Effect of welding speed on the microstructure and texture development in the individual weld zone of friction stir welded DP780 steel

Chaudry, Umer Masood; Han, Seung-Chang; Jun, Tea‐Sung

doi:10.1016/j.jmrt.2023.02.122

Cited by 12 publications

(5 citation statements)

References 41 publications

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“…The relative misorientation angles along L7 show that the misorientation angles of HAGBs perpendicular to the original grain boundary are 10–20°, which indicate that these HAGBs are transformed by LAGBs [ 23 , 27 ]. These characteristics are consistent with the typical GDRX phenomenon [ 40 , 41 , 42 , 43 ]. Therefore, GDRX is the main dynamic softening mechanism under the condition of lnZ ≤ 15.…”

Section: Resultssupporting

confidence: 86%

Hot Deformation Behavior and Dynamic Softening Mechanism in 7B50 Aluminum Alloy

Liu

et al. 2023

Materials

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The hot deformation behavior and dynamic softening mechanism of 7B50 aluminum alloy were studied via isothermal compression experiments in the range of 320–460 °C/0.001–1.0 s−1. According to the flow curves obtained from the experiments, the flow behavior of this alloy was analyzed, and the Zener–Hollomon (Z) parameter equation was established. The hot processing maps of this alloy were developed based on the dynamic material model, and the optimal hot working region was determined to be 410–460 °C/0.01–0.001 s−1. The electron backscattered diffraction (EBSD) microstructure analysis of the deformed sample shows that the dynamic softening mechanism and microstructure evolution strongly depend on the Z parameter. Meanwhile, a correlation between the dynamic softening mechanism and the lnZ value was established. Dynamic recovery (DRV) was the only softening mechanism during isothermal compression with lnZ ≥ 20. Discontinuous dynamic recrystallization (DDRX) becomes the dominant dynamic recrystallization (DRX) mechanism under deformation conditions of 15 < lnZ < 20. Meanwhile, the size and percentage of DDRXed grains increased with decreasing lnZ values. The geometric dynamic recrystallization (GDRX) mechanism and continuous dynamic recrystallization (CDRX) mechanism coexist under deformation conditions with lnZ ≤ 15.

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Section: Resultssupporting

confidence: 86%

Hot Deformation Behavior and Dynamic Softening Mechanism in 7B50 Aluminum Alloy

Liu

et al. 2023

Materials

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“…It shows that the welding speed is an important factor affecting the welding quality. If the welding speed is too low, the material will vaporize, while if the welding speed is too high, the weld will not penetrate and the performance of the joint will deteriorate (Chaudry et al, 2023).…”

Section: Resultsmentioning

confidence: 99%

Impact of various heat treatment processes and welding speeds on the mechanical properties and microstructures of soft/hard composite joints

Yu,

Wang,

Chen

et al. 2024

Front. Mater.

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There is a certain contradiction between the formability and strength of auto parts. In this work, the whole-process processing technology of hot stamping soft steel was designed, and 500 MPa grade mild steel (500HS) with uniform microstructure was prepared. To take into account the strength and formability of hot stamping soft steel, here, based on laser welding technology, 500 MPa grade soft steel, and 1500 MPa grade hard steel are benignly composited, and by adjusting the laser welding speed and heat treatment process, the loss of mechanical properties caused by the weld seam is eliminated. A soft/hard composite steel for automobiles with excellent strength, ductility and formability is obtained. To maintain excellent deformation resistance and bonding force of the weld, the heat-affected zone of 500HS retains part of bainite and pearlite, which is beneficial to the strain compatibility and stress partitioning with the microstructure of the base metal, and the hardness is low. After heat treatment, which helps to transfer the stress concentration effect to the 500HS base metal with strong energy absorption capacity, so that the clad steel has excellent comprehensive mechanical properties. This process is developed based on existing industrialized equipment and has broad application prospects.

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“…It is well known that toughness is mainly affected by the grain size, microstructure, and grain boundary characteristics [ 13 , 22 ]. Generally, the soft phase and fine grain size were favored for improving toughness, and HABs can effectively change the crack propagation direction, thereby reducing the crack propagation rate and improving the toughness [ 12 ]. Although the microstructure of FSW joints contained some hard martensite relative to the SMAW joints, the finer grain size in FSW joints can help to improve toughness.…”

Section: Resultsmentioning

confidence: 99%

“…As a solid-phase joining technology, friction stir welding (FSW) is widely used to join aluminum alloys, achieving good application results [ 9 ]. In recent years, FSW research has also begun to shift from non-ferrous metals to ferrous metals with high melting points, realizing reliable connections of pipeline steel, DP steel, and TRIP steel [ 10 , 11 , 12 ]. Compared with traditional fusion welding, the HAZ of FSW steel joint is narrow and the coarsening and embrittlement of microstructures in the joint are not obvious.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Toughness and Ductility of Friction Stir Welded SA516 Gr.70 Steel Joint via Post-Welding Annealing

Wang,

Miao,

Gong

et al. 2023

Materials

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The SA516 Gr.70 steel possessing excellent toughness and plasticity has been widely used in the cryogenic field. However, the appearance of coarse bainite in the heat affected zone (HAZ) of the fusion welded joint deteriorates the toughness and ductility. In this work, 4.5 mm thick SA516 Gr.70 steel was joined using shielded metal arc welding (SMAW) and friction stir welding (FSW), respectively, and the microstructure and mechanical properties of joints were investigated in detail. The Charpy energy in the HAZ in the FSW joint was 80 J/cm2, which was higher than that of the HAZ in the SMAW joint (60 J/cm2) and due to microstructure refinement. In addition, the total elongation (TE) of the SMAW joint was 17.5%, which was higher than that of the FSW joint (12.1%) and caused by a wider nugget zone with high hardness. The post-welding annealing was used to improve the toughness and ductility of the SMAW and FSW joints, and the microstructure and mechanical properties of the joints after annealing were analyzed. The toughness in the HAZ of the SMAW and FSW joints were 80 and 103 J/cm2, and the TE of the SMAW and FSW joints were 18.6% and 25.2%, respectively. Finally, the as-annealed FSW joints exhibited excellent toughness and ductility. The abovementioned excellent mechanical properties were primarily attributed to the appearance of tempering martensite, decrease in dislocation density, and fine grain.

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Effect of welding speed on the microstructure and texture development in the individual weld zone of friction stir welded DP780 steel

Cited by 12 publications

References 41 publications

Hot Deformation Behavior and Dynamic Softening Mechanism in 7B50 Aluminum Alloy

Hot Deformation Behavior and Dynamic Softening Mechanism in 7B50 Aluminum Alloy

Impact of various heat treatment processes and welding speeds on the mechanical properties and microstructures of soft/hard composite joints

Enhanced Toughness and Ductility of Friction Stir Welded SA516 Gr.70 Steel Joint via Post-Welding Annealing

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