scholarly journals Scanning the welded joints of aluminium alloys using subminiature eddy-current transducers

2018 ◽  
Vol 33 ◽  
pp. 02054
Author(s):  
Sergey Dmitriev ◽  
Alexey Ishkov ◽  
Vladimir Malikov ◽  
Anatoly Sagalakov
Keyword(s):  
Friction Stir Welding ◽  
Eddy Current ◽  
Welded Joints ◽  
Ease Of Use ◽  
Measuring System ◽  
Safety Requirements ◽  
Friction Stir ◽  
High Rise ◽  
Strength And Durability ◽  
Eddy Current Transducer

Aluminium has a reputation for ease of use, strength and durability. In addition to its exceptional aesthetic properties, solid aluminium does not burn. As architects, contractors, consultants and real estate owners look to meet stringent safety requirements in the construction and refurbishment of high-rise constructions for both residential and commercial uses, aluminium cladding provides an alternative that is not only safe but that is also durable and attractive. One of the ways to connect elements into a aluminium construction is welding. friction stir welding is one of the most efficient. The authors developed a measuring system based on subminiaturized eddy-current transducers aimed at examining locally the defects of welded joints in aluminium-magnesium alloy plates connected by means of friction stir welding. The authors made a modification of the Delyann filter, which allowed them to increase considerably the signal-noise relations. The dependency of the eddy-current transducer response on defects was provided, i.e. concealed cuts and openings inside the welded joint, at the frequencies of 100-10000 Hz of the exciting winding.

Features of structure formation processes in AA2024 alloy joints formed by the friction stir welding with bobbin tool

2021 ◽  
Vol 23 (2) ◽  
pp. 98-115
Author(s):  
Alexey Ivanov ◽  
◽  
Valery Rubtsov ◽  
Andrey Chumaevskii ◽  
Kseniya Osipovich ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Structure Formation ◽  
Welded Joints ◽  
Heat Input ◽  
Welded Joint ◽  
Welding Process ◽  
Tool Material ◽  
Travel Speed ◽  
Material System ◽  
Friction Stir

Introduction. One of friction stir welding types is the bobbin friction stir welding (BFSW) process, which allows to obtain welded joints in various configurations without using a substrate and axial embedding force, as well as to reduce heat loss and temperature gradient across the welded material thickness. This makes the BFSW process effective for welding aluminum alloys, which properties are determined by their structural-phase state. According to research data, the temperature and strain rate of the welded material have some value intervals in which strong defect-free joints are formed. At the same time, much less attention has been paid to the mechanisms of structure formation in the BFSW process. Therefore, to solve the problem of obtaining defect-free and strong welded joints by BFSW, an extended understanding of the basic mechanisms of structure formation in the welding process is required. The aim of this work is to research the mechanisms of structure formation in welded joint of AA2024 alloy obtained by bobbin tool friction stir welding with variation of the welding speed. Results and discussion. Weld formation conditions during BFSW process are determined by heat input into a welded material, its fragmentation and plastic flow around the welding tool, which depend on the ratio of tool rotation speed and tool travel speed. Mechanisms of joint formation are based on a combination of equally important processes of adhesive interaction in “tool-material” system and extrusion of metal into the region behind the welding tool. Combined with heat dissipation conditions and the configuration of the “tool-material” system, this leads to material extrusion from a welded joint and its decompaction. This results in formation of extended defects. Increasing in tool travel speed reduce the specific heat input, but in case of extended joints welding an amount of heat released in joint increases because of specific heat removal conditions. As a result, the conditions of adhesion interaction and extrusion processes change, which leads either to the growth of existing defects or to the formation of new ones. Taking into account the complexity of mechanisms of structure formation in joint obtained by BFSW, an obtaining of defect-free joints implies a necessary usage of various nondestructive testing methods in combination with an adaptive control of technological parameters directly in course of a welding process.

scholarly journals Characteristics of structural strength of D16T alloy welded joints, produced by friction stir welding

2018 ◽  
Vol 2018 (9) ◽  
pp. 17-22
Author(s):  
A.G. Poklyatsky ◽  
◽  
Yu.V. Golovatyuk ◽  
T.M. Labur ◽  
O.P. Ostash ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Welded Joints ◽  
Structural Strength ◽  
Friction Stir ◽  
D16t Alloy

scholarly journals The Effects of In-Process Cooling during Friction Stir Welding of 7475 Aluminium Alloy

