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● Hybrid sealing face design: This is the most distinctive feature of flat raised face flange. The center area of the sealing face is slightly raised (similar to RF), but the outer area extends to the bolt holes (similar to FF). Benefits include: 1. Automatic gasket centering for faster installation; 2. More uniform sealing contact stress distribution, avoiding edge overload of traditional RF; 3. Compatible with both full-face gaskets and raised face gaskets, providing flexible on-site replacement.
● 65% increase in bending strength: The bionic honeycomb structure makes the flange lighter and stiffer, especially suitable for withstanding pipeline bending moments.
● Ultra-high pressure bearing: DN300 burst pressure of 42MPa is 2.8 times that of traditional flanges (≤15MPa). Cyclic fatigue life of 20,000 cycles at 35MPa far exceeds industry standards.
● Extreme environment tolerance: -70°C impact energy of 89J, 5,000m deep-sea corrosion rate of 0.03mm/year, 120m/s sand and dust abrasion ≤8μm.
● Intelligent safety: Nano-zirconia wear indicator layer (color change warning when thickness <0.1mm) + double-conical bolt hole (preload attenuation ≤5%).
● Sealing face machining: CNC precision turning is used, with the raised height following ASME B16.5 standard RF dimensions (1.6mm to 6.4mm for Class 150~1500), but the raised root smoothly transitions to the entire flange face. Surface roughness Ra ≤3.2μm ensures good gasket contact.
● Gradient quenching: High-carbon steel undergoes controlled cooling to form a graded structure with surface hardness 45-50 HRC and core toughness ≥30J (at -70°C).
● Honeycomb structure: Bionic hexagonal grid inside the flange body, optimized by finite element analysis, provides 65% higher stiffness at the same weight.
● Titanium alloy reinforcement ring: A Ti-6Al-4V ring (yield strength 1,250MPa) is embedded in the neck with interference fit, preventing neck expansion under high pressure.
● Quality control: 100% dimensional inspection, 10% magnetic particle testing, random burst testing per batch. Traceable material certificates and heat treatment curves are provided.
The hybrid sealing face design of flat raised face flange makes it particularly suitable for the following scenarios:
| Scenario | Pain point with traditional flanges | Solution with this product |
|---|---|---|
| Old pipeline retrofitting | Original system may mix FF and RF flanges, gaskets not interchangeable | Hybrid sealing face is compatible with both gasket types, no pipeline modification needed |
| High-pressure gas media | RF flange gaskets may extrude under pressure pulsation | The outer flat area provides additional support, preventing gasket creep |
| Large-diameter low-pressure pipelines | FF flanges require full-size gaskets, high cost | The raised portion allows use of standard RF gaskets, reducing spare parts inventory |
| Deep-sea / polar environments | Single sealing face leaks after thermal cycling | Dual-zone sealing (raised + flat) provides redundant sealing paths |
Specific application areas include:
● Shale gas fracturing pump outlet pipelines (35-70MPa pulsating pressure)
● Deep-sea drilling platform wellhead connections (5,000m water depth)
● LNG receiving terminals (-70°C low temperature)
● Offshore Christmas tree acidic media pipelines (H₂S/CO₂)
● Free samples: International buyers can apply for one free sample (sample fee refundable, freight collect) for installation testing and sealing verification.
● Installation guidance: Chinese/English installation manuals are provided, including torque values for different gasket materials (graphite, spiral wound, PTFE). Remote video guidance is available.
● Technical consulting: The engineering team responds to selection and gasket matching questions within 4 hours.
● Quality traceability: Each flange has a unique ID, and test reports can be checked on the official website.
● Warranty: 18 months, free replacement for manufacturing defects.
● Third-party testing: SGS/BV on-site witnessed pressure testing can be arranged upon request.
1. Unique sealing face design: Most flanges on the market are either pure FF or pure RF. Our flat raised face flange allows you to obtain both the stress uniformity of FF and the sealing reliability of RF without changing the gasket type. It is especially suitable for retrofit projects where the original pipeline may be either FF or RF – this product is compatible with both.
2. Full life cycle cost advantage: 30-year total cost is only $6,200, saving 66% compared to traditional flanges at $18,500. Single replacement time is 2.5 hours (traditional 8 hours), annual maintenance frequency is 0.7 times (traditional 3.2 times).
3. Complete certification: API 6A PSL 3G, suitable for ultra-high pressure scenarios with H₂S and CO₂ gas media.
4. Verifiable real data: All performance indicators are available for customer witnessed on-site testing. Free samples are provided.
5. Fast response: Standard items ship within 3 days, custom items within 15-30 days.
Summary: Longan's flat raised face flange, with its hybrid sealing face design, solves the pain points of traditional flanges in gasket compatibility, stress distribution, and high-pressure sealing. Combined with the bionic honeycomb structure, gradient quenching, and titanium alloy reinforcement ring, its bending strength, burst pressure, and fatigue life are greatly improved. The API 6A PSL 3G certification and 66% reduction in 30-year full life cycle cost make it an ideal choice for shale gas, deep-sea engineering, and complex pipeline systems. Send your requirements to obtain free samples and professional sealing solutions.
Q: Can flat raised face flange replace an existing RF flange?
A: Yes. As long as the pressure rating and size match, it can directly replace an RF flange, and the original RF gasket can continue to be used. If the mating flange is FF, a full-face gasket is required, but the flat area of this product is large enough to be fully compatible.
Q: Does this hybrid sealing face require special gaskets?
A: No. You can continue to use standard ASME B16.21 RF gaskets (e.g., spiral wound with inner ring) or FF gaskets (full-face graphite gaskets). Our tests show that the sealing performance of both gasket types on this flange is superior to traditional single sealing faces.
Q: Will bolts loosen under 35MPa pulsating pressure?
A: This product uses double-conical bolt holes. Under 35MPa fluctuation, preload attenuation is ≤5%, while traditional round holes have attenuation ≥20%. It is recommended to use a hydraulic torque wrench in a cross pattern with three steps. We can provide a torque calculation table.
Q: Can different materials be provided, such as stainless steel?
A: Yes. The standard material for this product is gradient quenched high-carbon steel, but 316L, duplex stainless steel, etc., can also be provided upon request. The same honeycomb structure and titanium alloy reinforcement ring apply to stainless steel as well.
Q: How can we verify your claimed 42MPa burst pressure?
A: We welcome customers to witness burst tests at our factory. Regular stock products are randomly sampled every quarter, and test reports are stored on our website. You may also request a separate test on your sample; the cost is borne by us (the sample needs to be returned).
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NO. 620, MINGZHU ROAD, YONGXING STREET, LONGWAN DISTRICT, WENZHOU CITY, ZHEJIANG PROVINCE, CHINA.
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