A series of experiments of tandem narrow gap GMAW for flat welding position were carried out. The arc behavior and metal transfer process were observed by a high-speed photography system. The effects of the welding pa...A series of experiments of tandem narrow gap GMAW for flat welding position were carried out. The arc behavior and metal transfer process were observed by a high-speed photography system. The effects of the welding parameters on the metal transfer were investigated. The results show that the arc behavior and metal transfer process of tandem narrow gap GMA W are different from these of bead-on-plate tandem GMA W. The arc behavior and metal transfer process are influenced by the distance between the two wires, the peak voltage, the pulse frequency and the peak time. With the increase of the distance between the two wires, the metal transfer mode gradually transforms from one pulse-multi droplets into one pulse-one droplet, and the average welding current increases. With the increase of the peak voltage, pulse frequency or peak time, the metal transfer mode transforms from one pulse-one droplet into one pulse-multi droplets, and the arc tends to occur between the wire and the sidewall.展开更多
Compared with using semi-automatic gas shielded arc welding, using automatic TANDEM twin wire welding and twin wire gas metal arc welding （GMAW） to weld Q690 steel, a low-alloy high-strength structural steel used in...Compared with using semi-automatic gas shielded arc welding, using automatic TANDEM twin wire welding and twin wire gas metal arc welding （GMAW） to weld Q690 steel, a low-alloy high-strength structural steel used in the hydraulic support in the fully-mechanized mining face, the welding speed, deposition rate, production environment and welding quality can be obviously improved. Compared with GMAW twin wire welding, a refined micro- structure in the weld and heat-affected zone （HAZ）, narrow HAZ and improved joint strength were achieved with TANDEM on Q690. Also, due to the push-pull pulsed way in TANDEM welding, the droplet transfer, distribution on heat flow and interaction between two arcs were completely different from those in GMAW twin wire system. The heat input of TANDEM is only about 76.6% of GMAW, and correspondingly, the welding speed and welding seam can be obviously improved. The complete oscillation caused by TANDEM pulsed current occurred in the welding pool, which refined the grains in the microstructure. The results show that TANDEM twin wire welding is very suitable in the welding of Q690 used in the hydraulic support.展开更多
基金This research is supported by National Natural Science Foundation of China （Grant No. 51275109）.
文摘A series of experiments of tandem narrow gap GMAW for flat welding position were carried out. The arc behavior and metal transfer process were observed by a high-speed photography system. The effects of the welding parameters on the metal transfer were investigated. The results show that the arc behavior and metal transfer process of tandem narrow gap GMA W are different from these of bead-on-plate tandem GMA W. The arc behavior and metal transfer process are influenced by the distance between the two wires, the peak voltage, the pulse frequency and the peak time. With the increase of the distance between the two wires, the metal transfer mode gradually transforms from one pulse-multi droplets into one pulse-one droplet, and the average welding current increases. With the increase of the peak voltage, pulse frequency or peak time, the metal transfer mode transforms from one pulse-one droplet into one pulse-multi droplets, and the arc tends to occur between the wire and the sidewall.
基金Item Sponsored by National Natural Science Foundation of China(51005106)A Project Funded by Priority Academic Program Development of Jiangsu Higher Education Institutions of ChinaAdvanced Welding Technology Key Laboratory Open Foundation Funded Projects in Jiangsu Province of China
文摘Compared with using semi-automatic gas shielded arc welding, using automatic TANDEM twin wire welding and twin wire gas metal arc welding （GMAW） to weld Q690 steel, a low-alloy high-strength structural steel used in the hydraulic support in the fully-mechanized mining face, the welding speed, deposition rate, production environment and welding quality can be obviously improved. Compared with GMAW twin wire welding, a refined micro- structure in the weld and heat-affected zone （HAZ）, narrow HAZ and improved joint strength were achieved with TANDEM on Q690. Also, due to the push-pull pulsed way in TANDEM welding, the droplet transfer, distribution on heat flow and interaction between two arcs were completely different from those in GMAW twin wire system. The heat input of TANDEM is only about 76.6% of GMAW, and correspondingly, the welding speed and welding seam can be obviously improved. The complete oscillation caused by TANDEM pulsed current occurred in the welding pool, which refined the grains in the microstructure. The results show that TANDEM twin wire welding is very suitable in the welding of Q690 used in the hydraulic support.
