What are steel tee fittings and how do they work
A steel tee is a T-shaped forged fitting used to branch off a main pipeline or to join two separate flow paths into one. It has three openings: two on the run (the straight-through path) and one on the branch (at 90° to the run). When all three openings share the same nominal diameter, it's called an equal tee. When the branch is smaller than the run, it becomes a reducing tee, or a stainless steel reducing tee when manufactured in SS grades.
Every tee in our catalog is forged to ASME B16.11, the ASME standard governing dimensional tolerances, pressure–temperature ratings and marking requirements for socket weld and threaded forged fittings. Unlike cast fittings, forged tees are produced from solid bar or billet stock: forging compresses and aligns the grain structure, delivering higher strength, better fatigue resistance and greater reliability under cyclic loads and pressure transients.
Find the right finishing: Socket Weld, NPT, BSPT and G.CIL compared
The finishing defines the connection type at each end of the tee. We stock four options — each matched to a specific installation method, regional standard or service condition:
- Socket Weld (SW): The pipe inserts into a recessed socket in the fitting and is fillet-welded around the outside. The preferred choice for high-pressure, vibration-sensitive or leak-critical applications — oil and gas lines, steam systems, chemical process piping. Available in Classes 3000, 6000 and 9000.
- NPT (National Pipe Taper Thread): Tapered thread per ASME B1.20.1 (US standard). The taper creates a progressive mechanical seal as the connection is tightened. Available in Classes 2000, 3000 and 6000. Standard for most North American industrial and process applications.
- BSPT (British Standard Pipe Taper): Tapered thread per BS 21. Common in systems built to British, European or older international standards, and in instrumentation and utility piping.
- G.CIL (Gas Cylindrical / ISO 228): A parallel (straight) thread that relies on a face seal or thread sealant for pressure containment. Frequently used in pneumatic systems and low-pressure gas circuits.
Use the Finishing filter in the sidebar to view only the end type your system requires.
Material grades: which steel is right for your service?
Our range covers every major material family listed in ASME B16.11 and ASTM specifications. All grades available in our shop are listed below. You can filter by Steel in the sidebar to narrow to the alloy you need.
Carbon Steel and Low-Alloy Steel
- A/SA105N: General-purpose carbon steel for ambient-to-elevated temperature service; the standard choice for the majority of industrial piping applications.
- A/SA350 LF2 CL1, LF3: Low-temperature carbon steel grades for cryogenic and cold-climate service down to −46°C / −50°C.
- A/SA182 F1, F5, F9, F11 CL2, F12, F22 CL3, F91 (Type 1 & 2), F92: Chrome-moly alloy steels for elevated-temperature and high-pressure service in power generation, petrochemical, and refinery piping.
Austenitic Stainless Steel
- A/SA182 F304/L, F304/H: General-purpose grades; excellent corrosion resistance in a wide range of environments.
- A/SA182 F316/L, F316/H: Molybdenum addition gives superior resistance to chlorides, marine atmospheres and process acids. Food, pharmaceutical and marine applications.
- A/SA182 F310, F310/H: High-chromium, high-nickel grades for extreme high-temperature oxidation resistance.
- A/SA182 F317/L: Higher Mo content than 316L; strong acid resistance, chemical processing.
- A/SA182 F321, F321/H: Titanium-stabilised to prevent sensitisation; suitable for sustained high-temperature service.
- A/SA182 F347, F347/H: Niobium-stabilised; refinery and petrochemical service at elevated temperatures.
- A/SA182 F904L: High-alloy austenitic grade for aggressive corrosive media including sulphuric acid.
Duplex and Super Duplex Stainless Steel
- A/SA182 F51 (Duplex 2205 — UNS S31803): Dual-phase austenitic-ferritic structure; approximately twice the yield strength of 316L with excellent resistance to stress corrosion cracking and pitting. Oil & gas, chemical plant, pressure equipment.
- A/SA182 F53 (Super Duplex 2507 — UNS S32750): PREN 40–42; superior resistance to chlorides and marine environments. Offshore platforms, subsea components.
- A/SA182 F55 (Super Duplex — UNS S32760): Tungsten and copper addition enhances corrosion resistance further. Aggressive offshore and chemical processing environments.
- A/SA182 F44 (254 SMO — UNS S31254): Super austenitic with ~6% Mo and high nitrogen; PREN 42–45. Seawater, high-chloride media, subsea.
Nickel Alloys
- B/SB366 WP20CB-S (Alloy 20 / N08020): Designed for sulphuric acid resistance; chemical and pharmaceutical processing.
- B/SB366 WPHC276-S (Hastelloy C-276 / N10276): Outstanding resistance to oxidising and reducing acids; chemical and waste treatment.
- B/SB366 WPNC-S (Monel 400 / N04400): Seawater, caustics, hydrofluoric acid service.
- B/SB366 WPNIC-S (Incoloy 800 / N08800): High-temperature oxidation and carburisation resistance.
- B/SB366 WPNICMC-S (Incoloy 825 / N08825): Sulphuric and phosphoric acid environments, seawater.
- B/SB564 UNS N06625 (Inconel 625): Wide temperature range from cryogenic to 980°C; aerospace, subsea, chemical.
Available sizes and pressure classes
Our catalog covers the following range — use the sidebar filters to navigate:
Nominal diameter (NPS)
- 1/8″ – 6″ (Filter: Diameter)
Reducing tee branch size
- Available for most run sizes (Filter: Second Diameter)
Pressure classes (increasing pressure rating)
- S.2000 — Class 2000, threaded (NPT/BSPT), threaded ends only
- S.3000 — Class 3000, SW and threaded, most common class
- S.6000 — Class 6000, SW and threaded, high-pressure service
- S.9000 — Class 9000, SW, very high-pressure
- S.10000 — Class 10000, where stocked, special service
Product types
- Equal Tee, Reducing Tee (Filter: Product type)
All dimensions comply with ASME B16.11 tolerances. For full dimensional tables and weight data, download our product catalog.
Source your steel tees directly from M.E.G.A.: no distributor, no compromise
M.E.G.A. S.p.A. has been manufacturing forged pipe fittings since 1962. Ordering through our shop means buying direct from the production source — cutting out the distributor and every markup that comes with it. Here is what that means for your procurement:
- Full material traceability: Every fitting ships with its material certification. We forge, heat-treat, machine and test in-house across the full production cycle, so traceability is complete from billet to finished part.
- Certifications that matter: Our quality management system and products comply with ASME, ASTM, PED and ISO standards. We are also qualified for nuclear applications, a level of qualification few manufacturers worldwide achieve.
- From stock in 24–48 hours: Standard catalog items ship within 24–48 hours of order confirmation, no the weeks-long lead times typical of distribution channels.
- Price transparency: Log in to unlock full pricing immediately. Minimum order only €250.
- Direct technical access: Our team includes engineers who know the product. We are available for specification questions, material selection and sizing support before you place an order.
- Global supply track record: We export to major oil & gas operators, EPC contractors and engineering firms worldwide. Now the same catalog (same quality, same certifications) is available to you online.
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