Product Overview & Specification Matrix
Industrial gas distribution and mobile power systems require predictable structural integrity, controlled fatigue life, and strict compliance with high-pressure containment codes. These welded steel high-pressure LPG cylinders are engineered for continuous commercial deployment, fleet industrial forklifts, and high-draw withdrawal systems. Fabricated from killed carbon steel and low-alloy steel, each cylinder undergoes thermal stress relief and destructive hydrostatic testing to withstand cyclic operating pressures.
Technical Specification Table
|
Model |
Water Capacity (L) |
Nominal Tare Weight (kg) |
Working Pressure (MPa) |
Test Pressure (MPa) |
Min. Wall Thickness (mm) |
Material Grade |
Thread Standard |
Design Standard |
|
HP-LPG-20 |
47.6 |
18.5 |
2.1 |
3.2 |
2.5 |
HP325 / SG295 |
POL / W21.8 x 1/14 |
ISO 4706 / EN 1442 |
|
HP-LPG-35 |
83.2 |
29.0 |
2.1 |
3.2 |
2.8 |
HP325 / 34CrMo4 |
CGA 510 / W21.8 |
ISO 4706 / DOT-4BA |
|
HP-LPG-50 |
118.0 |
41.5 |
2.5 |
3.75 |
3.2 |
34CrMo4 |
3/4-14NGT |
ISO 11119 / DOT |
Material & Manufacturing Process
Mechanical durability relies on strictly controlled metallurgy and repeatable automated fabrication workflows.
Raw Material Verification: Deep-drawn or roll-formed from killed steel coils accompanied by certified mill test certificates (MTC), verifying controlled carbon, manganese, and sulfur limits alongside minimum yield strength.
Automated Seam Welding: Longitudinal and girth joints are welded using automated Submerged Arc Welding (SAW) and Gas Metal Arc Welding (GMAW) robotics to achieve full root penetration and eliminate operator-induced defects.
Thermal Normalizing: Post-weld heat treatment (PWHT) in continuous roller-hearth furnaces removes residual internal stresses generated during cold-forming and welding, uniforming the steel micro-structure.
Surface Preparation & Coating: External shells undergo mechanical shot blasting to achieve an SA 2.5 profile, followed by electrostatic application of an epoxy-polyester powder coating cured at 200°C for environmental corrosion resistance.
Quality Control & Mandatory Testing
Every production lot undergoes destructive and non-destructive examination (NDE) per international pressure vessel codes:
Hydrostatic Burst Testing: Representative samples from each 200-piece batch are pressurized to failure to record volumetric expansion limits and verify rupture thresholds.
Radiographic Examination: 100% X-ray inspection on critical girth and longitudinal welds to detect sub-surface porosity, inclusions, or micro-cracks.
Pneumatic Leak Testing: Conducted under 1.76 MPa air-water bath parameters post-valve insertion to verify thread seal integrity.
Mechanical Coupon Testing: Tensile, bend, and Charpy V-notch impact evaluations performed on designated test coupons from the same heat of steel.
Application Guide & Selection Criteria
Matching cylinders to specific industrial setups prevents pressure starvation and premature hardware wear.
Forklift Propulsion (Liquid & Vapor Withdrawal): Requires internal dip-tubes and secure mounting collars. Engineered to endure continuous dynamic vibration under vehicular operation.
Commercial Kitchens & Multi-Burner Skids: High continuous evaporation demands. Manifold configurations utilizing 50L cylinders prevent operational pressure drops caused by rapid liquid vaporization cooling.
Harsh Industrial Environments: Chemical plants or coastal facilities require upgraded exterior coatings and 34CrMo4 alloy specifications to mitigate stress corrosion cracking.
Compliance & Certifications
Export compliance meets statutory international design and manufacturing directives:
ISO 4706: Refillable welded steel cylinders for liquefied petroleum gas (LPG).
EN 1442: Transportable refillable welded steel cylinders for LPG.
DOT-4BA / 4BW: U.S. Department of Transportation specifications for welded steel cylinders.
TPED (2010/35/EU): Transportable Pressure Equipment Directive conformity for European distribution via notified body oversight.
Third-Party Inspection: Inspection reports issued by SGS, Bureau Veritas, or TÜV available per shipment.
Frequently Asked Questions
Q: What is the standard minimum wall thickness, and how do you prevent thinning during deep-drawing?
A: Minimum wall thickness ranges from 2.5 mm to 3.2 mm depending on the model. Ultrasonic thickness gauges monitor wall profiles in real time across the shoulder, sidewall, and base zones during the deep-drawing operation to prevent localized thinning below design thresholds.
Q: Can you customize collar stampings, color codes, and valve threads for target regional markets?
A: Yes. Stamped data on the steel collar (tare weight, water capacity, serial number, test pressure) and neck threads (POL, W21.8, CGA 510, G5/8) are configured to destination standards. Custom corporate powder coat colors and silk-screened safety markings are supported.
Q: What is the standard production lead time and minimum order quantity (MOQ) for custom OEM orders?
A: Standard production lead time is 30 to 45 days following artwork approval and deposit receipt. The minimum order quantity is typically one 20-foot container (200 to 500 units depending on cylinder volume) to optimize ocean freight logistics.
Q: What documentation is provided with each commercial shipment?
A: Shipments include the Manufacturer's Data Report (MDR), raw steel Mill Test Certificates (MTC), batch hydrostatic test reports, valve conformity certificates, and third-party inspection documentation (SGS/TÜV) when specified.
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