Seamless centre-bored bar for bushings, bearing races, valve sleeves, and pump-housing components
A solid bar drilled to a hollow profile loses 60 to 80 percent of its mass to chips. For sleeve bearings, valve seat sleeves, pump housing inserts, hydraulic cylinder liners, and any component with a long axial bore the natural feedstock is hollow bar, supplied with the centre bore already formed. The seamless extrusion route delivers a uniform wall thickness, no longitudinal weld seam, and the same wrought ferrite-austenite microstructure as solid bar. Ferralium 255 (UNS S32550, EN 1.4507) hollow bar is supplied solution-annealed at 1080 °C with water quench, ferrite content within the 35 to 55% qualifying band, hardness ≤ 32 HRC for NACE MR0175 sour-service. RFQ: info@torqbolt.com / WhatsApp +91-22-66157017.
| OD | ID | Wall | Length |
|---|---|---|---|
| 30 mm to 60 mm | 10 mm to 30 mm | 10 mm to 25 mm | up to 6 m |
| 60 mm to 120 mm | 20 mm to 80 mm | 15 mm to 40 mm | up to 6 m |
| 120 mm to 250 mm | 50 mm to 200 mm | 25 mm to 75 mm | up to 4 m |
| 250 mm to 500 mm | 150 mm to 400 mm | 50 mm to 100 mm | up to 3 m |
Hollow bar overlaps in profile with thick-wall pipe but the supply specification is different. Ferralium 255 pipe is supplied to ASTM A790 with hydrostatic test, ASME B31 wall-thickness schedule (Sch 10 / 40 / 80 / 160 / XXS), and intended for pressure-containing service. Hollow bar is supplied to a custom OD-ID-wall specification, no hydrostatic test, intended as machining feedstock where the customer's downstream operation produces the final pressure boundary. Use hollow bar where the part has a complex internal geometry that the customer machines from the bore (relief grooves, internal threads, stepped seats); use pipe where the as-supplied wall thickness is the final wall.
