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
Sensitivity of Nb to high-temperature ductility dip crack(HTDDC) of deposited metal of Inconel 690 welding wire was studied in detail. Strain to fracture test and high-temperature tensile test were selected as the tes...Sensitivity of Nb to high-temperature ductility dip crack(HTDDC) of deposited metal of Inconel 690 welding wire was studied in detail. Strain to fracture test and high-temperature tensile test were selected as the test methods to study the sensitivity of HTDDC. The deposited metals of four kinds of welding wire were observed and analyzed by OM and SEM. Experiment results show that Nb can effectively improve the ability of Inconel 690 to resist HTDDC and reduce the crack sensitivity of deposited metal. The mechanism of HTDDC is the grain boundary strength of deposited metal is lower than the intragranular strength. The(Nb, Ti) C can effectively block the grain boundary sliding and improve the resistance to deformation of the grain boundary.展开更多
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.
基金Project was supported by Talent Introduction Project of Guangdong University of Petrochemical Technology (Grant No.2019rc071)。
文摘Sensitivity of Nb to high-temperature ductility dip crack(HTDDC) of deposited metal of Inconel 690 welding wire was studied in detail. Strain to fracture test and high-temperature tensile test were selected as the test methods to study the sensitivity of HTDDC. The deposited metals of four kinds of welding wire were observed and analyzed by OM and SEM. Experiment results show that Nb can effectively improve the ability of Inconel 690 to resist HTDDC and reduce the crack sensitivity of deposited metal. The mechanism of HTDDC is the grain boundary strength of deposited metal is lower than the intragranular strength. The(Nb, Ti) C can effectively block the grain boundary sliding and improve the resistance to deformation of the grain boundary.
