Product Overview
Cold drawn precision tube starts from a hot rolled seamless shell that is pickled, cold drawn, annealed and straightened. Outside diameter holds within +/-0.1 mm and wall thickness within +/-10%, and the bore can be honed to Ra0.4-0.8 micron, which removes the boring operation when the tube is used directly as a cylinder barrel. Being seamless and dense in structure, it carries working pressures above 20 MPa without the bore scuffing seals.
Specifications
| Parameter | Value |
|---|---|
| Outside diameter | 25 – 325 mm |
| Inside diameter | 20 – 300 mm |
| Wall thickness | 2 – 30 mm |
| Grade | 20# / 45# / E355 / A106 Gr.B |
| OD tolerance | +/- 0.1 – 0.3 mm |
| Wall tolerance | +/- 10% |
| Bore roughness | Cold drawn Ra1.6 / honed Ra0.4 |
| Straightness | max 1 mm/m |
| Standard length | 5 – 12 m |
| Surface | Pickled bright / rust preventive oiled |
Applications
Used for excavator and loader hydraulic cylinder barrels, pneumatic cylinders, injection moulding machine barrels, shock absorber bodies, textile machinery roller sleeves and hydraulic support columns in mining. Construction equipment and hydraulic component makers are the main customers, and they often ask for the bore in dimensional bands so tube goes straight onto the assembly line.
Packing / Delivery / Payment
Shipped bare in 1-2 ton bundles with plastic end caps to prevent impact damage, and honed tubes get rust preventive oil and stretch film. A 20GP holds about 22-25 tons. Stock ships in 10-20 days and production orders in 30 days. Payment by L/C at sight or T/T with 30% deposit. Mill certificate, dimensional and roughness test reports, packing list and Certificate of Origin are provided.