Short answer: the material of a rupture disc is chosen by three criteria: it must resist corrosion from the fluid on both faces, retain its properties at the disc temperature, and allow the required burst pressure to be manufactured with a reasonable thickness. 316/316L stainless steel covers most services; nickel, Monel, Inconel, Hastelloy and tantalum are reserved for aggressive media or high temperatures; graphite and fluoropolymer seals are alternatives for acids.
By the P&V Control Devices technical team · Published October 4, 2026 · Reading time: 8 min
Why material is more critical in a disc than in a pipe
Direct answer: because a rupture disc is a very thin sheet calibrated to fail at an exact pressure. A thickness loss of a few microns, irrelevant in a pipe with a corrosion allowance, can noticeably lower the disc's burst pressure.
That is why a stricter criterion is applied to discs than to the rest of the equipment: the material must be practically immune to the fluid, not just "acceptable". The two faces must also be checked: the process face and the discharge face, which may be exposed to moisture, rain or gases from a shared relief header.
Materials and uses table
The table is indicative; final compatibility is confirmed with corrosion data for the actual fluid, including traces, moisture and temperature.
| Material | Strengths | Limitations | Typical services |
|---|---|---|---|
| 316/316L stainless steel | Good general resistance, readily available, economical | Sensitive to chlorides (pitting and stress corrosion cracking) | Steam, air, industrial gases, hydrocarbons, many chemicals |
| Nickel 200 | Excellent in alkalis | Not suitable for oxidizing media | Caustic soda, potash, dry chlorine |
| Monel 400 (Ni-Cu) | Hydrofluoric acid, seawater | Oxidizing media, wet ammonia | HF alkylation, marine services |
| Inconel 600 (Ni-Cr-Fe) | Mechanical strength at high temperature, oxidation | Cost | Hot services, oxidizing gases |
| Hastelloy C-276 (Ni-Mo-Cr) | Very wide chemical range, chlorides, wet chlorine | High cost | Fine chemicals, mixed acids, chlorinated media |
| Tantalum | Inert to most strong acids | Not suitable for hydrofluoric acid or hot concentrated alkalis; very high cost | Aggressive hydrochloric, sulfuric and nitric acids |
| Titanium | Oxidizing media, wet chlorine | Dry chlorine, some reducing acids | Chlor-alkali plants, oxidizers |
| Aluminum | Low burst pressures, lightweight | Limited chemical resistance | Low-pressure vents, air, dusts |
| Impregnated graphite | Excellent in many acids and at low cost | Brittle, fragments, sensitive to overtightening | Mineral acids, halogenated media |
| PTFE / FEP / PFA (seals) | Nearly universal chemical barrier | Limited maximum temperature; permeation in some gases | Seal layer in composite discs |
Metals: when to use each one
316/316L stainless steel: the starting point
It is the default option if there are no relevant chlorides or reducing acids. Its main enemy is chlorides: in the presence of moisture and temperature they can cause pitting or cracking, and in a thin foil that means premature rupture or leakage.
Nickel alloys
They are used when stainless steel is not enough. As a rule of thumb: nickel for caustics, Monel for hydrofluoric acid and marine environments, Inconel when temperature is the problem and Hastelloy C-276 when the medium is complex or variable (for example, a multipurpose reactor that processes different recipes).
Tantalum and titanium
Tantalum is practically inert in most strong acids, but has important exceptions (hydrofluoric acid, hot alkalis) and is costly. Titanium is useful in oxidizing media and wet chlorine, but can react violently with dry chlorine. Both require careful compatibility review.
Graphite and fluoropolymers
Direct answer: they are the economical route for aggressive acids, each with its own conditions.
- Graphite: resists many acids that would attack an expensive metal. In exchange, it is brittle, fragments on bursting (it must not go upstream of a valve without fragment retention) and requires controlled tightening and well-aligned flanges.
- Composite disc with fluoropolymer seal: the metal layer provides mechanical strength and the PTFE, FEP or PFA seal isolates the metal from the fluid. Its limit is usually the polymer temperature and, in some gases, permeation through the seal.
- Coatings: some metal discs have a coating or liner on the process face. It is worth confirming whether the coating is part of the calibrated design or an add-on.
Temperature and material
The strength of metals decreases as temperature rises, and the disc burst pressure drops with it. Each material has a different curve: nickel alloys retain their strength at high temperature better than aluminum, for example. At the cold end, austenitic materials (300 series stainless steels, nickel alloys) keep their ductility in cryogenic service, whereas carbon steels are not used for discs.
What matters to the user: specify the actual disc temperature and let the manufacturer calibrate the batch at that temperature. We explain it in how to select a rupture disc.
Practical selection method
- List all the components of the fluid, including traces (chlorides, water, H2S, oxidizers) and cleaning fluids (steam, caustic soda, passivation acids).
- It defines the maximum and minimum temperature of the disc, not just that of the process.
- Check what material the protected equipment uses and its corrosion history; if the vessel is Hastelloy, a 316 disc will hardly survive.
- Consider the discharge face: is there moisture, condensate or gases from other equipment?
- Choose the most economical material that is practically immune, not the one that "holds up for a while".
- If the resulting metal is very costly, consider graphite or a composite disc with a fluoropolymer seal.
- Verify that the disc holder is compatible: often only the wetted parts of the disc holder need the special alloy.
Common mistakes
- Choosing the material based on the main fluid and ignoring traces of chlorides or moisture.
- Overlooking cleaning: a caustic CIP or an acid passivation can be more aggressive than the process.
- Not checking the discharge face on shared headers.
- Using graphite where a non-fragmenting disc is required.
- Exceeding the seal temperature on composite discs during steam sterilization.
If a removed disc shows thinning, pitting or discoloration, it is a sign that the material is not suitable; the guide on common rupture disc failures explains how to interpret it.
To confirm the compatibility of a material with your fluid and to request a quote for the disc in the right alloy, you can consult the P&V Control Devices team.
Related guides: Disc types · Sanitary discs · Glossary