Master TIG welding for sheet metal fabrication. Learn about torch technique, parameter selection, filler metal choice, and quality control for precision welds.
Introduction
TIG (Tungsten Inert Gas) welding, also known as GTAW, produces the highest quality welds of all arc welding processes. At Fulei Metal, our 10 welding stations include dedicated TIG capabilities for precision sheet metal work serving automotive, medical, and aerospace clients worldwide.
What is TIG Welding?
TIG welding uses a non-consumable tungsten electrode to create the arc. An inert gas (typically argon) shields the weld pool. Filler metal is added separately by hand. This produces clean, precise welds with excellent control.
Advantages for Sheet Metal
Superior weld quality with no spatter. Excellent control over heat input, critical for thin materials. Works on all metals including steel, stainless, aluminum, copper, and titanium. Produces aesthetic welds. Low distortion when properly executed.
Equipment and Setup
Power Source
DC output for steel and stainless steel. AC output for aluminum and magnesium (cleans oxide layer). Pulsed DC for thin materials and precision work. At Fulei Metal, our TIG machines cover all requirements.
Torch
Air-cooled torches for low-amperage work (up to 150A). Water-cooled torches for high-amperage and continuous work. Torch size affects access to tight joints.
Gas Flow
Argon is the standard shielding gas. Argon-helium mixtures provide hotter arc for thicker materials. Flow rate: 8-15 liters per minute for most sheet metal work.
Parameters for Sheet Metal
Amperage
1 mm steel: 40-70 amps. 2 mm steel: 70-110 amps. 3 mm steel: 100-140 amps. 1 mm stainless: 35-60 amps. 2 mm aluminum: 80-120 amps AC.
Tungsten Electrode
Thoriated (red tip) for DC on steel and stainless. Ceriated or lanthanated for AC on aluminum. Diameter: 1.0-2.4 mm for sheet metal. Grind to a point for DC, rounded for AC.
Filler Metal
ER70S-6 for mild steel. ER308L or ER316L for stainless steel. ER4043 or ER5356 for aluminum. Diameter: 1.0-2.4 mm for sheet metal.
Technique
Torch Angle
15-20 degrees from vertical, tilted in the direction of travel. Gas cup size should match the joint. Keep arc length short (1-3 mm).
Travel Speed
Move steadily, watching the weld pool. Too fast: insufficient penetration. Too slow: excess heat, burn-through on thin materials.
Filler Addition
Dip filler into the front of the weld pool. Withdraw between dips. Maintain consistent rhythm. The filler melts into the pool, not the arc.
Pulsed TIG
Pulsing alternates between high and low current. Reduces heat input. Ideal for thin materials. Improves control on critical joints.
Common Applications
At Fulei Metal, we use TIG welding for: precision enclosures, stainless steel food equipment, medical device components, aluminum brackets, aerospace parts, and visible welds requiring aesthetic quality.
Quality Control
Visual inspection for weld appearance. Dimensional check for distortion. Leak testing for sealed enclosures. Penetrant testing for surface defects. Radiography for critical applications.
Common Problems
Burn-through on thin materials: reduce amperage, increase travel speed, use pulsed TIG. Porosity: check gas coverage, clean material, verify gas purity. Tungsten contamination: avoid touching filler to electrode. Distortion: control heat input, use tack welds, clamp properly.
Conclusion
TIG welding produces the highest quality welds for sheet metal. At Fulei Metal, our TIG capabilities and experienced welders ensure precision welds for demanding international clients.