HomeService by FluidNitric Acid (HNO₃)

corrosiveHNO₃CAS 7697-37-2

Valves for Nitric Acid (HNO₃) Service

Nitric acid is a strong oxidising acid used in fertiliser production, explosives manufacturing, stainless steel passivation, and pharmaceutical synthesis. Its strong oxidising nature means carbon steel passivates at high concentrations - but ordinary stainless steels generally perform well unlike with HCl or H₂SO₄.

Pressure Range

1–20 bar

Temperature

Ambient to 80°C

Industries

Fertiliser (ammonium nitrate), Explosives (TNT, RDX), Pharmaceutical synthesis

INDICATIVE ONLY - Reference DisclaimerFuming nitric acid is a category 1 oxidiser. All specifications for concentrated or fuming HNO₃ must be reviewed by a qualified process safety engineer. ATEX classification and emergency release protocols are mandatory. Vajra Industrial Solutions accepts no liability for material selection decisions based on this guide.

What valves are used for Nitric Acid (HNO₃) service?

SS 304L ball valve are recommended for Nitric Acid (HNO₃) service: Standard for all HNO₃ concentrations - best corrosion resistance.

Key Properties - Nitric Acid (HNO₃)

  • Strong oxidiser - passivates carbon steel above ~65% concentration
  • SS 304L and 316L perform well in dilute and concentrated HNO₃
  • Fuming HNO₃ (>85%) is a strong oxidiser - attacks organics, rubber
  • Red fuming HNO₃ contains dissolved N₂O₄ - extreme oxidiser
  • Does not cause chloride SCC (unlike HCl)

Vajra Industrial Solutions manufactures and supplies valves for Nitric Acid (HNO₃) service — including ss 304l ball valve — in corrosion-appropriate materials selected for the operating conditions described here, with full material and test documentation.

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Material Compatibility - Nitric Acid (HNO₃)

Ratings are indicative. Actual compatibility depends on concentration, temperature, velocity, and presence of contaminants. Always consult corrosion tables or a materials engineer.

MaterialRatingNotes
SS 304LExcellentStandard for all concentrations of HNO₃. More resistant than 316L due to lower Mo content.
SS 316LGoodSlightly lower corrosion resistance than 304L for HNO₃ due to molybdenum - but still widely used.
Carbon Steel (passivated)FairOnly for >65% concentration at ambient temperature - passivation layer forms.
Aluminium alloysGoodGood for dilute HNO₃ - used in food-grade applications.
PTFEGoodAcceptable for dilute and concentrated HNO₃ at ambient temperature. Verify for fuming acid.
Rubber (natural/NBR)Not RecommendedNitric acid attacks most rubbers and organics rapidly.
Hastelloy C-276FairNot ideal for HNO₃ - SS 304L is preferred due to Mo susceptibility.

Recommended Valves

SS 304L ball valve

Standard for all HNO₃ concentrations - best corrosion resistance

Full selection guide

SS 304L butterfly valve

Large bore, low-pressure HNO₃ service

Full selection guide

PTFE-seated ball valve

Prevents nitric acid contact with valve body - sealing reliability

Full selection guide

SS 304L diaphragm valve

Pharmaceutical or food-grade dilute HNO₃ - no dead-legs

Full selection guide

Valves to Avoid

Rubber-lined valves (nitric acid attacks all common rubbers)

Hastelloy C-276 for hot concentrated HNO₃ (Mo susceptibility)

Carbon steel for dilute HNO₃

Special Considerations

Fuming nitric acid (>85%) - extreme oxidiser, full PPE and emergency protocols required
All-welded construction preferred - no threaded joints in concentrated HNO₃
Stagnant acid in dead-legs causes localised attack - full-bore valves only
ATEX rating required where NOₓ fumes are present

Applicable Standards

ASME B16.34EN 1092ISO 15848 (for toxic concentrated service)

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Nitric Acid (HNO₃) Service — Procurement & Specification

Typical Applications

Fertiliser (ammonium nitrate)Explosives (TNT, RDX)Pharmaceutical synthesisMetal pickling and passivationElectronics etching

Available Standards

ASME B16.34EN 1092ISO 15848 (for toxic concentrated service)

Material Options

SS 304LSS 316LAluminium alloysPTFE

Documentation Available

  • -EN 10204 3.1 Material Test Certificates (heat traceable)
  • -API 598 hydrostatic shell & seat test reports
  • -Dimensional inspection reports
  • -Full Manufacturing Data Record (MDR) / data book on request
View documentation package

Inspection Options

  • -In-house QC inspection on every order
  • -Third-party inspection (SGS / Bureau Veritas / TÜV / DNV) coordination
  • -Witness and hold points accommodated on request
View inspection & testing

Order Quantities

Flexible — from single critical-spare valves to full project lots.

Export

Worldwide export with complete documentation (COO, EUR.1, packing lists) to 20+ countries.

Custom Engineering

Built to your specification — materials, trim, pressure class and special service (NACE, fire-safe, IBR, cryogenic).

Delivery Support

Dispatch from Vadodara, Gujarat with documented lead times and priority handling for urgent requirements.

Engineering references

Reviewed by Process Engineering, Vajra Industrial SolutionsDiscipline: Process & Fluid Service EngineeringLast reviewed: 20 June 2026

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