Variable polarity plasma arc-gas metal arc welding(VPPA-GMAW)integrates the advantages of VPPA and GMAW,and it is particularly applied to weld thick-plates aluminum alloys.High-speed camera and data acquisition system...Variable polarity plasma arc-gas metal arc welding(VPPA-GMAW)integrates the advantages of VPPA and GMAW,and it is particularly applied to weld thick-plates aluminum alloys.High-speed camera and data acquisition system were used to analyze the arc shape and the welding process electrical signal.According to the analysis of arc swing amplitude and the approximate entropy of arc voltage signal denoised by wavelet threshold method,the influence of VPPA frequency on the arc stability was studied.The results show that the approximate entropy of GMAW arc voltage decreases with the increase of VPPA frequency in a certain range,and the stability of the hybrid arc is significantly improved.The spectral analysis shows that the arc stability is reduced due to the resonance effect between the VPPA and the GMAW arc when the VPPA frequency closes to the GMAW arc pulse frequency.The results are helpful to understand hybrid welding mechanism and the selection of welding process parameters.展开更多
In order to develop a basic electrode with low fume and good usability, a uew slag system has been designed after analyzing several basic electrode slag systems. Then in view of uniform design method, arranging the ex...In order to develop a basic electrode with low fume and good usability, a uew slag system has been designed after analyzing several basic electrode slag systems. Then in view of uniform design method, arranging the experiment points by it, the influenced laws of the uew system coating compouents on the arc stability had been searched. In the formula, niue coating compouents were taken as independent variables and they were divided into six levels in all twenty-four experiments. The arc stability was taken as function and taken down the data when welding and then put them into the computer to be processed statistically. The analysis results give the mathematical model and trend diagrams between independent variables and the function. They indicate that the effects of many coating compouents on the arc stability are in the mutual form. The mutual effects between CaCO3 and BaF2, BaF2 and BaCO3 , increases the arc stability separately. While the mutual effects between CaF2 and iron powder, the square item of iron powder itself decreases the arc stability separately.展开更多
The aim of this work is to establish the influence of the relative position of the alloy charge C-Cr-Mn in the structure of the coating of rutile electrodes for hardfacing,on the operational behavior(arc stability).Fo...The aim of this work is to establish the influence of the relative position of the alloy charge C-Cr-Mn in the structure of the coating of rutile electrodes for hardfacing,on the operational behavior(arc stability).For this,three variants of electrodes with similar chemical composition are elaborated in the metallic core and the coating,differentiating only in the relative position that occupies the alloy charge(C-Cr-Mn)in the structure of the coating:internal,external and homogeneous.For the development of the research,a completely random design is used.The operative characterization of the electrodes is performed in terms of the arc stability.In conclusion,it can be seen that the position of the alloy load influences the operation behavior(stability of the arc).The variant of internal alloy charge in the coating presents the better arc stability performance.展开更多
Based on the phase state reconstruction of welding current in short-circuiting gas metal arc welding using carbon dioxide as shielding gas, the approximate entropy of welding current as well as its standard deviation ...Based on the phase state reconstruction of welding current in short-circuiting gas metal arc welding using carbon dioxide as shielding gas, the approximate entropy of welding current as well as its standard deviation has been calculated and analysed to investigate their relation with the stability of electric arc and welding process. The extensive experimental and calculated results show that the approximate entropy of welding current is significantly and positively correlated with arc and welding process stability, whereas its standard deviation is correlated with them negatively. A larger approximate entropy and a smaller standard deviation imply a more stable arc and welding process, and vice versa. As a result, the approximate entropy of welding current promises well in assessing and quantifying the stability of electric arc and welding process in short-circuiting gas metal arc welding.展开更多
A self-developed welding dynamic arc wavelet analyzer was adopted to analyze and assess the welding process of two CO2 arc welding machines. The experimental results indicate that the instantaneous energy can reflect ...A self-developed welding dynamic arc wavelet analyzer was adopted to analyze and assess the welding process of two CO2 arc welding machines. The experimental results indicate that the instantaneous energy can reflect the influence of the welding current and voltage on dynamic arc characteristic synthetically. Through calculating and analyzing the instantaneous energy, the energy during arc ignition and short circuit in CO2 welding process can be confirmed rationally, thus the foundation for the accurate design and control of the welding current and voltage can be provided. By reducing the ripple disturbance of the dynamic resistance, avoiding peak current and voltage waveform , and enhancing the transition frequency of short circuit suitably, the stability of the welding arc and the weld appearance can be improved.展开更多
