Heat-resistant Cr-Mo steels
FERVEO CMO 9
covered electrode · stick electrodeCatalogue only
also as: solid wireTIG rod
AWS class
E 8018-B8 H4
EN ISO class
E CrMo9 B 4 2 H5
Tensile strength (Rm)
590 MPa
Classification
| AWS class | E 8018-B8 H4 |
|---|---|
| EN ISO class | E CrMo9 B 4 2 H5 |
Purpose
- Low-hydrogen basic electrode (H4), 9% Cr–1% Mo (AWS E8018-B8 H4, EN ISO E CrMo9 B 42 H5) — for boilers, pressure vessels, and piping in high-heat-resistant Cr-Mo steel.
Why it works
The higher chromium content (9%, versus 5.2% for the FERVEO CMO 5 family) steps up creep and hot-oxidation resistance, with good weldability across all positions including vertical-down — unlike FERVEO CMO 9B, which doesn't cover that position.
Fields of application
- Boilers, pressure vessels, piping, and castings in high-heat-resistant Cr-Mo steel.
Chemical composition
| Element | Typical, % |
|---|---|
| C | 0.07 |
| Cr | 9 |
| Mn | 0.7 |
| Mo | 1 |
| Si | 0.4 |
Mechanical properties
| Tensile strength (Rm) | 590 MPa |
|---|---|
| Yield strength (Rp0.2) | 460 MPa |
| Elongation (A5) | 19 % |
| Impact energy (KV) | 34 J (20 °C) |
Process
| Polarity | DC+ |
|---|---|
| Positions | PAflatPBhorizontal-verticalPChorizontalPDhorizontal-overheadPEoverheadPFvertical-upPGvertical-down |
| Re-drying | 300–350 °C / ≥2 h |
| Heat treatment | 740-780°C / 2h / |
Sizes and part numbers
| Ø | Length | Current | Request |
|---|---|---|---|
| 2.5 mm | 350 mm | 60–90 A | |
| 3.2 mm | 350 mm | 90–130 A | |
| 4 mm | 450 mm | 120–160 A |
Base metals
X12CrMo9-1X7CrMo9-1GX12CrMo1O.
Advantages
- Also covers the vertical-down position, unlike FERVEO CMO 9B — more field-application flexibility.
- One step of creep and hot-oxidation resistance above the FERVEO CMO 5 family.
Limitations
- For higher temperature or pressure duty, see the family's top step (FERVEO CMO 91, vanadium-modified).