Plate Flange (PL)
Flat-type flange with simple structure, light weight and low cost — ideal for low-pressure pipeline systems.
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Slip On Flange (SO)
Sleeve-type flange slipped over the pipe and fixed by fillet welding — economical for medium and low pressure systems.
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SOSteel Pipe Flanges
Overview
Slip On Flange (SO) is a widely used flange type with a sleeve structure, which is sleeved on the pipe and fixed by fillet welding. It has the advantages of simple structure, easy alignment, low cost and convenient installation, and is suitable for medium and low pressure pipeline systems. As a versatile flange type, it is widely used in various industrial and civil pipeline systems and general export projects worldwide.
Size Range
½" – 56" (DN15 – DN1400)
Pressure Class
Class 150 – 600 / PN10 – PN40
Key Features
- Easy installation and alignment — sleeve design slips over pipe before fillet welding
- Cost-effective — simpler manufacturing than weld neck for medium and low pressure
- Good sealing performance — precision-machined face with gasket under rated pressure
- Wide compatibility — water, gas, oil and general chemicals at normal to medium temperature
- Global standard compliance — ISO, ASME, DIN, EN, JIS and GB manufacturing
- Sealing surfaces: RF, FF and MFM
- Carbon, stainless and alloy grades available
Benefits
- Lower cost than weld neck flanges for equivalent pressure class
- Simple field alignment before welding
- Proven gasket sealing for medium and low pressure service
- Customized per customer drawings, materials and standards
Specifications
| Standards | ISO 7005, ASME B16.5, DIN 2501, EN 1092-1, JIS B2220, GB/T 9116, HG/T 20592, HG/T 20615 |
| Materials | Carbon steel (A105, 20#, Q235B), stainless steel (304, 316L), alloy steel (16Mn, 15CrMo) — customizable per medium and conditions |
| Pressure Ratings | Class 150, 300, 600 / PN10, PN16, PN25, PN40 |
| Nominal Diameter | DN15 – DN1400 (NPS ½" – 56") |
| Sealing Surface | RF (Raised Face), FF (Flat Face), MFM (Male-Female Face) |
| Working Temperature | -40°C – 450°C (special grades on request) |
| Connection | Slip over pipe OD, fixed by fillet weld |
Applications
Petroleum and petrochemical (low and medium pressure)Natural gas distribution (low pressure)Water supply and drainageHVAC and chemical engineeringFood and beverage processingGeneral industrial and civil pipeline systems
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Standards
- • ISO 7005
- • ASME B16.5
- • DIN 2501
- • EN 1092-1
- • JIS B2220
- • GB/T 9116
- • HG/T 20592
- • HG/T 20615
Materials
- • Carbon Steel: A105, 20#, Q235B
- • Stainless Steel: 304, 316L
- • Alloy Steel: 16Mn, 15CrMo
Related Products
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Loose flange with stub end — convenient disassembly for large-diameter, low and medium pressure systems.
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Socket Weld Flange (SW)
Socket bore flange with fillet weld — compact and reliable for small-bore, high-pressure systems.
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