Fatigue Behaviour of Friction Stir Welded Steel Joints

2014 ◽  
Vol 891-892 ◽  
pp. 1488-1493 ◽  
Author(s):  
José Azevedo ◽  
Virgínia Infante ◽  
Luisa Quintino ◽  
Jorge dos Santos
Keyword(s):  
Base Material ◽  
Welding Process ◽  
Steel Structures ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Welded Steel ◽  
Shipbuilding Industry ◽  
Friction Stir ◽  
Steel Joints

The development and application of friction stir welding (FSW) technology in steel structures in the shipbuilding industry provide an effective tool of achieving superior joint integrity especially where reliability and damage tolerance are of major concerns. Since the shipbuilding components are inevitably subjected to dynamic or cyclic stresses in services, the fatigue properties of the friction stir welded joints must be properly evaluated to ensure the safety and longevity. This research intends to fulfill a clear knowledge gap that exists nowadays and, as such, it is dedicated to the study of welded steel shipbuilding joints in GL-A36 steel, with 4 mm thick. The fatigue resistance of base material and four plates in as-welded condition (using several different parameters, tools and pre-welding conditions) were investigated. The joints culminate globally with defect-free welds, from which tensile, microhardness, and fatigue analyses were performed. The fatigue tests were carried out with a constant amplitude loading, a stress ratio of R=0.1 and frequency between 100 and 120 Hz. The experimental results show the quality of the welding process applied to steel GL-A36 which is reflected in the mechanical properties of joints tested.

Assessment of the Fatigue Behaviour of Friction Stir Welded Joints: Aluminium Alloy 6082-T6

2007 ◽  
Vol 348-349 ◽  
pp. 209-212 ◽  
Author(s):  
Pedro Miguel Guimarães Pires Moreira ◽  
A.M.P. de Jesus ◽  
A.S. Ribeiro ◽  
Paulo Manuel Salgado Tavares de Castro
Keyword(s):  
Aluminium Alloy ◽  
Welded Joints ◽  
Base Material ◽  
Welding Process ◽  
Growth Curves ◽  
Fatigue Behaviour ◽  
Fatigue Properties ◽  
Friction Stir ◽  
Crack Propagation Resistance ◽  
Strength And Ductility

A study on the fatigue behaviour of friction stir butt welds of 3mm thick 6082-T6 aluminium alloy was carried out. Monotonic tensile and cyclic tests of welded joints and base material were performed to understand the influence of the welding process on the static and fatigue properties. Microhardness profiles were measured and fatigue crack growth curves were determined for cracks growing in different locations of the weldments. Friction stir material exhibited lower strength and ductility properties than the base material. However, an enhanced crack propagation resistance is observed.

Mechanical Behaviour of Al-Li Alloy Joints by Different Friction Stir Welding Parameters

2014 ◽  
Vol 1051 ◽  
pp. 799-807 ◽  
Author(s):  
Dan Dan Zhang ◽  
Wen Qing Qu ◽  
Qun Bo Lv ◽  
Yang Yang Liu ◽  
Wei Yan Li ◽  
...  
Keyword(s):  
Ultimate Strength ◽  
Base Material ◽  
Welding Process ◽  
Fatigue Properties ◽  
Welding Parameters ◽  
Fatigue Lifetime ◽  
Friction Stir ◽  
The Relationship ◽  
Microstructure And Mechanical Property ◽  
Made In

In this study, the Al-Li alloy plates were friction stir welded (FSW) at different welding parameters, and the effect of welding parameters on the hardness, tensile and fatigue properties of the butted and lapped FSWed joints were investigated. The experimental results showed that the ultimate strength and elongation of butted joints decreased as the heat input increasing, and the maximum ultimate strength of the joints was equivalent to 83% that of the base material. By comparison of the heat inputs during welding process at different parameter combinations, the relationship between the microstructure and mechanical property of FSWed joints was established. For the overlapped welds made in 2mm thick plates of Al-Li-S4 and 2099 alloys, the hooking defect was a typical and inevitable defect appearing on the TMAZ of both advancing and retreating sides, which would adversely damage the mechanical properties of overlapped joints. Furthermore, the length of pin significantly affected the tensile property of overlapped joints, when the length of pin varies from 2.8mm to 2.5mm, the ultimate strength increased 14% to 20%. In addition, the fatigue lifetime of overlapped joints was lower than that of butted joints and base metal.

