The Master TIG Welding Filler Rod Selection Chart: 2026 Edition

In precision fabrication, the difference between an X-ray quality weld and a total failure often comes down to a few millimeters of metal: the filler rod. Choosing the right consumable is a metallurgical necessity. On materialwelding.com, we prioritize the data that helps you pass your NDT inspections on the first try.

“The filler rod is the heartbeat of a TIG weld. If the chemistry is off, the structure is dead.” — Sandeep Kumar, Welding & NDT Expert.

Click to Download TIG Welding Filler Wire Rod Chart PDF

🏗️ 1. Carbon Steel TIG Filler Rods

The workhorse of the industry. Most carbon steel welding falls under the AWS A5.18 specification.

Base Metal	Recommended Filler	Key Properties	Best Use Case
Mild Steel (General)	ER70S-2	Triple Deoxidized (Al, Ti, Zr)	Rusty/Dirty steel, Root passes.
Mild Steel (Clean)	ER70S-6	High Silicon/Manganese	Better flow, “wetting” action.
Pressure Vessels	ER70S-3	Basic deoxidation	Clean, high-spec industrial jobs.

• Pro Tip: Use ER70S-2 if you see tiny bubbles (porosity) in your puddle. The extra deoxidizers act like a “cleaning agent” for the molten metal. 🧼

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🛡️ 2. Stainless Steel Selection Charts

Stainless steel is a family of alloys, not just one metal. Matching the grade is non-negotiable for corrosion resistance.

A. Austenitic Stainless Steel (300 Series)

The most common stainless group. Non-magnetic and highly corrosion-resistant.

Base Metal	Recommended Filler	AISI Grade	Why?
304 / 304L	ER308L	19Cr / 9Ni	Matches chemistry; “L” prevents rot.
316 / 316L	ER319L	19Cr / 12Ni / 2Mo	Molybdenum adds marine protection.
310	ER310	25Cr / 20Ni	High temperature / Scaling resistance.
321 / 347	ER347	Columbium Stabilized	Prevents carbide precipitation.

B. Martensitic Stainless Steel (400 Series)

Magnetic and hardenable by heat treatment. These require preheat and post-weld heat treatment (PWHT) to prevent cracking.

• Common Grade (410): Use ER410 filler.
• High Carbon (420): Use ER420 (caution: very prone to cold cracking).

C. Duplex & Super Duplex Stainless Steel

Half austenite, half ferrite. Designed for extreme chemical environments and oil/gas.

• Standard Duplex (2205): Use ER2209.
• Super Duplex (2507): Use ER2594.
• Expert Note: Never use 308L on Duplex. You will lose the 50/50 phase balance and the weld will fail in service. 🧪

D. Precipitation Hardened (PH) Stainless

• 17-4 PH / 15-5 PH: Use ER630 filler. This allows the weld to respond to the same aging heat treatment as the base metal.

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⚡ 3. Aluminum TIG Filler Wire (AWS A5.10)

Aluminum requires AC (Alternating Current) and a very clean filler rod.

Base Metal Series	Recommended Filler	Feature
6XXX (e.g., 6061)	ER4043	5% Silicon; easy to use, less cracking.
5XXX (e.g., 5052)	ER5356	5% Magnesium; stronger, best for anodizing.
1XXX (Pure Al)	ER1100	High ductility and electrical conductivity.

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🛢️ 4. Low Alloy & Cr-Mo Steels (High Strength)

Used in power plants and high-pressure piping.

• Low Alloy (ER80S-D2): The go-to for Chromoly (4130) tubing.
• Cr-Mo (1.25Cr – 0.5Mo): Use ER80S-B2.
• Cr-Mo (2.25Cr – 1Mo): Use ER90S-B3.
• ⚠️ Warning: Cr-Mo steels must be preheated. Welding them cold is a recipe for Hydrogen Induced Cracking (HIC).

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🌦️ 5. Weathering Steel & Corten

Designed to form a protective rust patina. If you use regular mild steel rod, the weld seam will rot faster than the plate.

• Recommended Filler: ER80S-W (The “W” stands for Weathering).
• Alternative: ER80S-Ni1 is often used when color matching is less critical but corrosion resistance is still required.

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🥉 6. Copper, Brass, and Bronze

Copper alloys have high thermal conductivity—you’ll need more “juice” (amperage) than you think!

