Article
ASTM A182 is the specification for forged or rolled alloy and stainless steel pipe flanges, forged fittings and valve parts for high-temperature service. In practice it is the standard used for almost all stainless and alloy steel flanges, socket weld and threaded fittings, and olets.
Main grade families
| Family | Grades | Typical use |
|---|---|---|
| Austenitic stainless | F304, F304L, F304H, F316, F316L, F316H, F316Ti, F317L, F321, F347, F310, F904L | Corrosion resistance and high-temperature service |
| Duplex / super duplex | F51 (2205), F53 (2507), F55, F60 | Seawater, offshore, chloride service |
| Martensitic / ferritic | F6a (410), F430 | Moderate corrosion, wear |
| Alloy (Cr-Mo) | F5, F9, F11, F22, F91 | High-temperature power and refinery service |
Dual certification
Stainless flanges are commonly supplied as F304/F304L or F316/F316L. The material meets the low carbon content of the L grade and the strength of the straight grade, so it satisfies orders for either.
Heat treatment
- Austenitic grades – solution annealed and quenched, typically at not less than 1040 °C, to dissolve carbides and restore corrosion resistance.
- Duplex grades – solution annealed and rapidly cooled to keep the right ferrite–austenite balance.
- Cr-Mo grades – normalised and tempered, or annealed, as the grade requires.
Testing
A182 requires chemical analysis and tensile testing, with hardness testing for each lot. Common supplementary requirements requested by buyers include intergranular corrosion testing (ASTM A262 Practice E), ultrasonic testing, PMI and, for duplex, ferrite count and ASTM A923 testing.
A182 vs A105 vs A350
- A105 – forged carbon steel for ambient and higher temperature service.
- A350 LF2 – forged carbon steel with impact testing for low temperature.
- A182 – stainless, duplex and alloy steel forgings.
What the certificate should show
An EN 10204 3.1 certificate for A182 flanges should list the heat number, grade, chemical analysis, tensile and hardness results, heat treatment details, dimensions standard, and any supplementary tests ordered.
Frequently asked questions
What is ASTM A182 F316L?
A forged low-carbon 316 stainless steel grade used for flanges, forged fittings and valve parts.
Is F51 a stainless steel?
Yes. F51 is duplex stainless steel UNS S31803/S32205, commonly called 2205.
What is the difference between A182 and A105?
A105 covers forged carbon steel, while A182 covers forged stainless, duplex and alloy steels.
Key takeaways
- A182 covers forged stainless, duplex and Cr-Mo flanges and fittings.
- Dual-certified F304/F304L and F316/F316L are standard.
- Check heat treatment and supplementary tests on the certificate.
Need these products?
Sawariya Metal Industries supplies stainless steel pipes, flanges and buttweld pipe fittings from Mumbai to buyers in India and overseas. Send your size, grade, standard and quantity through our enquiry form and we will reply with a clear quotation and the test documents you need. You can also browse our stainless steel pipes, flanges and buttweld fittings.