Lincoln Electric ED036499 Murex 316LSi MIG GMAW Stainless Steel Welding Wire (0.030 in, 33 lb Spool) is a solid-wire GMAW filler metal classified under AWS A5.9 as ER316LSi. The MUREX® brand represents Lincoln Electric's European and international market premium stainless steel wire range, recognized in the offshore, petrochemical, and food-processing industries for consistent arc performance and tight compositional control. The "LSi" designation combines two enhancements: "L" (low carbon, maximum 0.03% C) to prevent sensitization, and "Si" (elevated silicon, 0.65–1.00%) to improve wettability, reduce surface tension of the molten puddle, and produce a smoother, more self-leveling bead profile with reduced spatter in both spray transfer and pulsed transfer modes.
The 0.030 in (0.76 mm) wire diameter is one of the finer diameters available for stainless MIG, designed specifically for welding light-gauge stainless steel sheet, thin-wall tubing, and precision instrumentation components where fine control of heat input is the priority. The 33 lb spool provides a practical production run for pipe shop and vessel fabrication operations where frequent spool changes interrupt workflow. The 2–3% molybdenum addition to the alloy provides enhanced pitting and crevice corrosion resistance in chloride environments — the defining advantage of 316/316L over 304/304L stainless.
- AWS Classification: ER316LSi per AWS A5.9/A5.9M
- Carbon: 0.03% max (L = low-carbon)
- Chromium: 17.0–20.0%
- Nickel: 11.0–14.0%
- Molybdenum: 2.0–3.0%
- Silicon: 0.65–1.00% (elevated Si = improved wetting)
- Manganese: 1.0–2.5%
- Phosphorus: 0.03% max
- Sulfur: 0.03% max
- Diameter: 0.030 in (0.76 mm)
- Package: 33 lb spool
- Tensile Strength (as-welded): ≥80,000 psi (552 MPa)
- Yield Strength: ≥57,000 psi (393 MPa)
- Elongation: ≥25%
- Ferrite Number: 3–12 FN typical
The combination of 316L corrosion protection, improved silicon fluidity, and fine 0.030 in wire diameter makes Murex 316LSi the precision choice for demanding stainless applications:
- Pharmaceutical and Biotech Clean Piping: ASME BPE-compliant piping and vessel fabrication in 316L stainless for high-purity injectable and biologics manufacturing. The 0.030 in wire with short-circuit or pulsed transfer produces full-penetration, sanitary root beads with smooth internal geometry meeting ASME SF-1 through SF-4 surface finish requirements. 316L molybdenum content satisfies FDA biocompatibility requirements for product-contact surfaces.
- Marine and Offshore Stainless Piping: 316L piping and valve connections in seawater service where the combination of molybdenum (pitting resistance) and the elevated-silicon bead profile (reduced crevice initiation sites) is specified in the project's corrosion engineering review.
- Food Processing and Beverage Equipment: Hygienic-grade heat exchangers, CIP (clean-in-place) piping systems, and product-contact tank shells in 316L stainless where chloride cleaning agents and acidic product streams demand molybdenum corrosion resistance beyond what 304L provides.
- Chemical Process Instrumentation and Tube Work: Small-diameter 316L tubing, compression fittings, and manifold connections in instrumentation circuits for chemical plant process control. 0.030 in wire with short-circuit transfer enables full-penetration root pass welding on Schedule 5S and Schedule 10S thin-wall tubing without burn-through.
- Precision Sheet Metal Fabrication: 16 ga through 3/16 in 316L stainless cabinet, enclosure, and equipment housing fabrication where the Si-enhanced bead profile reduces post-weld finishing labor compared to standard ER316L wire.
- Cryogenic Equipment: 316L stainless maintains excellent toughness at liquid nitrogen temperature (–320 °F / –196 °C) — Murex 316LSi 0.030 in is used for thin-wall LN₂ storage vessels, cryogenic transfer tubing, and cold box fabrication.
