The development of welding robots suitable for specially unstructured working enviroments has been become an important development direction of industrial robot application because large-scale welding structures have ...The development of welding robots suitable for specially unstructured working enviroments has been become an important development direction of industrial robot application because large-scale welding structures have been used more and more widely in modern industry. In this paper,an intelligent mobile robot for welding of ship deck with the function of auto-searching weld line was presented. A wheeled motion mechanism and a cross adjustment slider are used for the welding robot body. A sensing system based on laser-PSD(position sensitive detector) displacement sensor was developed to obtain two dimensional deviation signals during seam tracking. A full-digital control system based on DSP and CPLD has also been realized to implement complex and high-performance control algorithms. Furthermore,the system has still the function of auto-searching weld line according to the characteristics information of weld groove and adjusting posture itself to the desired status preparing for welding. The experiment of auto-searching welding line shows that the robot has high tracing accuracy,and can satisfy the requirement of practical welding project.展开更多
This article presents the special requirements and features of the thyristor commutators of the welding current.Advantages of pulsed - arc welding are described.Specificity of the thyristor commutators op- eration is ...This article presents the special requirements and features of the thyristor commutators of the welding current.Advantages of pulsed - arc welding are described.Specificity of the thyristor commutators op- eration is presented. Semiconductor converter simulation allowing to create the engineering calculating techniques are considered.展开更多
The welding fixtures are the most important devices for an auto body welding assembly line. The current special fixtures used by many automotive manufactures are only fit for one or several specific welding processes,...The welding fixtures are the most important devices for an auto body welding assembly line. The current special fixtures used by many automotive manufactures are only fit for one or several specific welding processes, and the dimensional problem in the circle due to several variation sources accumulation has no adjustment. The active error compensating welding fixture system for auto body is designed and manufactured. The detecting model, coordinate transformation model, and adjusting model based on auto body coordinate system are presented. The dowel pin modular design is adopted in the structure of the fixture to suit different workpieces with some similar characteristics. The online detection and adaptive control system using eddy current sensors and adaptive adjusting devices is analyzed. Three kinds of the left rear wheel covers SGM60 are selected to test workpieces of the developed system, and the active error compensating experiments are performed in the lab for many times. Test results show the validity of mechanism reconfigurations, on-line detections and error compensations of the developed welding fixture.展开更多
This paper analyzed the characteristics of welding solidification crack of stainless steels,and clearly re- vealed the the of the deformation in the molten - the pool and the solidification shrinkage on the stress - s...This paper analyzed the characteristics of welding solidification crack of stainless steels,and clearly re- vealed the the of the deformation in the molten - the pool and the solidification shrinkage on the stress - strain fields in the trail of molten - weld pool.Moreover, rheologic properties of the alloys in solid - liquid zone were also obtained by measuring the hading and unloading deform curves of the steels.As a result, a numerical model for simulation of stress - strain distributions of welding solidifi- cation crack was developed. On the basis of the model,the thesis simulated the driving force of solidifi- cation crack of stainless steels, that is, stress - strain fields in the trail of molten-weld pool with fi- nite element method.展开更多
Commercial A7020-T6 plates in the overaged state were subjected to friction stir welding with four different tool rotational speeds of 500, 710, 1000, and 1400 r/min and a single traverse feed rate of 40 mm/min. The r...Commercial A7020-T6 plates in the overaged state were subjected to friction stir welding with four different tool rotational speeds of 500, 710, 1000, and 1400 r/min and a single traverse feed rate of 40 mm/min. The resultant changes in the welding heat input, microstructure, and the mechanical properties of the joints were investigated. The changes were related to the processes of growth, dissolution, and re-formation of precipitates. The precipitate evolution was examined by differential scanning calorimetry, and the microstructural analysis was conducted using optical, scanning, and transmission electron microscopes. The results showed that the grain size in the stirred zone(SZ) decreased substantially compared with the base metal, but increased with tool rotational speed because of the rise in temperature. We found that the width of the heat-affected zone increased with tool rotational speed. The hardness and the tensile strength in the SZ increased with increasing heat input compared with the base metal in the overaged condition. This recovery in mechanical properties of the joints can be attributed to the dissolution and re-formation of precipitates in the SZ and the thermomechanically affected zone. This process is referred to as an "auto-aging treatment."展开更多
The HAZ microstructure and performance of Quenching and Tempering mode temper bead welding and general welded joints which were made on SA508-3 steel of 60 mm thickness were compared in this article. The result shows ...The HAZ microstructure and performance of Quenching and Tempering mode temper bead welding and general welded joints which were made on SA508-3 steel of 60 mm thickness were compared in this article. The result shows that tempering sorbite which has excellent overall performance was obtained in both modes. The microstructure of Quenching and Tempering mode welded joints got more fine grain. Even though the hardness of tempering bead welded joints is higher than the general one,it still meets the standards which is lower than 350 HV. The impact absorbing energy of each district of tempering bead welded joints HAZ reached 170 J,which is equal to general one.展开更多
A primary study on Processing in X - ray inspection of spot weld for aluminum alloy spot welding,in- cluding for background simulation,acquisition of ideal binary image, and extraction and identifi- cation of defect f...A primary study on Processing in X - ray inspection of spot weld for aluminum alloy spot welding,in- cluding for background simulation,acquisition of ideal binary image, and extraction and identifi- cation of defect features was presented.展开更多
Based on the structure of chute - feed and autoleveHer, an analysis of their working principle and the verification of their practical production results have been carried out. Finally, the future investigation direet...Based on the structure of chute - feed and autoleveHer, an analysis of their working principle and the verification of their practical production results have been carried out. Finally, the future investigation direetiom of chute - feed and card autuleveller are put forward.展开更多
文摘The development of welding robots suitable for specially unstructured working enviroments has been become an important development direction of industrial robot application because large-scale welding structures have been used more and more widely in modern industry. In this paper,an intelligent mobile robot for welding of ship deck with the function of auto-searching weld line was presented. A wheeled motion mechanism and a cross adjustment slider are used for the welding robot body. A sensing system based on laser-PSD(position sensitive detector) displacement sensor was developed to obtain two dimensional deviation signals during seam tracking. A full-digital control system based on DSP and CPLD has also been realized to implement complex and high-performance control algorithms. Furthermore,the system has still the function of auto-searching weld line according to the characteristics information of weld groove and adjusting posture itself to the desired status preparing for welding. The experiment of auto-searching welding line shows that the robot has high tracing accuracy,and can satisfy the requirement of practical welding project.
