Product Overview
The more we work with HP235 gas cylinder steel, the more we realize it’s not a material that tries to stand out — but it performs in a very steady way.
In gas cylinder and pressure vessel production, many buyers initially look for higher strength grades. But after real production experience, a lot of them come back to HP235. Not because it is the strongest option, but because it behaves more predictably during forming and processing. It is easier to control, especially in stamping and welding.
From what we see in actual projects, HP235 is often used in standard gas cylinders and storage vessels where consistency matters more than pushing mechanical limits. It doesn’t feel “aggressive” in processing — it is stable, and that matters on a production line.
In this kind of application, the real concern is rarely just strength on paper. What matters more is whether the material stays consistent from batch to batch, and whether it behaves the same way every time you run it through production. HP235 tends to give that kind of reliability.
Over time, we’ve noticed that customers choosing HP235 are usually not experimenting anymore — they already know their process. What they need is a material that won’t interrupt it.
If you are looking at HP235, chances are you are not just comparing specifications. You are trying to make production more stable, more predictable, and easier to manage.
📖 Grade Explanation | HP Series Naming Rules
🔍 The steel grade consists of the first letters "HP" from the Chinese Pinyin of "Welded Cylinder" and the lower yield strength minimum value.
Example: HP235 → "HP" stands for welded gas cylinder steel; "235" represents the minimum lower yield strength of 235 MPa.
✅ This standard includes grades HP235, HP265, HP295, HP325, HP345. HP235 offers excellent comprehensive mechanical properties and weldability, making it the main material for conventional welded gas cylinders.
※ According to GB/T 6653-2017 standard, chemical composition and mechanical properties strictly comply with Table 1 and Table 2.
🌍 Grade Comparison | International Standard Comparison
Comparison of chemical composition between Chinese welded gas cylinder steel HP235 and European pressure vessel steels P245NB and P265NB:
HP235
GB/T 6653-2017 (China)
- Carbon (C) max ≤0.16%
- Silicon (Si) ≤0.10% *
- Manganese (Mn) max ≤0.80%
- Phosphorus (P) max 0.025%
- Sulfur (S) max 0.012%
- Aluminum (Al) min ≥0.015%
- Nb+V max ≤0.12%
※ For thickness ≥6mm, Si ≤0.35%; Yield strength ≥235MPa
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P245NB
EN 10207 (EU)
- Carbon (C) max ≤0.16%
- Silicon (Si) max ≤0.40%
- Manganese (Mn) max ≤0.80%
- Phosphorus (P) max 0.025%
- Sulfur (S) max 0.015%
- Aluminum (Al) total ≥0.020%
- Nb+Ti ≤0.05%
🔹 Yield strength ≥245MPa, can be substituted for HP235 with similar performance
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P265NB
EN 10207 (EU)
- Carbon (C) max ≤0.18%
- Silicon (Si) max ≤0.40%
- Manganese (Mn) max ≤1.00%
- Phosphorus (P) max 0.025%
- Sulfur (S) max 0.015%
- Aluminum (Al) total ≥0.020%
- Nb+Ti ≤0.05%
⚡ Yield strength ≥265MPa, suitable for medium to high pressure gas cylinders
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📌 Note: HP235, P245NB, and P265NB are all fine-grained killed steels. We can provide alternative solutions and dual-certified mill test certificates upon request.
🔧 Customizable Services
Full flexible production to meet engineering and special gas cylinder requirements:
- ✓ Custom dimensional tolerances (exceeding GB/T 708, GB/T 709)
- ✓ Delivery condition: Oiled / Pickled / Black surface
- ✓ Custom length and width slitting, cut-to-length
- ✓ Additional ultrasonic testing (UT)
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- ✓ Yield ratio ≤0.80 control (upon request)
- ✓ -40°C low-temperature impact test instead of room temperature
- ✓ High-standard non-metallic inclusion control
- ✓ Small batch sample orders, minimum lead time 35-45 days
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📏 Available Dimensions
🔥 Hot Rolled Steel Plates/Strips
Thickness: 2.0~14.0mm
Width: 800~2000mm |
❄️ Cold Rolled Steel Plates/Strips
Thickness: 1.5~4.0mm
Width: 800~1800mm
Annealed condition |
✂️ Tolerance Standards
GB/T 709 (Hot Rolled)
GB/T 708 (Cold Rolled) |
🎯 Special Dimensions
Length ≤12m custom cut
Width slitting ≥50mm |
※ Steel strip inner diameter 508/610mm, export packaging available. Regular stock thickness: 2.5/3.0/4.0/5.0/6.0/8.0/10.0mm.
🧪 Chemical Composition (Ladle Analysis, %)
| Grade |
C |
Si |
Mn |
P≤ |
S≤ |
Nb≤ |
V≤ |
Ti≤ |
Nb+V≤ |
Alt≥ |
| HP235 |
≤0.16 |
≤0.10* |
≤0.80 |
0.025 |
0.012 |
0.05 |
0.10 |
0.06 |
0.12 |
0.015 |
| *For thickness ≥6mm, Si ≤0.35%; Residual elements Cr, Ni, Mo ≤0.30%, Cu ≤0.20%. |
⚙️ Mechanical Properties & Process Performance
| Grade |
Lower Yield Strength (MPa) ≥ |
Tensile Strength (MPa) |
A(L₀=80mm)% ≥ |
A(L₀=50mm)% ≥ |
180° Bend Test |
| HP235 |
235 |
380~520 |
23 |
29 |
D=1.5a |
❄️ Charpy V-Notch Impact Properties
| Grade |
Specimen Size (mm) |
Room Temperature KV₂ (J) ≥ |
-40°C Impact (Optional) |
| HP235 |
10×5×55 (for thickness 6~8mm) |
23 |
18 (upon request) |
Impact test results average of three specimens meets standard, one individual value allowed below requirement but not less than 70%. Tensile and bend tests use transverse specimens.
🏭 Application Areas
LPG Welded Cylinders Refrigerant Tanks (R134a, R600a) Fire Extinguisher Cylinders Industrial High-Pressure Cylinders Hydrogen/Natural Gas Storage Cylinders CNG Cylinders
Chinese grade HP235 offers excellent cold forming and weldability, making it the ideal material for non-refillable welded cylinders and refillable gas cylinders, meeting EN 10207 (EU) pressure vessel standards.
❓ Frequently Asked Questions (FAQ)
1. Is HP235 steel suitable for deep drawing?
Yes, HP235 has high elongation (A80≥23%), bend test D=1.5a, making it suitable for cylinder head stamping and shell welding.
2. What are the differences between HP235 and European grades P245NB/P265NB?
HP235 has similar composition to P245NB, with slightly lower yield strength but comparable process performance; P265NB offers higher strength. We can supply all three grades and provide substitution recommendations.
3. What is the minimum order quantity? Lead time for custom dimensions?
Standard MOQ is 20 tons, trial orders negotiable from 5 tons. Custom dimension delivery: approximately 35-55 days.
4. Can you provide MTC and third-party inspection?
Yes, we can provide EN10204 3.1 mill test certificates and support third-party inspections such as SGS/BV before shipment.
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Standard: GB/T 6653-2017
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