GX2CrNiMoN26-7-4
Super duplex casting (the cast counterpart of 2507). One of the most resistant steel castings for valve bodies in warm seawater and aggressive chloride environments.
- Rp0.2 · MPa
- ≥ 480
- Rm · MPa
- 650–850
- TEMPERATURE
- ≤ +300 °C
- COST
Chemical composition
%, single values are maximums.
Mechanical properties
| STANDARD · CONDITION | Rp0.2 MPa | Rp1.0 MPa | Rm MPa | A % | KV J |
|---|---|---|---|---|---|
| EN 10213 · +AT, t ≤ 150 mm | 480 | — | 650–850 | 22 | — |
Room temperature, +AT (1140–1180 °C), t ≤ 150 mm.
Service temperature
The duplex structure is not used for long periods above ~300 °C (475 °C embrittlement).
This is the limit of the material itself. A valve's service temperature is usually set by the seal and seat materials; product pages give it for each seal option.
Physical properties and heat treatment
- HEAT TREATMENT
- Solution annealing 1140–1180 °C, rapid cooling.
Media suitability GENERAL TREND
Emsal assessment. The final choice is made from corrosion tables, taking concentration, temperature, chloride content and flow velocity into account.
Strengths and weaknesses
Strengths
- The highest resistance class among castings in seawater
- High strength
- Erosion and cavitation resistance
Weaknesses
- Risk of sigma phase: casting and heat treatment need strict control
- Expensive
- Not used above ~300 °C
Manufacturing and use
- ECONOMY
- High.
- MANUFACTURING METHODS
- Sand casting + solution annealing
- TYPICAL VALVE PARTS
- Seawater valve body · Disc
Source: EN 10213. Values compiled and verified by Emsal Vana; for binding values, refer to the current edition of the standard and the material certificate.