Fiber laser welding with filler material

The welding technology by fiber lasers continues to grow as a promising technique with developments in weld quality, reliability, and performance. Most fiber laser welding applications are regarded as autogenous, it means the weld is created entirely by melting parts of the base metal and no additional filler wire or powder is applied.

To be more precise, welding applications of a laser beam are almost always autogenous for a huge variety of materials. Nevertheless, there are specific materials and challenging applications of laser systems that need the use of filler material in the welding process resulting in great improvements.

The improved fiber laser system provides better joint fit-up tolerance, avoiding solidification cracking during the welding process, the laser system welding changes the chemical composition or the microstructure of the weld metal to obtain suitable mechanical properties as well as improves the weld profile.

It should be noted that it is possible to use powder or wire filler material during laser beam welding. Most industrials laser system applications are based on wire use. The main reason for its use is regarded as wire low cost because generally, powder feedstock is more expensive than wire for most materials.

Fiber laser welding with filler wire depends on several conditions that define quality, process speed, and cost. For instance, “the wire feed rate is dependent on welding speed, the cross-section area of the gap between the joint face and cross-sectional area of the filler wire.” Therefore, the application of filler wire in a laser system usually leads to 10-20% reduction in welding speed, for a given laser beam power, to compensate for the fiber laser energy that has to be used to melt the wire. 

Laser beam-filler wire interaction also plays a crucial role. The thing is that short length of wire interferes the wire from being melted at the initial part of the bead, therefore, the laser beam directly leads to the material being melted. The long length of wire, in turn, causes the extended wire end to be pressed against the plate surface. 

Moreover, it is necessary to pay careful attention to the focused spot size: it should be close to the filler wire diameter because small spot size of the fiber laser system compared to the wire diameter results in welds with porosity because the filler wire has not melted properly.

Finally, the fiber laser technology has been tested and demonstrated that fiber laser welding applying filler wire provided effective in producing high quality, robust welds with improved fit-up, reduced weld cracking, and better weld profile. Thus, it is possible to use fiber laser systems in a wide range of applications such as aerospace, automotive, and many industrial fabricating applications.

Optromix is a fast-growing fiber laser manufacturer and a vendor of optical fiber sensors and optical monitoring systems. The company offers fast turnkey solutions and creates sophisticated fiber laser systems for special purposes. Optromix uses only its technologies and develops a broad variety of fiber lasers. If you have any questions or would like to buy a laser system, please contact us at info@optromix.com

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