At 0.030 in diameter, two transfer modes are practical:
- Short-Circuit Transfer: 16–20 V / WFS 150–250 ipm — for light-gauge sheet (16 ga–12 ga), root pass on thin-wall pipe (<0.120 in wall), and all-position welding where spray transfer would provide too much heat input. Short-circuit with 0.030 in produces the cleanest root profile on thin-wall stainless tube.
- Spray Transfer: 23–27 V / WFS 250–350 ipm — for 3/16 in and thicker flat/horizontal stainless plate. Spray transfer with 0.030 in is achievable at lower amperages than with .035 or .045 in wire, providing spray-quality bead profile with less heat input — beneficial on 316L to control sensitization.
- Primary: 98% Argon / 2% Oxygen at 25–40 CFH. Ar+2%O₂ is the optimal stainless MIG shielding gas for both transfer modes — oxygen stabilizes the spray arc and promotes wetting while minimizing chromium oxide tint on the bead surface.
- Alternative: 90% Ar / 10% CO₂ for short-circuit work on non-critical 316L joints. Higher CO₂ increases oxidation tint and heat input slightly, reducing weld surface quality for food-grade and pharmaceutical applications.
- Flow rate: 25–40 CFH for 0.030 in wire. Do not exceed 45 CFH — turbulent gas flow on small-bore tubing can cause air entrainment and contamination at the bead surface.
Maximum 300 °F (149 °C). Monitor with a contact pyrometer between passes. Sensitization risk is real on 316L multi-pass welds even with low-carbon "L" grade filler — the interpass temperature limit is essential for maintaining corrosion resistance in the HAZ.
- Store in original moisture-barrier foil packaging with desiccant. 316LSi stainless MIG wire oxidizes in humid environments — inspect before use for uniform bright-white/silver surface free of yellow, bronze, or rust tinting.
- Once opened, place partially used spools in a sealed plastic bag with fresh desiccant or install in the wire feeder with the feeder cabinet door kept closed between shifts.
- Purge 12–18 in of wire from the conduit tip before starting a new shift's first weld. Conduit lubricant that collects at the wire tip overnight causes initial porosity and black smut on the first weld.
- Never use 316LSi spool wire on carbon steel — stainless wire in a carbon steel MIG weld produces a high-alloy deposit with unpredictable properties and wastes the high-cost stainless wire. Keep stainless spools physically segregated from carbon steel wire stores.
Murex 316LSi 0.030 in wire requires a wire feeder and power source capable of stable low-amperage short-circuit or spray transfer at this fine wire diameter. Recommended Lincoln Electric equipment:
- Lincoln Power MIG 210 MP and 215 MPi (precision short-circuit at low amperages for 0.030 in wire)
- Lincoln Power Wave S350 and S500 (pulsed spray for out-of-position 316L sheet work)
- Lincoln Invertec V350-Pro (stainless spray and pulsed transfer)
- Lincoln Magnum Pro 100L and 200 MIG guns (liners and tips in 0.030 in rated size)
- Lincoln Drive rolls rated 0.030 in — verify drive roll selection; V-groove knurled rolls are recommended for 0.030 in solid stainless wire to prevent wire deformation without excessive drive force.
Primary base metals:
- AISI 316 and 316L austenitic stainless (all product forms: sheet, plate, pipe, tube)
- ASTM A240 Grade 316/316L
- ASTM A312 Type TP316/316L pipe
- ASME SA-240 316/316L pressure vessel service
Secondary base metals:
- 321 stainless (Ti-stabilized, where 316LSi deposit is acceptable per engineering review)
- 317L stainless (higher Mo; 316LSi acceptable for repair)
Q1: What is the difference between ER316L and ER316LSi welding wire?
A: ER316L has standard silicon content (0.30–0.65%); ER316LSi increases silicon to 0.65–1.00%. Elevated silicon reduces surface tension of the molten stainless puddle, improving wettability, bead toe fusion, and reducing surface roughness. The visual result is a flatter, wider, more self-leveling bead profile with less spatter. Corrosion resistance, hydrogen classification, and mechanical properties are essentially identical. For code work, both are ER316L-class under AWS A5.9 (the Si variant is a sub-classification); verify that your WPS accepts ER316LSi if only ER316L is listed.
