A group of projection welding experiments and joints tension-shear tests are carried out for cold-rolled steel sheets, galvanized steel sheets (GSS) without treatment, GSS with phosphating and GSS with surface greasin...A group of projection welding experiments and joints tension-shear tests are carried out for cold-rolled steel sheets, galvanized steel sheets (GSS) without treatment, GSS with phosphating and GSS with surface greasing, respectively. The experimental results are regressively analyzed on the computers, then the projection welded joint tension-shear strength curve and the perfect welding currents range of each material are obtained. The results show that surface treatments of galvanized steels have effects on their spot weldabilities. Among the four kinds of materials, GSS with surface greasing have the worst spot weldability, for they need higher welding current and have a narrow welding current range.展开更多
Projection welding is a variation of electric resistance welding with the dynamic changes of the flow paths for heat and electrical properties with changing temperature caused by the large plastic deformation collapse...Projection welding is a variation of electric resistance welding with the dynamic changes of the flow paths for heat and electrical properties with changing temperature caused by the large plastic deformation collapse of projection. As the joint type between the auto door hinge and the inner plate, projection welding may bring welding distortions and would affect the assembly quality of auto body. A comprehensive electric-thermal-mechanical numerical simulation was performed to quantitatively simulate the processes of projection welding by using a coupled finite element method. The mechanism of projection collapse and the formation process of nugget were discussed and good conclusions have been achieved comparing with the test results.展开更多
Cable-type welding wire（CWW）CO2 welding is an innovative process arc welding with high quality,high efficiency and energy saving,in which CWW is used as consumable electrode.The CWW is composed of seven wires with a...Cable-type welding wire（CWW）CO2 welding is an innovative process arc welding with high quality,high efficiency and energy saving,in which CWW is used as consumable electrode.The CWW is composed of seven wires with a diameter of 1.2mm.One is in the center,while others uniformly distribute around it.The diameter of twisted wire is up to 3.6mm,which can increase the deposition rate significantly.With continual wire-feeding and melting of CWW,the formed rotating arc improved welding quality obviously.The arc behavior and droplet transfer were observed by the electrical signal waveforms and corresponding synchronous images,based on the high speed digital camera and electrical signal system.The results showed that the shape of welding arc changed from bell arc to beam arc with the increase of welding parameter.The droplet transfer mode changed from repelled transfer,globular transfer to projected transfer in turn.Droplet transfer frequency increased from 18.17 Hz to 119.05 Hz,while the droplet diameter decreased from 1.5times to 0.3times of the CWW diameter.展开更多
文摘A group of projection welding experiments and joints tension-shear tests are carried out for cold-rolled steel sheets, galvanized steel sheets (GSS) without treatment, GSS with phosphating and GSS with surface greasing, respectively. The experimental results are regressively analyzed on the computers, then the projection welded joint tension-shear strength curve and the perfect welding currents range of each material are obtained. The results show that surface treatments of galvanized steels have effects on their spot weldabilities. Among the four kinds of materials, GSS with surface greasing have the worst spot weldability, for they need higher welding current and have a narrow welding current range.
基金The National Natural Science Foundation of China(No.50575140)
文摘Projection welding is a variation of electric resistance welding with the dynamic changes of the flow paths for heat and electrical properties with changing temperature caused by the large plastic deformation collapse of projection. As the joint type between the auto door hinge and the inner plate, projection welding may bring welding distortions and would affect the assembly quality of auto body. A comprehensive electric-thermal-mechanical numerical simulation was performed to quantitatively simulate the processes of projection welding by using a coupled finite element method. The mechanism of projection collapse and the formation process of nugget were discussed and good conclusions have been achieved comparing with the test results.
基金Item Sponsored by National Natural Science Foundation of China(51275224,51575250,51505200)Prospective Joint Research Project of Jiangsu Province of China(BY2015065-06)Priority Academic Program Development of Jiangsu Higher Education Institutions of China
文摘Cable-type welding wire（CWW）CO2 welding is an innovative process arc welding with high quality,high efficiency and energy saving,in which CWW is used as consumable electrode.The CWW is composed of seven wires with a diameter of 1.2mm.One is in the center,while others uniformly distribute around it.The diameter of twisted wire is up to 3.6mm,which can increase the deposition rate significantly.With continual wire-feeding and melting of CWW,the formed rotating arc improved welding quality obviously.The arc behavior and droplet transfer were observed by the electrical signal waveforms and corresponding synchronous images,based on the high speed digital camera and electrical signal system.The results showed that the shape of welding arc changed from bell arc to beam arc with the increase of welding parameter.The droplet transfer mode changed from repelled transfer,globular transfer to projected transfer in turn.Droplet transfer frequency increased from 18.17 Hz to 119.05 Hz,while the droplet diameter decreased from 1.5times to 0.3times of the CWW diameter.
