Hemispherical Heads

Profile and terminology

A hemispherical head follows a half-sphere profile. Its inside spherical radius is half the inside diameter. Shape alone does not establish a pressure rating or the thickness required for a particular application.

GB/T 25198-2023 models: HHA

The HHA illustration in the inquiry tool shows the version without a straight flange. For that illustrated form, the inside depth equals the inside radius. If a drawing calls for an additional flange or another edge arrangement, describe it in the notes and provide the drawing reference.

What to include in your inquiry

Inside diameter; nominal thickness; minimum thickness after forming if specified; inside depth; edge or flange requirements; material grade; quantity.

Use millimetres for dimensions. Identify the exact material grade rather than only writing “steel” or “stainless steel”. You can also include edge preparation, inspection requirements, delivery needs and a drawing reference in the notes.

The configurator creates an inquiry list. The email button opens your mail application; it does not submit an order or send a message automatically.

Drawing and design review

These descriptions identify geometry and information needed for an inquiry. They do not establish allowable pressure, certify compliance or replace a vessel design calculation. Confirm the applicable standard, drawing and final dimensions before ordering.