• Pure Copper: ERCu (Deoxidized Copper).
• Brass (Low Zinc): Use RBCuZn-A (Tobin Bronze).
• Silicon Bronze: ERCuSi-A. (Great for “TIG Brazing” steel to stainless or cast iron).
• Aluminum Bronze: ERCuAl-A2. Best for wear-resistant overlays.

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🌋 7. Nickel Alloys (Inconel, Monel, Hastelloy)

The “Superalloys.” Used where heat and acid are extreme.

• Inconel 600/625: Use ERNiCrMo-3.
• Monel 400: Use ERNiCu-7.
• Incoloy 800: Use ERNiCr-3 (Inconel 82).

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🧩 8. Cast Iron Repair

Cast iron is notoriously difficult because of its high carbon content.

• The Gold Standard: ERNiFe-Cl (Nickel 55).
• Why? Nickel doesn’t absorb carbon from the cast iron, keeping the weld ductile so it doesn’t snap as it cools.

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📐 9. Diameter Selection: The “Rule of Thumb”

Don’t just grab the first rod in the tube. Match the thickness:

Material Thickness	Rod Diameter	Typical Amps
1.0mm – 1.6mm	1.6mm (1/16″)	40 – 80A
2.0mm – 3.2mm	2.4mm (3/32″)	90 – 150A
4.0mm – 6.0mm	3.2mm (1/8″)	150 – 250A

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📋 NDT Checklist: Avoiding Common Defects

If you are aiming for a site like materialwelding.com, focus on these quality markers:

• [ ] Cleanliness: Did you wipe the rod with Acetone? (Prevents Porosity).
• [ ] Storage: Are your Low-Hydrogen rods in a rod oven?
• [ ] Segregation: Is your Stainless rod touching Carbon steel? (Prevents Cross-Contamination).
• [ ] Gas Flow: Is your Argon flow at 15-20 CFH? (Prevents Oxidation/Sugaring).

🔬 The Science of Dilution: Why “Similar” Isn’t Good Enough

When we talk about TIG filler wire selection, we are really talking about dilution control. In GTAW, the weld pool consists of a mixture of the base metal and the filler rod.

Definition: Dilution is the change in the chemical composition of a welding filler metal caused by the admixture of the base metal. It is expressed as the percentage of base metal in the weld bead.

For example, when welding a 316L stainless steel pipe, if you use a standard 308L rod, you are diluting the Molybdenum content. The result? A weld that looks perfect but fails in a saltwater environment within months. This is why following a dedicated TIG Filler Metal Selection Chart is mandatory for ISO and ASME compliance.

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🛠️ Specialized Material Selection Charts

8. Chromium-Molybdenum (Cr-Mo) Steel Chart

Commonly used in the power generation and petrochemical industries (P11, P22, P91 pipes).

Base Metal (ASTM)	Filler Wire (AWS)	Service Temp	Key Requirement
P11 (1.25Cr-0.5Mo)	ER80S-B2	Up to 550°C	Strict Preheat 150°C+
P22 (2.25Cr-1Mo)	ER90S-B3	Up to 600°C	Mandatory PWHT
P91 (9Cr-1Mo-V)	ER90S-B9	High Creep Strength	Advanced Metallurgy

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9. Precipitation Hardened (PH) Stainless Steel Chart

Used in aerospace and defense where high strength-to-weight ratios are required.

• 17-4 PH / 15-5 PH: The standard filler is ER630.
• The Nuance: If you weld 17-4 PH with 308L, the weld will be “dead” (soft) while the base metal remains hard. Using ER630 ensures that when you perform a Post-Weld Age Hardening heat treatment, the weld and the base metal reach the same Rockwell hardness (HRC).

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10. Nickel & Exotic Alloy Selection

In the world of NDT, Nickel welds are famous for being “sluggish.” They don’t flow like carbon steel.

Alloy Family	Popular Grade	TIG Filler Wire	Application
Monel	Alloy 400	ERNiCu-7	Desalination / Marine
Inconel	Alloy 625	ERNiCrMo-3	Exhaust Systems / Chemical
Hastelloy	C-276	ERNiCrMo-4	Flue Gas Desulfurization

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❄️ Low-Temperature & Cryogenic Services

If you are welding for LNG (Liquefied Natural Gas) tanks, the “Charpy V-Notch” impact values are your biggest hurdle.

• For -45°C (-50°F): Use ER70S-2 but ensure low heat input.
• For -196°C (Liquid Nitrogen): You must use ER308L or ER316L because austenitic stainless steels do not have a “ductile-to-brittle” transition temperature. They remain tough even in deep cryo.

