Harris Supermissileweld Steel TIG GTAW Welding Rod (1/16 in × 36 in, 10 lb Box — 03SMW30) is a low-alloy, high-strength filler metal classified under AWS A5.28 as ER80S-D2. It is the TIG (GTAW) form of the Supermissileweld® family of alloys — a trade name that reflects the wire's origins in aerospace and military structural applications where high strength-to-weight ratio and excellent toughness at low temperatures are required in the same joint. The alloy's defining chemistry is a combination of ~0.5% molybdenum and 1.6–2.1% manganese, which work together to produce a weld deposit with significantly higher as-welded tensile strength than standard ER70S-6, without requiring the elevated preheat temperatures associated with higher-carbon low-alloy consumables.
Supermissileweld TIG rod is particularly valued in applications involving high-yield-strength base metals — HSLA steels, quenched-and-tempered plate grades, and chrome-moly alloys where an ER70S-6 deposit would be under-matched. The manganese-molybdenum chemistry also delivers excellent notch toughness at temperatures down to –60 °F (–51 °C) when tested per Charpy V-notch requirements, satisfying the impact requirements of many pressure vessel and structural codes for low-temperature service.
- AWS Classification: ER80S-D2 per AWS A5.28/A5.28M
- Carbon: 0.07–0.12%
- Manganese: 1.60–2.10%
- Silicon: 0.50–0.80%
- Molybdenum: 0.40–0.60%
- Phosphorus: 0.025% max
- Sulfur: 0.025% max
- Tensile Strength (as-welded): ≥80,000 psi (550 MPa) minimum
- Yield Strength (0.2% offset): ≥68,000 psi (469 MPa)
- Elongation: ≥19%
- Charpy Impact (–60 °F / –51 °C): ≥20 ft-lbf (27 J) typical
- Available Diameter (this SKU): 1/16 in (1.6 mm)
- Rod Length: 36 in (914 mm)
- Package: 10 lb box
The combination of high strength, molybdenum toughening, and low-temperature impact performance makes Supermissileweld TIG rod a versatile choice across multiple industries:
- Aerospace and Defense Structures: Airframe components, missile structural members, military vehicle hulls, and structural brackets in HSLA steels (HY-80, HY-100, A514, A517) where weld joint strength must match base metal yield strength.
- Structural Steel Fabrication (High-Yield): ASTM A572 Grade 65, A514, and A517 steel structures — bridges, heavy-equipment booms, crane components — where standard ER70S-6 under-matches the base metal.
- Pressure Vessels and Piping in Low-Temperature Service: LNG and cryogenic service piping, offshore platform components, and arctic pipeline welds where Charpy impact at –60 °F is specified in the welding procedure specification (WPS).
- Oil and Gas Drilling Equipment: Drill collars, BOP components, and wellhead hardware fabricated in high-strength alloy steel benefit from the ER80S-D2 molybdenum content when post-weld heat treat (PWHT) is not practical and the WPS calls for a low-hydrogen, high-strength TIG root pass.
- Mining and Heavy Equipment: Bucket teeth, ripper shanks, dipper lips, and wear-plate overlays where high manganese-molybdenum composition resists impact fatigue and abrasion in fabricated components.
- Chrome-Moly Transition Welds: As a "step-down" filler when transitioning from 1.25Cr-0.5Mo (P11) or 2.25Cr-1Mo (P22) chrome-moly to carbon steel in dissimilar metal welds, per the Harris and Lincoln filler metal selection guides.
Harris Supermissileweld 1/16 in TIG rod is designed for DCEN (direct current electrode negative) TIG welding on carbon and low-alloy steel base metals. Unlike aluminum TIG, steel TIG welding uses DCEN to maximize penetration and deposition rate while maintaining a stable arc.
ER80S-D2's elevated carbon equivalent (CE ~0.39) and molybdenum content place it in the moderate-preheat category for high-strength steel applications:
- Material up to 3/4 in thickness: 150 °F (66 °C) minimum preheat
- Material 3/4–1-1/2 in: 200–250 °F (93–121 °C) preheat
- Material over 1-1/2 in: 300–400 °F (149–204 °C) preheat — verify against WPS and base metal specification
- Maximum interpass temperature: 400 °F (204 °C)
- 1/16 in rod on 1/8 in plate: 60–110 A, 15–18 V
- 1/16 in rod on 3/16 in plate: 90–140 A, 16–19 V
- Tungsten: 2% ceriated (grey band) or 2% lanthanated (gold band), 3/32 in diameter for the 1/16 in rod range. Grind to a sharp point for DCEN steel TIG work.
- Cup size: #5–#7 Pyrex gas lens for open butt joints; #6–#8 for fillet welds in corners where access is limited.
- Standard: 100% Argon at 15–25 CFH. Argon produces the cleanest bead appearance with minimum oxidation on DCEN steel TIG.
- High-speed production: 75% Ar / 25% He blends at 20–30 CFH increase heat input for faster travel on thicker material (1/4 in and above) without increasing amperage to the point of tungsten contamination.
- Back-purge for root passes: When welding tubing or open-root pipe joints, back-purge with 100% Argon at 2–5 CFH until 1 oxygen reading less than 50 ppm is confirmed with an oxygen sensor to prevent sugar (oxidized root bead) on the inside diameter.
- Store in original packaging at 50–120 °F (10–49 °C) in low-humidity conditions (below 60% RH).
