Through the isothermal ageing treatments at 873, 923, 973, and 1023K, precipitation of sigma (σ) phase in type 316FR stainless steel weld metal was examined based on kinetics approach. Microstructural examination performed by scanning electron microscopy (SEM), backscatter diffraction (EBSD) transmission (TEM). The dominantly precipitated phases were chi (χ), nucleated δ-ferrite/austenite (γ) interface or interior δ-ferrite grains, consuming during holding each temperature. total amount...

A drop transfer mode and a rotating in high current gas metal arc welding named buried were modeled using particle method that was suitable for numerical simulations of fluid behavior with phase changes large deformations. Numerical the space weld pool formation processes both condition conducted computational models to clarify effects pressure distribution transport position molten droplets on space. Finally, conditions combining these modes imitate low frequency modulated voltage control...

For quantitative evaluation of solidification cracking susceptibility in two kinds type 316FR stainless steel (316FR-A and 316FR-B) laser welds, beam welding (LBW) transverse-Varestraint test was performed. As the speed increased from 1.67 to 40.0 mm/s, enlargement range brittle temperature (BTR) for 316FR-B (from 14 40 K) larger than that 316FR-A 37 46 K), respectively. Based on theoretical calculations solid/liquid coexistence by using Kurz-Giovanola-Trivedi segregation models, reason...

The effect of sodium on repair weldability SUS316FR steel under the remaining environment was investigated by transverse-Varestraint and laser cladding tests. Solidification brittle temperature range (BTR) with AF solidification mode 37 K. However, BTR expanded from to 67 K, as amount surface-adhered increased 0 7.99 mg/cm2. From microstructural observation weld metal, there would be a possibility that metallic existed at cell boundaries in metal during welding solidification. According...

This paper describes a high-current Gas Metal Arc Welding (GMAW) process using constant voltage power source developed for high-efficiency welding of thick stainless steel plates. A short arc length as condition is preferable to concentrate the and obtain deep penetration plate welding. However, it easily found that an unstable derived from circuit happens irregularly by general purpose GMAW with characteristics. ‘low-frequency modulated control’ was applied stabilizing can maintain without...

To address the recent need for improved efficiency in thick plate welding, a high-current buried-arc welding system has been developed. In process, it is necessary to adequately evaluate thermal effect of high heat input on welded joint. The mechanical properties have verified1), and present study, we focused observing microstructures. some regions weld metal joint through characteristic metallographic structure was observed which macrostructure appeared extremely coarse. However, this...

The effect of sodium on repair-weldability SUS316FR steel under the remaining environment was investigated by transverse-Varestraint and laser cladding tests. Solidification brittle temperature range (BTR) with AF solidification mode 37 K. However, BTR expanded from to 67 K, as amount surface-adhered increased 0 7.99 mg/cm2. From microstructural observation weld metal, there would be a possibility that metallic existed at cell boundaries in metal during welding solidification. According...

This paper describes a high-current Gas Metal Arc Welding (GMAW) process using constant voltage power source developed for high-efficiency welding of thick stainless steel plates. A short arc length as condition is preferable to concentrate the and obtain deep penetration plate welding. However, it easily found that an unstable derived from circuit happens irregularly by general purpose GMAW with characteristic. "low-frequency modulated control" was applied stabilizing can maintain without...

The pitting corrosion resistance of duplex stainless steel welds was investigated. Pitting mainly occurs in high-temperature heat-affected zone (HT-HAZ), where the peak temperature reaches ferrite single-phase region. Most HT-HAZ initiates from (Ti,Cr)N ferrite. Even titanium content is less than 50 ppm, titanium-containing nitrides precipitate HT-HAZ. While no clear Cr-depleted develops around (Ti,Cr)N, almost passive film forms on surface. Therefore, initiated not only by Cr nitride but...

Three-dimensional particle simulation of a molten metal behavior in the buried arc welding was conducted by computational model which drop transfer and rotating modes, that were observed during actual using lowfrequency modulated voltage control scheme, modeled to investigate effect frequency scheme on space formation this process. As result, diameter largely changed with collapses when switching those modes equivalent set be 50 Hz. On other hand, whose much larger than wire always...

The authors focused on a buried-arc phenomenon for high-efficiency thick-plate welding and developed "low-frequency modulated voltage control" in order to stabilize buried arc at high-current range, which repeats high low terms using power source with constant-voltage characteristic. When the control was applied solid wires of φ1.2mm φ1.4mm, rotating transfer mode observed high-voltage term. It clarified that stabilized by supporting space arc. On other hand, when low-frequency wire φ1.6mm,...

The authors focused on a buried-arc phenomenon for high-efficiency thick-plate welding and developed ‘low-frequency modulated voltage control’ in order to stabilize buried arc high-current range, which repeats high low terms using power source with constant-voltage characteristics. When the control was applied solid wires of φ1.2 mm φ1.4 mm, rotating transfer mode observed at term. It clarified that stabilized by supporting space arc. On other hand, when low-frequency wire φ1.6 it revealed...