What to check on a General Welding Consumables.
The ship's core off-the-shelf order - E7018 stick electrode and ER70S-6 wire for mild and low-alloy steel - has its own listing. This general group is where a repair falls once the parent metal or process is not standard mild steel: stainless steel and duplex electrodes for tanks and piping, aluminium filler for superstructure and boat repairs, cast iron rods for engine block cracks, bronze and nickel rods for dissimilar-metal joints, TIG tungsten electrodes, flux for submerged arc work done in the workshop, and the shielding and purging gases each…
What this category covers
The ship's core off-the-shelf order - E7018 stick electrode and ER70S-6 wire for mild and low-alloy steel - has its own listing. This general group is where a repair falls once the parent metal or process is not standard mild steel: stainless steel and duplex electrodes for tanks and piping, aluminium filler for superstructure and boat repairs, cast iron rods for engine block cracks, bronze and nickel rods for dissimilar-metal joints, TIG tungsten electrodes, flux for submerged arc work done in the workshop, and the shielding and purging gases each process needs.
Main types carried aboard
Stainless and duplex electrodes
Matched to the parent plate grade, such as 304, 316 austenitic or 2205 duplex, rather than to whatever is in the locker; using an unmatched rod on duplex stainless gives a weld with the wrong ferrite content and no corrosion resistance where it matters.
Aluminium filler
5356 or 4043 wire and rod depending on whether the base alloy is a 5000-series structural plate or a 6000-series extrusion; the two fillers are not interchangeable without changing the weld's strength and crack resistance.
Cast iron and dissimilar-metal rods
Nickel-based rods for cast iron engine blocks and pump casings, bronze rods for joining steel to copper-alloy fittings, kept in small quantity because the jobs are rare but the base metal cannot be repaired any other way.
TIG tungsten and flux
Thoriated, ceriated or lanthanated tungsten electrodes ground to the process in use, plus the flux and backing gas needed to keep a root pass clean on stainless pipe.
Shielding and purging gas
Argon, argon-CO2 mixes and pure CO2 cylinders, plus the regulators and flow meters that go with them; gas choice changes penetration and spatter as much as the wire does.
Selection
Match filler to base metal grade first, process second. A wrong filler on a pressure part - a boiler tube, a fuel line, a class-surveyed structural member - can pass a visual inspection and still fail the service it was meant for.
- Base metal certificate or plate marking, not assumption, decides the filler grade
- Diameter matched to plate thickness and position, since overhead work needs a smaller diameter and lower current
- Gas purity and mix matched to the process, especially for stainless root passes where oxygen contamination shows as sugaring on the back of the weld
- Storage condition, since basic-coated stick electrodes pick up moisture and must be held in a heated oven once opened
Regulations and handling
Any repair on a pressure part, a tank boundary or class-surveyed structure needs a hot work permit and, for anything structural, sign-off against a qualified welding procedure. Gas cylinders are carried and stowed under the ship's dangerous goods rules, secured upright, valves protected, and kept away from the consumable store's electrode ovens.
Typical faults
| Cause | Consequence |
|---|---|
| Damp stick electrode flux coating | Hydrogen porosity in the weld, cracking that can show up days later |
| Wrong filler grade for stainless or duplex plate | Loss of corrosion resistance at the weld, pitting starts exactly where the repair was made |
| Contaminated or wrong shielding gas | Porosity, poor fusion, discoloured stainless root passes |
| Tungsten contaminated by dipping into the weld pool | Tungsten inclusions in the weld, rejected on X-ray if the joint is inspected |
What to look for in a supplier
- Certificates of conformity per batch, traceable to the base material specification
- Consistent packaging that keeps basic-coated electrodes sealed until the oven
- A range wide enough to cover stainless, aluminium and cast iron in small pack sizes, since ship's stock cannot hold a full mill order of each
- Gas cylinder exchange or refill arrangements at the ports the vessel actually calls
Never substitute a mild steel rod because it is what is in the locker - a duplex stainless repair welded with the wrong filler often looks sound and fails by pitting corrosion within months.