Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Monel 400 Valve Trim — UNS N04400 per API 600 / API 6A
Monel 400 valve trim (UNS N04400) covers the wetted internals of valves running HF acid, hot seawater, brine, and reducing chemical service: seats, stems, discs, backseats, packing followers, and gland-bolt internals. TorqBolt supplies machined valve-trim components per API 600 (cast steel gate valves), API 6A (well-head equipment), and ASME B16.34. Material certification to EN 10204 3.1 / 3.2.
Valve Trim Components Supplied
- Gate valve seats (parallel + wedge)
- Globe valve seats and discs
- Ball valve seats (PTFE-reinforced Monel-seated)
- Stem (one-piece + two-piece configurations)
- Backseat ring
- Bonnet stud + nut sets
- Packing gland follower
- Position indicator stem extensions
Service Envelope
| Service | Monel 400 Trim Verdict |
|---|---|
| Hydrofluoric acid (any conc.) | PRIMARY CHOICE |
| Hot seawater (≤200°C) | EXCELLENT |
| Brine / produced water | EXCELLENT |
| Reducing acids (HCl, H2SO4 < 80%) | GOOD |
| Ammonia / amine | EXCELLENT |
| Sour gas (H2S) | NOT QUALIFIED — specify Monel K-500 or Inconel 625 |
| High-temp oxidizing > 480°C | NOT SUITABLE — specify Inconel 600 |
Standards Compliance
- API 600 - bolted bonnet steel gate valves
- API 6A - wellhead and christmas-tree equipment
- API 602 - small-bore gate valves
- ASME B16.34 - valves (flanged, threaded, and welding-end)
- NACE MR0103 - reducing-service materials (where applicable)
Heat Treatment & Finish
Trim components delivered in solution-annealed condition for maximum corrosion resistance. Mating surfaces lapped to 0.4 µm Ra (or per spec). Hard-faced trim (Monel 400 base with stellite or Colmonoy 6 overlay) available where erosion is the design driver.
Common Failure Modes Avoided
Compared to stainless steel trim, Monel 400 eliminates HF corrosion (SS pitting), reduces galling on metal-to-metal seats (Monel has moderate galling resistance vs SS's severe galling), and provides better caustic resistance (no SCC).
FAQs
Why is Monel 400 the default trim for HF refinery valves?
HF cracks chromium-bearing alloys at grain boundaries. Stainless steel and Inconel both fail in HF service. Monel 400's zero-chromium chemistry is the only economically viable trim material for HF — refinery specifications mandate it.
Can Monel 400 trim run with carbon-steel body?
Yes, very common. Body sees only the external environment; trim sees the corrosive process fluid. Monel-clad bodies are also available for critical applications.
Is Monel 400 trim NACE MR0175 / ISO 15156 qualified for sour service?
No. For H2S service NACE qualifies Monel K-500 (precipitation-hardened) or Inconel 625 / Hastelloy C-276. Monel 400 base material is not sour-service qualified.
What's the lead time for custom valve trim?
Standard sizes ship in 6-10 weeks. Custom geometry or hard-faced trim 10-16 weeks. Request quote with valve drawing and material spec.
Related
- Monel 400 flanges
- Monel 400 fittings
- Monel 400 round bar (forging stock for stems)
- Monel 400 vs K-500 (sour service)
- UNS N04400 specification
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