---
title: "AISI 304"
description: "AISI 304 (sometimes called 18-8 stainless for its ~18% Cr, ~8% Ni composition) is the most widely-used austenitic stainless steel. In sonic-horn manufacture, 304 is the economy option for external mountings, brackets, accessories and parts that do not see directly corrosive flue-gas chemistry."
canonical_url: "https://sylio.co/glossary/aisi-304"
last_updated: "2026-06-28T02:29:34.882Z"
---

**AISI 304** (sometimes called *18-8 stainless* for its ~18% Cr, ~8% Ni composition) is the most widely-used austenitic stainless steel. In sonic-horn manufacture, 304 is the economy option for external mountings, brackets, accessories and parts that do not see directly corrosive flue-gas chemistry.

## Why not 304 everywhere

- **Chloride pitting** — 304 is vulnerable to localised pitting in chloride-bearing environments (most cement, WtE, biomass and coastal applications). [AISI 316 / 316L](/glossary/aisi-316-316l-stainless) is preferred.
- **Continuous high temperature** — 304 begins to scale and lose creep strength above ~500 °C.

For external accessories — mounting brackets, support frames, weatherproof enclosure panels — 304 is cost-effective without compromising horn performance.

## Related terms

- [AISI 316 / 316L stainless](/glossary/aisi-316-316l-stainless)
- [Bell horn](/glossary/bell-horn)