Ternary gas mixtures combine argon's stability, CO2's wetting improvement, and helium's heat input boost to optimize stainless steel welding characteristics. These three-component blends allow fine-tuning of arc behavior, penetration, and metallurgical properties impossible with binary mixes alone.
Ternary Mix Theory: Ar/CO2/He for Stainless Steel
The Three-Gas Balance
- Argon (base, 70-95%). Provides arc stability and inert protection for stainless steel's corrosion resistance.
- CO2 (wetting agent, 2-8%). Improves bead shape and penetration while staying below carbide formation thresholds.
- Helium (heat enhancer, 5-25%). Increases heat input for better fusion on thick sections or high-speed welding.
Why Stainless Needs Ternary Mixes
- Carbide sensitivity. Too much CO2 (>8%) causes chromium carbides that destroy corrosion resistance.
- Heat requirements. Stainless steel's low thermal conductivity benefits from helium's heat boost.
- Wetting challenges. Pure inert gases give poor bead shapes on stainless compared to carbon steel.
- Oxidation balance. Need enough oxidation for wetting but not enough to form harmful oxides.
Common Ternary Compositions
90% Ar / 8% CO2 / 2% He: General-purpose stainless, good balance for 3-10mm sections.
85% Ar / 5% CO2 / 10% He: Increased heat input for thick stainless or high-speed production.
75% Ar / 5% CO2 / 20% He: Maximum heat input for very thick sections or poor-fit-up conditions.
93% Ar / 2% CO2 / 5% He: Precision applications requiring minimal oxidation.
Optimized Ternary
CRONIGON® 2He55
Complex Three-Gas MixWhy CRONIGON 2He55 excels: Precision-balanced ternary mixture provides optimal stainless steel characteristics while maintaining the low carbon potential critical for corrosion resistance.
Best applications for ternary mixes: Duplex stainless, super-austenitic grades, thick-section stainless, and any application where standard binary mixes fall short.
⚗️ Advanced Chemistry