Spun Tank Heads & Dished Ends
Seamless dished ends from 100 to 1,500 mm diameter, spun to your crown radius and flanged to your mating geometry — with mill certificates and dimensional reports.
Part of our custom metal spinning services: tank heads and dished ends are spun to Ø1,500 mm in one piece on the same lathes used for every other part we quote.
Four Profiles, One Process
A tank head is a shape plus an edge condition, and most sourcing problems come from the edge. We agree the profile and the flange geometry on the drawing before anything is spun, because a head that arrives with the wrong knuckle radius or an unprepared edge stops your welding line.
| Head type | Typical application |
|---|---|
| Hemispherical | Pressure vessels and cryogenic tanks where the highest strength-to-weight ratio matters; deepest draw, spun in two or three passes |
| 2:1 ellipsoidal | The workhorse of process and storage vessels — a good balance of capacity, strength and head height |
| Torispherical (flanged & dished) | Low-pressure tanks, silos and hoppers where a shallower head keeps overall height down |
| Conical / dished cone | Hopper bottoms, cyclone inlets and transition pieces; concentric or eccentric |
| Flat flanged head | Access covers and blind flanges with a rolled or turned edge for bolting |
Size and thickness envelope
| Specification | Range |
|---|---|
| Diameter | 100 mm – 1,500 mm (larger heads quoted as fabricated-and-spun assemblies) |
| Thickness | 1.0 mm – 8 mm depending on diameter and pressure requirement |
| Materials | 304, 316L, 321, carbon steel Q235/Q345, aluminum 5052/5083, copper |
| Edge preparation | Straight flange, rolled knuckle, bevelled for welding, or trimmed square only |
| Crown radius tolerance | ±1% of nominal radius; profile checked against a template |
| Out-of-roundness | ≤0.5% of diameter on CNC-spun heads |
| Documentation | EN 10204 3.1 mill certificate, dimensional report, template check sheet |
What Goes in the Box
Heads are usually one component in a vessel that somebody else certifies, so our job is to make your inspection boring. Every lot ships with a document pack that lets your welding engineer accept it without a site visit.
- Mill certificate traceable to heat number, matched to the head serial number
- Dimensional report: diameter, overall height, crown radius, flange width, squareness
- Template check sheet for the profile, photographed against the physical head
- Thickness readings at crown, knuckle and flange on a 12-point grid
- Surface report — pits, roller marks and scratches logged, with acceptance against your drawing
- Optional: PMI (positive material identification) test on 316L and duplex heads
We do not issue pressure-vessel certification. If your head needs a design-code stamp, tell us at enquiry stage and we will work with your notified body or supply the head for your own certification scope.
Getting a Big Round Part There Undamaged
A 1,200 mm head in 1.5 mm stainless will dent if it is strapped to a pallet like a box of castings. Large heads ship nested in pairs where the geometry allows, each one supported on a plywood cradle cut to the crown radius, with the flange protected by a rolled cardboard ring.
- Nested pairs for hemispherical and 2:1 heads up to 1,500 mm
- Plywood cradle cut to the crown profile for single heads
- Flange edge protected with rolled board and stretch film
- Fumigation-free plywood crates, ISPM 15 compliant
- Loading photos and container plan sent before the truck leaves
For repeat programmes we keep the cradle drawing on file, so the second shipment is packed exactly like the first one that arrived clean.
Questions Buyers Ask Us
Can you spin a head with a rolled knuckle and a straight flange?
What is the largest head you can produce?
Do you supply heads in carbon steel?
How do you verify the crown radius?
What lead time should I plan for?
Related Capabilities
China Sourcing Service
If your vessel needs fittings, flanges or valves from other suppliers.
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