Oscillography Based Analysis of the Arc Stability in Manual Welding with Coated Electrode in Pulsed Current

2015 ◽  
Vol 1128 ◽  
pp. 209-216
Author(s):  
Mircea Burcă ◽  
Ioan Lucaciu
Keyword(s):  
Low Frequency ◽  
Welding Current ◽  
Pulsed Current ◽  
Metal Bath ◽  
Arc Voltage ◽  
Transfer Mode ◽  
Coated Electrode ◽  
Points Of View ◽  
Different Levels ◽  
Coated Electrodes

Welding in pulsed current is specific to welding procedures carried out in MIG / MAG and WIG shielding gases environment, and which is appealling from both technological and process quality points of view because of the advantages this procedure provides, especially controlling the transfer mode and the power introduced into components. Making use of pulsed current in manual welding with coated electrodes is a new challenge to modern inverter based sources with potential technological advantages. In this case the advantage of pulsed current is linked to controlling the molten metal bath, its volume as a result of partial solidification, similar to the manual WIG welding using low frequency pulsed current < 5 Hz. The paper presents some technological issues related to the use of pulsed current in the case of manual welding with coated electrodes by arc oscillograpy. Experimental research aimed at recording the shapes of current pulses for different brands of electrodes and diameters, and for different parameters of welding current, different levels of pulses frequency respectively, and the oscillograms analysis through the variation of welding current and arc voltage in order to explain phenomena occurring in the arc when welding. This will allow also a better understanding of the technological issues in the case of manual welding with coated electrode in pulsed current.

scholarly journals Analysis of the Covered Electrode Welding Process Stability on the Basis of Linear Regression Equation

2014 ◽  
Vol 59 (3) ◽  
pp. 905-909
Author(s):  
J. Słania ◽  
B. Ślązak
Keyword(s):  
Linear Regression ◽  
Welding Process ◽  
Welding Current ◽  
Process Stability ◽  
Arc Voltage ◽  
Welding Arc ◽  
Instantaneous Values ◽  
Welding Properties ◽  
The Impact ◽  
Coated Electrodes

Abstract The article presents the process of production of coated electrodes and their welding properties. The factors concerning the welding properties and the currently applied method of assessing are given. The methodology of the testing based on the measuring and recording of instantaneous values of welding current and welding arc voltage is discussed. Algorithm for creation of reference data base of the expert system is shown, aiding the assessment of covered electrodes welding properties. The stability of voltage–current characteristics was discussed. Statistical factors of instantaneous values of welding current and welding arc voltage waveforms used for determining of welding process stability are presented. The results of coated electrodes welding properties are compared. The article presents the results of linear regression as well as the impact of the independent variables on the welding process performance. Finally the conclusions drawn from the research are given.

scholarly journals Application of Fast Fourier Transform (FFT) in the Analysis of a Welding Current Instantaneous Values Waveforms during Welding with a Covered Electrode

2014 ◽  
Vol 59 (2) ◽  
pp. 569-573 ◽  
Author(s):  
J. Słania ◽  
B. Ślązak ◽  
M. Fidali
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Welding Current ◽  
Arc Voltage ◽  
Applied Method ◽  
Welding Arc ◽  
Instantaneous Values ◽  
Welding Properties ◽  
Coated Electrodes

Abstract The article presents the process of production of coated electrodes and their welding properties. The factors concerning the welding properties and the currently applied method of assessing are given. The methodology of the testing based on measuring and recording of instantaneous values of welding current and welding arc voltage is discussed. The article presents the application of Fast Fourier Transform (FFT) for the analysis of instantaneous values of welding current and welding arc voltage. The results of coated electrodes welding properties are compared. Finally the conclusions drawn from the research are presented.

Effect of Helium Addition in Argon Shielding Gas on Metal Transfer Behavior in Gas Metal Arc Welding of Aluminum

2013 ◽  
Vol 545 ◽  
pp. 219-224 ◽  
Author(s):  
Pakpoom Jittavisuttiwong ◽  
Bovornchok Poopat
Keyword(s):  
Short Circuit ◽  
Welding Current ◽  
Metal Transfer ◽  
Gas Mixture ◽  
Spray Transfer ◽  
Arc Voltage ◽  
Pure Argon ◽  
Transfer Mode ◽  
Transfer Behavior ◽  
Current Region

