1.7220 34CrMo4 Alloy Steel | Seamless High-Pressure Gas Cylinders

Gnee Steel (Tianjin) Co., Ltd. is one of the most professional 1.7220 34crmo4 alloy steel | seamless high-pressure gas cylinders manufacturers and suppliers in China. Welcome to wholesale customized 1.7220 34crmo4 alloy steel | seamless high-pressure gas cylinders at competitive price from our factory. Good service and quality products are available.

 

34CrMo4 (1.7220) is a chromium-molybdenum alloy steel specifically engineered for the manufacturing of seamless high-pressure gas cylinders and pressure vessels. As one of the most widely certified materials in the gas cylinder industry, 34CrMo4 offers an exceptional combination of high strength, excellent toughness, and superior hardenability, making it the global standard for CNG cylinders, industrial gas storage, and fire extinguisher bodies.

 

This material is fully compliant with multiple international standards including EN 10083-3, GB/T 18248, and ISO 9809-1, ensuring global acceptance for pressure equipment applications.

 

Material Equivalents:

Standard	Grade
AISI/SAE	4130
DIN	1.7220 / 34CrMo4
JIS	SCM435
GB	30CrMo / 35CrMo
BS	CDS110

 

 

Element	Content (%)
C	0.30 – 0.37
Si	0.10 – 0.40
Mn	0.60 – 0.90
Cr	0.90 – 1.20
Mo	0.15 – 0.30
P	≤ 0.025
S	≤ 0.025

Alloying elements enhance strength, wear resistance, and hardenability

 

 

 

Property	Value
Yield Strength	≥ 850 MPa
Tensile Strength	900 – 1100 MPa
Elongation	≥ 12%
Impact Energy	≥ 35 J (room temperature)

✔ Ideal for high-pressure and safety-critical applications

 

 

Step	Temperature	Cooling Method
Quenching	830-870°C	Oil or Water
Tempering	530-630°C	Oil or Water

 

Heat Treatment: To achieve the best properties (high strength and toughness), the steel requires proper quenching and tempering.

 

Manufacturing: The pipes are commonly produced via cold drawing or hot rolling to ensure a seamless structure for high-pressure applications.

 

Safety & Compliance: Manufacturers must follow strict safety standards regarding heat treatment and non-destructive testing to ensure safety in high-pressure environments.

 

Equivalents: 34CrMo4 is often equivalent to AISI/SAE 4135 (USA) or 35CD4 (France).

 

 

 

 

High Tensile Strength: Minimum tensile strength of 980 MPa with yield strength ≥835 MPa, providing exceptional pressure-bearing capacity for cylinders operating at 20-30 MPa.

 

Superior Low-Temperature Toughness: Maintains impact energy ≥27J at -50°C, crucial for cylinders operating in extreme cold environments.

 

Excellent Hardenability: Chromium and molybdenum alloying elements ensure uniform through-hardening even in thick-walled cylinders (up to 55mm wall thickness).

 

Proven Fatigue Resistance: Extensive industry validation shows excellent performance under cyclic pressurization over 15+ years of service life.

 

Superior Formability: Optimized for hot drawing and flow forming processes, enabling production of large-diameter seamless cylinders with uniform wall thickness.

 

 

 

Available Product Forms

📌 Seamless Steel Tubes (for cylinders)

Outer Diameter: 140 mm – 426 mm

Wall Thickness: 5 mm – 60 mm

Length: ≤ 12 m

 

📌 Round Bars / Forgings

Diameter: 20 mm – 500 mm

✔ Custom dimensions available based on cylinder design

 

 

Manufacturing Process Compatibility

Process	Recommended Form	Key Considerations
Hot Drawing + Flow Forming	Seamless Tube	Best for large-diameter, thin-wall cylinders; achieves superior grain refinement
Hot Extrusion + Cold Drawing	Seamless Tube	Suitable for smaller diameters; tighter dimensional tolerances
Hot Rotary Forging	Billet + Formed	For seamless cylinders without longitudinal welds

 

Cylinder Type & Application

 

For CNG Cylinders (20-30 MPa):

Require strict inclusion control (A/B/C/D ≤1.0) to prevent fatigue failure

Low-temperature impact testing at -50°C is essential

Wall thickness typically 4-7mm for 50L cylinders

 

For Industrial Gas Cylinders (150-300 bar):

Higher strength requirements → confirm tensile ≥980 MPa

Consider 35CrMo/30CrMo for cost-sensitive applications

Ensure compliance with transport regulations (UN, DOT, etc.)