The variable polarity power source which incorporates a constant current power and a secondary inverter does not need special apparatus for stabilizing arc. The pulse for stabilizing arc is created by the circuit stru...The variable polarity power source which incorporates a constant current power and a secondary inverter does not need special apparatus for stabilizing arc. The pulse for stabilizing arc is created by the circuit structure itself. The paper analyzes the principle of acquiring the pulse, provides the better method to improve the arc stabilization under smaller welding current. Test shows the arc is highly stable , and the process has no high frequency electromagnetic interference, which is suitable for automatic welding case.展开更多
The gasdynamic and electromagnetic factors affecting the position of arc roots in a tubular arc heater are analyzed.Magnitudes of the various factors are estimated through numerical modelling,and the overall action on...The gasdynamic and electromagnetic factors affecting the position of arc roots in a tubular arc heater are analyzed.Magnitudes of the various factors are estimated through numerical modelling,and the overall action on the arc assessed.It is found that the actions on the arc in the rear electrode can be balanced in a stable manner and the arc root can be stabilized at a certain axial position.In the front electrode,the various factors cannot be balanced,and the are root can only stay within the electrode through the mechanism of recurrent shunting.These conclusions agree with experimental observations.展开更多
Arc length stability and droplet transition consistency are key factors for the pulse metal inert gas （MIG） welding quality. A new control strategy is proposed based on pulse current waveform adjustment to stabilize...Arc length stability and droplet transition consistency are key factors for the pulse metal inert gas （MIG） welding quality. A new control strategy is proposed based on pulse current waveform adjustment to stabilize the welding process. After sufficient analysis of the droplet transition process, key current waveform parameters are refined that can affect the welding quality greatly. In order to achieve the optimal nonlinear control of parameters, the fuzzy controller is designed successfully with two inputs and three outputs in field programmable gate array （ FPGA ）, which occupies fewer resources than PID controller and has higher control performance. Experimental results show that the arc length can be adjusted fast in full range of welding current, the welding process is stable, the droplet transition has good consistency, and the welding quality is perfect.展开更多
A hot cathode bucket ion source is used for the EAST（experimental advanced superconducting tokamak）neutral beam injector.The thermal electrons emitted from the surface of the cathode are extracted and accelerated by...A hot cathode bucket ion source is used for the EAST（experimental advanced superconducting tokamak）neutral beam injector.The thermal electrons emitted from the surface of the cathode are extracted and accelerated by the electric field formed by the arc voltage,which is applied between the arc chamber of the ion source and the cathode.This paper analyzes the effects of arc voltage on the arc discharge in a hot cathode high current ion source.展开更多
基金supported by the National Natural Science Foundation of China(51665044)Natural Science Foundation of Inner Mongolia(2019LH05017)+1 种基金Science and Technology Programs of Inner Mongolia(2020GG0313)Major Basic Research Open Subjects of Inner Mongolia Autonomous Region.
文摘Variable polarity plasma arc-gas metal arc welding(VPPA-GMAW)integrates the advantages of VPPA and GMAW,and it is particularly applied to weld thick-plates aluminum alloys.High-speed camera and data acquisition system were used to analyze the arc shape and the welding process electrical signal.According to the analysis of arc swing amplitude and the approximate entropy of arc voltage signal denoised by wavelet threshold method,the influence of VPPA frequency on the arc stability was studied.The results show that the approximate entropy of GMAW arc voltage decreases with the increase of VPPA frequency in a certain range,and the stability of the hybrid arc is significantly improved.The spectral analysis shows that the arc stability is reduced due to the resonance effect between the VPPA and the GMAW arc when the VPPA frequency closes to the GMAW arc pulse frequency.The results are helpful to understand hybrid welding mechanism and the selection of welding process parameters.
基金Supported by Research Project of Heilongjiang Education Science and Technology (11521051)
文摘In order to develop a basic electrode with low fume and good usability, a uew slag system has been designed after analyzing several basic electrode slag systems. Then in view of uniform design method, arranging the experiment points by it, the influenced laws of the uew system coating compouents on the arc stability had been searched. In the formula, niue coating compouents were taken as independent variables and they were divided into six levels in all twenty-four experiments. The arc stability was taken as function and taken down the data when welding and then put them into the computer to be processed statistically. The analysis results give the mathematical model and trend diagrams between independent variables and the function. They indicate that the effects of many coating compouents on the arc stability are in the mutual form. The mutual effects between CaCO3 and BaF2, BaF2 and BaCO3 , increases the arc stability separately. While the mutual effects between CaF2 and iron powder, the square item of iron powder itself decreases the arc stability separately.
