No. The main reason is to create a really inert environment, avoid the presence of oxygen, nitrogen, other gases more reactive than the noble gases. They're just trying to avoid the formation of oxides or other compounds that could weaken the weld joint. Apparently, there have been some accidents because of lousy welding, including a famous 747 crash in Japan because of careless behavior during the welding of a plane back wing! A popular Japanese composer, Kyu Sakamoto, died in this crash. He composed, among many others, a famous song called "Sukiaki", worldwide hit in the 60's 70's.