Hyundai SMT-625 ERNiCrMo-3 Nickel Alloy 625 MIG Wire

The Hyundai SMT-625 is a nickel-base solid welding wire classified to AWS A5.14 / ASME SFA-5.14 ERNiCrMo-3, JIS Z 3334 SNi6625 and EN ISO 18274 Ni 6625. Hyundai Welding publishes it for gas metal arc welding with DC+ pulsed current under argon or argon-helium shielding, in the 1G, 2F, 3G and 4G positions. The wire chemistry is typically 63.9% nickel, 22.7% chromium, 9.1% molybdenum and 3.55% niobium, and the datasheet reports an impact toughness of 150 J at -196 °C. It carries ABS, BV, DNV, KR, LR and NK approvals according to the manufacturer. Seven Star LLC supplies the Hyundai SMT-625 in Oman and the GCC, with the official datasheet attached to this page.

Overview

Alloy 625 filler wire is used wherever a weld must combine strength, toughness at very low temperature and resistance to aggressive corrosion. Compared with stick electrodes, a solid MIG wire delivers continuous welding and higher deposition, which makes it attractive for long seams on LNG tank shells, cladding and overlay of large components, and production welding of heat exchangers and process equipment.

The Hyundai SMT-625 is intended for pulsed GMAW. Pulsed current gives good control of the relatively sluggish nickel alloy weld pool, reduces spatter and allows positional welding with spray-like metal transfer at a moderate average heat input.

Features from the Datasheet

• AWS A5.14 ERNiCrMo-3 (alloy 625 type) solid wire.
• Good impact toughness at extra low temperature.
• Suitable for dissimilar steels, including Inconel 601, Incoloy 800/800H or combinations of these with other alloys.
• Polarity: DC+ (pulse).
• Shielding gas: Ar or Ar + He.
• Welding positions: 1G, 2F, 3G and 4G.
• Approvals shown: ABS, BV, DNV, KR, LR and NK.
• Wire diameters: 1.2 mm (0.045 in) and 1.6 mm (1/16 in).

Typical Chemical Composition of the Wire (wt%)

The very low iron content of the wire (0.3%) is useful in overlay work, where specifications often limit iron at the finished surface; the actual result depends on dilution from the base metal.

Typical Mechanical Properties of All-Weld Metal

Applications

Hyundai Welding lists LNG storage tanks, equipment for gas desulfurisation, petrochemical plants, heat exchangers and 9% nickel steel as application areas for the Hyundai SMT-625. In the Omani market these translate into:

• Semi-automatic and mechanised welding of 9% nickel steel inner tanks for LNG storage.
• Corrosion-resistant weld overlay of valves, wellhead components, vessel internals and pipe ends for sour and seawater service.
• Fabrication and repair of heat exchanger tubesheets, channels and shells in refineries and petrochemical plants.
• Dissimilar joints between carbon steel, low alloy steel, stainless steel and nickel alloys such as alloy 800H.
• Flue gas desulfurisation equipment in power generation.

General Notes on Pulsed GMAW with Nickel Alloy Wire

The following guidance is general welding knowledge and does not come from the Hyundai datasheet. A modern inverter power source with synergic pulse programs for nickel alloys makes setting up much easier, because peak current, background current and frequency are linked to wire feed speed. Pure argon is common for thin material, while argon-helium mixtures improve wetting and travel speed on thicker sections; the Hyundai SMT-625 datasheet lists both. Use a wire feeder with smooth, matched drive rolls and a suitable liner, since nickel wire is softer than steel and can be marked or deformed by excessive roll pressure. Joint surfaces must be thoroughly cleaned of oil, paint, marking crayon and oxides, and interpass temperatures are kept low to protect corrosion resistance. Overlay procedures normally control bead overlap and travel speed to limit dilution and meet the iron limit required at the surface.

Why Choose the Hyundai SMT-625

The Hyundai SMT-625 stands out for its cryogenic toughness: the 150 J typical impact value at -196 °C gives a comfortable margin for LNG and other low-temperature service. Combined with a 770 MPa typical tensile strength and 45% elongation, the deposit offers both strength and ductility. The list of six marine classification approvals on the datasheet is relevant for shipbuilding, chemical carriers and offshore structures, and the two diameters cover both positional work (1.2 mm) and higher deposition in the flat position (1.6 mm). For contractors in Oman who already use Hyundai consumables for carbon and stainless steel, the Hyundai SMT-625 keeps purchasing and documentation within one manufacturer.

Wire Diameters and Package Formats

The datasheet for the Hyundai SMT-625 lists two wire diameters, 1.2 mm and 1.6 mm. It does not print a package format, so the spool type and weight should be confirmed at the time of quotation to suit your wire feeder. As general good practice, nickel alloy wire should stay in its sealed packaging until use, be stored in a dry area, and be covered or removed from the feeder when work stops, to avoid contamination of the wire surface that can lead to porosity.

Choosing Between Wire and Electrode

For shop fabrication and long seams, the Hyundai SMT-625 solid wire offers higher productivity than stick welding. For site repairs, tie-ins and areas with difficult access, an ENiCrMo-3 covered electrode may be more practical. Many fabricators stock both, using the same alloy 625 chemistry across processes so that procedure qualifications and material records stay consistent. Seven Star LLC can supply either option.

Related Products

Seven Star LLC also lists the Lincoln Electric SuperArc L-59 ER70S-6 Solid MIG Welding Wire for carbon steel MIG welding, the LongTeng EL8 Carbon Steel Submerged Arc Welding Wire for submerged arc welding and the Lincoln Electric Power Wave S500 multi-process power source. More solid wires are available in our Solid Welding Wire category.

Order the Hyundai SMT-625

Send Seven Star LLC the wire diameter, spool or package format and quantity you require for the Hyundai SMT-625, along with any project specification or certificate requirements. Our Muscat team will provide the manufacturer datasheet, confirm the order details and arrange delivery to your workshop or site in Oman and across the GCC.