GB 18248 Gas Cylinder Steel Tubes
The GB 18248 standard is specifically designed for the production of seamless steel pipes used in gas cylinders and accumulator shells. It primarily covers materials such as 37Mn, 30CrMo, 35CrMo, and 34CrMo4 seamless steel tubes, which are widely used in oil and gas applications, hydraulic systems, and industrial pressure vessels.
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
GB 18248 outlines the dimensions, shape, weight, technical specifications, testing methods, inspection procedures, packaging, marking, and quality certification requirements for seamless steel pipes used in gas cylinders and accumulators. This standard ensures that the pipes meet high-quality mechanical and chemical performance criteria, making them suitable for critical applications in various industries.
Manufacturing Process: Pipes under GB/T 6479 should be produced using hot rolling or cold drawing techniques to ensure dimensional accuracy and structural integrity.
Heat Treatment: For wall thickness (WT) ≤ 30 mm, normalization and tempering are required. For WT > 30 mm, quenching and tempering or normalization and tempering are recommended to achieve optimal mechanical properties.
Inspection and Testing: Comprehensive tests include chemical composition analysis, tensile testing, flattening test, expansion test, impact testing, macroscopic examination, non-metallic inclusion assessment, non-destructive testing, surface inspection, and dimensional verification. These ensure the product meets strict quality standards.
Standard Lengths: 4000 mm, 6000 mm, 9000 mm, 12000 mm, and more. The maximum unrolled length can reach up to 30 meters. Additional processing options such as U-bending, finning, and nailing are also available upon request.
Surface Options: External shot blasting to remove scale and achieve a matte finish, or surface polishing for subsequent processing 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 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%
|
|
Drink Dispenser
Electric Liquor Dispenser,Electric Beverage Dispenser,Automatic Drink Dispenser,Touchless Drink Dispenser,Water Dispenser
Shenzhen Baidi Technology Co.,Ltd , https://www.szpaddy.com