Tips on Using Nitrogen Gas Mixtures in Stainless Steel Pipes Laser Welding

In order to laser weld stainless steel pipes, a mixture of helium and nitrogen is needed. The machine will operate at a maximum power of 12 kW. A laser beam is used in order to weld the pipes. With the use of the laser beams, the process takes a little time to complete. It also allows deeper penetration compared to traditional processes such as TIG welding, plasma welding, and MIG welding.

Laser welding requires higher power densities to focus the laser beam with the use of one or more mirrors in the work pieces that needed to be welded. The high power densities results to vaporization at the surface and could make the pieces expand to the outside. It can also lead to progressive cratering of the weld pool and the formation of deep vapor capillary known as keyhole. The capillary is formed due to the metal vapor or metal vapor plasma mixture that absorbs the laser beam and traps the energy inside the capillary.

Another problem with laser welding is the formation of shielding gas plasma. The metal vapor plasma generates a shielding gas with free electrons. It can lead to the formation of shielding gas plasma that can be detrimental to the welding process. The laser beam will be obstructed by the gas plasma that can absorb the laser beam. It can also be diffracted and decrease the effectiveness of the laser beam.

When welding a stainless steel pipe, it is important to get the maximum penetration of the weld to avoid fracturing the pipe that can lead to flaring or bending, especially when the pipe is used to transport corrosive materials. Therefore it is important to get the right Ar/He mix in order to get the maximum amount of penetration power from the laser beam when welding stainless steel pipes.

Photo in this post By Krorc (Own work) [CC-BY-SA-3.0], via Wikimedia Commons