Corrosion-resistant buttweld fittings for acids, solvents, chlorinated compounds, caustic, and mixed chemical environments. 316L to Hastelloy C-276 — the right alloy for every chemical service. EN 10253 Type B with PED certification for EU plants.
Request Chemical Plant Fittings Quote| Chemical / Service | Concentration | Recommended Material | EN W.Nr. | Notes |
|---|---|---|---|---|
| Hydrochloric acid (HCl) | All concentrations | Hastelloy C-276 | 2.4819 | Best overall; avoid SS entirely for HCl |
| Sulphuric acid (H₂SO₄) | Dilute <10% | 904L or Hastelloy C-276 | 1.4539 / 2.4819 | Temperature-dependent — consult |
| Sulphuric acid (H₂SO₄) | 10–80% | Hastelloy C-276 | 2.4819 | Most reliable across this range |
| Sulphuric acid (H₂SO₄) | >96% ambient | Carbon steel (passivation layer) | 1.0345 | Concentrated cold H₂SO₄ passivates CS |
| Nitric acid (HNO₃) | All concentrations | Hastelloy C-22 or 304L/316L | 2.4602 / 1.4307 / 1.4404 | C-276 NOT suitable >50% HNO₃ — use C-22 |
| Phosphoric acid (H₃PO₄) | All conc., high temp | 904L or Hastelloy C-276 | 1.4539 / 2.4819 | Incoloy 825 also suitable |
| Caustic / NaOH | All concentrations | 316L or Duplex 2205 | 1.4404 / 1.4462 | SS excellent for caustic; avoid Cu alloys |
| Chlorinated solvents | — | 316L | 1.4404 | Check temperature — SCC risk above 60°C |
| Mixed acids (HNO₃ + HF) | — | Hastelloy C-22 | 2.4602 | Mixed oxidising/reducing environment |
| Acetic acid / organic acids | All conc. | 316L or 316Ti | 1.4404 / 1.4571 | 316L widely specified for organic acid plants |
| Chlorine / hypochlorite | — | 254 SMO or Hastelloy C-276 | 1.4547 / 2.4819 | SS grades must have PRE >40 for Cl₂ service |
| Ammonia (NH₃) | All concentrations | 316L or Carbon Steel | 1.4404 / 1.0345 | Avoid copper alloys — ammonia causes SCC in Cu |
Material selection is concentration- and temperature-dependent. This table provides general guidance — consult a corrosion engineer for definitive selection on safety-critical systems.
HCl (all conc.), H₂SO₄ (10–80%), seawater, FGD. Best single-alloy choice for mixed aggressive chemical service. Limitation: HNO₃ >50%.
Higher Cr — better oxidising acid resistance (HNO₃, hot H₂SO₄). Pharmaceutical API and pesticide synthesis. Mixed oxidising/reducing environments.
Universal chemical plant stainless — organic acids, acetic acid, caustic, mild acid service. Dominant EU specification. EN 10253-2 Type B available.
German chemical plant standard. Ti-stabilised — resists sensitisation to 550°C. Preferred over 316L in Germany for welded chemical plant applications.
25Ni-20Cr-4.5Mo-Cu. Exceptional H₂SO₄ and H₃PO₄ resistance. Pulp & paper bleach plants, phosphoric acid, sulphuric acid dilute streams. PRE ~33.
6% Mo super-austenitic. PRE ≥43. Chlorine, hypochlorite, bleach, seawater cooling. Step above duplex for pitting resistance without going to nickel alloy.
Hydrochloric acid (HCl) at any concentration requires nickel-molybdenum alloys. Hastelloy C-276 (EN 2.4819, UNS N10276) is the primary material — it resists HCl at all concentrations from dilute to concentrated, up to and including elevated temperatures. Hastelloy B-2 (NiMo28, 2.4617) is used for very concentrated reducing HCl where even C-276 may be marginal. Stainless steels (316L, 304L) are categorically NOT suitable for HCl service — trace HCl concentrations cause rapid pitting and crevice corrosion on all standard grades including duplex.
Sulphuric acid material selection depends heavily on concentration and temperature. Dilute H₂SO₄ (<10%): 904L (1.4539) or Hastelloy C-276 (2.4819). Intermediate concentrations (10–80%): Hastelloy C-276 provides the most reliable corrosion resistance. Concentrated H₂SO₄ (>96%) at ambient temperature: carbon steel (a passive iron sulphate film forms). Hot concentrated H₂SO₄ (acid plant absorption towers): specialist high-silicon alloys. Hastelloy C-276 is the most reliable single alloy across the widest H₂SO₄ range.
Yes. For EU chemical plants regulated under PED 2014/68/EU Category III–IV, we supply EN 10253-2 (stainless steel) and EN 10253-4 (nickel alloys) Type B fittings with EN 10204 3.2 certificates witnessed by TUV Rheinland or Lloyd's Register Asia. Specify PED category, design pressure, temperature, and required TPI in your RFQ. For Category I–II, EN 10253 Type A with EN 10204 3.1 is typically sufficient.
