Get a tailored quotation for pressure vessel heads, stainless spheres, or firepit bowls. Our engineers review your drawings, materials, standards, and quantities to provide accurate pricing and delivery options.
Get a tailored quotation for pressure vessel heads, stainless spheres, or firepit bowls. Our engineers review your drawings, materials, standards, and quantities to provide accurate pricing and delivery options.
You’d think this would be simple. Cone is cone, right?
Not quite.
If you’ve ever had a job stall because a “cone head” showed up and didn’t match the fit-up, you already know the pain. A lot of people casually say conical head when they actually mean toriconical head. And that one word can change your drawing, your forming method, your weld details, and how the inspector looks at your transitions.
Let’s clear it up.
A conical head is a straight-sided cone section that closes a vessel or acts as a transition.
Picture a funnel. That’s the basic geometry: a cone angle, a big end diameter, and a small end diameter (or a point, in theory). In pressure vessel work, you almost always have a large end that meets a shell and a small end that meets a nozzle, reducer, or another shell.
Here’s the catch: the “cone to cylinder” junction is where stress gets spicy. If you keep it as a sharp intersection, you’ll typically need reinforcement details or a different transition strategy.
A toriconical head is a cone that includes a toroidal knuckle (a rounded transition) where it meets the shell.
That “tori-” part matters. It means you don’t go from cylinder to cone in a sharp line. You blend it with a radius (knuckle radius). This improves stress distribution and usually makes the design easier to justify in a code review package.
It’s the rounded corner that smooths the geometry change. Like the curve between a bowl and its rim. Without it, you’ve got a hard corner. Hard corners hate pressure cycling.
If your detail shows a knuckle radius between the cone and the cylinder, you’re looking at a toriconical head.
Quick checklist:
If the drawing calls out things like knuckle radius, tangent line, or specific transition rules, it’s almost certainly toriconical.
Because “conical” vs “toriconical” changes fit-up, stress, inspection risk, and cost.
I’ve seen RFQs that say “cone head, 60°” and nothing else. No knuckle. No tangent location. No straight flange. The shop builds what they think you meant. The buyer thinks they ordered something else. Now everyone’s mad and nobody’s sleeping.
Here’s what changes:
Toriconical heads reduce stress concentration at the transition. Conical heads can work fine, but you must treat the junction carefully in design and fabrication.
Knuckle area + junction weld geometry affects:
If you’re building to ASME Section VIII or PED/EN, reviewers will expect the geometry you claim. A toriconical transition often reads “cleaner” in review packages because it’s explicit.
Toriconical heads usually behave better under pressure at the junction. Not because the cone wall magically gets stronger, but because the transition doesn’t punish the material with a sharp stress riser.
That said, “stronger” depends on:
So yeah… stronger, usually. Not always.
Choose a conical head when you want a simple reducer shape and the junction is handled properly.
Common use cases:
I’m not saying “cone heads are bad.” I’m saying they need clear specs so you don’t end up with an awkward weld intersection and a nervous inspector.
Choose a toriconical head when you want a cleaner transition and less risk at the shell junction.
Typical drivers:
If your project has a tough client engineer who asks “show me the knuckle radius and the tangent points,” just save yourself the back-and-forth and spec the toriconical properly.
Always specify the geometry inputs that define the transition.
Minimum RFQ fields I like to see:
If you don’t know a value, say “supplier to propose” instead of leaving it blank. Blank fields create surprises.
| Item | Conical Head | Toriconical Head |
|---|---|---|
| Transition to shell | Direct junction | Rounded knuckle radius |
| Stress at junction | Higher risk if poorly detailed | Typically lower, smoother |
| RFQ clarity needed | High | Very high (more parameters) |
| Fabrication | Often simpler | Often more controlled/complex |
| Code review friendliness | Depends on details | Usually easier to justify |
| Typical use | Reducers, hoppers, transitions | Pressure transitions, fatigue-sensitive |
Got a drawing you’re unsure about? Paste the key dimensions (OD, t, cone angle, knuckle radius if any), and I’ll tell you which one it really is—and what your supplier will need to quote it cleanly.
