... , welding, flame processingnitrogen≥99.5GB-T3864-1996bottle/cylinderReplacement gas and protection gas for chemical industry, metallurgy, and electric industry.hydrogen≥99.9GB-T3634-1995bottle/cylinderChemical ... , 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