GB 18248 gas cylinder tubes are designed for the production of seamless steel pipes used in gas cylinders and accumulator shells. These pipes are primarily available in grades such as 37Mn, 30CrMo, 35CrMo, and 34CrMo4, suitable for oil pipe applications in gas cylinders.
Standard: GB 18248
Equivalent Standards: JIS G3429, EN 10297-1, ASTM A372, EN 1964-1, EN ISO 11120, ISO 11439, ISO 9809-1, JIS B8230, JIS B8241
Available Brands: 37Mn, 34Mn2V, 30CrMo, 35CrMo, 34CrMo4, 30CrMnSiA
Outer Diameter: 48 - 711 mm
Wall Thickness: 3.1 - 38 mm
Length: 4 - 12 meters
Delivery Condition: As rolled, quenched and tempered, normalized and tempered, or not heat treated
GB 18248 outlines the specifications, dimensions, weight, technical requirements, testing methods, inspection rules, packaging, marking, and quality certificates for seamless steel pipes used in gas cylinders and accumulator casings. This standard is widely used for manufacturing high-quality seamless pipes for industrial and commercial gas storage systems.
Manufacturing Process: Pipes conforming to GB/T 6479 can be manufactured using hot rolling or cold drawing techniques. Heat treatment is essential based on wall thickness—normalizing and tempering for wall thickness less than 30 mm, and quenching and tempering for thicker sections. All pipes undergo rigorous testing including chemical composition analysis, tensile testing, flattening tests, expansion tests, impact testing, macroscopic inspection, non-metallic inclusion checks, non-destructive testing, surface inspection, and dimensional verification.
Available Lengths: 4,000 mm; 6,000 mm; 9,000 mm; 12,000 mm; and more. Maximum unfolded length can reach up to 30 meters. Additional processing options include U-bending, finning, and nailing. Surface treatments like shot blasting for scale removal and polishing for further processing are also available upon request.
| Chemical Composition |
C, % |
Si, % |
Mn, % |
P, % |
S, % |
Cr, % |
Ni, % |
Cu, % |
Mo, % |
0.08–0.15 |
0.50 max |
0.40–0.60 |
0.025 max |
0.015 max |
2.00–2.50 |
0.30 max |
0.20 max |
0.90–1.13 |
|
| Mechanical Properties |
Tensile Strength, MPa |
Yield Strength, MPa |
Elongation, % |
Impact (KV2)/J at 20°C |
450–600 |
280 min |
20 min |
40 (OD≥76mm & WT≥6.5mm) |
|
| Outside Diameter & Tolerance |
Hot Rolled |
Outside Diameter, mm |
Tolerance |
OD≤159 |
+1% or +0.50mm |
OD>159 |
Cold Drawn |
Outside Diameter, mm |
Tolerance |
Ordinary |
Advanced |
OD≤30 |
±0.20mm |
±0.15mm |
30 |
±0.30mm |
±0.25mm |
OD>50 |
±0.50% |
±0.50% |
|
| Wall Thickness & Tolerance |
Hot Rolled |
Outside Diameter, mm |
Tolerance |
OD≤159 |
+12.5%/-10% or +0.50mm/-0.40mm |
OD>159, WT/OD≤0.05 |
+15%/-10% |
OD>159, 0.05 |
+12.5%/-10% |
OD>159, WT/OD>0.10 |
±10% |
Cold Drawn |
Wall Thickness, mm |
Tolerance |
Ordinary |
Advanced |
WT≤2.0 |
+12.5%/-10% |
±10% |
WT>2.0 |
±10% |
±7.5% |
|
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