Why noble gases such as helium and argon are used in welding?

Answer 1

maybe because helium is lighter

If you are asking in re: to TIG welding, Oxygen is corrosive and a "live" gas that will destroy the molten metal. You need an "inert" gas to protect the molten puddle. If you are asking in re: to cutting or welding with the Oxy/Fuel process then Helium is an "inert" gas and does not burn or support combustion.

Answer 2

Helium is an inert gas (dead) and was used when TIG welding was first developed. Now most TIG welding uses Argon, another inert gas. Oxygen breaks down metals by attacking the elements. This is called oxidation. In iron and steel it is called rust. Aluminum also oxidizes. At high temperatures this takes place very fast. Therefore a shield of inert gas prevents the oxygen in the air we breathe from doing this. In stick welding the heat of the arc burns up the oxygen while the smoke forms a shield around the weld puddle. The coating on the electrode produces the smoke and also the slag which protects the weld till it cools. Caution, windy conditions can blow away the gas shield whether TIG, MIG or stick welding.

Answer 3

Helium and Argon are inert gases, meaning they do not combine or react with other elements. Oxygen reacts with most elements, combining with them. This is why Iron rusts when exposed to the air we breathe. This reaction happens much faster when Iron is heated and becomes molten. Oxygen reacts with Iron producing Iron Oxide RUST. This was a problem when arc welding was a new process. Uncoated electrodes were being used and the welds were very poor as Oxygen was combining with the molten Iron. Coated electrodes were developed to produce an inert gas to keep Oxygen away from the molten Iron. When GTAW or TIG welding was first developed (Heliarc) Helium was the inert gas used to protect the molten metal. Now most GTAW applications use Argon as it is cheaper and also heavier and stays in the weld area longer. On the plus side, Oxygen reacting with Aluminum produces Aluminum Oxide a valuable product used as an abrasive for "sand paper". Living things cannot survive in an inert atmosphere. A person can "drown" if too much Helium, Argon, CO2 or other inert gas is present. Be aware of this danger.

Answer 4

Most GTAW setups use Argon. Helium was first used because it was developed primarily to weld aluminum and Helium being a lighter gas allows more heat transfer to the metal. But it is more expensive so most companies (I have worked for) use Argon.

Answer 5

because it is a type of gas and you can only use certain gases go welding.

Answer 6

Because they are unreactive and do not react with the hot metals involved and ensure a strong weld is made

Answer 7

Welding involve high temperatures and the oxydation is increased; helium is unreactive.

Answer 8

Because they are unreactive and inert.