Selectarc Inox 347 E347-17 Stabilised Stainless Electrode

Niobium-stabilised 19 9 electrode for 321 and 347 steels

The Selectarc Inox 347 is a rutile-basic coated stick electrode that deposits 18% Cr – 8% Ni stainless weld metal stabilised with niobium (columbium). It is classified AWS A5.4 E347-17 and ISO 3581-A / EN 1600 E 19 9 Nb R 3 2, and is intended for welding titanium- or niobium-stabilised austenitic stainless steels.

The deposit contains about 8% delta ferrite, which helps resist hot cracking, and according to Selectarc it is resistant to intercrystalline corrosion at service temperatures up to 400 °C. The electrode is described as having soft fusion without spatter, easy striking and restriking, and very easy slag removal.

Technical specifications

Base materials and typical uses

The data sheet lists UNS S30400 (304, 1.4301), S30403 (304L, 1.4306), S32100 (321, 1.4541) and S34700 (347, 1.4550). In refineries and petrochemical plants these stabilised grades are common in heater tubes, hydroprocessing piping, heat exchangers and other equipment that operates in the sensitisation range, where an unstabilised high-carbon deposit could lose corrosion resistance through chromium carbide precipitation at the grain boundaries.

Niobium ties up carbon as stable carbides, so a 347 deposit keeps its resistance to intergranular attack after exposure to elevated temperature. Note that 321 base metal is titanium-stabilised, but titanium does not transfer well across the arc, which is why a niobium-stabilised filler such as E347 is the conventional choice for both 321 and 347 steels.

Using the electrode

Inox 347 runs on DC positive or on AC with an open circuit voltage of about 70 V. Redry for 1 hour at 250 °C if the electrodes have picked up moisture, and keep the interpass temperature below 200 °C. Five diameters from 2.0 to 5.0 mm cover thin sheet through to heavier plate, with typical currents ranging from 45 A to 180 A.

Clean the joint thoroughly, use stainless-only brushes and grinding discs, and remove all slag between passes. For components that will undergo post-weld heat treatment or long service at high temperature, discuss the expected ferrite level and any requirement for stabilising heat treatment with your welding engineer before production starts.

For low-carbon 304L or 316L components that will never see the sensitisation range, a standard L-grade filler is usually adequate; the stabilised 347 deposit is mainly worth specifying where elevated-temperature service or post-weld heat treatment is part of the design. When joining stabilised stainless steel to carbon steel, a more highly alloyed 309 type filler is normally used instead.

Documents and quotation

The Selectarc Inox 347 data sheet is attached for download. Find more stainless grades in our Welding Electrodes category.

Send the diameters, quantities and certificate needs for a quotation.