Sanicro® 625 is an austenitic nickel-chromium alloy characterized by:
- Extremely good corrosion resistance in widely varying acidic and chloride containing environments
- High strength
- Excellent fabrication properties.
Sanicro® 625 can be used in a wide range of temperatures from -196°C to 815°C (-321°F to 1500°F). Typical uses include hydraulic and instrumentation systems, heat-exchangers and high-temperature applications. However, it should be noted that prolonged exposure to temperatures above 600°C (1100°F) may lead to embrittlement.
Standards
- UNS: N06625
- ISO: NW6625
Product standards
ASTM B444, Grade 1 and Grade 2
ASME SB444, Grade 1 and Grade 2
ISO 6207
Chemical composition (nominal)
| C | Si | Mn | P | S | Cr | Ni | Mo | Fe | Nb |
|---|---|---|---|---|---|---|---|---|---|
| 0.025 | 0.2 | 0.15 | ≤0.015 | ≤0.015 | 21.5 | 61 | 8.7 | 4 | 3.5 |
Applications
Sanicro® 625 is an extremely versatile nickel alloy, suitable for use in both oxidizing and reducing acidic environments, such as:
- Hydrochloric acid
- Nitric acid
- Phosphoric acid
- Chloride containing environments
The grade can also be used for a wide range of temperatures from -196°C to 815°C (-321°F to 1500°F). Typical areas of use include hydraulic systems, heat-exchangers and high-temperature applications.
Some industrial examples are:
- High temperature aerospace
- Chemical process industry
- Power industry
Corrosion resistance
Wet corrosion
Sanicro® 625 shows very good resistance to pitting corrosion, intergranular corrosion and is virtually immune to stress corrosion cracking in chloride-containing environments. The grade is able to withstand general corrosion in both severe oxidizing and non-oxidizing acids.
Resistance in chloride environments is also extremely good owing to the high PRE number, ≥48.
Pitting Resistance Equivalent, PRE
PRE = %Cr + 3.3 x %Mo + 16 x %N
High temperature corrosion
In addition to its excellent wet corrosion resistance, Sanicro® 625 is also able to resist oxidation and scaling at high temperature.
Forms of supply
Sanicro® 625 seamless nickel alloy tubing is supplied bright annealed in the outside diameter range 6 - 42 mm (0.25" - 1.625") and wall-thickness 0.89 - 5.0 mm (0.035" - 0.197"). Some dimensions may be supplied annealed and white pickled.
Tubing is supplied as:
- Annealed (Grade 1)
- Solution annealed (Grade 2)
Tolerances
| Size OD, mm |
Tolerances OD, mm |
Wall thickness % |
|---|---|---|
| 6-30 | +/-0.08 | +/-10 |
| 32-40 | +/-0.15 | +/-10 |
| 42 | +/-0.20 | +/-10 |
Mechanical properties
At 20oC, metric units
| Condition | Proof strength | Tensile strength | Elongation |
|---|---|---|---|
| Rp0.21) | Rm | A2" | |
| MPa | MPa | % | |
| Grade 12) | ≥415 | ≥827 | ≥30 |
| Grade 23) | ≥276 | ≥690 | ≥30 |
At 68oF, imperial units
| Condition | Proof strength | Tensile strength | Elongation |
|---|---|---|---|
| Rp0.21) | Rm | A2" | |
| ksi | ksi | % | |
| Grade 12) | ≥60 | ≥120 | ≥30 |
| Grade 23) | ≥40 | ≥100 | ≥30 |
1) Corresponds to 0.2% offset yield strength
2) Annealed at 871ºC (1600ºF) minimum
3) Solution annealed at 1093ºC (2000ºF) minimum
Physical properties
Density: 8.36 g/cm3, 0.30 lb/in3
Welding
The weldability of Sanicro® 625 is good. Suitable methods of fusion welding are manual metal-arc welding (MMA/SMAW) and gas-shielded arc welding, with the TIG/GTAW method as first choice.
For Sanicro® 625, heat-input of <1.5 kJ/mm and interpass temperature of <100°C (210°F) are recommended. A string bead welding technique should be used.
Recommended filler metals
TIG/GTAW or MIG/GMAW welding
ISO 18274 S Ni 6625/AWS A5.14 ERNiCrMo-3 (e.g. Exaton Ni60)
MMA/SMAW welding
ISO 14172 E Ni 6625/AWS A5.11 ENiCrMo-3 (e.g. Exaton Ni60)
Disclaimer: Recommendations are for guidance only, and the suitability of a material for a specific application can be confirmed only when we know the actual service conditions. Continuous development may necessitate changes in technical data without notice. This datasheet is only valid for Alleima materials.