2:1 elliptical (EHA)
Crown height D/4. The most economical profile for vessels that need headroom and pressure capability.
Reference
Head types, size range and materials
What we can press, what it is called in a specification, and what we hold it to. If your drawing uses different nomenclature, send the drawing — the profile is what matters.
Profiles
Torispherical (THA)
Crown radius with a knuckle — typically R ≈ D and r ≈ 0.1D, or to your drawing. Standard for water-heater cylinders and low-pressure tanks.
Hemispherical (HHA)
Half-sphere with a straight flange, crown height D/2. Highest pressure capability per unit of wall thickness.
Conical (CHA)
Conical bottoms and transitions, apex angle and knuckle radius to your drawing, with or without a straight flange.
Flat (FHA)
Flat heads and bottoms with a straight flange for welding, to drawing.
Profiled and non-standard
Necked openings, lift-pad heads, stepped profiles and shapes that need tooling built specifically.
Size and standard table
| Code | Head profile | Reference standard (form) | Outside diameter | Wall thickness | Typical use |
|---|---|---|---|---|---|
| EHA | Elliptical head, 2:1 (D/2h = 2) | GB/T 25198 · ASME VIII Div.1 UG-32(d) form | Ø203–3000 mm | 1.5–20 mm | Storage and pressure vessels, air receivers, jacket vessels |
| THA | Torispherical (dished) head | GB/T 25198 · DIN 28011 form | Ø203–1500 mm | 0.6–12 mm | Solar water heaters, heat-pump cylinders, low-pressure tanks |
| HHA | Hemispherical head | GB/T 25198 · ASME VIII Div.1 UG-32(e) form | Ø300–3000 mm | 2–16 mm | High-pressure vessels, LNG service, cryogenic Dewar flasks |
| CHA | Conical head | GB/T 25198 · customer drawing | Ø300–1500 mm | 2–16 mm | Hoppers, conical bottoms, separators, silos |
| FHA | Flat head / flat bottom | GB/T 25198 · customer drawing | Ø200–3000 mm | 2–20 mm | Tank bottoms, covers, low-pressure closures |
| Custom | Non-standard and profiled heads | To drawing | Up to Ø3000 mm | 0.6–20 mm | Necked openings, lift pads, manways, stepped and dished profiles |
The diameters above are what the equipment is rated for, not a record of work already run — production to date sits in the smaller sizes. If we have not made your size before, we press a first article and dimension it for your approval before the batch runs. Heavy-wall work at the top of the range also depends on which press is free, so tell us the size and we will confirm before quoting.
One more thing we would rather you hear from us: EHA and THA pressure vessel heads are the newest part of this plant's work, starting in 2019. The forming experience behind them goes back to 2001 in solar tank heads, but if your tender requires a supplier with decades of vessel-head references, that is a fair question to ask us and we would rather answer it at enquiry stage than have you find it later.
Materials and finishes
| Family | Grades | Typical use |
|---|---|---|
| Carbon steel | Q235B, Q345B, SA-36, SA-414G (Q345R on request) | Storage tanks, receivers, general fabrication |
| Stainless steel | 201, 304/2B, 304/BA, 30408 (304L and 316L on request) | Solar and hot-water cylinders, food, pharma, chemical |
| Aluminium | 5083-O and other 5xxx grades | LNG vehicle cylinders, Dewar flasks, cryogenic service |
| Finishes | 2B, BA, pickled, polished — necking zone Ra ≤ 0.4 µm | Where appearance or cleanliness matters |
Heads off the press
Finished parts photographed at the plant — elliptical and dished profiles with pressed openings, plain heads, and a mirror-polished head for a sanitary application.
Finished heads, photographed at the plant: elliptical and dished profiles with pressed openings, plain heads, and a mirror-polished head for a sanitary application.
Features we press into a head
Necked openings
Multi-stage progressive necking for nozzles and connections, held to Ra ≤ 0.4 µm in the necked zone.
Lift pads and flats
Four-flat and lift-pad heads for gas cylinders and cylinders that need handling points.
Openings and bosses
Sensor bosses, sight ports and multiple openings positioned to your drawing.
Welding
Butt, socket and necking welds, with in-house inspection on the joints that carry pressure.
Request a quote
Send us a drawing, a size list or just the application.
Open the RFQ formsales@formedheads.com
Quotes usually go out within one working day. Drawings stay confidential.