2021 ◽  
Vol 50 (9) ◽  
pp. 2743-2754
Author(s):  
Ashish Jacob ◽  
Sachin Maheshwari ◽  
Arshad Noor Siddiquee ◽  
Abdulrahman Al-Ahmari ◽  
Mustufa Haider Abidi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Welded Joints ◽  
Positive Impact ◽  
Welding Process ◽  
Fusion Welding ◽  
Friction Stir ◽  
Cooling Conditions ◽  
Zero Degree ◽  
Welding Technique

Certain age hardenable alloys such as AA7475 cannot be joined with perfection using fusion welding techniques. This requires non-conventional welding technique such as friction stir welding process to join these ‘difficult to weld’ alloys. In this study, three different cooling conditions i.e. cryogenic, sub-zero, and zero-degree Celsius temperature conditions have been analyzed to understand its impact on the welding process. In-process cooling was found to behave effectively and also enhanced the mechanical properties of the welded joints. A stable microstructure was clearly seen in the images observed under the metallurgical microscope. The weld efficiencies were found to be good in each of the samples which are indicative of a strong metallic joint. The effective cooling conditions employed had an overall positive impact on the joint.

Effects of Tool Pin Profile and Tool Shoulder Diameter on the Tensile Behaviour of Friction Stir Welded Joints of Aluminium Alloys

2014 ◽  
Vol 984-985 ◽  
pp. 586-591 ◽  
Author(s):  
R. Ashok Kumar ◽  
M.R. Thansekhar
Keyword(s):  
Friction Stir Welding ◽  
Aluminium Alloy ◽  
Tensile Properties ◽  
Welded Joints ◽  
Tensile Behaviour ◽  
Light Weight ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Shoulder Diameter ◽  
Weight Structures

— For fabricating light weight structures, it requires high strength-to weight ratio. AA6061 aluminium alloy is widely used in the fabrication of light weight structures. A356 aluminium alloy has wide spread application in aerospace industries. Friction stir welding is solid state joining process which is conducting for joining similar and dissimilar materials. The friction stir welding parameters play an important role for deciding the strength of welded joints. In this investigation, A356 and AA6061 alloys were friction stir welded by varying triangular, square, hexagonal pin profiles of tool keeping the remaining parameters same and AA6061 alloys were friction stir welded by varying tool shoulder diameter as 12mm,15mm,18mm without changing other parameters. Tensile properties of each joint have been analyzed microscopically. From the experimental results, it is observed that hexagonal pin profiled tool and 15mm shoulder diameter tool provides higher tensile properties when compared to other tools.

A Study on Friction Stir Welding Process for AA2219/AA2195 Joints

2018 ◽  
Vol 762 ◽  
pp. 339-342
Author(s):  
Ho Sung Lee ◽  
Koo Kil No ◽  
Joon Tae Yoo ◽  
Jong Hoon Yoon
Keyword(s):  
Friction Stir Welding ◽  
Welded Joints ◽  
Rotation Speed ◽  
Microstructural Analysis ◽  
Frictional Heat ◽  
Welding Parameters ◽  
Manufacturing Cost ◽  
Significant Saving ◽  
Friction Stir ◽  
Rotation Direction

The object of this study was to study mechanical properties of friction stir welded joints of AA2219 and AA2195. AA2219 has been used as an aerospace materials for many years primarily due to its high weldability and high specific strength in addition to the excellent cryogenic property so to be successfully used for manufacturing of cryogenic fuel tank for space launcher. Relatively new Aluminum-Lithium alloy, AA2195 provides significant saving on weight and manufacturing cost with application of friction stir welding. Friction stir welding is a solid-state joining process, which use a spinning tool to produce frictional heat in the work piece. To investigate the effect of the rotation direction of the tool, the joining was performed by switching the positions of the two dissimilar alloys. The welding parameters include the travelling speed, rotation speed and rotation direction of the tool, and the experiment was conducted under the condition that the travelling speed of the tool was 120-300 mm/min and the rotation speed of the tool was 400-800 rpm. Tensile tests were conducted to study the strength of friction stir welded joints and microhardness were measured with microstructural analysis. The results indicate the failure occurred in the relatively weaker TMAZ/HAZ interface of AA2219. The optimum process condition was obtained at the rotation speed of 600-800 rpm and the travelling speed of 180-240 mm/min.

Sign in / Sign up

Export Citation Format

Share Document