Microstructure, crystallography, and toughness in nugget zone of friction stir welded high-strength pipeline steel

2020 ◽  
Vol 791 ◽  
pp. 139620 ◽  
Author(s):  
R.H. Duan ◽  
G.M. Xie ◽  
Z.A. Luo ◽  
P. Xue ◽  
C. Wang ◽  
...  
Keyword(s):  
Pipeline Steel ◽  
High Strength ◽  
Nugget Zone ◽  
Friction Stir

Microstructure and Mechanical Properties of a Friction Stir Processed Al-Zn-Mg-Cu Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 1428-1431 ◽  
Author(s):  
Margarita Vargas ◽  
Sri Lathabai
Keyword(s):  
Mechanical Properties ◽  
Rotational Speed ◽  
High Strength ◽  
Travel Speed ◽  
Nugget Zone ◽  
Friction Stir ◽  
Complex Interactions ◽  
Cu Alloy ◽  
Microstructure And Mechanical Properties ◽  
Aa 7075

Friction stir processing (FSP) was performed on AA 7075-T6, a heat treatable high strength Al-Zn-Mg-Cu alloy. The two main FSP parameters, the tool rotational and travel speed, were varied systematically in order to understand their influence on the microstructure and mechanical properties of the processed zone. At a given rotational speed, increasing the travel speed increased the microhardness of the nugget (stir) zone; for a given travel speed there appeared to be an optimum rotational speed which resulted in the highest microhardness. The range of FSP parameters used did not significantly influence the nugget zone grain size. It is suggested that the observed mechanical properties are a result of the complex interactions between the FSP thermo-mechanical effects and the processes of dissolution, coarsening and re-precipitation of the strengthening precipitates in this alloy.

Stability of nugget zone grain structures in high strength Al-alloy friction stir welds during solution treatment

2003 ◽  
Vol 51 (7) ◽  
pp. 1923-1936 ◽  
Author(s):  
Kh.A.A Hassan ◽  
A.F Norman ◽  
D.A Price ◽  
P.B Prangnell
Keyword(s):  
Solution Treatment ◽  
High Strength ◽  
Al Alloy ◽  
Nugget Zone ◽  
Friction Stir ◽  
Grain Structures

scholarly journals Microstructure and Mechanical Properties of Dissimilar Friction Stir Welded AA2024-T4/AA7075-T6 T-Butt Joints

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 128
Author(s):  
Mohamed M.Z. Ahmed ◽  
Mohamed M. El-Sayed Seleman ◽  
Zeinab A. Zidan ◽  
Rashad M. Ramadan ◽  
Sabbah Ataya ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
High Strength ◽  
Travel Speed ◽  
Nugget Zone ◽  
Butt Joints ◽  
Friction Stir ◽  
Aircraft Skin ◽  
Ebsd Technique ◽  
High Strength Aluminum Alloys ◽  
Electron Back Scattered Diffraction

Aircraft skin and stringer elements are typically fabricated from 2xxx and 7xxx series high strength aluminum alloys. A single friction stir welding (FSW) pass using a specially designed tool with shoulder/pin diameter ratio (D/d) of 3.20 is used to produce dissimilar T-butt welds between AA2024-T4 and AA7075-T6 aluminum alloys at a constant travel speed of 50 mm/min and different rotational speeds of 400, 600 and 800 rpm. The AA2024-T4 is the skin and the AA7075-T6 is the stringer. Sound joints are produced without macro defects in both the weld top surfaces and the joint corners at all rotational speeds used (400, 600, and 800 rpm). The hardness value of the nugget zone increases by increasing the rotational speed from 150 ± 4 Hv at 400 rpm to 167 ± 3 Hv at 600 rpm, while decreases to reach the as-received AA2024-T4 hardness value (132 ± 3 Hv) at 800 rpm. Joint efficiency along the skin exhibits higher values than that along the stringer. Four morphologies of precipitates were detected in the stir zone (SZ); irregular, almost-spherical, spherical and rod-like. Investigations by electron back scattered diffraction (EBSD) technique showed significant grain refinement in the sir zone of the T-welds compared with the as-received aluminum alloys at 600 rpm due to dynamic recrystallization. The grain size reduction percentages reach 85 and 90 % for AA2024 and AA7075 regions in the mixed zone, respectively. Fracture surfaces along the skin and stringer of T-welds indicate that the joints failed through mixed modes of fracture.

Effects of bottom plate in friction stir welding of AA6061-T6

2020 ◽  
Vol 118 (1) ◽  
pp. 108
Author(s):  
M.A. Vinayagamoorthi ◽  
M. Prince ◽  
S. Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Axial Load ◽  
Weld Zone ◽  
Welding Process ◽  
Bottom Plate ◽  
Welding Parameters ◽  
Nugget Zone ◽  
Friction Stir ◽  
Weld Joints ◽  
Fine Grain

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.

scholarly journals Tribological characterisation of magnesium matrix nanocomposites: A review

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110090
Author(s):  
Sudip Banerjee ◽  
Prasanta Sahoo ◽  
J Paulo Davim
Keyword(s):  
Weight Ratio ◽  
High Strength ◽  
Stir Casting ◽  
Tribological Behaviour ◽  
Magnesium Matrix ◽  
Friction Stir ◽  
Wear Friction ◽  
Melt Deposition ◽  
Mechanical And Tribological Characteristics ◽  
Matrix Nanocomposites

Magnesium matrix nanocomposites (Mg-MNCs) are high grade materials widely used in aerospace, electronics, biomedical and automotive sectors for high strength to weight ratio, excellent sustainability and superior mechanical and tribological characteristics. Basic properties of Mg-MNCs rely on type and amount of reinforcement and fabrication process. Current study reviews existing literatures to explore contribution of different parameters on tribological properties of Mg-MNCs. Effects of particle size and amount of different reinforcements like SiC, WC, Al2O3, TiB2, CNT, graphene nano platelets (GNP), graphite on tribological behaviour are discussed. Incorporation of nanoparticles generally enhances properties. Role of different fabrication processes like stir casting (SC), ultrasonic treatment casting (UST), disintegrated melt deposition (DMD), friction stir processing (FSP) on wear and friction behaviour of Mg-MNCs is also reviewed. Contributions of different tribological process parameters (sliding speed, load and sliding distance) on wear, friction and wear mechanism are also examined.

scholarly journals Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa

2021 ◽  
Vol 11 (12) ◽  
pp. 5728
Author(s):  
HyeonJeong You ◽  
Minjung Kang ◽  
Sung Yi ◽  
Soongkeun Hyun ◽  
Cheolhee Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Joint Strength ◽  
Solid Phase ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Low Carbon ◽  
Friction Stir ◽  
Welding Processes

High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels.

Sign in / Sign up

Export Citation Format

Share Document