Comparing Common Welding Processing Methods: TIG, MIG, and Stick

Which Welding Process Delivers the Best Results for Structural Steel?

For custom welded structural steel parts, MIG (GMAW) offers the optimal balance of productivity, quality, and cost-effectiveness for most production scenarios. However, TIG (GTAW) is the undisputed choice for critical, thin-wall, or aesthetic welds, while Stick (SMAW) remains the go-to for outdoor, dirty, or field repairs. The “best” method depends entirely on material thickness, position, environment, and required mechanical properties. Data from our production lines shows that MIG achieves deposition rates 3–5× higher than TIG, but TIG provides defect rates below 0.5% for stainless steel components, compared to 1.2–1.8% for MIG in the same conditions.

Process Fundamentals: How TIG, MIG, and Stick Differ

Each process uses a distinct heat source, shielding mechanism, and filler metal delivery. Understanding these basics is the first step toward process selection.

TIG (Gas Tungsten Arc Welding)

Uses a non-consumable tungsten electrode to create the arc. Filler metal is added separately by hand. Shielding gas (typically 100% Argon or Ar-He mixes) protects the weld pool. Heat input is precisely controlled via foot pedal or remote amperage, making it ideal for thin materials (0.5–6 mm) and critical root passes.

MIG (Gas Metal Arc Welding)

Employs a continuously fed consumable wire electrode that also serves as filler. Shielding gas (usually Ar-CO₂ blends) protects the arc. Deposition rates are high (3–8 kg/h), and the process is semi-automatic, enabling long, uninterrupted welds. Suitable for thicknesses from 1 mm to over 25 mm with proper procedures.

Stick (Shielded Metal Arc Welding)

Uses a flux-coated consumable electrode. The flux decomposes to form shielding gas and slag. No external gas is required, making it highly portable. Works well on dirty, rusty, or painted surfaces. Typical deposition rates are 1–3 kg/h, suitable for materials above 3 mm thickness.

Key Performance Comparison: Data-Driven Insights

The table below summarizes critical metrics collected from over 500 production runs of structural steel parts (S355JR grade) at our facility. All data are real-world averages, not theoretical maxima.

MIG offers the lowest cost per metre and highest productivity, while TIG excels in quality and precision. Stick welding, despite its lower deposition, remains irreplaceable for on-site erection and repair.

Application-Specific Recommendations for Structural Steel

Choosing the right process for a given component ensures both mechanical integrity and production efficiency. Based on our experience manufacturing EN1090-compliant parts, here are clear guidelines.

Heavy Sections (>15 mm) – MIG and Stick

For thick-walled beams, columns, and base plates, MIG with spray transfer (using 90% Ar + 10% CO₂) delivers deep penetration and high travel speeds. Alternatively, Stick welding with basic electrodes (e.g., E7018) is preferred for tack welding and field assembly due to its tolerance of moisture and minor mill scale. In our shop, MIG accounts for 78% of all heavy weldments because of its 40% higher productivity than Stick.

Thin-Walled Structures (2–6 mm) – TIG and Pulsed MIG

For hollow sections, brackets, and decorative components, TIG produces flawless, spatter-free welds with minimal distortion. However, pulsed MIG (with advanced waveform control) can achieve similar quality at 2–3× the speed. For carbon steel parts under 4 mm, we use pulsed MIG in 65% of cases, reserving TIG for stainless steel or when aesthetics are paramount.

Outdoor & Field Repairs – Stick

When wind, humidity, or poor access are factors, Stick welding’s self-shielding characteristic is invaluable. No external gas cylinder means lower setup time and greater mobility. Our service team uses Stick for emergency repairs and erection joints, achieving full penetration in vertical-up positions with E7018 electrodes at a consistent 120–140 A.

Quality and Certification: Meeting EN1090 & ISO3834

All welding processes used in our facility are qualified to EN1090 EXC3 and ISO3834-2 requirements. These certifications mandate strict control over procedure specifications, welder qualifications, and non-destructive testing (NDT).

For MIG and TIG, we implement real-time monitoring of voltage, amperage, and wire feed speed with a tolerance of ±2%. Stick welding parameters are controlled via calibrated inverter machines. Regular cross-section macro-etch tests show that MIG welds have a penetration depth consistency of ±0.5 mm, while Stick varies by ±1.2 mm under similar conditions.

To comply with ISO9001 and ISO14001, all processes are documented with digital traceability. Our NDT pass rate (UT/MT) averages 98.7% for MIG, 99.2% for TIG, and 96.5% for Stick, confirming that TIG yields the fewest internal flaws.

Process Selection Flowchart – From Design to Production

The following decision diagram summarizes how we select the optimal welding method at Jiaxing Dingshi. It integrates material, thickness, position, and environmental factors.

This flowchart is used daily by our production planners to ensure the right process is assigned to every order, reducing rework by 22% since 2022.

Cost and Efficiency Considerations for Volume Production

While welding cost comprises only 15–25% of total fabrication expense, it directly impacts throughput and delivery schedules. We break down the total cost per metre of weld for each process.

• TIG – Higher labour cost (skilled operator) and slower speed. Average cost per metre: €3.5. Best for low-volume, high-value parts.
• MIG – Lower labour cost per kg deposited. Consumables (wire + gas) are moderate. Average cost per metre: €1.6. Most economical for batch production over 50 units.
• Stick – Low equipment cost but higher electrode waste (10–15% stub loss). Average cost per metre: €2.0. Preferred for short runs and field work.

Our financial analysis shows that for a typical 10-metre structural weld, MIG saves 2.3 labour hours compared to Stick and €19 in total cost versus TIG. This is why we recommend MIG as the primary process for most structural steel contracts.

Practical Tips for Process Optimization

Based on years of hands-on experience, here are actionable recommendations to get the best out of each welding method.

• For TIG: Use 2% lanthanated tungsten (WL20) for DCEN welding of steel. Maintain a stick-out of 3–5 mm and use a gas lens for better shielding at low flow rates (6–8 L/min).
• For MIG: Optimize wire feed speed and voltage according to the “synergic” curve. For 1.2 mm wire in spray transfer, set at 27 V / 320 A for 12 mm plate. Use 82% Ar + 18% CO₂ for a good balance of penetration and spatter.
• For Stick: Store electrodes in a drying oven at 120–150 °C. For vertical-up welding, use a weave technique and keep arc length as short as possible to prevent slag entrapment.

Implementing these tips has improved our first-pass yield by 8.5% across all processes in the last fiscal year.

Summary: When to Choose Which Process

To conclude, we present a clear decision summary based on the most common scenarios encountered in structural steel fabrication.

• Choose TIG when: material < 6 mm, stainless steel, or root pass requires zero defects.
• Choose MIG when: plate thickness 6–25 mm, indoor production, and high throughput is needed.
• Choose Stick when: outdoor/field work, dirty surfaces, or equipment portability is critical.

At Jiaxing Dingshi Machinery Manufacturing Co., Ltd., we leverage all three processes, with MIG as the workhorse (62% of total arc time), TIG for 18% of precision jobs, and Stick for 20% of erection/repair tasks. This balanced approach, backed by EN1090 and ISO certifications, ensures we deliver structurally sound and cost-effective solutions to our global clients.