PLSteel Pipe FlangesPlate Flange (PL)
Flat-type flange with simple structure, light weight and low cost — ideal for low-pressure pipeline systems.
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Lap Joint Flange (LJ)
Loose flange with stub end — convenient disassembly for large-diameter, low and medium pressure systems.
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LJSteel Pipe Flanges
Overview
Lap Joint Flange (LJ), also known as Loose Flange, is composed of a flange ring and a stub end (lap joint short section). The flange ring is loosely sleeved on the stub end, which is welded to the pipe, and the flange ring is connected by bolting. It offers convenient disassembly, low cost, and no damage to the pipe during maintenance — ideal for large-diameter systems requiring frequent inspection.
Size Range
2" – 80"
Pressure Class
Class 150 – 600 / PN10 – PN40
Key Features
- Two-piece design: loose flange ring + stub end
- Quick disassembly without damaging pipe weld
- Cost-effective for large nominal sizes
- Adapts to slight pipeline misalignment
- RF and FF sealing surfaces
Benefits
- Flange ring rotates for easy bolt-hole alignment
- Economical replacement of worn rings only
- Ideal for lined or coated pipe systems
Specifications
| Standards | GB/T 9118, ASME B16.5, EN 1092-1, DIN 2501 |
| Pressure Ratings | Class 150, 300, 600 / PN10 – PN40 |
| Nominal Diameter | DN50 – DN2000 (NPS 2" – 80") |
| Working Temperature | -20°C – 450°C |
| Components | Flange ring + lap joint stub end |
Applications
Petroleum and petrochemicalNatural gas and water treatmentMarine and offshore pipingSystems requiring frequent maintenance access
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Standards
- • ISO 7005
- • ASME B16.5
- • EN 1092-1
- • DIN 2501
- • JIS B2220
- • GB/T 9115–9119
- • HG/T 20592
Materials
- • Carbon Steel: A105, 20#, Q235B, A234 WPB
- • Stainless Steel: 304, 304L, 316, 316L, 321
- • Alloy Steel: 16Mn, F11, F22, 15CrMo
- • Duplex & Super Duplex: F51, F53, 2205
- • Special alloys: Monel, Hastelloy, Titanium (on request)
Related Products
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Sleeve-type flange slipped over the pipe and fixed by fillet welding — economical for medium and low pressure systems.
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WNSteel Pipe FlangesWelding Neck Flange (WN)
High-pressure flange with tapered neck and butt-weld connection — the standard for critical HPHT service.
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