Harris Supermissileweld Steel TIG GTAW Welding Rod (3/32 in × 36 in, 10 lb Box — 03SMW50) is a bare low-alloy steel TIG filler classified as ER80S-D2 under AWS A5.28/A5.28M. The 3/32 in (2.4 mm) diameter version of the Supermissileweld® family is sized for TIG welding structural and pressure-vessel base metals in the 3/16 in to 3/8 in thickness range, providing a higher deposition rate per pass than the 1/16 in rod while remaining practical for out-of-position and pipeline root pass work. Like all Supermissileweld rod, the alloy contains approximately 0.5% molybdenum and 1.6–2.1% manganese, yielding a minimum 80,000 psi tensile strength deposit with excellent Charpy V-notch toughness at temperatures down to –60 °F (–51 °C).
The trade name "Supermissileweld" originated from the product's aerospace and military heritage — it was developed to meet the demanding strength, toughness, and weld procedure qualification requirements of military structural steels (HY-80, HY-100) and aerospace-grade quenched-and-tempered plates (A514, A517). Today it is widely used in heavy structural fabrication, offshore platforms, mining equipment, and any application where an ER70S-6 deposit under-matches the base metal yield strength. Harris Products Group — a Lincoln Electric company — manufactures this rod to full AWS A5.28 classification at ISO 9001:2015-certified facilities.
- 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
- Diameter: 3/32 in (2.4 mm)
- Rod Length: 36 in (914 mm)
- Package: 10 lb box
- Tensile Strength (as-welded): ≥80,000 psi (550 MPa)
- Yield Strength (0.2% offset): ≥68,000 psi (469 MPa)
- Elongation: ≥19%
- Charpy CVN (–60 °F / –51 °C): ≥20 ft-lbf (27 J) typical
The 3/32 in rod is the workhorse size of the Supermissileweld family, suited for the mid-range thickness applications most commonly encountered in structural and industrial welding:
- Heavy Structural Steel Fabrication: ASTM A514, A517, and A572 Grade 65 structural members — crane booms, heavy-lift rigging hardware, earth-moving equipment booms and buckets — where weld joint tensile strength must match or exceed 80 ksi base metal yield strength.
- Offshore and Marine Structural Welds: Jacket nodes, brace connections, and leg cans in offshore platforms fabricated from high-strength structural steel (API 2H Grade 50, ASTM A633) in arctic or sub-zero temperature environments where Charpy CVN requirements at –60 °F are specified in the WPS.
- Power Generation and Boiler Fabrication: Pressure-part welds in HRSGs, auxiliary boilers, and steam headers where ASME Section IX WPS qualification calls for ER80S-D2 filler at elevated pressure classes (Class 1500–2500).
- Pipeline Root Pass Welding (Cellulosic Cap): Where the root pass is TIG (GTAW) with ER80S-D2 for maximum tensile strength and CVN toughness, followed by SMAW fill and cap with E8010-G or similar high-strength electrode.
- Military Vehicle and Defense Structures: HY-80 and HY-100 naval steel fabrication, armored vehicle hull repair, and military bridge structures where qualified ER80S-D2 procedure qualifications under MIL-STD-248 are maintained.
- Mining Equipment and Wear Hardfacing Base Layers: Wear plates, bucket shells, and excavator boom welds in high-strength abrasion-resistant steels (AR400, AR500) where ER80S-D2 provides the strength buffer layer between the carbon steel base and a final hardfacing overlay pass.
ER80S-D2's carbon equivalent (CE ≈ 0.39) and molybdenum content require measured preheat, especially on thicker material and high-carbon-equivalent base metals:
- Material up to 3/4 in (19 mm), CE < 0.40: 150 °F (66 °C) minimum
- Material 3/4–1-1/2 in (19–38 mm): 250 °F (121 °C) minimum
- Material over 1-1/2 in (38 mm): 300–400 °F (149–204 °C) — verify against WPS
- Maximum interpass: 400 °F (204 °C) — exceeding this on A514/A517 causes HAZ softening
- 3/32 in rod on 3/16 in plate: 80–130 A
- 3/32 in rod on 1/4 in plate: 110–160 A
- 3/32 in rod on 3/8 in plate: 140–200 A
- Tungsten: 3/32 in or 1/8 in 2% ceriated (grey) or 2% lanthanated (gold/black), sharpened to a taper for DCEN work
- Cup: #6–#8 Pyrex gas lens cup for flat/horizontal; #7–#10 ceramic cup for overhead where tungsten protection is important
- Standard: 100% Argon at 15–25 CFH for clean, low-oxidation beads
- Production option: 75% Ar / 25% He at 20–30 CFH for higher travel speed on thick section — He increases arc voltage and heat input without increasing current
- Back-purge: 100% Ar at 2–5 CFH for open-root pipe joints to prevent atmospheric oxygen attack on the root bead ID. Oxygen sensor confirmation (<50 ppm) before commencing root pass is good practice on critical pipeline work.
Feed 3/32 in rod at 15–20° to the torch axis. Maintain a consistent arc length of 1/16–3/32 in for optimal penetration profile. On butt welds, use a tight keyhole technique for root passes — confirm the keyhole closes uniformly before advancing. On fillet welds in the flat position, oscillate 1/16–1/8 in laterally to ensure tie-in at both toes without excess reinforcement. Allow each pass to cool to below 400 °F before depositing the next pass; use a contact pyrometer or Tempilstik to verify interpass temperature on the base metal adjacent to the weld.