文摘The aim of this work is to establish the influence of the relative position of the alloy charge C-Cr-Mn in the structure of the coating of rutile electrodes for hardfacing,on the operational behavior(arc stability).For this,three variants of electrodes with similar chemical composition are elaborated in the metallic core and the coating,differentiating only in the relative position that occupies the alloy charge(C-Cr-Mn)in the structure of the coating:internal,external and homogeneous.For the development of the research,a completely random design is used.The operative characterization of the electrodes is performed in terms of the arc stability.In conclusion,it can be seen that the position of the alloy load influences the operation behavior(stability of the arc).The variant of internal alloy charge in the coating presents the better arc stability performance.
基金Project supported by the National Natural Science Foundation of China(Grant Nos50375053 and 50575077)
文摘Based on the phase state reconstruction of welding current in short-circuiting gas metal arc welding using carbon dioxide as shielding gas, the approximate entropy of welding current as well as its standard deviation has been calculated and analysed to investigate their relation with the stability of electric arc and welding process. The extensive experimental and calculated results show that the approximate entropy of welding current is significantly and positively correlated with arc and welding process stability, whereas its standard deviation is correlated with them negatively. A larger approximate entropy and a smaller standard deviation imply a more stable arc and welding process, and vice versa. As a result, the approximate entropy of welding current promises well in assessing and quantifying the stability of electric arc and welding process in short-circuiting gas metal arc welding.
文摘A self-developed welding dynamic arc wavelet analyzer was adopted to analyze and assess the welding process of two CO2 arc welding machines. The experimental results indicate that the instantaneous energy can reflect the influence of the welding current and voltage on dynamic arc characteristic synthetically. Through calculating and analyzing the instantaneous energy, the energy during arc ignition and short circuit in CO2 welding process can be confirmed rationally, thus the foundation for the accurate design and control of the welding current and voltage can be provided. By reducing the ripple disturbance of the dynamic resistance, avoiding peak current and voltage waveform , and enhancing the transition frequency of short circuit suitably, the stability of the welding arc and the weld appearance can be improved.
基金This research was supported inpart by the Found ation !(No .990 951 1 1 2 )for Research admini stered by HarbinInstituteof Te
文摘The variable polarity power source which incorporates a constant current power and a secondary inverter does not need special apparatus for stabilizing arc. The pulse for stabilizing arc is created by the circuit structure itself. The paper analyzes the principle of acquiring the pulse, provides the better method to improve the arc stabilization under smaller welding current. Test shows the arc is highly stable , and the process has no high frequency electromagnetic interference, which is suitable for automatic welding case.
基金The project supported by National Natural Science Foundation of China
文摘The gasdynamic and electromagnetic factors affecting the position of arc roots in a tubular arc heater are analyzed.Magnitudes of the various factors are estimated through numerical modelling,and the overall action on the arc assessed.It is found that the actions on the arc in the rear electrode can be balanced in a stable manner and the arc root can be stabilized at a certain axial position.In the front electrode,the various factors cannot be balanced,and the are root can only stay within the electrode through the mechanism of recurrent shunting.These conclusions agree with experimental observations.
基金This research is supported by the National Natural Science Foundation of China （ No. 51207083 ） , Jinan Youth Science and Technology Star Plan （No. 20110304） and Independent Innovation Foundation of Shandong University （No. 2010GN067 ）.
文摘Arc length stability and droplet transition consistency are key factors for the pulse metal inert gas （MIG） welding quality. A new control strategy is proposed based on pulse current waveform adjustment to stabilize the welding process. After sufficient analysis of the droplet transition process, key current waveform parameters are refined that can affect the welding quality greatly. In order to achieve the optimal nonlinear control of parameters, the fuzzy controller is designed successfully with two inputs and three outputs in field programmable gate array （ FPGA ）, which occupies fewer resources than PID controller and has higher control performance. Experimental results show that the arc length can be adjusted fast in full range of welding current, the welding process is stable, the droplet transition has good consistency, and the welding quality is perfect.
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2013GB101000)National Natural Science Foundation of China(No.11405207)
文摘A hot cathode bucket ion source is used for the EAST（experimental advanced superconducting tokamak）neutral beam injector.The thermal electrons emitted from the surface of the cathode are extracted and accelerated by the electric field formed by the arc voltage,which is applied between the arc chamber of the ion source and the cathode.This paper analyzes the effects of arc voltage on the arc discharge in a hot cathode high current ion source.
