Product Introduction
The seamless tubes shall be used for the manufacturing of refillable seamless steel quench & tempered gas cylinder with actual maximum tensile strength less than 950Mpa. Since the gas cylinders are manufactured by hot spinning process the steel grade used shall be compatible for the manufacturing of high pressure gas cylinders. GB 18248 specifies the size, shape, weight, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of seamless steel pipes for gas cylinders and accumulator housings. GB 18248 is suitable for manufacturing seamless steel pipes for gas cylinders and accumulator housings.
Product Display
Mechanical Properties
| Tensile strength (MPa) | Yield strength (MPa) | Elongation (%) |
| ≥750 | ≥630 | ≥16 |
Chemical Composition (%)
| ELEMENT | C | Si | Mn | p | S | P+S | Al | Ni | Cu |
| Min | 0.32 | 0.20 | 1.40 | — | — | — | 0.035 | — | — |
| Max | 0.38 | 0.30 | 1.70 | 0.02 | 0.01 | 0.025 | 0.060 | 0.15 | 0.30 |
Product parameters
Manufacture: tubes to GB/T 6479 shall be manufactured by hot rolled or cold drawn.
Heat Treatment: the tubes shall be produced by heat treated, WT≤30mm normalizing & tempering, WT>30mm quenching & tempering or normalizing & tempering.
Inspection & Test: chemistry composition analysis, tension test, flattening test, flaring test, impact test, macroscopic examination, non-metallic inclusions, NDT, surface inspection and dimension check.
Length: 4000mm; 6000mm; 9000mm; 12000mm; and so on.
Max developed length: 30 meters, also U bending, finning, studded process can be provided.
Option: shot blasting on the outside surface to remove mill scale, make the surface matte colour; surface polishing as preparation work done for further processing, for instance finning.
OD: Φ50-325mm.
WT: 3-55mm.
Tolerance of OD: ±0.75%.
Tolerance of Wall thickness: -10%——+12.5%.
Roundness of the inner and outer diameters: 80% of the tolerance of the outer diameter is not exceeded.
The inclination of the end face: ≤2mm.
Straightness: 1mm/1m.