... chemically inert. It is used as shielding gas in welding, detecting gas and illuminant gas puritystandardunitApplicationoxygen≥99.5GB-T3863-1995bottle/cylinder Steel cutting, welding ... , analysis Pure argon ≥99.99 GB/T4842-95Bottle Welding shielded welding, stainless steel smelting, container, steel structure manufacture, mold processing, etc. 99.999% argon gas