- Unlike SMAW electrodes, bare TIG rod does not have a flux coating susceptible to moisture pickup, but surface rust or scale will cause porosity and inclusions. Inspect rods before use and reject any showing discoloration or pitting.
- Keep rod dry and clean. Use gloves or clean cotton rags when handling — skin oils and drawing lubricants from the rod surface burn at arc temperature and introduce carbon into the weld deposit, potentially raising hardness above the WPS limit.
- For applications with documented WPS hydrogen control requirements (e.g., HY-80 submarine structure), store rod in a sealed dry box and track rod exposure time per the procedure's requirements even though the rod itself carries negligible diffusible hydrogen in the as-drawn condition.
Any DC-capable TIG welder is suitable for Supermissileweld ER80S-D2 rod. Lincoln Electric platforms commonly paired with this filler include:
- Lincoln Precision TIG 225 (K2533-1, DCEN mode)
- Lincoln Square Wave TIG 200 and 300 (DCEN mode for steel)
- Lincoln Electric PTA-17, PTA-17V, PTA-26 TIG torches
- Lincoln Dynasty 200 and 280 DX (DC mode)
Primary base metals:
- ASTM A514 and A517 (quenched-and-tempered structural plates, Fy = 100 ksi)
- ASTM A572 Grade 65 high-strength low-alloy structural steel
- MIL-S-16216 HY-80 and HY-100 naval structural steel
- AISI 4130 and 4140 chrome-moly steel (normalized condition, post-weld anneal recommended)
Secondary / dissimilar applications:
- Carbon steel to low-alloy steel transitions in weld joint strength matching
- Root pass on P1/P2 carbon steel pipe where high-strength cap pass is specified
Q1: What is Supermissileweld — is it a proprietary alloy or an AWS classification?
A: "Supermissileweld" is a Harris Products Group trade name for the ER80S-D2 classification under AWS A5.28. The ER80S-D2 designator is a standard AWS classification: "ER" = electrode/rod for GMAW or GTAW, "80" = 80 ksi minimum tensile strength, "S" = solid wire, "D2" = the specific chemistry grade (Mn-Mo composition group). Any welding procedure written to "ER80S-D2" accepts Supermissileweld rod.
Q2: Can I use Supermissileweld ER80S-D2 as a drop-in replacement for ER70S-6?
A: You can use ER80S-D2 anywhere ER70S-6 is specified, as it over-matches the 70 ksi minimum tensile strength. However, ER80S-D2 requires higher preheat than ER70S-6 on thicker material due to its higher carbon equivalent, so review your WPS before substituting. If your procedure is qualified for ER70S-6, the substitution upward to ER80S-D2 generally requires a re-qualification unless the code you're working under (AWS D1.1, ASME, etc.) permits it.
Q3: What is the difference between ER80S-D2 and ER80S-Ni1?
A: Both are 80 ksi class TIG rod, but with different alloying strategies. ER80S-D2 uses manganese-molybdenum for strength and toughness — optimized for HSLA steels and quench-and-tempered steels. ER80S-Ni1 adds ~1% nickel instead, which provides excellent CVN impact toughness at lower temperatures (–100 °F / –73 °C range). Use ER80S-Ni1 for extreme low-temperature applications; use ER80S-D2 for high-strength structural and aerospace work.
Q4: Do I need post-weld heat treatment (PWHT) with Supermissileweld?
A: PWHT requirements are driven by the base metal specification and the applicable construction code, not solely by the filler metal. For P1 carbon steel to P1 welds under ASME B31.3, PWHT is required only when wall thickness exceeds the code limit. For HY-80 and A514 welds, the military or owner specification governs. Harris recommends consulting the applicable code and the WPS — ER80S-D2 deposits are compatible with stress-relief temperatures of 1,050–1,150 °F (566–621 °C) per standard practice.
Q5: Why would I choose 1/16 in rod diameter over 3/32 in for TIG welding?
A: The 1/16 in diameter (1.6 mm) rod is ideal for thinner base metals (1/8–3/16 in), root pass welding on pipe with tight root openings, and precision welding on aerospace structures where narrow bead width and low heat input are required. The smaller diameter melts more quickly at lower amperage, giving the welder fine control over deposition. The 3/32 in (2.4 mm) rod is better for fillet passes on thicker material (3/16 in and above) where higher amperage and deposition rate are needed.
Q6: Can Supermissileweld be used for GTAW root pass on chrome-moly pipe?
A: For P11 (1.25Cr-0.5Mo) pipe, use ER80S-B2 TIG rod, not ER80S-D2. For P22 (2.25Cr-1Mo), use ER90S-B3. Supermissileweld (ER80S-D2) is appropriate for carbon steel to low-alloy steel dissimilar root passes and for P1/P2 carbon steel pipe that requires a high-strength deposit. Using ER80S-D2 on P11 or P22 pipe would create a compositional mismatch that could cause creep failure at elevated service temperatures.
Q7: What certification does Harris Supermissileweld carry?
A: Harris Supermissileweld TIG rod is manufactured to AWS A5.28 ER80S-D2 and is produced in ISO 9001:2015-certified Harris Products Group facilities. Certificates of Conformance (C of C) and full chemical and mechanical test reports are available on request. Military applications requiring MIL-SPEC documentation should specify the requirement at time of order.