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

Alipooramirabad, Houman; Paradowska, Anna; Nafisi, Shahrooz; Reid, Mark; Ghomashchi, Reza

doi:10.3390/ma13245801

Cited by 15 publications

(7 citation statements)

References 49 publications

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“…These microstructural changes can negatively impact the mechanical properties, including strength, ductility, and impact toughness. in general, high strength steels like X70 undergo PwhT to reduce residual stress and dislocation density from the welding process and improve their mechanical properties [5,6]. This study aimed to investigate the influence of PwhT on the microstructure and mechanical properties of welded X70 pipes.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Post Weld Heat Treatment on Microstructure and Mechanical Properties of API X70 Linepipe using Submerged Arc Welding

Park,

Lee,

Jang

et al. 2024

Archives of Metallurgy and Materials

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API X70 steel requires high strength and toughness for safety in extreme environments like high pressure and low temperature. Submerged Arc Welding (SAW ) is effective for manufacturing thick steel pipes. However, the welding heat input during SAW alters the microstructure and mechanical properties of the heat affected zone (HAZ). Therefore, investigating the correlation between microstructure and mechanical properties in welded X70 pipes is important to address potential degradation of HAZ and weld metal (WM). In this study, post weld heat treatment (PWHT) was performed to improve mechanical properties of HAZ and WM and to reduce residual stress caused by the welding process. We performed PWHT at 640°C for 15 hours and followed by air cooling. After heat treatment, we observed the microstructure through OM and SEM analysis, and investigated the mechanical properties through tensile test, hardness test, and Charpy impact test.

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Section: Introductionmentioning

confidence: 99%

The Effects of Post Weld Heat Treatment on Microstructure and Mechanical Properties of API X70 Linepipe using Submerged Arc Welding

Park,

Lee,

Jang

et al. 2024

Archives of Metallurgy and Materials

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“…Neutron diffraction offers unique advantages over more accessible X-ray diffraction techniques due to the increased penetration capability of neutrons which is up to 50 mm in steel compared to 50 µm for X-ray radiation, which limits X-ray diffraction techniques to near surface measurements [ 19 , 20 ]. This enables internal, triaxial strain to be recorded non-destructively, making it a powerful technique for analysis of laser clad components by enabling sub-surface measurements in the cladding, heat affected regions, and substrate [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

Application of a New Alloy and Post Processing Procedures for Laser Cladding Repairs on Hypereutectoid Rail Components

et al. 2022

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The development of a laser cladding repair strategy is critical for the continued growth of heavy-haul railway networks. Premium hypereutectoid rails have undergone laser cladding using a new martensitic stainless-steel alloy, 415SS, developed for high carbon rails after standard cladding metals were found to be incompatible. Non-destructive neutron diffraction techniques were used to measure the residual stress in different layers generated across a dissimilar metal joint during laser cladding. The internal stress distribution across the cladding, heat-affected zone (HAZ), and substrate was measured in the untempered rail, after 350 °C and 540 °C heat treatment procedures and two surface grinding operations. The martensitic 415SS depositions produce compressive stress in the cladding, regardless of tempering procedures, which may inhibit fatigue crack propagation whilst grinding operations locally relive surface stress. Balancing tensile stresses were recorded below the fusion boundary in the HAZ due to thermal gradients altering the microstructure. The combination of 540 °C tempering and 0.5 mm surface layer removal produced a desirable combination of compression in the cladding deposition with significantly reduced tensile stresses in the HAZ. A comparison with the current literature shows that this alloy achieves a unique combination of desirable hardness, low tensile stress, and compression in the cladding layer. Data obtained during strain scanning has been used to determine the location of microstructural changes at the fusion boundary and HAZ through correlation of the stress, strain, full width at half maximum (FWHM), and intensity profiles. Therefore, neutron diffraction can be used for both the accurate measurement of internal residual stress and to obtain microstructural information of a metallurgical join non-destructively.

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“…[21] The required level of mechanical properties of welded joints of highstrength steels can be ensured by postwelding heat treatment (PWHT), the aim of which is to optimize the microstructure of welded joints [25][26][27] and reduce the residual stress. [28,29] Another method of enhancing the microstructure morphology of welded joints in the case of nanobainitic steels is heat treatment during the welding process, regeneration technique. [30][31][32][33] In this research, the experimental welding process is compared with physical and numerical simulations.…”

Section: Introductionmentioning

confidence: 99%

The Microstructure Prediction during the Welding Process of Fe–C–Si Steel Using Physical and Numerical Simulation: A Comparative Study

Królicka

Zalecki

Kuziak

et al. 2022

steel research int.

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Overall, medium‐carbon, multiphase steels subjected to welding processes can be described as difficult and require dedicated process conditions. In these investigations, an attempt is made to characterize the welding process of commercial 55Si7 steel with a high carbon equivalent (CE = 0.73). An experimental tungsten inert gas (TIG) welding process is performed by the use of preheating. Then, to understand and explain the processes during welding, a numerical (finite element method [FEM]) and physical (dilatometry) simulation is carried out. Measurement points located in the heat‐affected zone (HAZ) are selected based on the obtained data of thermal cycles. Significant differences in the results obtained with the three approaches are assessed and indicated. The cause of the discrepancies in the test results is also identified. The essence of the implementation of material data, which precisely defines the kinetics of phase transformation, is confirmed. A detailed analysis of the contribution of the phases is performed, together with their morphological assessment, as well as the hardness distributions are conscientiously compared. Moreover, it seems that the segregation of the chemical composition of austenite and the initial microstructure plays a crucial role in terms of the quality of the prediction.

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

Cited by 15 publications

References 49 publications

The Effects of Post Weld Heat Treatment on Microstructure and Mechanical Properties of API X70 Linepipe using Submerged Arc Welding

The Effects of Post Weld Heat Treatment on Microstructure and Mechanical Properties of API X70 Linepipe using Submerged Arc Welding

Application of a New Alloy and Post Processing Procedures for Laser Cladding Repairs on Hypereutectoid Rail Components

The Microstructure Prediction during the Welding Process of Fe–C–Si Steel Using Physical and Numerical Simulation: A Comparative Study

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