Wyniki wyszukiwania - Biblioteka Nauki

1

Arc voltage behavior in GMAW-P under different drop transfer modes

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Praveen P. , Kang M. J. , Yarlagadda P. K. D. V.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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tom Vol. 32, nr 2

196-202

EN

Purpose: Experimental measurements have been made to investigate meaning of the change in voltage for the pulse gas metal arc welding (GMAW-P) process operating under different drop transfer modes. Design/methodology/approach: Welding experiments with different values of pulsing parameter and simultaneous recording of high speed camera pictures and welding signals (such as current and voltage) were used to identify different drop transfer modes in GMAW-P. The investigation is based on the synchronization of welding signals and high speed camera to study the behaviour of voltage signal under different drop transfer modes. Findings: The results reveal that the welding arc is significantly affected by the molten droplet detachment. In fact, results indicate that sudden increase and drop in voltage just before and after the drop detachment can be used to characterize the voltage behaviour of different drop transfer mode in GMAW-P. Research limitations/implications: The results show that voltage signal carry rich information about different drop transfer occurring in GMAW-P. Hence it’s possible to detect different drop transfer modes. Future work should concentrate on development of filters for detection of different drop transfer modes. Originality/value: Determination of drop transfer mode with GMAW-P is crucial for the appropriate selection of pulse welding parameters. As change in drop transfer mode results in poor weld quality in GMAW-P, so in order to estimate the working parameters and ensure stable GMAW-P understanding the voltage behaviour of different drop transfer modes in GMAW-P will be useful. However, in case of GMAW-P hardly any attempt is made to analyse the behaviour of voltage signal for different drop transfer modes. This paper analyses the voltage signal behaviour of different drop transfer modes for GMAW-P.

2

Optimisation of the wire feed rate during pulse MIG welding of Al sheets

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Park H. J. , Kim D. C. , Kang M. J. , Rhee S.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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tom Vol. 27, nr 1

83-86

EN

Purpose: This paper aims at optimizing the wire feed speed against the welding speed during the pulse-MIG (Metal Inert Gas) lap joint fillet weld of 1.6 mm aluminium alloy typically used for the light-weight car body. Design/methodology/approach: Welding experiments were conducted with various wire feed speeds of 0.5 m/min, 1.0 m/min, and 1.5 m/min, and the bead characteristics were evaluated. As shape factors of the weld bead, the bead width, back bead width, and bead cross-section area were measured. According to the weld quality and defined objective functions, the wire feed speed was optimized for various welding speeds. Findings: The wire feed speed that induces the optimum weld quality was found with welding speeds of 0.5 m/min, 1.0 m/min, and 1.5 m/min. The optimum lap welding conditions were then suggested for 1.6 mm aluminium alloy considering the productivity and quality. Research limitations/implications: The optimization will be extended to various aluminium alloys and the optimized results will be stored in the Al welding database of the intelligent welding power source development. Practical implications: With the increase of the welding speed for aluminium sheet welding, the corresponding wire feed speed should increase as well. On the other hand, it is clear that the maximum value of the objective function has decreased. Originality/value: This research revealed the relationship between the welding speed and the wire feed speed considering the welding productivity and quality. In addition, the criterion to evaluate the degree of weldability during lap welding is suggested according to the quality and objective functions.

3

Characterization of dynamic behaviour of short circuit in pulsed Gas Metal Arc Welding of aluminium

100%

Praveen P. , Kang M. J. , Yarlagadda K. D. V. P.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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tom Vol. 14, nr 1-2

75--82

EN

Purpose: This paper studies dynamic characteristics of short circuit in the pulsed current gas metal arc welding (GMAW-P). Design/methodology/approach: Welding experiments with different values of pulsing parameter and simultaneous recording of high speed camera pictures and welding signals (such as current and voltage) were used to identify different short circuit conditions in GMAW-P. The investigation is based on the synchronization of welding signals and high speed camera to characterize different types of short circuit occurring in GMAW-P system. The behaviour of short circuit under the influence of different pulsing conditions is also investigated. Findings: It will be shown in the paper that short circuit in GMAW-P occurs in different forms which can be categorized depending upon time of short circuit and phase (peak or base time) of the pulse. Further investigation involves study of the dynamic behaviour of short circuit with variation of different pulsing parameters. Research limitations/implications: The results show that by varying the pulse parameters, behaviour of short circuit in GMAW-P is changed. The pulse parameters can be adjusted to avoid occurrence of short circuit in GMAW-P. Future work should concentrate on development of practical indices in terms of pulse welding parameters for quantitative estimation of short circuit occurrence and avoidance. Originality/value: Determination of proper working parameters with GMAW-P is crucial for the appropriate selection of pulse welding parameters. As short-circuiting is common between the welding electrode and the workpiece in GMAW-P, so in order to estimate the working parameters and ensure stable GMAW-P understanding dynamic behaviour of short circuit in GMAW-P will be useful. However, in case of aluminum hardly any attempt is made to analyse the dynamic behaviour of short circuit in GMAW-P. This paper analyses the short circuit phenomenon in GMAW-P and their behaviour with varying pulsing parameters.

4

Arc voltage behavior of one drop per pulse mode in GMAW-P

100%

Praveen P. , Kang M. J. , Yarlagadda P. K. D. V.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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tom Vol. 17, nr 1-2

389--392

EN

Purpose: Experimental measurements have been made to investigate the meaning of the change in voltage for the pulse gas metal arc welding process through one drop per pulse mode (ODPP). Design/methodology/approach: Welding experiments with different values of pulsing parameter and simultaneous recording of high speed camera pictures and welding signals (such as current and voltage) were used to identify ODPP drop transfer mode in pulse gas metal arc welding. The investigation is based on the synchronization of welding signals and high speed camera to study the behaviour of voltage signal under ODPP. Findings: The results reveal that the welding arc is significantly affected by the molten droplet detachment. In fact, sudden increase and drop in voltage just before and after the drop detachment characterizes the voltage behaviour of ODPP drop transfer mode in pulse gas metal arc welding. Research limitations/implications: The results show that voltage signal carry rich information about different drop transfer occurring in pulse gas metal arc welding. Hence it’s possible to detect different drop transfer modes. Future work should concentrate on development of filters for detection of different drop transfer modes. Originality/value: Determination of drop transfer mode with pulse gas metal arc welding is crucial for the appropriate selection of pulse welding parameters. As change in drop transfer mode results in poor weld quality in pulse gas metal arc welding, so in order to estimate the working parameters and ensure stable pulse gas metal arc welding understanding the voltage behaviour of different drop transfer modes in pulse gas metal arc welding will be useful. However, in case of pulse gas metal arc welding hardly any attempt is made to analyse the behaviour of voltage signal for different drop transfer modes. This paper analyses the voltage signal behaviour of ODPP mode for pulse gas metal arc welding. ODPP mode widely used to achieve best quality weld.