ER80S-D2 – Mn-Mo wire and rod for 4140, 4340 and C-½Mo steels
High-strength Mn-Mo filler metal, used in repairs and joints of quenched and tempered steels such as 4140, 4340 and 9315, and on C-½Mo steel (F1).
Product forms and equivalents
| Process | Classification |
|---|---|
| TIG rod (GTAW) | ER80S-D2 |
| Solid MIG/MAG wire (GMAW) | ER80S-D2 |
| Covered electrode (SMAW) | E9018-D1 – AWS A5.5 (approximate)* |
| Submerged arc wire (SAW) | EA3K + flux – AWS A5.23 (approximate)* |
| Designation | Value |
|---|---|
| AWS | ER80S-D2 |
| Specification | AWS A5.28/A5.28M / ASME SFA-5.28 |
| UNS | K10945 |
| Others | EN ISO 14341-A / 21952-A: G 4Mo / W 4Mo (aproximado)*; AWS A5.28M: ER55S-D2 |
Chemical composition (%)
| Element | wt. % |
|---|---|
| C | 0.07 – 0.12 |
| Mn | 1.60 – 2.10 |
| Si | 0.50 – 0.80 |
| Mo | 0.40 – 0.60 |
| Ni | ≤ 0.15 |
| P | ≤ 0.025 |
| S | ≤ 0.025 |
| Cu | ≤ 0.50 |
Properties of the deposited metal
| Property | Value |
|---|---|
| Tensile strength of deposited metal | ≥ 550 MPa (AWS minimum) |
| Yield strength | ≥ 470 MPa (AWS minimum) |
| Elongation | ≥ 17 % (AWS minimum) |
Materials welded with ER80S-D2
Dissimilar joints: Can join these steels to carbon steel. On quenched and tempered 4140 and 4340, the bead falls below the strength of the base metal; when matching strength is required, the joint must be qualified with a higher-strength wire and full heat treatment.
Why the composition differs from the base metal
The wire has much less carbon than 4140 or 4340 (about 0.1 % versus 0.4 %). A bead with 0.4 % C would harden to a very high hardness and crack; the wire trades carbon for manganese and molybdenum, which give strength without embrittling the weld.
Welding precautions
- 4140 and 4340 steels: preheat and interpass of about 250 to 350 °C, with post-heating and slow cooling.
- Temper or PWHT right after welding when the design allows.
- Nitriding steel (34CrAlNi7): weld only before nitriding; the nitrided case is not weldable.
- Use dry, clean wire and bevel to limit hydrogen.
Frequently asked questions
What is ER80S-D2 used for?
High-strength Mn-Mo filler metal, used in repairs and joints of quenched and tempered steels such as 4140, 4340 and 9315, and on C-½Mo steel (F1).
Why is the composition of ER80S-D2 different from the material it welds?
The wire has much less carbon than 4140 or 4340 (about 0.1 % versus 0.4 %). A bead with 0.4 % C would harden to a very high hardness and crack; the wire trades carbon for manganese and molybdenum, which give strength without embrittling the weld.
Which covered electrode corresponds to ER80S-D2?
E9018-D1 – AWS A5.5 (approximate)*.
What precautions apply when welding with ER80S-D2?
4140 and 4340 steels: preheat and interpass of about 250 to 350 °C, with post-heating and slow cooling. Temper or PWHT right after welding when the design allows. Nitriding steel (34CrAlNi7): weld only before nitriding; the nitrided case is not weldable. Use dry, clean wire and bevel to limit hydrogen.
