Deutsche Version: Formstücke aus 13CrMo4-5 (1.7335)
13CrMo4-5 · 1Cr-0.5Mo · EN 10253-2 Type B
Entry-level chromium-molybdenum grade for pressure service to 550°C. HRSG, refinery fractionation columns, moderate-temperature steam headers. PWHT mandatory on all P12 weld joints.
Post-weld heat treatment is mandatory for P12. Welding without PWHT produces a hard, brittle heat-affected zone susceptible to hydrogen cracking under service conditions. Time-temperature chart and HAZ hardness test results are included on the EN 10204 3.1 certificate for all P12 fitting orders.
P12 (EN designation: 13CrMo4-5 per EN 10216-2; material number 1.7335) is the entry point of the chromium-molybdenum alloy steel ladder. With 0.70–1.15% Cr and 0.40–0.60% Mo, it offers significantly better creep resistance and oxidation resistance than carbon steel above 450°C while remaining straightforward to weld with standard preheat and PWHT procedures.
The grade is used extensively in combined-cycle and steam-cycle power plant HRSG circuits, refinery fractionation column overhead piping, and moderate-temperature petrochemical steam services. Its relative simplicity compared to P22 and above makes it the default choice for applications up to approximately 550°C where the higher allowable stresses of P22 are not required.
| Element | Min | Max | Note |
|---|---|---|---|
| Carbon (C) | 0.10 | 0.17 | Low C for weldability |
| Silicon (Si) | — | 0.35 | Low Si (vs P11) |
| Manganese (Mn) | 0.40 | 0.70 | — |
| Chromium (Cr) | 0.70 | 1.15 | Oxidation + creep |
| Molybdenum (Mo) | 0.40 | 0.60 | Creep resistance |
| Phosphorus (P) | — | 0.025 | — |
| Sulphur (S) | — | 0.010 | — |
| Grade | Cr% | Mo% | Max Temp | ASME P-No. | Primary Use |
|---|---|---|---|---|---|
| P12 (1.7335) | 0.70–1.15 | 0.40–0.60 | 550°C | 4 | HRSG, fractionation, steam headers |
| P22 (1.7380) | 1.90–2.60 | 0.87–1.13 | 580°C | 5A | Hydroprocessing, H₂ service |
| P5 (1.7362) | 4.00–6.00 | 0.44–0.65 | 650°C | 5B | Refinery furnaces, catalytic reforming |
| P91 (1.4903) | 8.00–9.50 | 0.85–1.05 | 650°C | 15E | Supercritical power, HP HRSG |
150–200°C minimum. Maintain interpass temperature ≤300°C. Preheat is critical to prevent hydrogen-assisted cold cracking in the HAZ.
ER80S-B2 (GTAW/GMAW) or E8018-B2 (SMAW). Match filler to base metal Cr-Mo chemistry.
690–730°C. Hold time per wall thickness — minimum 1 hour per 25 mm. Furnace or local PWHT acceptable.
HAZ hardness ≤248 HBW (per EN 15614). Reported on EN 10204 3.1 certificate.
| EN designation | 13CrMo4-5 |
| Material number | 1.7335 |
| ASTM equivalent | A234 WP12 |
| ASME P-Number | P-No.4 |
| Max temperature | ≤550°C (sustained) |
| Min yield strength | 205 MPa |
| PWHT | 690–730°C (mandatory) |
| Filler (GTAW) | ER80S-B2 |
| Standard | EN 10253-2 Type B |
| Certificate | EN 10204 3.1 standard |
PWHT time-temperature chart + hardness results on every 3.1 certificate. Third-party 3.2 (TÜV / Lloyd's) available. Tell us your fitting schedule, sizes, and delivery port.
Get QuoteDN15–DN600 and larger. Outside diameters follow the EN 10220 / EN ISO 1127 pipe series; wall thickness is matched to your connecting pipe.
| Size | OD (mm) |
|---|---|
| DN 15 | 21.3 |
| DN 20 | 26.9 |
| DN 25 | 33.7 |
| DN 32 | 42.4 |
| DN 40 | 48.3 |
| DN 50 | 60.3 |
| DN 65 | 76.1 |
| DN 80 | 88.9 |
| DN 100 | 114.3 |
| DN 125 | 139.7 |
| DN 150 | 168.3 |
| DN 200 | 219.1 |
| DN 250 | 273.0 |
| DN 300 | 323.9 |
| DN 350 | 355.6 |
| DN 400 | 406.4 |
| DN 450 | 457.0 |
| DN 500 | 508.0 |
| DN 600 | 610.0 |
The nearest ASTM grade is A234 WP12 (1Cr-0.5Mo), ASME P-No. 4.
For sustained pressure service up to about 550°C, typically in HRSG, moderate-temperature steam headers and refinery service.
Yes. PWHT at 690–730°C is mandatory on all weld joints, and ER80S-B2 filler is used for GTAW.