Helium is widely used as mixing with argon for a shielding gas in GMAW process of Aluminum in order to improve weld quality and increase heat transfer to the weld pool. It has been known that helium could affect metal transfer behavior; however, its behavior has not been well understood. In this study, an analysis of the metal transfer behavior in the GMAW of aluminum was studied. The main objective is to study the effect of Helium on metal transfer in two main regions, short circuit (low welding current region) and spray transfer (high current region). The composition of 5 types of shielding gases were pure argon, 75%Ar + 25%He, 50%Ar + 50%He, 25%Ar + 75%He and pure helium. The welding parameters were fixed at 90A/17.0V, 100A/18.2V, 140A/24.6V and 180A/27.6V. Aluminum plates were welded bead-on-plate in a flat position. The metal transfer behavior was analyzed by using acoustic signals and arc voltage signals. For the result, at low welding current of 90A and 100A with pure argon, short-circuit transfer mode was observed. Adding helium in gas mixture gave no effect in metal transfer mode in low welding current regions but the metal transfer rate was slightly increased. At high welding currents of 140A and 180A with pure argon, spray transfer mode was observed and when increasing helium in gas mixture resulted in changing from spray transfer to combined mode of spray-globular. In these high welding currents, adding helium in gas mixture resulted in decreasing the metal transfer rate since helium gas tended to promote globular metal transfer. Acoustic signal and arc voltage signal can be used effectively in determining modes of metal transfer.

INVESTIGATION OF PULSE FREQUENCY ON FUSION ZONE CHARACTERISTICS OF GTA WELDED AZ31B MAGNESIUM ALLOY JOINTS

2020 ◽  
Vol 15 (2) ◽  
Author(s):  
Subravel V
Keyword(s):  
Magnesium Alloy ◽  
Tensile Properties ◽  
Fusion Zone ◽  
Welding Speed ◽  
Pulse Frequency ◽  
Pulsed Current ◽  
Az31b Magnesium Alloy ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Different Levels

In this investigation an attempt has been made to study the effect of welding on fusion characteristics of pulsed current gas tungsten arc welded AZ31B magnesium alloy joints. Five joints were fabricated using different levels of welding speed (105 mm/min –145 mm/min). From this investigation, it is found that the joints fabricated using a welding speed of 135 mm/min yielded superior tensile properties compared to other joints. The formation of finer grains and higher hardness in fusion zone and uniformly distributed precipitates are the main reasons for the higher tensile properties of these joints

The Determination of Noxes Emissions in Case of Manual Arc Welding Process with Coated Electrode

2018 ◽  
Vol 69 (7) ◽  
pp. 1826-1829
Author(s):  
Claudiu Babis ◽  
Augustin Semenescu ◽  
Oana Roxana Chivu ◽  
Maria Alina Gligor ◽  
Gabriel Iacobescu ◽  
...  
Keyword(s):  
Production System ◽  
Arc Welding ◽  
Welding Process ◽  
Practical Method ◽  
Machine Building ◽  
Short Exposure ◽  
Metal Bath ◽  
Coated Electrode ◽  
Manual Arc Welding ◽  
Arc Welding Process

The occupational risk assessment of a machine building company must cover each activity and workstation, taking into account each component of the production system (work system), each workload, work equipment and the work environment. This assessment is an extremely complicated and complex issue since the production system of such an enterprise is particularly complex and complicated. Welding assembly is a highly polluting technology process, especially of the atmosphere and soil. The formation of gases in the welding process is the result of burning of the electrodes, powders, forming the molten metal bath and making the weld seam. Welding operators are exposed to smoke and toxic gases resulting from the welding process, which can in many cases be hazardous to health. Many acute intoxications that may be caused by excessive exposure to or short exposure to smoke and gas resulting from the welding process have been studied over time. In the paper are presented the elements of risk related to the welding process and the most widespread occupational diseases that can occur in the ranges of the welding operators. The following are presented the noxious emissions from welding and are determined by a practical method the emission of noxious at welding deposition of a welding sample, using the manual arc welding process with coated electrode.

Effect of Current Waveform on Metal Transfer in Controlled Short Circuiting Gas Metal Arc Welding

2013 ◽  
Vol 718-720 ◽  
pp. 202-208 ◽  
Author(s):  
Mao Ai Chen ◽  
Yuan Ning Jiang ◽  
Chuan Song Wu
Keyword(s):  
Transfer Process ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Metal Transfer ◽  
Arc Voltage ◽  
Metal Arc Welding ◽  
Maximum Stability ◽  
The Stability ◽  
Welding Inverter

With high-speed welding inverter and precisely controlling the welding current with arc-bridge state, advanced pulse current waveforms can be produced to optimize the transfer characteristics of short circuiting transfer welding. In this paper, the images of droplet/wire, and the transient data of welding current and arc voltage were simultaneously recorded to study the influence of peak arcing current, background arcing current and tail-out time on the stability of short circuiting transfer process. It was found that maximum short circuiting transfer stability is reached under specific welding conditions. Any deviation from these conditions will cause abnormal rises in arc voltage indicating instantaneous arc extinguishing and greater spatter. Optimal welding conditions were obtained to achieve the maximum stability of short circuiting metal transfer process.