scholarly journals Friction Stir Welding of dissimilar aluminum-steel joints for the shipbuilding industry

2021 ◽  
Author(s):  
Davide Campanella ◽  
Gianluca Buffa ◽  
Livan Fratini
Keyword(s):  
Friction Stir Welding ◽  
Energy Savings ◽  
Research Work ◽  
Welding Process ◽  
Welding Parameters ◽  
Dissimilar Joints ◽  
Shipbuilding Industry ◽  
Lightweight Structures ◽  
Friction Stir ◽  
Steel Joints

In recent years, the development of innovative joining methods has increased significantly due to the demands of several industries, such as the naval one, for lightweight structures. In fact, the safeguarding of the sea takes place through the reduction of climate-altering gas emissions, which is induced by energy savings. The latter can be achieved by the adoption of innovative technological solutions inherent to both the manufacturing processes and the increase in the use of light alloys. These solutions can reduce the environmental impact of vessels both in refitting operations and in new buildings. Although its potential in producing effective joints of different materials, the Friction Stir Welding process is still poorly used in the naval field due to difficulties in welding dissimilar joints of thick plates. In this paper, Friction Stir Welding was used to produce joints, in lap configuration, out of two very different, yet widely used in the naval sector, materials. This research work focuses on the engineering of the process, in terms of identification of welding parameters aimed at welding AA5083 H321 aluminum alloy and naval steel grade DH 36 plates with a thickness of 6mm. The results obtained indicate that sound joints can be obtained with a reasonably wide process parameters window when the aluminum plate is placed on top of the steel one.

Numerical analysis of the fatigue behaviour of friction stir welded joints in aluminum bridge decks

2021 ◽  
Author(s):  
Mahmoud Trimech ◽  
Charles-Darwin Annan ◽  
Scott Walbridge ◽  
Sofiene Amira
Keyword(s):  
Bridge Decks ◽  
Welding Process ◽  
Fatigue Behaviour ◽  
Fatigue Properties ◽  
Lap Joint ◽  
Friction Stir ◽  
Notch Stress ◽  
Aluminum Extrusions ◽  
Geometrical Features ◽  
Effective Notch Stress

<p>Friction stir welding (FSW), a relatively new welding technique, has been widely used in the aero- space and manufacturing industries, showing superior mechanical and durability properties. How- ever, its application in civil engineering is very limited due to the absence of appropriate standards and quality control guidelines. FSW appears to be a promising welding solution for the fabrication of vehicular bridge decks made from aluminum extrusions, with a potential to reduce distortions and improve fatigue properties. The fatigue behaviour of common FSW joint types such as the butt FSW has extensively been investigated and documented in literature. However, certain practical configurations such as the butt-lap joint used in the fabrication of extruded aluminum bridge decks have rarely been studied, especially in the area of fatigue performance. In this context, the present research provides first an overview on the welding process of typical aluminum friction stir welded bridge deck extrusions presenting the butt-lap configuration. Then, the fatigue behaviour of butt- lap FSW joints is assessed using the effective notch stress (ENS) approach. The effect of geometrical features on the fatigue behaviour of butt-lap FSW joints is numerically investigated also by the ENS approach.</p>

scholarly journals A Method for Comparing the Fatigue Performance of Forged AZ80 Magnesium

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1290
Author(s):  
Andrew Gryguć ◽  
Seyed Behzad Behravesh ◽  
Hamid Jahed ◽  
Mary Wells ◽  
Bruce Williams ◽  
...  
Keyword(s):  
Base Material ◽  
Fatigue Behaviour ◽  
Fatigue Properties ◽  
Closed Die Forging ◽  
Geometry Configuration ◽  
Automotive Suspension ◽  
Process Structure ◽  
Durability Performance ◽  
Strength And Ductility ◽  
Structure Properties