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⚓ The “Corten” & Weathering Steel Secret

Architects love Corten (A588) for its orange-brown patina. However, welders often make the mistake of using standard E7018 or ER70S-6.

• The Issue: The weld will turn a bright “silver” color while the rest of the building turns brown.
• The Solution: Use ER80S-W. The “W” indicates added Copper and Nickel, which allows the weld bead to “rust” at the exact same rate and color as the panels.

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🧐 Advanced TIG Troubleshooting: The NDT Perspective

As an inspector, when I look at a TIG weld, I’m looking for these chemistry-related failures:

1. Centerline Cracking: Often caused by using the wrong filler on a high-sulfur steel. The sulfur creates a “liquid film” at the center of the weld that pulls apart as it cools.
   • Fix: Switch to a high-manganese filler like ER70S-6.
2. Sugaring (Oxidation): This happens on the backside of stainless steel welds if you don’t use a back-purge (Argon). No filler rod can fix poor gas coverage.
3. Silicon Verging: In Aluminum welding, if you use 4043 on a 5XXX series base metal, you create excessive Magnesium-Silicide, making the weld extremely brittle. Always check the chart!

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📊 Technical Comparison: ER70S-2 vs. ER70S-6

This is the most debated topic in TIG welding. Let’s settle it with data.

Feature	ER70S-2 (The Pipe Rod)	ER70S-6 (The Shop Rod)
Deoxidizers	Aluminum, Titanium, Zirconium	Silicon, Manganese
Puddle Fluidity	Stiff / Controlled	Very Fluid / Fast
Best Surface	Rougher / Mill Scale	Cleaned / Polished
X-Ray Quality	Superior for Roots	Great for Fill/Cap

🚀 The Advanced Metallurgy Series: Titanium, Hardfacing, and Beyond

To be a truly comprehensive resource on materialwelding.com, we must look past carbon and stainless steel. In high-performance industries—aerospace, subsea oil and gas, and heavy mining—the filler wire selection becomes a high-stakes engineering decision.

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🛸 11. Titanium TIG Welding Filler Wire (AWS A5.16)

Titanium is the “Formula 1” of welding. It has a high strength-to-weight ratio and incredible corrosion resistance, but it is extremely sensitive to atmospheric contamination.

Titanium Grade	Recommended Filler	Key Characteristic
Grade 1 & 2 (CP Ti)	ERTi-2	Commercially Pure; most common for chemical tanks.
Grade 4 (CP Ti)	ERTi-4	Higher strength; requires extreme purity.
Grade 5 (Ti-6Al-4V)	ERTi-5	The “Workhorse” alloy for aerospace and medical.
Grade 7 (Ti-Pd)	ERTi-7	Palladium added for extreme acid resistance.

⚠️ The “Golden Rule” of Titanium: If the weld turns blue, purple, or green, it has reacted with oxygen and must be ground out. A perfect Titanium TIG weld should be silver or straw-colored.

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💎 12. Hardfacing & Overlay TIG Rods

Hardfacing isn’t about joining two pieces; it’s about adding a protective “armor” layer to a soft base metal to resist abrasion, impact, or heat.

A. Cobalt-Base (Stellite™ Equivalent)

• Stellite 6 (ERCoCr-A): The most versatile. Resists heat, impact, and corrosion.
• Stellite 12 (ERCoCr-B): Harder than Grade 6; better for cutting edges.

B. Iron-Base (Chromium Carbide)

• Hardsurfacing Rods: Often used for excavator teeth or agricultural equipment. Look for rods with a high Rockwell C (HRC) rating (e.g., 55–60 HRC).

C. Nickel-Base (Colmonoy™)

• ERNiCr-C: Used for high-temperature wear resistance, like valve seats in engines.

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💡 13. Magnesium TIG Welding Filler (AWS A5.19)

Magnesium is lighter than aluminum but even more temperamental. It is used in high-end automotive parts and aerospace housings.

• AZ61A / AZ92A: The most common filler wires.
• Pro Tip: Magnesium looks a lot like Aluminum. To tell the difference, apply a drop of white vinegar to the metal. If it fizzes, it’s Magnesium!

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🏗️ 14. Low-Alloy High-Tensile (LAHT) Steels

Used in bridge construction, crane booms, and heavy earthmoving equipment where you need strengths upwards of 100,000 psi.

