Stub End
What is a Stub End?
A Stub End is a type of buttweld fitting used in conjunction with lap joint flanges. It consists of a short piece of pipe with a flared end that sits inside a lap joint flange. Only the stub end is in contact with the fluid, while the flange provides mechanical strength. This makes it highly economical in corrosive environments, as the flange can be carbon steel while the stub end is stainless or alloy.
Stub ends are commonly used in food processing, chemical handling, water treatment, and marine systems where frequent flange disassembly is required.
Key Features
Leak-Proof
Jointing
Durable
Construction
High Pressure
Resistance
Wide
Compatibility
Corrosion
Resistant
Specifications
| Specification Category | Parameter / Feature | Details / Options |
|---|---|---|
| Size Range | Nominal Size | ½” to 48″ (custom sizes available) |
| Pressure Ratings | ANSI / ASME Class | Class 150, 300, 600, 900, 1500, 2500 |
| PN Ratings | PN6, PN10, PN16, PN25, PN40, PN64 | |
| Product Types | Long Stub End | Standard, Heavy Duty |
| Material Options | Carbon Steel | ASTM A182 F304/F316, ASTM A105, ASTM A182 F5/F9 |
| Stainless Steel | ASTM A182 WP304, WP316, WP321, WP347 | |
| Alloy Steel | ASTM A182 F5, F9, F11, F22 | |
| Other Alloys | Monel, Inconel, Titanium | |
| Standards & Certifications | ASTM | ASTM A182, ASTM A105 |
| ASME / ANSI | ASME B16.9, ASME B16.11 | |
| MSS | MSS SP-43, MSS SP-79 | |
| European Standards | EN 10253-1, EN 10222 | |
| Certifications | ISO 9001, PED 2014/68/EU, NACE MR0175, CE Marked | |
| Design Features | Wall Thickness | Schedule 40, Schedule 80, Schedule 160 |
| End Connections | Butt Weld Connection | |
| Pressure Class | 2000#, 3000#, 6000#, 9000# | |
| Tolerance | Dimensional Tolerance | As per ASME B16.9 / B16.28 |
| Coating & Surface Finish | Anti-Corrosion Coating | Passivation, Epoxy Coating, Zinc Plated |
| Surface Finish | Mill Finish, Polished, Pickled, Bead Blasted | |
| Testing & Inspection | Pressure Testing | Hydrostatic, Pneumatic |
| Non-Destructive Testing | Radiography (RT), Ultrasonic (UT), Dye Penetrant (DPT), Magnetic Particle (MPI) | |
| Destructive Testing | Tensile, Hardness, Impact, Flattening |
Dimensions
| Fitting Type | Nominal Size (NPS) | Outside Diameter (OD) | Wall Thickness (Schedule) | Length (L) | Weight per Piece |
|---|---|---|---|---|---|
| Long Stub End | ½” | 21.3 mm | Schedule 40, 80 | 60 mm | 200g |
| Long Stub End | ¾” | 26.7 mm | Schedule 40, 80 | 70 mm | 300g |
| Long Stub End | 1″ | 33.4 mm | Schedule 40, 80 | 80 mm | 450g |
| Long Stub End | 1½” | 48.3 mm | Schedule 40, 80 | 90 mm | 600g |
| Long Stub End | 2″ | 60.3 mm | Schedule 40, 80 | 100 mm | 800g |
| Long Stub End | 2½” | 73.0 mm | Schedule 40, 80 | 120 mm | 1.2kg |
| Long Stub End | 3″ | 88.9 mm | Schedule 40, 80 | 140 mm | 1.5kg |
| Long Stub End | 4″ | 114.3 mm | Schedule 40, 80 | 160 mm | 2.0kg |
Mechanical Properties
| Property | Value | Unit / Standard |
|---|---|---|
| Tensile Strength | 485 – 750 | MPa (Carbon Steel, Stainless Steel, Alloy Steel) |
| Yield Strength | 170 – 450 | MPa |
| Hardness | 120 – 200 | HB (Brinell) |
| Elongation | ≥ 20 – 30 | % |
| Density | 7.8 – 8.0 | g/cm³ (Carbon Steel), 7.9 – 8.0 g/cm³ (Stainless Steel) |
| Impact Toughness | ≥ 27 – 70 | J (Charpy, grade-dependent) |
| Modulus of Elasticity (E) | ~200 | GPa |
| Fatigue Strength | 250 – 450 | MPa |
| Corrosion Resistance | Good to Excellent (SS > CS > Alloy Steel) | – |
| Thermal Conductivity | 15 – 50 | W/m·K |
| Coefficient of Thermal Expansion | 11 – 17 ×10⁻⁶ | /°C |
| Yield Ratio (YS/UTS) | 0.40 – 0.65 | – |
| Poisson’s Ratio | 0.27 – 0.30 | – |
| Brinell Hardness Range | 120 – 200 | HB |
| Surface Finish | Mill Finish, Pickled, Polished, Bead Blasted | – |
| Welding Type | Butt Weld Ends | – |
| Operating Temperature Range | -46 to 600 | °C (material-dependent) |
| Pressure Rating | Class 150, 300, 600, 900, 1500, 2500 | ASME B16.9 / B16.28 |
Chemical Composition
| Element | SS 304 | SS 304L | SS 316 | SS 316L |
|---|---|---|---|---|
| Chromium (Cr) | 18.0 – 20.0 | 18.0 – 20.0 | 16.0 – 18.0 | 16.0 – 18.0 |
| Nickel (Ni) | 8.0 – 10.5 | 8.0 – 12.0 | 10.0 – 14.0 | 10.0 – 14.0 |
| Carbon (C) | ≤ 0.08 | ≤ 0.03 | ≤ 0.08 | ≤ 0.03 |
| Manganese (Mn) | ≤ 2.00 | ≤ 2.00 | ≤ 2.00 | ≤ 2.00 |
| Silicon (Si) | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.045 | ≤ 0.045 | ≤ 0.045 | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 | ≤ 0.030 | ≤ 0.030 | ≤ 0.030 |
| Iron (Fe) | Balance | Balance | Balance | Balance |
| Molybdenum (Mo) | — | — | 2.0 – 3.0 | 2.0 – 3.0 |
Applications of Long Stub End
Construction &
Infrastructure
Automotive & Heavy
Equipment
Manufacturing &
Fabrication
Medical & Laboratory
Equipment
Electrical &
Electronics Assembly
Oil, Gas & Petrochemical
Installations
Do you have questions?
What is the benefit of using a long stub end with a lap joint flange?
Are both long and short stub ends available?
Are stub ends used in high-pressure systems?
Can stub ends be custom-machined?
