ER320LR – wire and rod for Alloy 20
Niobium-stabilized 20Cr-34Ni-2.5Mo-3.5Cu filler metal, with reduced residuals, for welding Alloy 20 in sulfuric acid plants.
Product forms and equivalents
| Process | Classification |
|---|---|
| TIG rod (GTAW) | ER320LR |
| Solid MIG/MAG wire (GMAW) | ER320LR |
| Covered electrode (SMAW) | E320LR-15/-16 – AWS A5.4 |
| Submerged arc wire (SAW) | ER320LR + flux |
| Designation | Value |
|---|---|
| AWS | ER320LR |
| Specification | AWS A5.9/A5.9M / ASME SFA-5.9 |
| UNS | N08022 |
| Trade designation | Alloy 20 / 20Cb-3 (designação de material) |
Chemical composition (%)
| Element | wt. % |
|---|---|
| C | ≤ 0.025 |
| Cr | 19.0 – 21.0 |
| Ni | 32.0 – 36.0 |
| Mo | 2.0 – 3.0 |
| Cu | 3.0 – 4.0 |
| Nb | 8 × C min. – 0.40 |
| Mn | 1.5 – 2.0 |
| Si | ≤ 0.15 |
| P | ≤ 0.015 |
| S | ≤ 0.02 |
Properties of the deposited metal
| Property | Value |
|---|---|
| Tensile strength of deposited metal | ≥ 520 MPa (AWS A5.4 minimum for E320LR, reference) |
| Elongation | ≥ 30 % (AWS A5.4 minimum for E320LR, reference) |
Materials welded with ER320LR
Why the composition differs from the base metal
The “LR” (low residuals) version has much lower carbon, silicon, phosphorus, sulfur and niobium than wrought Alloy 20. The bead is fully austenitic and high in nickel, and those elements form low-melting films that would crack the weld.
Welding precautions
- No preheating; interpass up to 100 °C.
- Low heat input, stringer beads and filled craters to avoid hot cracking.
- Shielding and purging with pure argon.
Frequently asked questions
What is ER320LR used for?
Niobium-stabilized 20Cr-34Ni-2.5Mo-3.5Cu filler metal, with reduced residuals, for welding Alloy 20 in sulfuric acid plants.
Why is the composition of ER320LR different from the material it welds?
The “LR” (low residuals) version has much lower carbon, silicon, phosphorus, sulfur and niobium than wrought Alloy 20. The bead is fully austenitic and high in nickel, and those elements form low-melting films that would crack the weld.
Which covered electrode corresponds to ER320LR?
E320LR-15/-16 – AWS A5.4.
What precautions apply when welding with ER320LR?
No preheating; interpass up to 100 °C. Low heat input, stringer beads and filled craters to avoid hot cracking. Shielding and purging with pure argon.
