Description
GB/T18248 37Mn 30Crmo 35CrMo 42CrMo 30CrMnSiA High Pressure Gas Cylinder Tube
High Pressure Gas Cylinder Tube conforming to GB/T 18248 are manufactured from fine-grain carbon and low-alloy steels, offering exceptional strength, toughness, and dimensional precision. They are available in a wide range of diameters (3 – 965 mm) and wall thicknesses (0.5 – 120 mm), with typical lengths of 4 – 12 m, catering to diverse cylinder applications. Five common steel grades—37Mn, 30CrMo, 35CrMo, 42CrMo, and 30CrMnSiA—each exhibit tailored chemical compositions and mechanical properties optimized for high-pressure service. Key features include high yield and tensile strengths, excellent impact toughness, and tight tolerances on surface quality and dimensions. These tubes meet GB/T 18248 requirements and are equivalent to several international standards, making them suitable for sectors such as automotive CNG, medical oxygen, firefighting, diving, welding, and industrial gas storage.
Material
High Pressure Gas Cylinder Tube under GB/T 18248 are produced from fine-grain carbon and low-alloy steels designed for optimal hardenability and toughness. Common grades include 37Mn, which provides good formability; 30CrMo and 35CrMo, which are quenched-and-tempered alloys with enhanced strength; 42CrMo, known for superior high-temperature performance; and 30CrMnSiA, which adds silicon and manganese for improved fatigue resistance.
Specifications
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Outer Diameter (OD): 3 – 965 mm
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Wall Thickness (WT): 0.5 – 120 mm
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Length: 4 – 12 m (standard); up to 12 m maximum
Chemical Composition
| Grade | C (wt %) | Si (wt %) | Mn (wt %) | P (max) | S (max) | P+S (max) | Cr (wt %) | Mo (wt %) | Ni (max) | Cu (max) |
|---|---|---|---|---|---|---|---|---|---|---|
| 37Mn | 0.34 – 0.40 | 0.10 – 0.30 | 1.35 – 1.65 | ≤ 0.030 | ≤ 0.030 | ≤ 0.055 | ≤ 0.30 | – | ≤ 0.30 | ≤ 0.20 |
| 30CrMo | 0.26 – 0.34 | 0.17 – 0.37 | 0.40 – 0.70 | ≤ 0.030 | ≤ 0.030 | ≤ 0.055 | 0.80 – 1.10 | 0.15 – 0.25 | ≤ 0.30 | ≤ 0.20 |
| 35CrMo | 0.32 – 0.40 | 0.17 – 0.37 | 0.40 – 0.70 | ≤ 0.030 | ≤ 0.030 | ≤ 0.055 | 0.80 – 1.10 | 0.15 – 0.25 | ≤ 0.30 | ≤ 0.20 |
| 42CrMo | 0.38 – 0.45 | 0.17 – 0.37 | 0.50 – 0.80 | ≤ 0.020 | ≤ 0.010 | – | 0.90 – 1.20 | 0.15 – 0.25 | ≤ 0.30 | ≤ 0.20 |
| 30CrMnSiA | 0.28 – 0.34 | 0.90 – 1.20 | 0.80 – 1.10 | ≤ 0.020 | ≤ 0.020 | ≤ 0.030 | 0.80 – 1.10 | ≤ 0.10 | ≤ 0.30 | ≤ 0.20 |
Mechanical Properties
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) |
|---|---|---|---|
| 37Mn | ≥ 750 | ≥ 630 | ≥ 16 |
| 30CrMo | ≥ 930 | ≥ 785 | ≥ 12 |
| 35CrMo | ≥ 980 | ≥ 835 | ≥ 12 |
| 42CrMo | > 1080 | > 930 | > 12 |
| 30CrMnSiA | ≥ 1080 | ≥ 885 | ≥ 10 |
Main Features
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High Strength: Quenched-and-tempered low-alloy steels deliver tensile strengths up to 1 100 MPa and yield strengths up to 930 MPa.
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Excellent Toughness: Impact toughness > 27 J at –50 °C for 42CrMo and similar for other grades, ensuring resistance to cracking under dynamic loads.
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Corrosion Resistance: Alloying elements and controlled heat treatments enhance resistance to corrosive gases and moisture.
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Dimensional Precision: OD tolerances of ± 0.75 – 1.0 mm and WT tolerances of – 10 %/ + 12.5 – 15 % guarantee uniform wall thickness and seamless surface quality.
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Surface Finish: Bright annealed or fine-grain finish minimizes defects such as cracks, delamination, and scarring.
Standards
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GB/T 18248: Seamless steel tubes for gas cylinders and accumulator shells (2021)
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JIS G3429: Japanese standard for seamless steel tubes for gas cylinders
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EN 10297-1: European standard for seamless steel tubes for pressure purposes
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ASTM A372: U.S. specification covering carbon and alloy steel seamless mechanical tubing
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ISO 11120 / ISO 11439 / ISO 9809-1: International standards for gas cylinder design and manufacturing
Application Fields
High Pressure Gas Cylinder Tube are integral to sectors requiring safe, reliable gas storage and transport:
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Automotive CNG Cylinders: On-board natural gas storage at pressures up to 250 bar.
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Medical Oxygen Cylinders: Cylinder manufacturing for hospitals and ambulances, operating at 150 – 200 bar.
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Firefighting Equipment: High-pressure vessels for fire suppression systems, filled with inert gases at 200 – 300 bar.
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SCBA (Self-Contained Breathing Apparatus): Compressed air cylinders for industrial and rescue teams, ensuring consistent supply under demanding conditions.
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Industrial Welding and Cutting: Acetylene and argon cylinders for fabrication shops, requiring precise pressure control and durability.
