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1 – 10 of over 1000
Article
Publication date: 21 May 2020

Venkata Suresh Bade, Srinivasa Rao P. and Govinda Rao P.

The purpose of this study is to explore the importance of vibrations during welding process. In recent years, welding has gained its supremacy in the field of production. The main…

Abstract

Purpose

The purpose of this study is to explore the importance of vibrations during welding process. In recent years, welding has gained its supremacy in the field of production. The main set back of the welding process is induced residual stresses, which is a major cause for many welding defects. These defects can be minimized by post-weld heat treatment methods, which is a time consuming and laborious process. In the recent past, a technique of exciting the weld-pool by vibrating the work-pieces was also adopted to minimize the above-mentioned stresses. A novel technique of electrode vibration is another effective way of transferring the vibrations to the weld-pool to influence the induced residual stress.

Design/methodology/approach

In this research, the electrode is vibrated with the help of an electric motor. The specimens were prepared as per American Society for Testing and Materials standards and welded with varying frequencies and voltages. The weldments are tested for hardness along the weld bead and heat affected zone, also the microstructure of the fusion zone is analyzed.

Findings

It is observed that there is an improvement in the hardness because of the grain refinement, which is a result of proper excitation of the weld-pool. It is observed that there is an improvement in hardness test up to 28.69% when compared with the conventional welding process. The peak value of hardness is observed at a frequency of 4,450 Hz. This is because of fine grain structure at this frequency, which is observed through the microstructure analysis.

Originality/value

A novel technique is introduced to refine the weld-pool through electrode vibrations. To improve the hardness of the welded joints, vibrations play a major role by refining the grain structure. The vibrations are imparted with the help of a special equipment attached to the electrode.

Details

World Journal of Engineering, vol. 17 no. 4
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 16 September 2020

Venkata Suresh Bade, Srinivasa Rao P. and Govinda Rao P.

The purpose of this paper is to investigate the prominence of mechanical excitations at the time of welding. In the past years, the process of welding technology has expanded its…

Abstract

Purpose

The purpose of this paper is to investigate the prominence of mechanical excitations at the time of welding. In the past years, the process of welding technology has expanded its influence in manufacturing. The crucial drawback of conventional welding is prompted by internal stresses and distortions, which is the focal reason for weld defects. These weld defects can be diminished by the process called post-weld heat treatment (PWHT), which consumes more working hours and needs skilled workers. To replace these PWHT processes, mechanical vibrations are introduced during the process of welding to diminish these weld defects.

Design/methodology/approach

In the current research, the mechanical vibrations are transferred to weld-pool through vibro-motor and DC motor connected to the electrode. As per standards, the tensile test specimens were prepared for welding with different voltages of vibro-motor and DC motor respectively. The weld joints were tested for tensile strength and analyzed the microstructure at the fusion zone.

Findings

Melt-ability at fusion zone of 1018 mild steel was investigated by the single-stroke intense heat process of fusion welding. It is observed that the mechanical vibrations technique has a profound influence on the enhancement of the fusion zone characteristics and grain structure. The peak value of the tensile strength is observed at 100 s of vibration, 190 V of vibro-motor voltage and 18 V of electrode voltage. The tensile strength of the welded joints with vibrations is increased up to 22.64% when it is compared with conventional welding. The enhancement of the tensile strength of the weld bead was obtained because of the formation of fine grain structure. So, mechanical vibrations are identified as the most convenient method for improving the mild steel alloys weld quality.

Originality/value

A novel approach called mechanical vibrations during the process of welding is implemented for fusion zone refinement.

Details

World Journal of Engineering, vol. 17 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 1 February 1991

Peter J. Wells

One option available to the design engineer who requires a permanent joining of thermoplastic parts is to weld them together.

Abstract

One option available to the design engineer who requires a permanent joining of thermoplastic parts is to weld them together.

Details

Assembly Automation, vol. 11 no. 2
Type: Research Article
ISSN: 0144-5154

Article
Publication date: 1 June 2002

Ian Jones

The latest developments in the use of lasers for welding plastics are reviewed. Lasers were demonstrated as being suitable for welding plastics in 1970. However, it is only now…

1645

Abstract

The latest developments in the use of lasers for welding plastics are reviewed. Lasers were demonstrated as being suitable for welding plastics in 1970. However, it is only now that they are finding wide application following technical developments in transmission laser welding and ClearWeld™, and the availability of small, economic diode laser systems.

Details

Assembly Automation, vol. 22 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 1 September 1997

Kalpana Mistry

Plastics are the engineering materials for future technological development. Advances in plastics processing and fabrication techniques have facilitated the production of novel…

1895

Abstract

Plastics are the engineering materials for future technological development. Advances in plastics processing and fabrication techniques have facilitated the production of novel plastics devices and components in major business sectors such as the automotive, medical and packaging industries. Reviews the current techniques available for welding plastics material and highlights their advantages, limitations and stage of development.

Details

Assembly Automation, vol. 17 no. 3
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 9 June 2023

Zimou Tang, Min Yang, Jianxiong Xiao, Zheng Shen, Liming Tang and Jibin Wang

This paper aims to present an engineering computational method for fatigue life evaluation of welded structures on large-scale equipment under random vibration load.

Abstract

Purpose

This paper aims to present an engineering computational method for fatigue life evaluation of welded structures on large-scale equipment under random vibration load.

Design/methodology/approach

Based on a case study of the traction transformers, virtual fatigue test (VFT) was proposed via numerical simulation approach. Static analysis was conducted to identify the risky zone and then dynamic response of the risky welds under random vibration load was calculated based on frequency-domain structural stress method (FDSSM) theory, life distribution and associated survivability at various locations of the structure were obtained. Structural modification was finally performed according to the evaluation results. Moreover, experimental test was carried out and compared with the virtual test result.

