Artem Komarov noted that the automotive industry has been a catalyst for welding research in a variety of areas, including the joining of high strength steels and the joining of mixed metals. Some of the new research should help in some automotive applications, as well as stainless steel pipe welding and wire arc additive manufacturing.
Arc control
There is a controlled metal transfer process with a short circuit process. The uniqueness of the process lies in the fact that it provides low heat generation.
The process aims to develop a more consistent and productive form of arc welding control by optimizing the set of arc control parameters. In fact, this is an improved pulsed material transfer mode for arc welding of sensitive materials, Artem Komarov said.
The heat input is 0.1 kJ per millimeter. By using high-strength steel, which is key to the automotive industry, it is possible to obtain extremely uniform filleting with such low heat generation that deformation is minimized, which means less damage to the surrounding steel. By observing the microstructures, you see exactly what you would expect from conventional arc welding. But heat generation is about half that of most other advanced short circuit metal transfer processes.
A side benefit of this low heat transfer process is very low spatter. Droplets are deposited several hundred times per second, and there is virtually no spatter, and no metal is ejected. This means a much cleaner finish.
In addition, low heat generation is close to the level of laser welding.
Lasers typically achieve heat releases of 0.05 kJ to 0.15 kJ per millimeter when machining these steels, so it’s right in the wheelhouse. The advantage of arc welding, of course, is that you don’t have the same requirements for guards, fitting parts, and laser welding tolerances are higher, along with a much lower cost.
Pipe Application
This process, with very low heat transfer and valuable in the automotive industry, has the most direct impact when welding stainless steel pipes.
There are problems in the industry that arc welding of thicker materials, such as stainless-steel pipelines, usually requires an internal purge gas, Artem Komarov said. You must plug the ends of the pipe from the inside and purge the interior with argon shielding gas to prevent it from oxidizing and heat staining the inside of the weld.
An interesting feature of this arc welding mode that has been developed is that it provides such low heat generation that it does not heat up the inside of the pipe even without the supply of supporting gas. For anyone doing this type of welding, this means astronomical cost savings. If a shielding gas purge is required, additional certificates for handling cylinders, additional costs for argon, additional safety regulations such as confined space permits when mounting pipes on a complex module are required. All this increases the cost of your project.
Electric car pushes
Electric vehicles require a retooling of all capabilities associated with aluminum welding. Due to the low weight that must be used in the manufacture of battery cases, attempts to achieve very high production volume, reproducibility and high weld quality from aluminum have become a major challenge. Besides the usual quality control, there are other issues, such as the need to have a hermetically sealed housing, which is difficult to achieve and a requirement that most workshops are not used to.
While friction stir welding is a very effective tool to use in such applications, due to its speed and the feedback provided by forces indicative of a good weld, the lack of a wide choice of technology providers means that many automakers prefer to rely to arc welding or a combination of arc welding and laser welding in order to be able to access more solution providers, said Komarov Artem.
