With the continuous research and innovation of welding technology, a high-quality and high-efficiency welding technology has been continuously applied in the field of shipbuilding manufacturing. This is a new type of special welding method--laser--MIG hybrid welding . We know that in the metal joining technology process, on the one hand, the welding speed is high and the deformation is small, on the other hand, there is a good weld bridging ability. Everyone knows that the traditional single laser welding process is impossible to solve the above problems.
There is no doubt that the development of laser welding and gas metal arc welding processes has been around for a long time and they have a wide range of applications in material joining technology. Laser hybrid welding combines these two welding techniques (laser welding and arc welding) organically to achieve excellent overall performance, improving the welding quality and production process while improving the cost-benefit ratio. At present, laser hybrid welding has achieved remarkable results in the shipbuilding industry, and the economics of this technology is also very attractive. It is especially important that laser hybrid welding has high welding precision and can achieve very good mechanical/process performance. The laser power supply for hybrid welding can be equipped with different laser sources. At present, the main research is to combine CO2 laser, YAG laser, fiber laser and GMAW process. How to use the laser hybrid welding trolley of the weld seam tracking system to weld long welds is mentioned in the research schedule.
1 Introduction
High quality and high efficiency, low deformation and easy assembly, laser welding has broad prospects in the welding of steel structural parts. Laser arc hybrid welding technology can improve the weld bridging ability, which is of great significance for welding with large gap. The development and application of laser welding and gas metal arc welding have been around for a long time. They have been widely used in the industrial field and material joining technology. The two welding methods are the process of energy transfer to the workpiece and the formation of energy flow. They all differ to form their specific application areas.
Laser beam welding transfers energy from the laser emitter to the workpiece through the fiber. Arc welding uses large currents to transfer energy through an arc column. The welding heat affected zone of laser welding is very narrow, and the aspect ratio of the weld is very high. Due to its small diameter of focus, the weld bridging ability of laser beam welding is poor. On the other hand, the welding speed of laser beam welding is very high.
The energy density of arc welding is relatively low, so that the diameter of the focus on the surface of the workpiece is relatively large, and the welding speed is relatively low. Laser hybrid welding combines these two welding techniques organically to obtain excellent comprehensive performance, and improve the cost efficiency ratio while improving welding quality and production processability. At present, laser-composite welding has achieved remarkable results in the automotive industry, and the economics of this technology in the shipbuilding industry are also very attractive: higher connection speed and very good mechanical/process performance.
As early as the 1970s, people knew how to combine laser and arc organics in one process. But since then, for a long period of time, no further research has been conducted. Recently, people have once again turned their attention to this topic and tried to develop laser hybrid welding technology. Of course, one of the reasons for this is that in the early days, lasers have not been widely used in the industry, and now lasers have become standard equipment in many factories.
The welding technique of laser welding combined with another welding method is called laser hybrid welding, and the laser beam and the arc simultaneously act on the welding zone to influence and support each other. The current research direction is to explore a wider and deeper application field for this process. A typical example is the application of the CO2 laser GMA hybrid welding process to the shipbuilding industry. Here we demonstrate the possibility of applying and discussing this application area.
2. Laser welding process
Laser welding requires not only a good laser source, but also a high quality laser beam to ensure the desired "deep penetration deep soldering". A high quality laser beam can achieve a smaller focus diameter or a larger focal length. The line energy is extremely low and the amount of deformation is significantly reduced. As with advanced automated arc welding, off-line programming, weld tracking and other necessary welding control systems are also required for laser welding of large workpieces.
If laser welding is used alone, the gap between the weld joints is 0.1 to 0.2 mm. However, the wider gap requires us to add filler metal. Usually, the filler metal can be used to achieve a weld bridging capacity of 0.4 mm. A 12 kW CO2 laser source has been used in the industrial field. At this time, the conduction of the laser is performed through the mirror surface. The laser beam is applied to the workpiece by a focusing device at a focusing distance of 300 mm. A 4 kW Dengura YAG laser and a 7 KW fiber laser also appeared in this study.
3. Laser-MIG (LaserHybrid) hybrid welding
The laser beam gathering intensity when laser welding metal can reach 106W/cm2 or more. When the laser beam is clicked on the surface of the material, the temperature at that point rapidly rises to the volatilization temperature, and a volatilization hole is formed due to the volatilization of the metal vapor. The most notable feature of the weld is its high aspect ratio. The energy density of the free-burning arc of MIG arc welding is slightly higher than 104 W/cm2.
Figure 1 depicts the basic principles of laser hybrid welding, especially the metal transitions therein. From the figure we can see that the laser beam inputs heat to the top of the weld and the arc also inputs heat to the weld. Laser-MIG hybrid welding is not a method in which two welding methods are applied to the welding zone in sequence, but simultaneously to the welding zone. Both laser and arc affect the performance of the weld. The use of different arc or laser processes and the choice of process parameters can have different effects on the welding process.
Laser hybrid welding increases the penetration depth and welding speed. During the welding process, the metal vapor volatilizes and reacts to the plasma zone. The plasma zone absorbs the laser slightly, but it can be ignored. The characteristics of the entire welding process depend on the ratio of the selected laser and arc input energy.
The temperature of the surface of the workpiece greatly affects the absorption of the energy of the laser beam. When the surface of the workpiece reaches the volatilization temperature, a volatilization hole is formed, so that almost all the energy can be transmitted to the workpiece. The energy required for welding is determined by the surface absorbance as a function of temperature and the energy lost by the conduction of the workpiece. In laser-MIG welding, volatilization occurs not only on the surface of the workpiece, but also on the surface of the filler wire, which means more metal volatilization, which makes the energy transfer of the laser easier. It also guarantees the integrity of the welding process. This makes the energy transfer of the laser easier. It also guarantees the integrity of the welding process.
Moreover, the first thing that must be done in shipbuilding is that there is sufficient bridging connection capability when the weldment gap is large, which is the main goal of the research. Because in the welding process, it is inevitable that the gap tolerance will vary, so there are more parameters to adjust during welding, such as: laser power, welding speed, wire feeding speed and angle adjustment.
Next page
Human Monkeypox Virus (MPV) Antigen Rapid Test Device (colloidal gold) is an in vitro diagnostic test for the qualitative detection of human monkeypox virus antigens in Nasopharyngeal swab,saliva and exudate of blain using the rapid immunochromatographic method. The identification is based on the monoclonal antibodies specific for the human monkeypox virus antigen. It will provide information for clinical doctors to prescribe correct medications.
monkeypox virus test,monkeypox virus,virus monkeypox,monkey poxs,monkey pox
Yong Yue Medical Technology(Kunshan) Co.,Ltd , https://www.yonyuemedicalcare.com