High-power Laser Welding Joints Toughness Of The Marine E Grade Steel

Laser welding technology is widely applied to the aviation and aerospace, shipbuilding, locomotive manufacturing, machinery parts manufacturing and other fields for its superior to the traditional connection technology, such as high energy density, a small amount of heat input, weld depth-width ratio, small distortion, the rapid expansion of its applications. Compared with laser welding, laser - arc hybrid welding which overcomes the pure laser welding and electric arc welding defects will be a combination of both together to form a more perfect method of welding process. This paper studies the home-made Marine E-class steel including its high-power CO2 laser welding and laser-MIG hybrid welding process, joints and mechanical properties of features.First, Using laser welding technology and laser-MIG hybrid welding technology, by changing the laser power,welding speed and Arc energy to observe the different energy input on the Marine E-class steel welded joints organizations and mechanical properties. Second, Using the optical microscope, SEM and TEM to confirm the organization of different energy input; Tests confirmed that under the conditions of fewer heat input, a large number of BG existed in the zone of HAZ. when the heat input increased, BG decreased and P increased.Thirdly, Through experimental study and theoretical analysis .observe the relationship between the laser power, welding speed, wire feed speed, laser and laser-MIG welding wire spacing and weld sharp. At the same time using high-speed camera methods and collection of current and voltage values to studied welding process.Fourthly, according to CCS ship standards, welding joints of different energy input were tested its tensile, hardness and low temperature impact . The results showed that the smaller the energy input, the better low-temperature toughness of HAZ zone.