With carbon extraction replica technique, electron diffraction and EDAX analysis, second particle size distribution in two Ti microalloyed steels and their heat-affected zones were investigated. The results show that ...With carbon extraction replica technique, electron diffraction and EDAX analysis, second particle size distribution in two Ti microalloyed steels and their heat-affected zones were investigated. The results show that the particles in the Ti microalloyed steels are TiN particles, and the TiN particles in the steel with lower Ti/N ratio exhibit smaller size and lower dissolution and coarsening rate and extent. Based on the investigation results, kinetic models for TiN particle dissolution and coarsening during welding thermal cycle were developed. The predicted values calculated by using the models are in good agreement with the experimental ones.展开更多
In the double-sided arc welding system (DSAW) composing of PAW+TIG arcs, the PAW arc is guided by the TIG arc so that the current mostly flows through the direction of the workpiece thickness and the penetration is gr...In the double-sided arc welding system (DSAW) composing of PAW+TIG arcs, the PAW arc is guided by the TIG arc so that the current mostly flows through the direction of the workpiece thickness and the penetration is greatly improved. To analyze the current density distribution in DSAW is beneficial to understanding of this process. Considering all kinds of dynamic factors acting on the weldpool, this paper discusses firstly the surface deformation of the weldpool and the keyhole formation in PAW+TIG DSAW process on the basis of the magnetohydrodynamic theory and variation principles. Hence, a model of the current density distribution is developed. Through numerical simulation, the current density distribution in PAW+TIG DSAW process is quantitatively analyzed. It shows that the minimal radius of keyhole formed in PAW+TIG DSAW process is 0.5 mm and 89.5 percent of current flows through the keyhole.展开更多
基金The authors appreciate the financial support of the Fund for Doctor of Shandong University.
文摘With carbon extraction replica technique, electron diffraction and EDAX analysis, second particle size distribution in two Ti microalloyed steels and their heat-affected zones were investigated. The results show that the particles in the Ti microalloyed steels are TiN particles, and the TiN particles in the steel with lower Ti/N ratio exhibit smaller size and lower dissolution and coarsening rate and extent. Based on the investigation results, kinetic models for TiN particle dissolution and coarsening during welding thermal cycle were developed. The predicted values calculated by using the models are in good agreement with the experimental ones.
基金The authors wish to express their gratitude to the financial support to this project from the project foundation of the National Key Laboratory of Advanced Welding Production Technology of Harbin Institute of Technology and the US National Science Foundation under grant No.DMI 9812981
文摘In the double-sided arc welding system (DSAW) composing of PAW+TIG arcs, the PAW arc is guided by the TIG arc so that the current mostly flows through the direction of the workpiece thickness and the penetration is greatly improved. To analyze the current density distribution in DSAW is beneficial to understanding of this process. Considering all kinds of dynamic factors acting on the weldpool, this paper discusses firstly the surface deformation of the weldpool and the keyhole formation in PAW+TIG DSAW process on the basis of the magnetohydrodynamic theory and variation principles. Hence, a model of the current density distribution is developed. Through numerical simulation, the current density distribution in PAW+TIG DSAW process is quantitatively analyzed. It shows that the minimal radius of keyhole formed in PAW+TIG DSAW process is 0.5 mm and 89.5 percent of current flows through the keyhole.