scholarly journals Temporal Features of Spectral Integration in the Inferior Colliculus: Effects of Stimulus Duration and Rise Time

2009 ◽  
Vol 102 (1) ◽  
pp. 167-180 ◽  
Author(s):  
Donald Gans ◽  
Kianoush Sheykholeslami ◽  
Diana Coomes Peterson ◽  
Jeffrey Wenstrup
Keyword(s):  
Inferior Colliculus ◽  
Rise Time ◽  
Low Frequency ◽  
Auditory Pathway ◽  
Spectral Integration ◽  
Auditory Responses ◽  
Temporal Features ◽  
Vocal Signals ◽  
Inhibitory Interactions ◽  
Different Levels

This report examines temporal features of facilitation and suppression that underlie spectrally integrative responses to complex vocal signals. Auditory responses were recorded from 160 neurons in the inferior colliculus (IC) of awake mustached bats. Sixty-two neurons showed combination-sensitive facilitation: responses to best frequency (BF) signals were facilitated by well-timed signals at least an octave lower in frequency, in the range 16–31 kHz. Temporal features and strength of facilitation were generally unaffected by changes in duration of facilitating signals from 4 to 31 ms. Changes in stimulus rise time from 0.5 to 5.0 ms had little effect on facilitatory strength. These results suggest that low frequency facilitating inputs to high BF neurons have phasic-on temporal patterns and are responsive to stimulus rise times over the tested range. We also recorded from 98 neurons showing low-frequency (11–32 kHz) suppression of higher BF responses. Effects of changing duration were related to the frequency of suppressive signals. Signals <23 kHz usually evoked suppression sustained throughout signal duration. This and other features of such suppression are consistent with a cochlear origin that results in masking of responses to higher, near-BF signal frequencies. Signals in the 23- to 30-kHz range—frequencies in the first sonar harmonic—generally evoked phasic suppression of BF responses. This may result from neural inhibitory interactions within and below IC. In many neurons, we observed two or more forms of the spectral interactions described here. Thus IC neurons display temporally and spectrally complex responses to sound that result from multiple spectral interactions at different levels of the ascending auditory pathway.

scholarly journals Low frequency pulsed current and pressure ulcer healing

1994 ◽  
Vol 2 (4) ◽  
pp. 225-233 ◽  
Author(s):  
A. Jercinovic ◽  
R. Karba ◽  
L. Vodovnik ◽  
A. Stefanovska ◽  
P. Kroselj ◽  
...  
Keyword(s):  
Pressure Ulcer ◽  
Ulcer Healing ◽  
Low Frequency ◽  
Pulsed Current

Effect of Stretching during Welding Process on the Weldability of Dissimillar Metals Resistance Spot Welded between Carbon Steel and Low Nickel Stainless Steel

2014 ◽  
Vol 894 ◽  
pp. 206-211 ◽  
Author(s):  
Triyono ◽  
Heru Sukanto ◽  
Nurul Muhayat ◽  
Sutiyono
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Local Heating ◽  
Welding Process ◽  
Welding Current ◽  
Welding Deformation ◽  
Tensile Shear ◽  
Resistance Spot ◽  
Weld Time ◽  
Different Levels

Due to the local heating of welding, deformation will occur on the welding structure. To mitigate this deformation, the method called stretching technology was proposed by previous study. In this method, plate was stretched to certain pre-strain, kept in this condition and then welded to another sheet. It can reduce the welding deformation significantly. However, pre-strain will change the properties of joined materials and lead different behavior of welded materials. It will be complicated if dissimilar metals are welded due to different physical and metallurgical properties. Carbon steel SS400 with the thickness of 3.0 mm and 1.0 mm thick-low nickel stainless steel were welded using resistance spot welding (RSW) process with constant electrode pressure and weld time of 6 kN and 5 second respectively. During welding process, low nickel stainless steel was stretched in four different levels pre-strain of 0%, 1%, 1.5% and 2%. Welding current were varied in the range from 3.02 to 4.20 kA. Microstructure investigations and tensile-shear tests were conducted to evaluate the weldability of RSW joint. Generally, stretching during welding process decreased the fussion zone area of RSW joint. In the low welding current, there is no fussion in the interface of stretched plate, but fussion still occured in the interface of unstretched plate. In all levels of welding current, stretching during welding decreased fussion zone area and led to decrease tensile-shear load bearing capacity of RSW joint.

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