TIG welding produces the highest quality welds through precise control of heat input using a non-consumable tungsten electrode and separate filler rod. Success depends on proper tungsten preparation, optimal gas coverage with VARIGON® or pure argon, and maintaining consistent arc length for clean, porosity-free results.
TIG Welding Fundamentals: Master GTAW Process Control
Essential TIG Setup Parameters
- Tungsten Electrode Preparation. Grind 2% thoriated tungsten to a point length 2.5x the electrode diameter. Use dedicated tungsten grinder with longitudinal marks parallel to electrode axis.
- Gas Selection and Flow. Use VARIGON® He30 for critical applications or pure argon for general work. Set flow rate 8-12 L/min for standard nozzles, 6-8 L/min with gas lens systems.
- Current Selection. Use DCEP (electrode negative) for steel and stainless, AC for aluminum. Set 30-40A per mm of material thickness as starting point.
- Arc Length Control. Maintain 2-3mm arc gap for consistent heat input. Use arc length equivalent to tungsten diameter as reference guide.
- Filler Rod Technique. Feed filler at 15-20° angle to torch, adding material to leading edge of molten pool. Match filler rod composition to base material.
Critical TIG Welding Mistakes
- Don't contaminate tungsten electrode by touching filler rod or base material - this causes inclusion defects and arc instability.
- Don't use inadequate post-flow time - tungsten oxidation during cooling creates arc starting problems and contamination.
- Don't grind tungsten on contaminated wheels - steel particles embedded in tungsten will contaminate aluminum welds.
- Don't use excessive current density - overheating tungsten causes rapid consumption and tungsten inclusions in weld metal.
- Don't weld without proper backing gas on critical applications - atmospheric contamination on root side causes porosity.
- Don't ignore wind protection - even slight air movement disrupts gas coverage leading to oxidation and porosity.
TIG Process Optimization for Different Materials
Carbon steel (1-6mm): Use DCEP with 2% thoriated tungsten. VARIGON® or pure argon both work well. Pre-flow 1-2 seconds, post-flow 8-10 seconds. Travel speed 100-200mm/min.
Stainless steel (all grades): DCEP with 2% lanthanated tungsten preferred. Use CRONIGON® backing gas for root passes. Reduce heat input 20% vs carbon steel to prevent carbide precipitation.
Aluminum alloys: AC current with pure tungsten or zirconiated tungsten. Pure argon or VARIGON® He30 for thick sections. Cleaning action removes oxide layer - balance penetration vs cleaning.
Precision root passes: Use gas lens nozzle with FORMIER® backing gas. Reduce current 30% and use keyhole technique for full penetration control.
Exotic materials (titanium, Inconel): Trailing gas shields essential. Use high-purity argon or helium mixtures. Chamber welding recommended for critical applications.
Premium TIG Gas
VARIGON® He30 (Ar + 30% He)
Professional GradeWhy VARIGON® He30 superior for TIG: Helium addition increases arc voltage and heat input for better penetration on thick sections. Superior arc stability and cleaning action compared to pure argon, especially beneficial for aluminum and stainless steel.
Optimal usage parameters: Flow rate 8-10 L/min with gas lens systems. Excellent for materials >6mm thickness where penetration is critical. Reduces required current by 15-20% vs pure argon.