Welded Cylinder Assemblies
Tube-to-head, tube-to-base and rod-to-eye welded sub-assemblies, machined after welding where the drawing calls for it.
Weld first, machine after
Welding moves metal. Where the drawing tolerance is tighter than the distortion a weld produces, the sequence has to be weld, stress relieve if required, then machine, and the machining datum has to be established after welding rather than before.
Sending us both the detail drawings and the assembly drawing lets us plan that sequence properly. Sending only the detail parts usually produces an assembly that is dimensionally correct part by part and out of tolerance as a whole.
Specification
| FIELD | UNIT | ORISE VALUE |
|---|---|---|
| Welding processes | — | MIG / MAG · submerged arc · TIG |
| Automation | — | CNC seam welding stations for tube-to-head and tube-to-base joints |
| Maximum assembly length | mm | 6000 |
| Maximum assembly weight | kg | 3000 |
| Crane capacity in the welding bay | t | 10 |
| Welder qualification | — | Qualification records held per welder and per procedure, copies supplied with the first article |
| Welding quality system | — | Welding is covered by the ISO 9001 system. ISO 3834 is not held and is not claimed |
| Post-weld machining | — | Datum re-established after welding, finish machined in a single set-up |
| Stress relief | — | Furnace stress relief 550 to 650 °C, parts up to 6000 mm |
| Pressure / leak test | — | Hydrostatic bench to 40 MPa, hold time to your specification |
| NDT | — | Visual, magnetic particle and ultrasonic in house · radiography through a qualified partner |
Welder qualification records. Ask for them at the quotation stage rather than at the audit. We keep qualification records per welder and per procedure and can supply copies with the first article.
On ISO 3834. We do not hold it and we do not claim it. Almost no Chinese supplier in this trade does, and stating a welding quality certification that cannot be produced on request is one of the fastest ways to fail a supplier audit. If your specification requires ISO 3834-2 or EN 15085, say so at enquiry stage and we will tell you plainly whether the work should go elsewhere.
What we need on the drawing
- The assembly drawing, not only the detail drawings
- Weld symbols with size, process and any required weld quality level
- Which dimensions are to be held after welding, and their datums
- Whether stress relief is required and to what specification
- Test requirement: pressure, hold time and acceptance criteria
- Paint or protective coating specification for the finished assembly
Send the drawing
Quotation within 48 hours of a complete drawing package.