TIG rods are the filler material that is manually added to the molten pool during TIG (Tungsten Inert Gas) welding, a process in which the tungsten electrode does not contribute material but instead generates the electric arc. The choice of the appropriate rod depends on the base material, the thickness of the workpiece and the mechanical or finish requirements of the joint; therefore, understanding the main types is key to achieving a uniform weld bead that is compatible with the metal being welded.
Classification of TIG rods according to base material
TIG rods are mainly categorised according to the material to be welded, as each alloy requires a compatible chemical composition to prevent defects such as cracks, porosity or a loss of mechanical properties.
Carbon steel welding rods, such as the W3Si1, are manufactured in accordance with the UNE-EN ISO 636-A standard and are equivalent to the AWS ER70S-6 classification. They have a tensile strength of up to 540 N/mm² and a yield strength of up to 420 N/mm², making them suitable for welding in the flat, horizontal and vertical-up positions in the construction, boiler-making and shipbuilding industries.
For stainless steel, there are variants such as 308LSi, 316LSi and 309LSi, which are suitable for martensitic and austenitic stainless steels, including: 316, 316L, 316Ti and 316Nb. They can withstand temperatures of up to 1,100 °C, making them suitable for use in construction, machinery and pipework repairs.
In aluminium, the TIG rods differ primarily in their magnesium or silicon content: ER5356 contains 5% magnesium, ER4043 contains 5% silicon, and ER4047 has a silicon content of up to 12%, with small amounts of magnesium and copper. They are used in construction, shipbuilding and the automotive industry, improving the fluidity of the molten metal and the corrosion resistance of the joint.
For copper and its alloys, the ERCuSi-A rod is used; it is suitable for CuSi3-type bronze alloys in the manufacture of electrical components and pipework, and is also suitable for copper-nickel alloys. It offers high corrosion resistance, good performance at high temperatures and the electrical conductivity required for critical applications.
Comparison of TIG rods by base material
Base material | Designation / standard | CHAVESBAO reference | Typical application |
|---|---|---|---|
Carbon steel | W3Si1 (UNE-EN ISO 636-A) / equivalent to AWS ER70S-6 | GW STICK 3.10 | Construction, boilermaking, shipbuilding |
Stainless steel | 308LSi / 316LSi / 309LSi (UNE-EN ISO 14343-A) | GW STICK 3.30 / 3.31 / 3.32 | Construction, machinery, pipe repair |
Aluminium | ER5356 / ER4043 / ER4047 (UNE-EN ISO 18273-A) | GW STICK 3.50 / 3.51 / 3.53 | Construction, shipbuilding, automotive |
Copper and alloys | UNE-EN ISO 24373 | ERCuSi-A rod | Electrical components, pipework, applications requiring high conductivity |
TIG rod diameters by base material
The available diameter varies not only between materials, but also between grades of the same material:
Base material | Reference | Available diameters (mm) |
|---|---|---|
Carbon steel | W3Si1 | 1.6 / 2.0 / 2.4 / 3.2 |
Stainless steel | 308LSi | 1.0 / 1.2 / 1.6 / 2.0 / 2.4 / 3.2 |
Stainless steel | 316LSi | 1.0 / 1.2 / 1.6 / 2.0 / 2.4 / 3.2 |
Stainless steel | 309LSi | 1.6 / 2.0 / 2.4 |
Aluminium | ER5356 | 1.6 / 2.0 / 2.4 / 3.2 |
Aluminium | ER4043 | 1.6 / 2.0 / 2.4 / 3.2 |
Aluminium | ER4047 | 2.0 / 2.4 |
The 308LSi and 316LSi offer the widest range of diameters, with sizes starting from 1.0 mm for precision thin sheet metal. The 309LSi and ER4047 have a more limited range of sizes: the former ranges from 1.6 mm to 3.2 mm, whilst the latter is only available in 2.0 and 2.4 mm. Generally speaking, smaller diameters are used for thin-walled parts or precision work, whilst larger diameters allow more material to be deposited on thicker sections or during build-up passes. It is advisable to confirm the exact diameter of the selected product code before ordering, as not all rods made from the same material cover the same range.
Criteria for choosing the right TIG rod
When selecting a TIG rod, consideration must be given to the base material and its composition, the thickness of the workpiece, the welding position and the service conditions of the joint, such as exposure to corrosion or mechanical stresses. Incompatibility between the rod and the base material can lead to cracks, lack of fusion or a loss of properties following the welding process.
Choosing the correct type and diameter of TIG rod helps to improve the stability of the molten pool, the quality of the weld bead and the reliability of the joint in metal fabrication, industrial maintenance and precision work.
At CHAVESBAO, we stock TIG rods for carbon steel, stainless steel, aluminium and copper, manufactured to UNE-EN ISO and AWS standards, ready to suit different base materials and welding requirements. Consult our TIG rod catalogue and contact our technical team with any queries regarding the most suitable product for your project.
