What Is ASTM A182 F304?
ASTM A182 covers forged or rolled alloy and stainless steel flanges, fittings, valves and parts for high-temperature service. Grade F304 is the classic 18Cr-8Ni austenitic stainless forging — the stainless equivalent of a general-purpose flange material.
Temperature Range
F304 is rated up to 538°C in ASME B16.5 pressure-temperature tables; the allowable pressure declines with temperature.
Material Group (per ASME B16.5)
Per ASME B16.5-2025 Table 1A, F304 (18Cr-8Ni) belongs to Material Group 2.1, together with F304H and plate A240 Gr. 304.
Corrosion Resistance
In the Schweitzer Corrosion Resistance Tables (Part A 2004 / Part C 2021, Type 304/347 row), F304 is rated excellent to good in the large majority of media tested — oxidizing conditions, many organic acids, food and pharmaceutical fluids. It is rated unsatisfactory in concentrated hydrochloric, some aluminum chloride and fluoride media. Watch for chloride pitting and stress-corrosion cracking in chloride-bearing service, where F316 is the safer choice.
Typical Applications
- ASME B16.5 stainless flanges, NPS 1/2–24
- ASME B16.11 socket-welding and threaded stainless fittings
- Food, beverage, pharmaceutical and clean-water piping
- General chemical and utility piping at moderate temperatures
Chemistry & Mechanical Properties
Composition and mechanical properties per ASTM A182 — consult the standard for exact limits. Mill certificates (3.1) supplied with every order.
Related Standards
- ASME B16.5 — Pipe Flanges (NPS 1/2–24)
- ASME B16.11 — Socket-Welding & Threaded Fittings
- ASME B16.47 — Large-Diameter Flanges (NPS 26–60)
- ASTM A182 F304L — Low-Carbon 304
- ASTM A182 F316 — Molybdenum-Bearing Stainless
- Our Flange Range
FAQ
What temperature range does F304 cover?
Up to 538°C per the ASME B16.5 Group 2.1 pressure-temperature tables.
What is the difference between F304 and F304L?
F304L is the low-carbon version: less carbide precipitation after welding, better intergranular corrosion resistance, and a lower allowable strength (B16.5 Group 2.3 rating table).
Is F304 suitable for seawater or chloride service?
Not ideally — 304 is susceptible to chloride pitting and stress-corrosion cracking. Choose F316 (or duplex F51) for chloride-bearing service.
Can F304 be used for food-grade piping?
Yes — 304 is standard for food and beverage equipment, and the Schweitzer tables rate it excellent/good in the media typically encountered.
Can F304 be welded?
Yes — welding is standard practice. For heavy welded joints where post-weld annealing is not done, F304L (low carbon) is the preferred choice.
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