A closed die forging process was developed to successfully forge an automotive suspension component from AZ80 Mg at a variety of different forging temperatures (300 °C, 450 °C). The properties of the forged component were compared and contrasted with other research works on forged AZ80 Mg at both an intermediate forging and full-scale component forging level. The monotonic response, as well as the stress and strain-controlled fatigue behaviours, were characterized for the forged materials. Stress, strain and energy-based fatigue data were used as a basis for comparison of the durability performance. The effects of the starting material, forging temperature, forging geometry/configuration were all studied and aided in developing a deeper understanding of the process-structure-properties relationship. In general, there is a larger improvement in the material properties due to forging with cast base material as the microstructural modification which enhances both the strength and ductility is more pronounced. In general, the optimum fatigue properties were achieved by using extruded base-material and forging using a closed-die process at higher strain rates and lower temperatures. The merits and drawbacks of various fatigue damage parameters (FDP’s) were investigated for predicting the fatigue behaviour of die-forged AZ80 Mg components, of those investigated, strain energy density (SED) proved to be the most robust method of comparison.

scholarly journals Effect of FSW Traverse Speed on Mechanical Properties of Copper Plate Joints

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1937 ◽  
Author(s):  
Tomasz Machniewicz ◽  
Przemysław Nosal ◽  
Adam Korbel ◽  
Marek Hebda
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Rolling Direction ◽  
Base Material ◽  
Traverse Speed ◽  
Travel Speed ◽  
Fatigue Tests ◽  
Copper Plate ◽  
Friction Stir ◽  
Microstructural Evaluation

The paper describes the influence of the friction stir welding travel speed on the mechanical properties of the butt joints of copper plates. The results of static and fatigue tests of the base material (Cu-ETP R220) and welded specimens produced at various travel speeds were compared, considering a loading applied both parallel and perpendicularly to the rolling direction of the plates. The mechanical properties of the FSW joints were evaluated with respect to parameters of plates’ material in the delivery state and after recrystallisation annealing. The strength parameters of friction stir welding joints were compared with the data on tungsten inert gas welded joints of copper plates available in the literature. The results of microhardness tests and fractographic analysis of tested joints are also presented. Based on the above test results, it was shown that although in the whole range of considered traverse speeds (from 40 to 80 mm/min), comparable properties were obtained for FSW copper joints in terms of their visual and microstructural evaluation, their static and especially fatigue parameters were different, most apparent in the nine-fold greater observed average fatigue life. The fatigue tests turned out to be more sensitive criteria for evaluation of the FSW joints’ qualities.

scholarly journals The Effects of Notches on the Fatigue Strength of Steel Structures

2019 ◽  
Vol 279 ◽  
pp. 02001
Author(s):  
Pavol Juhas
Keyword(s):  
Fatigue Strength ◽  
Steel Structures ◽  
Life Time ◽  
Fatigue Tests ◽  
Constructional Steel ◽  
Fatigue Properties ◽  
Stress Range ◽  
Time Data ◽  
Butt Weld ◽  
Applied Loading

The paper informs about the research devoted to load–carrying capacity, fatigue strength and life–time of welded steel structures. The experimental programme comprises fatigue tests of constructional steel S380 (QStE 380 TM). In the first stage 35 specimens were tested: 9 without any weld connection, 14 with transverse milled butt weld and 12 with transverse rough butt weld. The applied loading in this stage was harmonic with constant stress range. All tests ended by fatigue failure. The second part of the research comprised the tests with block simulated loading with variable stress range. The third part applied continuous recording of stresses and strains in critical sections, that gave information about the local failure development in time. Data sets have allowed to define fatigue properties of investigated steel and degradation effects of used welds including the initiation time of remarkable changes in stress-strain stage expressed through the total kinetic energy. The degradation effects of welds on fatigue strength of structural steels were confirmed, especially it was the case of rough welds - without additional milling. Additionally, the differences in the fatigue curves inclinations were indicated that can depend on the level of fatigue strength. The applied approach gives an opportunity to analyse the effects of actual loading process and improve the methodology of judgement of fatigue strength and life-time of steel elements. Reasonable fatigue properties of this steel suggest it for using also in severe technology structures.

