GB 18248 gas cylinder tube

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GB 18248 Gas Cylinder Tube

The GB 18248 standard is specifically designed for the production of seamless steel pipes used in gas cylinders and accumulator shells. It covers a wide range of materials such as 37Mn, 30CrMo, 35CrMo, and 34CrMo4, which are commonly used for oil pipes in gas cylinder applications. This standard ensures that the tubes meet high-quality requirements for strength, durability, and safety.

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, normalized and tempered, quenched and tempered, or normalized and tempered

GB 18248 outlines the specifications, dimensions, technical requirements, testing procedures, inspection rules, packaging, marking, and quality assurance for seamless steel pipes used in gas cylinders and accumulators. The standard is essential for manufacturers to ensure compliance with industry standards and to produce reliable and safe products.

Manufacturing Process: Pipes conforming to GB/T 6479 are typically produced through hot rolling or cold drawing, depending on the required mechanical properties and application needs.

Heat Treatment: For wall thickness (WT) ≤ 30 mm, the pipes should be normalized and tempered. For WT > 30 mm, quenching and tempering or normalization and tempering is required to achieve the desired mechanical properties.

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. These ensure the quality and performance of the final product.

Standard Lengths: 4000mm, 6000mm, 9000mm, 12000mm, and more. Maximum unrolled length can reach up to 30 meters. Additional processing options like U-bending, finning, and nailing are also available.

Surface Options: Available finishes include shot blasting to remove scale and create a matte finish, or surface polishing for further processing such as 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 and Tolerance
Hot Rolled
Outer Diameter, mm
Tolerance
OD≤159
+1% or +0.50mm
OD>159
Cold Drawn
Outer Diameter, mm
Tolerance
Ordinary
Advanced
OD≤30
±0.20mm
±0.15mm
30
±0.30mm
±0.25mm
OD>50
±0.50%
±0.50%
Wall Thickness and 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
Tolerance
Ordinary
Advanced
WT≤2.0
+12.5%/-10%
±10%
WT>2.0
±10%
±7.5%

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