A new method of laser composite welding: the production cost and emissions of steel structure tower for wind power generation are reduced by 90%

Recently, a team of scientists at the Wind Energy Technology Center of the Federal Institute for Materials Research and Testing (BAM) in Germany has developed a method that uses laser composite welding to make wind power steel towers faster and more economically. It is reported that this method reduces the cost of welding by 90%, while reducing the carbon dioxide emissions during the production of wind power towers by 90%.

Specifically, the new method reduces the welding time of a modern 120-meter-high wind power steel tower by a factor of eight (from 96 hours to less than 12 hours); At the same time, it can also reduce the process energy consumption from 4,000 KWH to 900 KWH.

Breaking through the thickness limit, welding quality to a higher level

The modern wind power tower common today has a total length of about 700 meters and is made of steel plates up to 30 mm thick tightly connected by several layers of welds. In the past, people used submerged arc welding to do this, but this method can take up to 100 hours to complete. This also limits the capacity of Germany's four remaining production sites to about 520 steel towers per year, which is only about half the German government's target for onshore wind expansion. In this case of insufficient efficiency, more steel towers in Germany are still imported from China.

For more than 20 years, laser composite welding (typically a combination of laser beam and arc welding) has been used to process welds quickly and with little rework. It was originally used in the automotive industry to connect metal plates with a thickness of 1-3mm, and then began to show its strength in the shipbuilding industry, and parts processing thickness has reached 10mm.

At present, laser composite welding technology requires only one welding layer, which is one of its advantages. However, until now, it has only been approved by the industry for welding of 12mm thick sheets. This is because when welding thicker sheets, the liquefied metal under the weld will form droplets due to gravity, which can both endanger the stability of the weld and lead to costly and time-consuming rework processes.

In recent years, researchers at Germany's Federal Institute for Materials Research and Testing (BAM) have developed a solution to this long-standing problem. It involves installing a system of electromagnets in the weld area that counteract the effects of gravity by generating what is known as a Lorentz force, preventing droplet defects from forming at the weld. This innovation enables rapid connection of thick steel plates using laser composite welding without compromising the stability of the welding.

New scheme of electromagnetic laser rewelding, more abundant scene

The new laser composite welding method they developed uses electromagnets to counteract the effects of gravity to prevent droplet defects from forming on the weld.

Four scientists at the BAM Wind Energy Capability Center are setting up their own spin-off company to commercialize the technology, with the goal of developing it into a marketable industrial system within the next two years.

Fatma Akyel, who is in charge of research and development for the new company, explains: "Experts have confirmed that our system will have the potential to disrupt the wind energy industry. At the same time, wind power steel towers are just one of the applications of our innovation. This technology has the potential to be used in many scenarios where thick-walled steel plates are connected together, including the construction of hydrogen pipelines, liquefied gas/chemical containers, ships and Bridges."

This work has been supported by the EXIST funding program of the German Federal Ministry for Economic and Climate Action (BMWK). In addition to speeding up the production of wind farms, the technology could save time and money for the manufacturing of cruise ships, pipelines, gas turbines, fuel tanks, and many other industrial structures.

Source: OFweek