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Lap Joint Stub Ends for Flanged Connections in Piping Systems
Krishna Forge manufactures high-quality butt weld stub ends designed for lap joint flanged connections in piping systems. Our stub ends provide cost-effective solutions for flanged connections while allowing easy alignment and disassembly for maintenance.
Size Range: 1/2" to 24"
Wall Thickness: Schedule 10 to XXS
Types: Type A, B, C
Pressure Class: 150 to 1500
Face Types: Flat Face, Raised Face
Pattern: Long & Short
Comprehensive range of stub end designs for various flange connections
MSS SP-43 Type A stub ends are machined to match the dimensions of lap joint flanges. Most commonly used type.
MSS SP-43 Type B stub ends have a straight hub and are used with slip-on flanges for specific applications.
MSS SP-43 Type C stub ends have a tapered hub and are used for special applications requiring tapered connections.
Extended length stub ends that provide additional space for insulation, painting, or special requirements.
Standard length stub ends for general applications where space is not a constraint.
Manufactured in various materials for diverse industrial requirements
| Material Grade | Standards | Applications | Temperature Range | Features |
|---|---|---|---|---|
| Carbon Steel A403 WPB, WPC |
ASTM A403, MSS SP-43 | General industrial applications | -20°C to 425°C | Economical, weldable |
| Stainless Steel 304/304L ASTM A403 WP304/304L |
ASTM A403, MSS SP-43 | Food, pharmaceutical industries | -196°C to 800°C | Corrosion resistant |
| Stainless Steel 316/316L ASTM A403 WP316/316L |
ASTM A403, MSS SP-43 | Marine, chemical industries | -196°C to 800°C | Enhanced corrosion resistance |
| Alloy Steel A403 WP5, WP9, WP11 |
ASTM A403, MSS SP-43 | High temperature service | Up to 1100°C | High temperature strength |
| Duplex Steel UNS S31803, S32750 |
ASTM A815, MSS SP-43 | Oil & gas, offshore | -50°C to 300°C | High strength, corrosion resistant |
| Nickel Alloys Inconel, Monel, Hastelloy |
ASTM B366, MSS SP-43 | Extreme corrosion, high temp | Up to 1200°C | Exceptional performance |
Proper heat treatment including normalizing, annealing, quenching & tempering for alloy materials.
Rigorous quality control including dimensional inspection, NDT testing, and material certification.
Various surface finishes including pickling & passivation, sand blasting, and protective coatings.
Benefits of using lap joint stub ends in piping systems
Significant cost savings compared to weld neck flanges, especially for expensive materials like stainless steel and alloys.
Simple bolt hole alignment during installation. The lap joint flange can rotate freely for perfect alignment.
Quick disassembly for inspection, cleaning, or replacement without disturbing the pipe alignment.
Only the stub end needs to be in expensive corrosion-resistant material, while the backing flange can be carbon steel.
Can be used with various flange types including slip-on, lap joint, and threaded flanges.
Allows for thermal expansion and contraction without stressing the flange bolts.
Comprehensive specifications and dimensional data
| NPS | Outside Diameter | Length (Short) | Length (Long) |
|---|---|---|---|
| 1/2" | 21.3 mm | 51 mm | 76 mm |
| 1" | 33.4 mm | 51 mm | 102 mm |
| 2" | 60.3 mm | 64 mm | 152 mm |
| 4" | 114.3 mm | 102 mm | 203 mm |
| 6" | 168.3 mm | 102 mm | 305 mm |
| 8" | 219.1 mm | 152 mm | 305 mm |
| 12" | 323.8 mm | 203 mm | 457 mm |
| Parameter | Tolerance | Remarks |
|---|---|---|
| Outside Diameter | ±0.8% | Maximum ±1.6 mm |
| Wall Thickness | ±12.5% | Minimum 87.5% of nominal |
| Length | ±1.6 mm | For sizes ≤ 24" |
| Face Flatness | 0.4 mm | Maximum deviation |
| Bolt Circle | ±1.6 mm | Diameter tolerance |
| Face Type | Description | Applications | Gasket Type | Pressure Rating |
|---|---|---|---|---|
| Raised Face (RF) | 1.6 mm raised surface | General service | Spiral wound, RTJ | 150 to 1500 |
| Flat Face (FF) | Completely flat surface | Low pressure, cast iron | Full face gasket | 150 to 300 |
| Ring Type Joint (RTJ) | Grooved for RTJ gasket | High pressure, high temp | RTJ gasket | 600 to 2500 |
| Tongue & Groove (T&G) | Interlocking design | Critical sealing | T&G gasket | 150 to 1500 |
| Male & Female (M&F) | Male-female matching | High pressure sealing | M&F gasket | 150 to 1500 |
Wide range of applications across multiple industries
Reactors, distillation columns, and process equipment requiring frequent maintenance and inspection.
Sanitary processing equipment, clean rooms, and systems requiring frequent cleaning and sterilization.
Ship piping systems, offshore platforms, and marine applications requiring corrosion resistance.
Processing plants, dairy equipment, and food production systems requiring hygiene and cleanability.
Power plants, boiler systems, and turbine connections requiring high temperature resistance.
Water treatment plants, desalination systems, and municipal water distribution networks.
Proper installation procedures for butt weld stub ends
Clean pipe ends and stub end mating surfaces. Ensure proper bevel preparation as per ASME B16.25.
Align stub end with pipe, ensuring proper fit-up with maximum 1.6mm gap for welding.
Weld stub end to pipe using qualified welding procedure. Use proper filler material.
Slide lap joint flange over stub end. Align bolt holes with mating flange.
Place appropriate gasket between flange faces. Ensure proper alignment and centering.
Tighten bolts in criss-cross pattern to specified torque values for even gasket compression.
Contact us for expert consultation and customized manufacturing solutions for your specific flanged connection requirements.
ISO Certified manufacturer of high quality pipe fittings with 15+ years of industry experience.