Slip-On Flange Carbon Steel — Factory Direct Supplier | Huaxia-Steel
A carbon steel slip-on flange is a ring-shaped flange that slips over the end of a pipe and is welded both on the inside and outside of the flange hub. Slip-on flanges are among the most economical and widely used flange types, favored for their ease of alignment, lower cost, and simpler installation compared to weld neck flanges. Huaxia-Steel supplies carbon steel slip-on flanges in full compliance with ASME B16.5, EN 1092-1, and JIS B2220 standards, available in sizes from 1/2″ to 48″ and pressure classes from 150 to 2500.
Slip-on flanges feature a low hub that allows the pipe to slide into the flange before welding. This design makes them easier to align and install than weld neck flanges, and they require less precise pipe cutting. While they have lower mechanical strength than weld neck flanges under severe cyclic loading, slip-on flanges are perfectly suited for lower-pressure, lower-temperature applications where cost efficiency is a priority.
Product Overview
Carbon steel slip-on flanges from Huaxia-Steel are forged or plate-produced and precision-machined to standard dimensions. The double-weld configuration (inside fillet + outside fillet) provides a reliable seal for general-purpose piping. They are the default choice for water, air, low-pressure steam, and many process lines where the service conditions do not demand the full structural integrity of a weld neck flange.
Specifications & Dimensions
Typical dimensions for ASME B16.5 carbon steel slip-on flanges (raised face):
| Nominal Size | Class 150 OD (mm) | Class 150 Thk (mm) | Class 300 OD (mm) | Class 300 Thk (mm) | Bore (approx, mm) |
|---|---|---|---|---|---|
| 1/2″ (DN15) | 89 | 11.2 | 95 | 14.2 | 22 |
| 1″ (DN25) | 108 | 12.7 | 117 | 17.5 | 35 |
| 2″ (DN50) | 152 | 15.9 | 165 | 22.2 | 61 |
| 4″ (DN100) | 229 | 19.0 | 254 | 30.2 | 114 |
| 6″ (DN150) | 279 | 22.2 | 318 | 39.7 | 168 |
| 8″ (DN200) | 343 | 25.4 | 381 | 47.6 | 219 |
| 12″ (DN300) | 483 | 31.8 | 559 | 66.7 | 324 |
The bore is slightly larger than the pipe outside diameter to allow the pipe to slip in freely. Standard slip-on flanges have a hub height of approximately 16mm for Class 150.
Weight Reference (Approximate)
| Size | Class 150 (kg) | Class 300 (kg) | Class 600 (kg) |
|---|---|---|---|
| 2″ (DN50) | 2.2 | 3.9 | 5.8 |
| 4″ (DN100) | 5.8 | 10.5 | 17.5 |
| 6″ (DN150) | 10.5 | 21.0 | 35.0 |
| 8″ (DN200) | 16.0 | 34.0 | 58.0 |
Available Carbon Steel Grades
| Grade | Standard | Yield (min MPa) | Tensile (min MPa) | Temperature Range | Application |
|---|---|---|---|---|---|
| A105 | ASTM A105 | 250 | 485 | -29°C to 425°C | General service |
| A350 LF2 | ASTM A350 | 250 | 485 | -46°C to 425°C | Low-temperature |
| A516 Gr.70 | ASTM A516 | 260 | 485 | -46°C to 425°C | Pressure vessel |
| Q235B | GB/T 700 | 235 | 370 | Ambient | Structural |
| S235JR | EN 10025 | 235 | 360 | Ambient | European structural |
Manufacturing Standards
Our carbon steel slip-on flanges conform to:
Slip-On vs Weld Neck Flange
| Feature | Slip-On Flange | Weld Neck Flange |
|---|---|---|
| Cost | Lower (20–30% less) | Higher |
| Installation | Easy, forgiving alignment | Requires precise pipe fit-up |
| Welds Required | 2 (inside + outside fillet) | 1 (full penetration butt weld) |
| Strength | Moderate | High (handles stress/cycling) |
| Best For | Low-pressure, general service | High-pressure, cyclic loading |
| Pipe Cutting | Less precise required | Precise square cut needed |
Applications
Carbon steel slip-on flanges are ideal for:
- Water and wastewater systems — low-pressure distribution lines
- HVAC and building services — chilled water, heating loops
- Air and gas lines — non-critical utility piping
- Fire protection systems — sprinkler and hydrant mains
- Low-pressure process piping — where weld neck is not required
- Maintenance and retrofit — easy field installation
- Irritating but non-hazardous services — where leak-tightness is moderate priority
Quality Assurance
Our quality control program ensures every slip-on flange meets specification:
Packaging & Shipping
- Anti-rust oil on all machined surfaces
- Individual wrap or grouped with VCI protection
- Seaworthy wooden cases or pallets with steel strapping
- Detailed packing list with heat traceability
- Expedited and standard lead times: 15–30 days
We ship worldwide under FOB, CIF, CFR, or DAP terms with complete export documentation including commercial invoice, packing list, certificate of origin, and MTC.
Why Choose Huaxia-Steel
- Factory-direct pricing with full quality assurance
- Complete inventory of common sizes and classes
- Certified materials with EN 10204 3.1 documentation
- MOQ from 1 ton, mixed-size orders welcome
- Third-party inspection support
- Fast global delivery with proper export paperwork
Get a competitive quote on carbon steel slip-on flanges. Contact Huaxia-Steel with your specifications—size, class, facing, grade, and quantity—and receive a detailed offer within 24 hours.