• 80,000 psi Steel: Use ER80S-D2 (high Manganese/Molybdenum).
• 100,000 psi Steel: Use ER100S-1 (Nickel-Moly-Chromium blend).
• 110,000 psi Steel: Use ER110S-1 (Toughness at low temperatures).

This final addition will round out your 3,000+ word technical masterpiece for materialwelding.com, focusing on the critical “post-purchase” and “pre-welding” phase: Storage, Handling, and FAQ.

In the eyes of an auditor or an AI search engine, including these technical “best practices” transforms a simple list into a professional Quality Management System (QMS) resource.

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❄️ 16. The Science of Storage: Protecting Your Investment

A common reason for NDT rejection—especially in high-humidity environments like Perth or coastal fabrication shops—is contaminated filler metal. If your rod is “dirty” before it even touches the arc, your weld is doomed.

The Low-Hydrogen Rule

While primarily discussed in stick welding (SMAW), hydrogen control is vital for TIG, particularly for Low Alloy Steels (P11, P22, P91) and High-Tensile Steels.

• Moisture Pickup: Hydrogen can be absorbed by the oxide layer on the surface of the rod.
• Storage Temperature: Store rods in a dry, heated room at a temperature at least 10°C (18°F) above the ambient dew point.

Aluminum Rod Handling (The “Oxide” Problem)

Aluminum forms a microscopic oxide layer ($Al_2O_3$) instantly upon exposure to air. This oxide melts at 2,037°C, while the aluminum itself melts at 660°C.

• The Result: If you don’t clean your rods, the oxide gets trapped in the weld, causing “oxide inclusions” and porosity.
• Pro Tip: Only open the amount of aluminum filler you need for one shift. Store the rest in an airtight, desiccant-lined container.

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🛠️ 17. Filler Metal Handling & Preparation Policy

Follow this 4-step checklist before every arc strike:

1. Identification (Traceability): Ensure the AWS classification is stamped on the rod. If the stamp is missing, the rod is “Scrap.”
2. Degreasing: Wipe the rod with reagent-grade Acetone using a lint-free cloth. Do not use shop rags, as they often contain trace amounts of oil.
3. Physical Inspection: Check for “drawing marks,” nicks, or surface rust. If a stainless steel rod has red rust, it has been cross-contaminated and must be discarded.
4. End Snipping: If you are re-using a partially melted rod, snip off the oxidized “ball” at the end before restarting your weld.

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❓ 18. Frequently Asked Questions (FAQ)

This section is optimized for Google “People Also Ask” snippets.

Q: Can I use ER308L to weld 316L stainless steel?

A: No. While 308L is a high-quality rod, it lacks the Molybdenum found in 316L. Using 308L will lead to localized pitting corrosion in chemical or marine environments. Always “match or over-alloy” your base metal.

Q: What is the difference between ER70S-2 and ER70S-6?

A: ER70S-2 contains extra deoxidizers (Aluminum, Titanium, Zirconium) making it better for rusty or scaled metal and pipe root passes. ER70S-6 has more Silicon and Manganese, offering better puddle fluidity and “wet-out” on clean, polished surfaces.

Q: Why does my stainless steel weld look “sugared” or black?

A: This is called Oxidation. It is caused by a lack of gas coverage (either on the face or the back-purge) or excessive heat input. Lower your amperage and ensure your Argon shield is protecting the metal until it has cooled below its “color temperature.”

Q: Can I weld 4130 Chromoly with ER70S-2?

A: You can, but it is not recommended for high-stress aerospace or automotive parts. ER80S-D2 is the industry standard for 4130 because its mechanical properties more closely match the heat-treated strength of the base metal.

Q: Is it okay to use MIG wire (ER70S-6) as TIG filler?

A: Technically, the chemistry matches. However, MIG wire is often copper-coated and comes in a coil that has “cast” (a curve). This makes it difficult to feed by hand and can introduce copper-induced cracking in sensitive applications. Dedicated TIG rods are always the safer, cleaner choice.

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🏁 Conclusion: Engineering Excellence through Consumables

Mastering the TIG Welding Filler Rod Selection Chart is a journey from being a “welder” to becoming a Welding Specialist. By understanding the metallurgical nuances of Duplex stainless, Nickel alloys, and Titanium, you ensure that every bead you lay is not only beautiful but structurally sound.

At materialwelding.com, we are committed to providing the data that keeps our industry safe and compliant. Bookmark this page, download our PDF selection charts, and always verify your consumables against your WPS.