Fatigue Properties of Al-Li Plates Joined by Friction Stir Welding

2008 ◽  
Vol 385-387 ◽  
pp. 849-852 ◽  
Author(s):  
Pasquale Cavaliere ◽  
Francesco W. Panella ◽  
Antonio Squillace
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Testing Machine ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Control Mode ◽  
Fatigue Properties ◽  
Amplitude Control ◽  
Friction Stir

Al-Li alloys are characterized by a strong anisotropy in mechanical properties and microstructure with respect to the rolling direction. Plates of 2198 Al-Li alloy were friction stir welded by employing maximum rotation speed: 1000 rev/min and welding speed of 80 mm/min, both in parallel and orthogonal directions with respect to the rolling one. The joints mechanical properties were evaluated by means of tensile tests at room temperature. In addition, fatigue tests performed with a resonant electro-mechanical testing machine under constant amplitude control up to 250 Hz loading, were conducted in axial control mode with R(σmin/σmax)=0.33, for all the welding and rotating speed conditions. The fatigue crack propagation experiments were performed by employing single edge notched specimens.With the aim to characterize the weld performances, both the microstructure evolution at jointed cross sections, related to the welding variables, and the fractured surfaces were respectively analyzed by means of optical and scanning electron microscopy.

scholarly journals Investigation of Interfacial Layer for Friction Stir Scribe Welded Aluminum to Steel Joints

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Kaifeng Wang ◽  
Piyush Upadhyay ◽  
Yuxiang Wang ◽  
Jingjing Li ◽  
Xin Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Driving Force ◽  
Bond Formation ◽  
Welding Process ◽  
High Strength ◽  
Bimaterial Interface ◽  
Joint Interface ◽  
Friction Stir ◽  
Transmission Electron ◽  
Steel Joints

Friction stir scribe (FSS) welding as a recent derivative of friction stir welding (FSW) has been successfully used to fabricate a linear joint between automotive Al and steel sheets. It has been established that FSS welding generates a hook-like structure at the bimaterial interface. Beyond the hook-like structure, there is a lack of fundamental understanding on the bond formation mechanism during this newly developed FSS welding process. In this paper, the microstructures and phases at the joint interface of FSS welded Al to ultra-high-strength steel were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that both mechanical interlocking and interfacial bonding occurred simultaneously during the FSS welding process. Based on SEM observations, a higher diffusion driving force in the advancing side was found compared to the retreating side and the scribe swept zone, and thermally activated diffusion was the primary driving force for the interfacial bond formation in the scribe swept region. The TEM energy-dispersive X-ray spectroscopy (EDXS) revealed that a thin intermetallic compound (IMC) layer was formed through the interface, where the thickness of this layer gradually decreased from the advancing side to the retreating side owing to different material plastic deformation and heat generations. In addition, the diffraction pattern (or one-dimensional fast Fourier transform (FFT) pattern) revealed that the IMC layer was composed of Fe2Al5 or Fe4Al13 with a Fe/Al solid solution depending on the weld regions.

Temperature Distribution of Aluminum Alloys under Friction Stir Welding

2011 ◽  
Vol 264-265 ◽  
pp. 217-222 ◽  
Author(s):  
Ben Yuan Lin ◽  
P. Yuan ◽  
Ju Jen Liu
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Cross Section ◽  
Base Material ◽  
Welding Process ◽  
Measuring System ◽  
Close Correspondence ◽  
Distribution Profile ◽  
Butt Welding ◽  
Friction Stir

The temperature distribution of 6061-T6 aluminum alloy plates under a friction stir butt-welding was investigated by using experiment and numerical simulation. A real-time temperature measuring system was used to measure the temperature change in the welding process. Vickers hardness profiles were made on the cross-section of the weld after welding. A commercial software of FlexPDE, a solver for partial different equations with finite element method, was used to simulate the experimental welding process of this study. Comparison the experimental and numerical results, the temperature cycles calculated by numerical are similar to those measured by experiment. The temperature distribution profile obtained from the numerical simulation is symmetrical to the weld center and has a close correspondence with the hardness configuration and the microstructure of the weld. The region with the temperature over 300 °C is the zone of softening within the boundaries of base material and HAZ. The regions of 350 °C with minimum hardness are located near the boundary of HAZ and TMAZ. The maxima temperature about 500 °C distributes around the upper part of the weld center. However, the region above 400 °C only matches with the upper half of the weld nugget.

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