The unique properties of Helium welding gas are firstly shown in its outstanding thermal conductance (0.151 W/m·K, 6 times argon) and reduced weight (0.1785 kg/m³), which has the ability to attain a further penetration when welding (40% over argon). It reduces the heat affected zone width down to 1.2 mm. For example, helium gas mixture (He-75% + Ar-25%) was used by Boeing in making titanium alloy parts for 787 aircraft, welding speed increased by 30%, porosity from 0.8% dropped to 0.1%, and tensile strength was up to 950MPa, meeting the aviation AS9100 standard.
When welding superalloys, helium welding gas is able to well shield oxygen and nitrogen due to its inertia. In spaceflight fuel pipe nickel-based alloy welding, NASA applies pure helium protection gas to control the weld oxidation impurity content below 50ppm (the argon program is 200ppm) and achieves stable welding temperature of 2400℃±50℃ and 90% decreased crack rate. Thyssenkrupp’s German nuclear reactor pressure vessel welding project showed that helium shielding extended the fatigue life of the weld to 25,000 cycles (17,000 cycles for argon), and the equipment life was extended by 47%.
Shortage and expense are obstacles to use. Helium is approximately 8 times more expensive than argon (2023 market price: helium 35/m)
Argon 4.5/m³), but is optimized in terms of cost with mixed gas technology. Japanese automaker Toyota uses He-50% + CO₂-50% mixed gas welding aluminum alloy body, consumption of gas down by 40%, efficiency up by 25%, and only manufacturing cost for the bicycle goes up by 3%. Helium recovery system of Qatar Gas can recover and recycle 95% of the helium from exhaust gas of welding, saving 60% of procurement costs for a year.
For helium welding gas in precision electronics, the low ionization energy (24.6 eV) can produce a more stable arc. Apple’s supplier Foxconn used a helium-encapsulated high-frequency pulse TIG welder in welding the stainless steel middle frame of iPhone, which limited the welding deformation within 0.05 mm (0.15 mm using argon) and enhanced the yield from 88 percent to 99.5 percent. In 2023, MIT research proved that helium arc electron density (1.5×10²¹ m⁻³) is three times greater than that of argon, and 0.01mm miniature solder joint accuracy can be achieved, which is suitable for medical implant welding.
In the face of global helium resource scarcity (reserves: 40% in the United States, 30% in Qatar), technological innovation continues to progress. The Helium Cycle Welding Chamber produced by China Baosteel Group reduced the helium consumption of one welding from 15L/min to 8L/min based on the gas dynamic balance algorithm, and the overall cost was reduced by 45%. The cryogenic helium recovery unit funded by the Horizon 2020 initiative of the EU has a recovery efficiency of 99.8% at -269 ° C, and the payback period of the equipment is reduced from 5 years to 2.3 years. These characteristics make welding gas helium irreplaceable in the high-end manufacturing sector, with a global market size valued at $1.2 billion in 2023 and is estimated to reach $2.8 billion in 2030, with a compound annual growth rate of 13%.