GB 18248 gas cylinder tube

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GB 18248 Gas Cylinder Tubes

The GB 18248 standard is designed for the production of seamless steel pipes used in gas cylinders and accumulator shells. It primarily provides high-quality seamless steel pipes such as 37Mn, 30CrMo, 35CrMo, and 34CrMo4, suitable for oil piping applications in gas cylinder systems.

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: Not heat-treated, normalized and tempered, quenched and tempered

GB 18248 outlines the dimensions, shape, weight, technical specifications, testing methods, inspection rules, packaging, marking, and quality certificates for seamless steel pipes used in gas cylinders and accumulator casings. This standard ensures the reliability and performance of pipes used in high-pressure environments.

Manufacturing Process: Pipes conforming to GB/T 6479 are produced through hot rolling or cold drawing. Heat treatment is required depending on wall thickness: for wall thickness ≤30mm, normalization and tempering is applied; for wall thickness >30mm, quenching and tempering or normalization and tempering is recommended.

Testing and Inspection: Comprehensive tests include chemical composition analysis, tensile testing, flattening test, expansion test, impact test, macroscopic inspection, non-metallic inclusion evaluation, non-destructive testing, surface inspection, and dimensional checks.

Standard Lengths: 4000mm, 6000mm, 9000mm, 12000mm, etc.
Maximum Unfolded Length: Up to 30 meters. Additional processing options include U-bending, finning, and nailing.

Surface Options: External shot blasting to remove scale and achieve a matte finish, or surface polishing for subsequent processes like fin trimming.

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℃
450–600
280 min
20 min
40 (OD≥76mm & WT≥6.5mm)
Outer Diameter & Tolerance
Hot Rolled
Outer Diameter, mm
Tolerance
OD≤159
+1% or +0.50mm
OD>159
Cold Drawn
Outer Diameter, mm
Ordinary
Advanced
OD≤30
±0.20mm
30
±0.30mm
OD>50
±0.50%
Wall Thickness & Tolerance
Hot Rolled
Outer 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
Ordinary
Advanced
WT≤2.0
+12.5%/-10%
WT>2.0
±10%

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