Each hole carries one to three circumferential grooves, machined specifically to increase the pull-out resistance of an expanded tube-to-sheet joint — added strength at the joint without changing the base material.
| Structural Principle | Grooves increase mechanical interlock of an expanded (rolled) tube joint |
| Typical Groove Count | 1-3 grooves per hole, per TEMA |
| Applicable Joint Type | Expanded joints only — not applicable to welded joints |
| Groove Geometry | Depth and spacing per TEMA standard requirements |
| Governing Codes | TEMA groove specifications |
Grooving is a joint-strength decision independent of structural type or material family.
One to three grooves per hole is typical, per TEMA guidance, with the exact count depending on tube diameter, wall thickness, and the required joint strength for the service.
No — grooving strengthens an expanded joint specifically. If the service requires the leak-tight assurance of a welded joint, welding is still specified, sometimes in addition to grooving for extra security.
Only during original machining, before the tube sheet is put into service — grooves can't practically be added to holes with tubes already installed.
Every enquiry is checked against governing code, material compatibility and manufacturing feasibility before a quote is issued. Use our product, material, grade and standards guides to freeze the RFQ — then confirm with engineering.
Send your diameter, material, pressure class and quantity — we'll confirm thickness and price.