 

For Fire Extinguishers:

Specific material approval required per GB 4351 (34CrMo4 explicitly listed)

Thread specification: PZ27.8 tapered thread for steel cylinders

 

 

 

Size & Dimension Selection

Small Diameter (50-140mm OD): Cold drawn tubes offer better surface finish and tighter tolerances

Large Diameter (140-325mm OD): Hot rolled or hot expanded tubes are more cost-effective

Heavy Wall (>20mm): Verify hardenability; may require water quenching

 

 

Certification Requirements

Certificate	When Required
EN 10204 Type 3.1	Standard mill certificate for EU/International
EN 10204 Type 3.2	Third-party inspection (SGS, BV, Lloyd's) for critical applications
ISO 9809-1	Required for gas cylinder manufacturing worldwide
DOT-3AA / 3AAX	For cylinders entering US market

 

 

 

34CrMo4 is the preferred material for the following high-pressure applications:

 

CNG (Compressed Natural Gas) Cylinders

Vehicle-mounted fuel cylinders (Type I and Type II)

Requires high strength-to-weight ratio and excellent fatigue resistance

Certified to ISO 11439, GB 17258, NGV2 standards

 

Industrial Gas Cylinders

Oxygen, Nitrogen, Argon, CO₂, Hydrogen storage

Operating pressures from 150 bar to 300 bar

Seamless construction ensures zero leakage risk

 

Fire Extinguishers

CO₂ fire extinguisher bodies

Portable and wheeled extinguishers

Compliant with GB 4351, EN 3 standards

 

Accumulator Housings

Hydraulic accumulators for energy storage systems

High-cycle fatigue applications

 

Scuba Tanks

Diving air cylinders requiring lightweight and corrosion resistance

 

  

 

 

 

 

 

 

Grade	Type	Strength Level	Application
P265NB	Carbon steel	Low	LPG cylinders
HP295	Carbon steel	Medium	Welded cylinders
34CrMo4	Alloy steel	High	Seamless high-pressure cylinders

34CrMo4 is the best choice for high-pressure, safety-critical cylinders

 

 

Mill-Direct Supply – Competitive pricing with consistent quality control

Large Inventory – Ready-to-ship stock for standard sizes (OD 60-325mm, WT 3-20mm)

Custom Processing – Precision cutting, beveling, heat treatment, and surface finishing

Global Shipping Experience – Proven export record to 30+ countries including India, Vietnam, Indonesia, Nigeria, Brazil

Technical Support – Metallurgical engineering team available for application guidance

 

Packaging & Delivery

• Bundled with steel straps
• Anti-rust oil coating
• Export seaworthy packing
• ⏱ Delivery Time: 15–35 days
• 🚢 Shipping: Container / Bulk vessel

 

  

 

 

 

Contact now to get the request free sample & technical support

 

 

 

What is the material equivalent of 1.7220?

General Introduction to the 35CD4 Steel Alloy.From a standards perspective, 35CD4 (AFNOR, with specification AIR 9160/C) is also referred to as 34CrMo4 (EN 10083-3) or 1.7220 (WNr) in Germany. In the United States, its equivalent is 4135 (AISI/SAE).

 

 

What is 34CrMo4 material?

Steel grade 34CrMo4 is an alloy steel intended for quenching and tempering and produced according to the requirements of ISO 683-2 and EN 10083-3.

 

What is the ASTM equivalent of 34CrMo4?

The nearest equivalents are 34CrMo4 in EN10083-3 or 4130 in ASTM A29 with some deviations. The material is delivered as rolled or annealed.

 

Why is 34CrMo4 better than carbon steel for cylinders?
It offers significantly higher strength and fatigue resistance, making it suitable for high-pressure applications.

 

Is heat treatment necessary?
Yes, quenching and tempering are essential to achieve required mechanical properties.

 

Can it be used for hydrogen cylinders?
Yes, but additional testing (e.g., hydrogen embrittlement resistance) may be required.

 

What standards does it comply with?
EN 10083-3 and can meet ISO cylinder manufacturing standards.

 

Do you support customized production?
Yes, we provide tailor-made sizes and technical support.

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