Special Alloy Valves
Nickel alloy valves are built for services that stainless and duplex steels cannot withstand, such as strong acids, chlorine, hydrofluoric acid, caustic and high-temperature oxidation. Alloy selection depends directly on the chemistry, concentration and temperature of the fluid.
Overview
Inconel (Alloy 600/625) stands out in high-temperature and oxidizing environments, Monel (Alloy 400/K500) in hydrofluoric acid, seawater and alkaline environments, Hastelloy C276 in strong acids, chlorine and mixed chemicals, and Nickel 200 in caustic (NaOH) service. All parts are verified by PMI; delivery schedules depend largely on the availability of the alloy raw material.
Technical specifications
| Alloys | Alloy 600, 625; Alloy 400, K500; Alloy C276; Nickel 200 |
|---|---|
| Valve types | Ball, gate, globe, check, knife gate, triple offset butterfly |
| Construction | Full alloy body or alloy wetted parts only (trim/overlay) |
| Quality control | 100% PMI, EN 10204 3.1 / 3.2, non-destructive examination |
Key features
- Alloy selection specific to acid, chlorine and caustic services
- Full alloy body or alloy trim option
- 100% alloy verification by PMI
Alloy and material program
Body, bonnet and internal parts can be produced as castings or forgings in the alloys below. Material is selected by fluid, concentration, temperature and chloride content; for alloy materials, 100% PMI and EN 10204 3.1 certificates are standard.
| Alloy group | Cast (ASTM) | Forged / bar (UNS) | Typical service |
|---|---|---|---|
| Duplex stainless | A995 4A (CD3MN) | A182 F51 (S31803), F60 (S32205) | Chloride-bearing water, sour service; seawater depending on conditions |
| Super duplex | A995 5A (CE3MN), 6A (CD3MWCuN) | A182 F53 (S32750), F55 (S32760) | Seawater, high chloride, pressurized lines |
| Super austenitic | A351 CK3MCuN (6Mo) | S31254 (6Mo), N08904 (904L) | Seawater, chloride-bearing process fluids |
| Alloy 20 | A351 CN7M | B462 N08020 | Sulfuric acid |
| Ni-Cu (Monel 400 / K-500) | A494 M35-1 | N04400, N05500 | Hydrofluoric acid, seawater, brine solutions |
| Ni-Cr-Mo (Inconel 625) | A494 CW6MC | N06625 | High temperature, chloride and acid mixtures |
| Ni-Mo-Cr (Hastelloy C-276 / C-22) | A494 CW12MW, CX2MW | N10276, N06022 | Wet chlorine, hypochlorite, mixed acids |
| Ni-Fe-Cr (Incoloy 800H / 825) | n/a | N08810, N08825 | High temperature, phosphoric and sulfuric acid |
| Pure nickel | n/a | Ni 200 / 201 (N02200 / N02201) | Caustic (NaOH) service |
| Titanium | B367 (Gr. C-2, C-3, C-5, C-12) | Gr. 2, 3, 5, 7, 12 (B381 / B348) | Seawater, chlorinated media, oxidizing acids |
| Zirconium | n/a | Zr 702, 705 | Hot acids (e.g. acetic and formic acid processes) |
| Nickel-aluminum bronze | B148 C95800 | n/a | Seawater, shipboard systems |
Documentation and testing
On industrial projects the documentation package matters as much as the valve. We confirm the certificate and test scope for every line item at quotation stage:
- EN 10204 3.1 material certificates for pressure-retaining and wetted parts, traceable by heat number
- EN 10204 3.2 with third-party inspection, on request
- Pressure test reports to API 598 or EN 12266-1: shell, seat and, where specified, gas tests
- Fire-test certificates (API 607 / ISO 10497) for fire-safe type-tested designs
- PMI reports for alloy and stainless materials
- Dimensional, visual and coating inspection records
- PED 2014/68/EU CE declaration for equipment within its scope
- NACE MR0175 / ISO 15156 compliance statement for sour (H₂S) service
Technical datasheet
Frequently Asked Questions
Does the whole valve need to be made of nickel alloy?
Not always. Depending on the fluid and service, only the wetted parts (ball, disc, seat, stem) can be specified in alloy, or a carbon steel body can be overlaid with alloy. The decision weighs corrosion rate, safety and cost together.
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