Q2: Is 0.030 in wire diameter practical for MIG welding on anything thicker than 3/16 in?
A: 0.030 in wire can be used on material thicker than 3/16 in in flat/horizontal position with spray transfer, but productivity is limited — the 0.030 in wire simply deposits less metal per pass at its practical amperage ceiling (~250–280 A for spray). For 1/4 in and thicker 316L plate in flat/horizontal production, .035 in or .045 in wire provides significantly higher deposition rates and lower cost per pound of deposit. The 0.030 in wire's advantage is precision heat control and access to thin-gauge and tube work — reserve it for those applications rather than using it as an all-purpose stainless wire for heavy plate.
Q3: Why use 316LSi instead of 316L TIG rod for stainless tube root passes?
A: For the highest-quality root pass on pharmaceutical or food-grade pipe, 316L TIG rod with back-purge remains the gold standard — the clean, autogenous TIG root with back-purge is the only method that reliably produces an ASME BPE SF-1 level root bead. However, for production environments where TIG root speed is a bottleneck, 0.030 in 316LSi MIG with short-circuit transfer (or RMD/CMT waveform-controlled transfer modes on Lincoln Power Wave) provides a viable alternative with adequate root quality for less-critical specifications (SF-2 and below), at significantly higher deposition rates than manual TIG root pass welding.
Q4: What ferrite number should I expect in Murex 316LSi MIG welds?
A: Murex 316LSi is formulated to deposit within the 3–12 FN range, satisfying AWS D1.6 and most pressure vessel code requirements for austenitic stainless weld deposits (minimum 3 FN for hot-crack resistance, maximum 15 FN to protect corrosion resistance and ductility). The actual FN of a specific deposit depends on dilution from the base metal — more dilution from a higher-alloy 316L base metal may reduce FN toward the lower end of the range. Measure FN with a calibrated Feritscope on completed welds if code compliance requires FN documentation.
Q5: Can I use 98% Ar / 2% O₂ shielding gas for both short-circuit and spray transfer with Murex 316LSi?
A: Yes — Ar+2%O₂ is appropriate for both short-circuit (low-voltage) and spray transfer modes with ER316LSi. It is the most universal choice for stainless GMAW and produces the best combination of arc stability, bead appearance, and corrosion resistance across both transfer modes. Some welders prefer 100% Ar for short-circuit to reduce the heat input further (the O₂ addition adds a small amount of heat), but the difference is minor at 0.030 in wire at short-circuit parameters.
Q6: How do I avoid sensitization when making multi-pass welds with Murex 316LSi?
A: Use the following controls: (1) monitor interpass temperature with a contact pyrometer — do not deposit the next pass until the base metal adjacent to the weld cools to ≤300 °F (149 °C); (2) use the lowest practical heat input (V × A × 60 / ipm) that still provides complete fusion; (3) deposit stringer beads rather than wide weave passes; (4) complete the weld promptly — avoid holding the assembly at temperature between shifts; (5) for critical pharmaceutical applications, solution anneal the completed weldment at 1,900–2,100 °F (1,038–1,149 °C) followed by rapid quench to fully dissolve any carbides that may have precipitated during fabrication.
Q7: What contact tip and liner should I use for 0.030 in stainless MIG wire?
A: Use a 0.030 in rated contact tip (Lincoln KP4738-035 or equivalent) in copper or chrome-zirconia material — chrome-zirconia tips last longer with stainless wire, which is harder than carbon steel wire and accelerates tip bore wear. The wire liner should be a steel or Teflon-lined conduit rated for 0.030 in wire — do not use a carbon steel liner sized for .035 or .045 in wire on 0.030 in wire, as the loose fit causes wire feed instability. Replace the liner when feed resistance increases or wire casting (natural curl) changes — a kinked or worn liner is the most common cause of inconsistent wire feed on fine-diameter stainless MIG wire.