A5001178659- Welding Techniques and Residual Stresses
- Laser and Thermal Forming Techniques
- Laser Material Processing Techniques
- Advanced Welding Techniques Analysis
- Additive Manufacturing Materials and Processes
- Hydrogen embrittlement and corrosion behaviors in metals
- Engineering Applied Research
- Non-Destructive Testing Techniques
- High-Temperature Coating Behaviors
- Aluminum Alloy Microstructure Properties
- High Entropy Alloys Studies
- Corrosion Behavior and Inhibition
- Advanced Surface Polishing Techniques
- Surface Roughness and Optical Measurements
- Metal and Thin Film Mechanics
- Manufacturing Process and Optimization
- Magnesium Alloys: Properties and Applications
- Microstructure and Mechanical Properties of Steels
- Structural Load-Bearing Analysis
- Mechanical Behavior of Composites
- Solid State Laser Technologies
- Material Properties and Applications
- Laser-induced spectroscopy and plasma
- Titanium Alloys Microstructure and Properties
- Information Technology Governance and Strategy
Japan Agency for Marine-Earth Science and Technology
2019-2024
Osaka University
2013-2022
Shanghai Shipbuilding Technology Research Institute
2007-2020
National Science and Technology Development Agency
2018
Hitachi (Japan)
2015-2017
Japan Atomic Energy Agency
2016-2017
Mie University
2016-2017
Nippon Steel (Germany)
2015
Anan National College of Technology
2012-2015
Industrial Technology Center of Okayama Prefecture
2013
The behavior and effect of a plasma plume on the weld penetration are greatly different between CO2 laser welding YAG, disk or fiber welding. effects power density elucidated. Spattering leading to formation underfilled beads is controlled by inclining beam. Porosity formed from bubbles generated tip keyhole at low speed middle part high density. Cracking easily occurs in pulsed spot aluminum alloys.
The objectives of this research are to investigate penetration characteristics, clarify welding phenomena and develop high quality procedures in bead on plate type 304 austenitic stainless steel plates with a 10 kW fibre laser beam. depth reached 18 mm at the maximum 5 s −1 . At 50 or lower speeds, however, porosity was generated any spot diameter. On other hand, 100 higher underfilling humping weld beads were formed under conventionally tightly focused conditions respectively. generation...
The fibre laser has been receiving great attention due to its advantages of high efficiency, power and beam quality, is expected be one the most desirable heat sources for high-speed deep-penetration welding. In this study, therefore, in bead-on-plate welding Type 304 stainless steel plates with 6 kW laser, effects power, density speed on formation sound welds were investigated four beams 130, 200, 360 560 µm spot diameter, their phenomena clarified video cameras an x-ray transmission...
This study was performed to evaluate the characteristics and strengths of dissimilar joints between carbon fibre reinforced plastics (CFRP) stainless steel using high brightness continuous wave disc laser. Tensile shear tests demonstrated that strong CFRP joint with ∼4800 N could be produced. The were tightly bonded on atomic or molecular sized level through Cr–Fe oxide film metal surface, small fragments type 304 detected fractured CFRP. Many bubbles submillimetre size formed all over...
Laser direct joining of carbon fiber reinforced plastic (CFRP) to aluminum alloy was performed using a high quality continuous wave diode laser with line-shaped beam. The tensile shear test results demonstrated that strong lap joint about 3000 N could be produced between CFRP (of 3 mm thickness and 20 width) 2 30 width). joints fractured along the interface or in melted zone CFRP. It observed from cross sections many bubbles submillimeter size were irregularly formed wide shallow Moreover,...
This study was undertaken to clarify the relationship among laser-induced plume ejected from keyhole, melt flows in molten pool, and formation mechanisms of spatters pool during 10 kW laser welding a pure titanium plate. High-speed video camera observation results showed that plumes occurred at intervals about 0.5 ms, maximum ejection velocity reached 250 m/s. Three-dimensional X-ray transmission in-situ weld with tungsten carbide tracers revealed flowed mainly along bottom keyhole tip rear...
A blue diode laser has a higher absorption rate than traditional laser, while the maximum power is limited. We report structure and beam profile of 250 W high-power (445 nm) for material processing. The system steel was 2.75 times that single-mode fiber (1070 nm). characteristics after irradiation were determined, validating potential this processing, such as heat treatment cladding. cost developed lower existing one. To best our knowledge, first with high W.
The objective of this research is to obtain a fundamental knowledge generation behaviour and ionised state plume or plasma induced during bead on plate welding 20 mm thick type 304 stainless steel with 10 kW fibre laser beam 0˙9 MW –2 power density, the basis 000 40 flames s –1 high speed video observation spectroscopic analysis. produced partial penetration weld 12 in depth at 50 speed. According pictures, was repeatedly generated from keyhole interval about 0&dot5 ms period reach...
Conventional fusion welding of aluminium and copper dissimilar materials is difficult because poor weldability arising from the formation brittle intermetallic compounds on weld zone as well different chemical, mechanical thermal properties welded joints. Joining Al Cu plates or sheets offers a metallurgical challenge due to unavoidable compounds. Therefore, it necessary effectively suppress growth Al–Cu For sheets, no systematic work has been conducted reduce these defects. Thus, this paper...
The authors have developed a new chamber for laser welding under the low vacuum conditions achieved by using rotary pumps. High-power disk bead-on-plate was performed on Type 304 stainless steel or A5052 aluminium alloy plate at powers of 10, 16 and 26 kW various speeds vacuum. sound welds more than 50 70 mm in penetration depth could be produced pressure 0.1 kPa, speed 0.3 m/min power kW, respectively. Similar A 5052 aluminum alloy. Welding phenomena were also understood observing behavior...
In this manuscript, weld pool dynamics in laser welding of various series aluminum alloys were investigated by the situ X-ray phase contrast imaging system. The experimental results showed that metal irradiated was evaporated immediately, which generated keyhole. Then surrounding keyhole melted gradually with heat from growth rate depth had a positive linear correlation total content low boiling temperature elements (TCE), so did and diameter at stable stage. Longitudinal view area molten...
A 100 kW fiber laser was first used to weld steel. Speeds at the range between 0.3 and 5.0 m/min were tested, maximum bead depth of 70 mm achieved by single pass welding. Solidification cracking porosity occurred when welding speed lower than 0.5 m/min, while undercut appeared higher 3.0 m/min. Both ratio width cross section area had a positively linear relationship with speed. high camera observe characteristics keyhole molten pool. The average number spatters increased speed, diameter...
In this study, welding with hybrid heat sources combined a high power disk laser and metal active gas (MAG) arc was carried out on 780 MPa strength steel plates of 12 mm in thickness. The effects respective conditions, such as power, root gap speed the penetration, geometry, defects weld beads, were investigated. results showed that process window conditions for production good welded joints narrow. Also, keyhole behavior, molten pool melt flows inside observed by high-speed x-ray...
This paper describes a variety of fundamental research results laser welding which the authors have recently performed. The behavior and characteristics laser-induced plume were elucidated. Especially, in remote with fiber laser, effect tall leading to shallow weld was interpreted by considering interaction an incident beam against zone low refractive index from Mickelson interferometer results. absorption plate higher case smaller focused lower speed power, reason size location keyhole...
An experimental system to observe the inner phenomenon of keyhole and molten pool through glass plate by high speed camera spectrometer in power density laser welding was set up. Two circular flows were observed camera, which transferred mass from front rear keep balance. Temperature distribution firstly detected spectrometer, indicated that acted as cooling take heat away keyhole. The porosity formation process also mechanism discussed.