Argon: Characteristics
Why a heavy, lazy gas is perfect for welding
What this tab covers The physical and chemical properties that set its grade, price and uses, with the commercial grades and the standards that define them.Purity and form matter. Welding argon is 99.99-99.996%; electronics and crystal growth need 99.999% or better with ppb limits on oxygen and moisture. Argon is denser than air and has low thermal conductivity, which suits weld shielding and window insulation.
Properties that matter commercially
| Property | Value / specification | Why it matters | Source |
|---|---|---|---|
| Purity | 99.996% (grade 4.6) to 99.9999% (grade 6.0) | sets suitability for welding, metals or electronics | industry grades (indicative) |
| Boiling point | -186 C | liquid storage and transport | physical data |
| Density of gas | 1.78 kg per m3 at 0 C (USGS: 1 m3 = 0.0018 t) | heavier than air, so it blankets welds | USGS MCS 2026 |
| Share of air | 0.93% by volume, 1.29% by mass | caps recovery per tonne of oxygen | physical data |
Commercial grades
- Welding grade argon and argon-CO2 blends
- High purity 99.999% for metals and lighting
- Electronic and UHP grades for fabs and solar ingots
- Liquid argon (bulk)