Findings

By applying the virtual test, fatigue life of the complex welded structures on large-scale equipment can be accurately and efficiently obtained considering dynamic effect under random vibration load. Meanwhile, risky welds can be directly determined and targeted modification scheme can be accordingly concluded. Validity of the VFT result was proved by comparing with the experimental test.

Originality/value

The proposed method can help obtain equivalent structural stress and fatigue life distribution of the welded structure at any position with various survivability and make quantitative evaluation on the life-extending effect of the structural modification. This method shows significant cost and efficiency advantages over experimental test during design stage of the large-scale structures in numerous manufacturing industries.

Article
Publication date: 1 June 2000

Robert W. Messler

Joining, while first and foremost a pragmatic undertaking, concerned more with needs and results than with theory, will likely have to change with the dawn of the twenty‐first…

1775

Abstract

Joining, while first and foremost a pragmatic undertaking, concerned more with needs and results than with theory, will likely have to change with the dawn of the twenty‐first century to a true science. As materials become ever‐more sophisticated in their chemical composition, molecular morphology, micro‐ and nano‐structure, and macro‐structural arrangement to provide ever‐better functionally specific properties, a more complete and precise understanding of how such materials can be joined for optimal effectiveness and efficiency will become essential. Traditional options for joining will surely evolve – sometimes to provide unimagined capabilities. But, in addition, totally new methods will almost certainly emerge as evolution of materials gives way to revolution to meet unimagined new designs and design demands. This paper takes a glance at the past and a hard look at the present in the hope of catching a glimpse of the future.

Details

Assembly Automation, vol. 20 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 1 February 1941

Ing. E. Reichel

THE first electrical welding tests by the Arado firm were carried out at Warnemiinde in the year 1933 with a Rudolf welding machine. These tests were suggested by the welding of…

271

Abstract

THE first electrical welding tests by the Arado firm were carried out at Warnemiinde in the year 1933 with a Rudolf welding machine. These tests were suggested by the welding of seaplane float frames by the Heinkcl firm, under the direction of Koppenhöfer, with machines of the same type. The results obtained with this welding machine were not very satisfactory since it was not possible, owing to the mechanical operation of the switch, to obtain uniform spot‐welds. The machine had the further disadvantage that the commutator contacts became badly overheated and had to be frequently cleaned. In order to improve the spot‐welding by this machine an agreement was reached with the I. G. Farbenindustrie in Bitterfeld in the autumn of 1933; as a result of which further tests were made with this same machine by the I. G. concern itself at Bitterfeld.

Details

Aircraft Engineering and Aerospace Technology, vol. 13 no. 2
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 4 September 2020

M. Vykunta Rao, Srinivasa Rao P. and B. Surendra Babu

Vibratory weld conditioning parameters have a great influence on the improvement of mechanical properties of weld connections. The purpose of this paper is to understand the…

Abstract

Purpose

Vibratory weld conditioning parameters have a great influence on the improvement of mechanical properties of weld connections. The purpose of this paper is to understand the influence of vibratory weld conditioning on the mechanical and microstructural characterization of aluminum 5052 alloy weldments. An attempt is made to understand the effect of the vibratory tungsten inert gas (TIG) welding process parameters on the hardness, ultimate tensile strength and microstructure of Al 5052-H32 alloy weldments.

Design/methodology/approach

Aluminum 5052 H32 specimens are welded at different combinations of vibromotor voltage inputs and time of vibrations. Voltage input is varied from 50 to 230 V at an interval of 10 V. At each voltage input to the vibromotor, there are three levels of time of vibration, i.e. 80, 90 and 100 s. The vibratory TIG-welded specimens are tested for their mechanical and microstructural properties.

Findings

The results indicate that the mechanical properties of aluminum alloy weld connections improved by increasing voltage input up to 160 V. Also, it has been observed that by increasing vibromotor voltage input beyond 160 V, mechanical properties were reduced significantly. It is also found that vibration time has less influence on the mechanical properties of weld connections. Improvement in hardness and ultimate tensile strength of vibratory welded joints is 16 and 14%, respectively, when compared without vibration, i.e. normal weld conditions. Average grain size is measured as per ASTM E 112–96. Average grain size is in the case of 0, 120, 160 and 230 is 20.709, 17.99, 16.57 and 20.8086 µm, respectively.

Originality/value

Novel vibratory TIG welded joints are prepared. Mechanical and micro-structural properties are tested.

Details

World Journal of Engineering, vol. 17 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 1 December 2000

Weihua Shi and Trevor Little

Investigates the potential for building smart seams by incorporating optic fibers ultrasonically. The heating and bonding mechanisms of ultrasonic welding process in fabrics were…

1980

Abstract

Investigates the potential for building smart seams by incorporating optic fibers ultrasonically. The heating and bonding mechanisms of ultrasonic welding process in fabrics were studied. Battle dress uniform (BDU) (50/50 nylon/cotton), 100 percent cotton, 100 percent polyester and Nomex fabrics were used and were bonded ultrasonically with and without polyurethane adhesives. The effects of three important welding parameters, namely weld pressure, weld time and amplitude of vibration, on the joint strength and the temperature profile at the interface were examined. The temperature profiles for different fabrics were measured during ultrasonic welding process. The attenuation degree of signal transition properties of optic fibers incorporated was tested to determine if ultrasonic process provided a possible way of embedding optic fibers into seams and achieving sufficient joint strength while the signal transmission properties of optic fibers incorporated were not changed significantly.

Details

International Journal of Clothing Science and Technology, vol. 12 no. 5
Type: Research Article
ISSN: 0955-6222

Keywords

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