- Store in original packaging in a controlled environment at 50–120 °F (10–49 °C) with relative humidity below 60%.
- Unlike coated electrodes, bare TIG rod does not have a moisture-sensitive flux coating, but surface rust is a real risk in humid shops. Any rust on the rod surface will cause porosity and slag inclusions in the weld bead. Inspect rods before use.
- Keep rod in the tube or box until ready for use; do not leave rod exposed on the work surface where condensation from cold shop floors or morning temperature cycling can deposit moisture.
- Applications with documented WPS low-hydrogen requirements (AMS, MIL-SPEC, or API Level 3 procedures): track rod exposure time and store in a sealed dry box between uses per the procedure's hydrogen control annex.
Supermissileweld 3/32 in rod is suitable for all DC TIG power sources. Recommended Lincoln Electric platforms for structural and heavy-industry TIG:
- Lincoln Precision TIG 225 and 275 (K2533 series)
- Lincoln Dynasty 280 DX and 400 (amperage range matches heavy-section work)
- Lincoln Square Wave TIG 300
- Lincoln PTA-26, PTA-26V, and PTA-26FV TIG torches (rated for the higher amperage range required by 3/32 in rod on heavy plate)
Primary base metals:
- ASTM A514 and A517 quenched-and-tempered structural plate
- ASTM A572 Grade 65 HSLA structural steel
- API 2H Grade 50 offshore structural steel
- MIL-S-16216 HY-80 naval structural steel
- AISI 4130 and 4140 alloy steel in normalized condition
Q1: What is the difference between 3/32 in and 1/16 in Supermissileweld TIG rod — when should I choose each?
A: The 1/16 in (03SMW30) rod is optimized for thin base metals (1/8–3/16 in), tight root openings on pipe, and precision aerospace work where low heat input and fine bead control are required. The 3/32 in (03SMW50) rod works at higher amperages (80–200 A), making it more efficient for fillet and groove welds on base metals 3/16 in and thicker. For most structural fabrication and pipe welding where material is over 3/16 in, the 3/32 in rod provides better productivity without sacrificing weld quality.
Q2: Can I use Supermissileweld on A36 carbon steel?
A: Yes — ER80S-D2 significantly over-matches A36 (36 ksi yield, 58 ksi tensile). The weld joint will be stronger than the A36 base metal. There is no AWS code prohibition against using higher-strength filler on lower-strength base metal. The only consideration is the higher preheat requirement for ER80S-D2 compared to ER70S-6, which may not be needed for thin A36 but should be applied for A36 thicker than 3/4 in to manage hydrogen cracking risk from the higher carbon equivalent of ER80S-D2.
Q3: Does Supermissileweld ER80S-D2 require PWHT?
A: As with any low-alloy TIG filler, PWHT requirements depend on the applicable construction code and base metal specification, not solely on the filler metal. For ASME B31.3 on P1 carbon steel pipe, PWHT is required above the wall-thickness threshold specified in the code (~3/4–7/8 in depending on service temperature). For A514 structural steel, PWHT above 1,100 °F (593 °C) actually reduces the strength of the quenched-and-tempered base metal — consult ASTM A514 and the applicable structural code before specifying PWHT.
Q4: What is the minimum Charpy impact value for Supermissileweld ER80S-D2?
A: AWS A5.28 requires a minimum of 20 ft-lbf (27 J) at –60 °F (–51 °C) for the ER80S-D2 classification per AWS A5.28 Table 5. Typical Supermissileweld test results exceed this minimum significantly — actual lot values are available from Harris Products Group on request with a Certificate of Conformance and test report.
Q5: How does ER80S-D2 compare to ER90S-G for high-strength structural work?
A: ER80S-D2 meets 80 ksi minimum tensile strength; ER90S-G meets 90 ksi minimum. If the base metal has a specified minimum yield strength of 80 ksi or below (A572 Gr 65, A514 in the yield class up to 100 ksi), ER80S-D2 is appropriate. If the WPS or design specification calls for 90 ksi filler matching (very high strength alloy steels with yield 90+ ksi), ER90S-G is the correct choice. Do not over-specify filler strength beyond what the design requires — higher strength filler metal generally requires higher preheat and is more susceptible to hydrogen cracking.
Q6: What is the maximum hardness I should expect in an ER80S-D2 TIG weld?
A: As-deposited ER80S-D2 weld metal typically measures 200–230 HB (equivalent to approximately HRC 14–22) when properly preheated and cooled. The HAZ hardness in high-strength base metals (A514, HY-80) may be higher — typically 300–350 HB in the immediately adjacent HAZ — but should soften to 250–280 HB at 1/8 in from the fusion line with proper preheat and slow cooling rate. PWHT stress relief reduces peak hardness. Maximum acceptable HAZ hardness per AWS D1.1 for structural carbon steel is 325 HB.
Q7: Is Harris Supermissileweld 3/32 in available on spool for GMAW?
A: The ER80S-D2 classification is available both as spooled wire for GMAW/MIG applications and as cut TIG rod. The Harris Supermissileweld trade name specifically refers to the TIG rod (cut length) form. For GMAW ER80S-D2, Harris and Lincoln Electric offer equivalent spooled wire products under different product names. Confirm the specific product form (rod vs. spool) when ordering to receive the correct packaging for your welding process.