Heat-resistant Cr-Mo steels
FERVEO CMO 5B
covered electrode · stick electrodeCatalogue only
AWS class
(A5.4) : E 8018-B6 (E 502-15) H4
EN ISO class
E CrMo5 B 42 H5
Tensile strength (Rm)
590 MPa
Classification
| AWS class | (A5.4) : E 8018-B6 (E 502-15) H4 |
|---|---|
| EN ISO class | E CrMo5 B 42 H5 |
Purpose
- Low-hydrogen basic electrode (H4), 5.2% Cr–0.5% Mo (AWS E8018-B6 H4, EN ISO E CrMo5 B 42 H5) — for high-heat-resistant steels in petrochemical service, including pressurized-hydrogen vessels.
Why it works
The higher chromium content (5.2%, versus 2.2% for the FERVEO CMO 2 family) gives the deposit resistance to high-temperature, high-pressure hydrogen attack — the reason 5Cr-Mo steels are the classic choice for refinery process equipment handling hydrogen, not just general creep resistance.
Fields of application
- Petrochemical industry equipment in high-temperature, high-pressure hydrogen service.
- High-heat-resistant steels in general.
Chemical composition
| Element | Typical, % |
|---|---|
| C | 0.06 |
| Cr | 5.2 |
| Mn | 0.8 |
| Mo | 0.5 |
| Si | 0.4 |
Mechanical properties
| Tensile strength (Rm) | 590 MPa |
|---|---|
| Yield strength (Rp0.2) | 460 MPa |
| Elongation (A5) | 19 % |
| Impact energy (KV) | 47 J (20 °C) |
Process
| Polarity | DC+ |
|---|---|
| Positions | PAflatPBhorizontal-verticalPChorizontalPDhorizontal-overheadPEoverheadPFvertical-up |
| Re-drying | 300–350 °C / ≥2 h |
| Heat treatment | 730-755°C / 1h / |
Sizes and part numbers
| Ø | Length | Current | Request |
|---|---|---|---|
| 2.5 mm | 350 mm | 65–90 A | |
| 3.2 mm | 350 mm | 110–130 A | |
| 4 mm | 450 mm | 140–180 A | |
| 5 mm | 450 mm | 190–240 A |
Base metals
X12CrMo5GX12CrMo5
Advantages
- Resistance to high-temperature, high-pressure hydrogen attack — the reason 5Cr-Mo steels exist in refinery service, not just general heat resistance.
- Low diffusible hydrogen (H4) — minimal cold-cracking risk in the thick sections typical of process equipment.
Limitations
- Specifically intended for pressurized-hydrogen or high-heat-resistance petrochemical service — for conventional steam boilers without that risk, the FERVEO CMO 1/2 grades are usually sufficient and more economical.