities or indications of creep or overheating were found in the microstructure and hardness values. Upon examining the macro & microstructure of the connecting weld joint, several welding defects, such as non-metallic inclusions, few porosities, and lack of fusion between welded passes, were noticed. Scanning Electron Microscope (SEM) observations showed that fine striations as beach marks on the fractured surface provided strong evidence of fatigue failure. The identified crack originated from welding defects and progressed through the flange material due to fluctuating radial stresses due to the cyclic changes in working pressure during service. To prevent similar failures, it is recommended to apply proper welding procedure specifications (WPS) by qualified welders, conduct regular inspections and maintenance of the steam boiler, and keep working conditions stable.

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Metallurgical analysis of ASME SA213 T12 boiler vertical water-wall tubes failure

Cited by 11 publications

References 34 publications

Investigation of Multi-Factor Stress Corrosion Cracking Failure of Safe-End Feedwater Lines of Submarine Power System

Investigation of Multi-Factor Stress Corrosion Cracking Failure of Safe-End Feedwater Lines of Submarine Power System

Failure Analysis of Cracking on the Outer Pipe of 12Cr1MoV Water Wall in Thermal Power Plants

Failure Analysis of Welded Steam Boiler Flange

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