Laser Welding with Filling Wire

Laser welding with filling wire

Compared with traditional welding methods, laser welding has significant advantages - low heat input, fast welding speed, small heat-affected zone, small thermal deformation, etc. In recent years, laser welding has been widely used in high-tech industries such as the automotive industry, shipbuilding industry, nuclear power industry, aerospace industry, etc., and with the reduction of the cost of complete sets of equipment, its application in daily hardware products and other life-related fields has begun to grow rapidly.

In order to meet the needs of the development of various industries, the methods of laser welding have also been improved. Laser wire welding, due to its concentrated welding energy and small deformation, can reduce the gap margin during butt welding and reduce welding defects. It has become an effective alternative to traditional arc welding in the rail transportation and automobile industries.

Today we will introduce you to the wonderful uses of laser wire welding.

When performing laser wire welding

High-power fiber laser source are generally used.

Laser not only needs welding wire, but also needs to melt the base material and form the pinhole effect unique to laser deep penetration welding on the base material, forming a deeper molten pool. The welding wire components and the base metal components are fully mixed to form a new mixed molten pool. The element composition, proportion and quality of the mixed molten pool are quite different from those of the welding wire and the base material. Therefore, the performance defects of the base material itself can be targeted, and the appropriate welding wire can be selected to add to the welding process, so as to improve the crack resistance, fatigue resistance, corrosion resistance and wear resistance of the weld at the micro level.

In addition, laser wire welding can perform multi-pass stacking welding, because it can achieve deep penetration welding with pinhole effect, and can achieve full fusion of the upper and lower layers of welds, avoiding serious defects of unfused welds, so that it has the ability to weld large thickness joints.

With the development of laser wire welding technology and the increase of the upper limit of laser power, the application scope of laser wire welding is becoming more and more extensive:

Application areas of laser welding with filling wire

1. Laser welding of aluminum alloy with wire filling

2. Laser welding of dissimilar metals with wire filling

3. Improve weld formation

4. Narrow gap welding with wire filling

Among them, for the two applications of improving weld formation and narrow gap wire welding, we use actual application cases to look at the effect of laser wire welding.

Improve weld forming

Requirements: 1mm and 3mm stainless steel welding, the weld must be free of pores and have good forming.

Equipment: Raycus 4000W continuous fiber laser (fiber core diameter 200μm), wire feeder, welding head.

Process parameters: as shown in the following table.

Result: The forming is good and there is no pore in the weld, as shown in the weld forming and cross-sectional morphology in the figure below.

Narrow gap laser wire filling multi-pass welding

Requirements: 18mm thick Q345 marine steel plate welding, requiring less weld porosity, no unfused, joint tensile strength higher than the parent material, and better weld formation.

Equipment: Raycus 6000W continuous fiber laser (fiber core diameter 400μm), wire feeder, welding head.

Process parameters: The weld must be grooved, and the groove size is shown in the figure below.

Other welding process parameters are shown in the following table

Result: The forming is good, there is no incomplete fusion, and there is basically no porosity in the weld, as shown in the figure below. The tensile test proves that the weld breaks in the parent material, indicating that the tensile strength of the joint is higher than that of the parent material.

Metallographic diagram of weld cross section

For laser wire-filling welding of butt joints of commonly used materials, in order to improve weld formation, it is generally recommended that the laser source and fiber core diameters, and the welding head configuration should ensure that the focused spot diameter is between 0.4mm and 0.6mm, and the welding wire should be of appropriate grade.