文摘This article presents the special requirements and features of the thyristor commutators of the welding current.Advantages of pulsed - arc welding are described.Specificity of the thyristor commutators op- eration is presented. Semiconductor converter simulation allowing to create the engineering calculating techniques are considered.
基金Shanghai Leading Academic Discipline Project,China(No.B602)Patent Second Development Project of Science and Technology Commission of Shanghai Municipality,China(No.05dz52038)
文摘The welding fixtures are the most important devices for an auto body welding assembly line. The current special fixtures used by many automotive manufactures are only fit for one or several specific welding processes, and the dimensional problem in the circle due to several variation sources accumulation has no adjustment. The active error compensating welding fixture system for auto body is designed and manufactured. The detecting model, coordinate transformation model, and adjusting model based on auto body coordinate system are presented. The dowel pin modular design is adopted in the structure of the fixture to suit different workpieces with some similar characteristics. The online detection and adaptive control system using eddy current sensors and adaptive adjusting devices is analyzed. Three kinds of the left rear wheel covers SGM60 are selected to test workpieces of the developed system, and the active error compensating experiments are performed in the lab for many times. Test results show the validity of mechanism reconfigurations, on-line detections and error compensations of the developed welding fixture.
文摘This paper analyzed the characteristics of welding solidification crack of stainless steels,and clearly re- vealed the the of the deformation in the molten - the pool and the solidification shrinkage on the stress - strain fields in the trail of molten - weld pool.Moreover, rheologic properties of the alloys in solid - liquid zone were also obtained by measuring the hading and unloading deform curves of the steels.As a result, a numerical model for simulation of stress - strain distributions of welding solidifi- cation crack was developed. On the basis of the model,the thesis simulated the driving force of solidifi- cation crack of stainless steels, that is, stress - strain fields in the trail of molten-weld pool with fi- nite element method.
基金financial support provided by Shahid Chamran University of Ahvaz, Iran
文摘Commercial A7020-T6 plates in the overaged state were subjected to friction stir welding with four different tool rotational speeds of 500, 710, 1000, and 1400 r/min and a single traverse feed rate of 40 mm/min. The resultant changes in the welding heat input, microstructure, and the mechanical properties of the joints were investigated. The changes were related to the processes of growth, dissolution, and re-formation of precipitates. The precipitate evolution was examined by differential scanning calorimetry, and the microstructural analysis was conducted using optical, scanning, and transmission electron microscopes. The results showed that the grain size in the stirred zone(SZ) decreased substantially compared with the base metal, but increased with tool rotational speed because of the rise in temperature. We found that the width of the heat-affected zone increased with tool rotational speed. The hardness and the tensile strength in the SZ increased with increasing heat input compared with the base metal in the overaged condition. This recovery in mechanical properties of the joints can be attributed to the dissolution and re-formation of precipitates in the SZ and the thermomechanically affected zone. This process is referred to as an "auto-aging treatment."
基金supported by the Key State Science and Technology Projects(Grant No.2011ZX04016-061 and No.2012ZX06004-001-001-005)
文摘The HAZ microstructure and performance of Quenching and Tempering mode temper bead welding and general welded joints which were made on SA508-3 steel of 60 mm thickness were compared in this article. The result shows that tempering sorbite which has excellent overall performance was obtained in both modes. The microstructure of Quenching and Tempering mode welded joints got more fine grain. Even though the hardness of tempering bead welded joints is higher than the general one,it still meets the standards which is lower than 350 HV. The impact absorbing energy of each district of tempering bead welded joints HAZ reached 170 J,which is equal to general one.
文摘A primary study on Processing in X - ray inspection of spot weld for aluminum alloy spot welding,in- cluding for background simulation,acquisition of ideal binary image, and extraction and identifi- cation of defect features was presented.
文摘Based on the structure of chute - feed and autoleveHer, an analysis of their working principle and the verification of their practical production results have been carried out. Finally, the future investigation direetiom of chute - feed and card autuleveller are put forward.
