Valve Material Reference
ASTM A351 CN7M Valve
Alloy 20 Cast (CN7M)ASTM A351 CN7M is the cast equivalent of Alloy 20 (UNS N08020), a niobium-stabilised austenitic alloy engineered specifically for sulphuric acid service.
Form
Cast
Max Temp
+400°C (+750°F)
Min Temp
−73°C (−100°F)
Category
Stainless Steel
Chemical Composition — ASTM A351 CN7M
Temperature Range
−73°C to +400°C (−100°F to +750°F)
Maximum Temperature
+400°C (+750°F)
Minimum Temperature
−73°C (−100°F)
Equivalent Grades — ASTM A351 CN7M
| Standard | Equivalent Grade |
|---|---|
| UNS (cast) | J95150 |
| Wrought equivalent | Alloy 20 / N08020 (A182 F20) |
| DIN | similar to 1.4500 series |
Suitable Services
Sulphuric acid at concentrations 5–98% and temperatures up to 80°C
Phosphoric acid and mixed acid (H₂SO₄ + H₃PO₄) service
Sodium bisulphate and acidic salt solutions
Pharmaceutical and fine chemical synthesis where H₂SO₄ is used
Food-grade acidic processing (niobium stabilisation aids FDA compliance)
Fertiliser manufacturing — ammonium sulphate and superphosphate plants
Not Suitable For
Hydrochloric acid service — use Hastelloy C-276 or C-22
High-temperature oxidising chloride environments — risk of SCC
Fuming (oleum) sulphuric acid above 100°C without testing
Valve Body Applications
Gate, globe, and check valve bodies in sulphuric acid plants
Ball valve bodies in fertiliser (phosphoric acid) production
Valve bodies in mixed-acid (H₂SO₄ + HNO₃) chemical service
Pump casing and valve bodies in acid recovery systems
Trim Applications
Seats and discs in sulphuric acid service globe and gate valves
Stems and glands in acid dosing and transfer systems
Typical Valve Types in ASTM A351 CN7M
Gate valves: sulphuric acid plant isolation, Class 150–300
Globe valves: throttling in acid concentration circuits
Ball valves: full-bore transfer lines in H₂SO₄ service
Check valves: acid pump discharge non-return
Browse ASTM A351 CN7M Valves
All Valve Materials
Need ASTM A351 CN7M Valves?
We supply ASTM A351 CN7M (Alloy 20 Cast (CN7M)) gate valves, globe valves, ball valves, check valves, and more. Full certification documentation — EN 10204 3.1/3.2 MTCs, hydro test certs — as standard.