HP345 is a high-strength hot-rolled steel grade specifically designed for welded gas cylinders, widely used in manufacturing LPG cylinders, acetylene cylinders, oxygen cylinders, and other high-pressure gas storage containers.
Basic Characteristics of HP345 Gas Cylinder Steel
HP345 is a low-carbon, high-manganese microalloyed steel, produced via controlled rolling (TMCP) or hot rolling to ensure fine grain structure and stable mechanical properties.
Core Features
- High Strength & Safety: Yield strength ≥ 345 MPa, tensile strength ≥ 510 MPa, meeting the high-pressure bearing requirements of gas cylinders.
- Excellent Ductility & Toughness: Elongation ≥ 20%, good low-temperature impact resistance (≥ 27 J at room temperature), preventing brittle fracture.
- Superior Weldability: Low carbon equivalent, suitable for automatic welding and resistance welding, ensuring weld quality and safety.
- Good Formability: Excellent cold bending performance (D=2a), meeting the stamping and deep drawing requirements for cylinder heads and bodies.
- Wide Application Temperature: Suitable for -40°C to 60°C, adapting to various environmental conditions.
Standards & Specifications
- Chinese Standard: GB 6653-2008/2017 (Steel plates and strips for welded gas cylinders)
- Japanese Standard: JIS G 3116 (Hot-rolled steel sheets and strips for high-pressure gas containers)
- Thickness Range: Hot-rolled: 2.0–14.0 mm; Cold-rolled: 1.5–4.0 mm
- Delivery State: Hot-rolled, controlled rolling (TMCP), or heat-treated
Chemical Composition of HP345 Steel
HP345 is carefully alloyed to achieve a balance between strength and weldability:
| Element | Content (%) |
|---|---|
| C | ≤ 0.20 |
| Si | ≤ 0.35 |
| Mn | ≤ 1.50 |
| P | ≤ 0.025 |
| S | ≤ 0.015 |
| Al | ≥ 0.015 |
- Low carbon content improves weldability
- Manganese strengthening enhances mechanical performance
- Low P & S impurities ensure toughness and prevent brittleness
Mechanical Properties of HP345 Gas Cylinder Steel
HP345 delivers excellent mechanical performance required for pressure vessels:
| Property | Value |
|---|---|
| Yield Strength | ≥ 345 MPa |
| Tensile Strength | 510–620 MPa |
| Elongation | ≥ 17% |
| Impact Toughness | Good |
These properties ensure:
- High resistance to internal gas pressure
- Strong anti-deformation capability
- Reliable fracture resistance under stress
Equivalent Grades of HP345
HP345 has corresponding grades in major international standards, facilitating global procurement and application.
| Standard System | Equivalent Grade | Material Number |
|---|---|---|
| Chinese GB | HP345 | - |
| Japanese JIS | SG325 / AE345KR | - |
| European EN | P310NB | 1.0437 |
| German DIN | 17Mn4 | - |
| French NF | Fe E31 KR | - |
| British BS | BS3 | - |
Processing and Manufacturing Features
HP345 steel is typically produced via:
- Converter or electric furnace steelmaking
- Controlled rolling or heat treatment (normalizing)
It can be supplied as:
- Hot-rolled plates
- Steel coils
- Cold-rolled sheets
Its excellent processing properties reduce manufacturing defects such as:
- Cracking
- Wrinkling during forming
Typical Applications of HP345 Gas Cylinder Steel
HP345 is the preferred material for manufacturing various welded gas cylinders due to its comprehensive performance.
- LPG Cylinders: Household and commercial propane/butane cylinders.
- Industrial Gas Cylinders: Acetylene, oxygen, nitrogen, argon, and other high-pressure gas cylinders.
- Special Gas Cylinders: Liquefied chlorine, ammonia, and other corrosive or flammable gas containers.
- Vehicle-Mounted Cylinders: CNG/LNG cylinders for automobiles and ships.
HP345 vs Other Gas Cylinder Steel Grades
Compared to other grades in GB/T 6653:
| Grade | Yield Strength (MPa) | Application Level |
|---|---|---|
| HP295 | ≥295 | Low pressure |
| HP325 | ≥325 | Medium pressure |
| HP345 | ≥345 | Higher pressure |
HP345 stands out due to:
- Higher strength
- Better load-bearing capacity
- Enhanced safety margin
Why Choose HP345 from GNEE Steel?
As a professional supplier of gas cylinder steel, GNEE Steel provides high-quality HP345 products with the following advantages:
- Strict Quality Control: Produced in accordance with GB 6653 and JIS G 3116, with full inspection of chemical composition and mechanical properties.
- Stable Performance: Fine grain structure, uniform thickness, and excellent formability, reducing production defects.
- Customized Service: Available in various thicknesses, widths, and lengths; support for cutting, slitting, and processing.
- Global Supply: Fast delivery, competitive prices, and professional technical support for gas cylinder manufacturers worldwide.
Conclusion
HP345 gas cylinder steel is a high-performance material that perfectly balances strength, ductility, weldability, and safety, making it the first choice for manufacturing high-quality gas cylinders. GNEE Steel's HP345 products meet international standards and are widely recognized by global customers.
What packaging is used for HP345 gas cylinder steel export?
GNEE provides export-standard packaging for HP345 gas cylinder steel, ensuring protection during long-distance shipping.
How does GNEE ensure consistent supply of HP345 gas cylinder steel?
With strong production capacity and supply chain management, GNEE guarantees stable availability of HP345 gas cylinder steel.
Can HP345 gas cylinder steel replace European materials?
Yes, HP345 gas cylinder steel can be engineered to match or exceed equivalent European grades, offering a cost-effective alternative.
What industries use HP345 gas cylinder steel?
HP345 gas cylinder steel is widely used in gas storage, industrial cylinders, energy sectors, and transportation applications.
How does GNEE handle quality issues for HP345 gas cylinder steel?
GNEE provides full traceability and responsive after-sales service to quickly resolve any issues related to HP345 gas cylinder steel.
Why is HP345 gas cylinder steel a reliable choice for global buyers?
HP345 gas cylinder steel combines high strength, excellent formability, consistent quality, and strong technical support, making it a trusted solution for international customers.