Buttweld Cap
End Cap : Specifications | Materials | Types | Dimensions | Weight Chart | Tolerances | FAQ
Leading ASME B16.9 Buttweld Cap Manufacturer & Exporter – Stainless Steel, Carbon Steel, Alloy & High Nickel End Caps (Seamless & Welded, SCH 40 / SCH 80) Supplied Globally
Best Export Prices: sales@midlandforgefittings.com
Midland Forge and Fittings Pvt. Ltd. stands at the forefront of industrial pipe fittings manufacturing, offering high-quality ASME B16.9 Buttweld End Caps engineered for durability, precision, and global compliance. With decades of experience in the forging and fitting industry, the company has become a trusted partner for industries across oil & gas, petrochemical, energy, shipbuilding, and water treatment sectors.
Our Buttweld Pipe Caps are designed to close the ends of pipe systems securely and reliably, preventing leakage or damage. Whether you’re handling corrosive fluids or high-pressure flow, Midland ensures superior material integrity using Stainless Steel, Carbon Steel, Alloy Steel, and High Nickel Alloys. Available in seamless and welded types with Sch 40, Sch 80, and custom wall thicknesses, our caps meet stringent global standards.
As a global exporter, Midland Forge and Fittings delivers to clients in over 40+ countries, including Germany, UAE, Australia, South Africa, and the USA. Each end cap undergoes strict quality control and is certified to international norms — ensuring you’re working with products you can rely on.
Buttweld End Cap Specifications, Sizes & Standards
Pipe Cap – Materials, Grades & Standards
| Material Category | Grade | Standards (ASTM / ASME) | Typical Use/Application |
|---|---|---|---|
| Stainless Steel | 304 / 304L / 304H | ASTM A403 WP304/304L/304H | General purpose, corrosion resistance |
| 316 / 316L / 316H | ASTM A403 WP316/316L/316H | Marine & chemical applications | |
| 317 / 317L | ASTM A403 WP317/317L | High corrosion resistance | |
| 321 / 321H | ASTM A403 WP321/321H | High temperature, stabilized | |
| 347 / 347H | ASTM A403 WP347/347H | High-temp pressure systems | |
| 904L | ASTM A403 WP904L / B625 | Acid handling, sulfuric environments | |
| 254 SMO | ASTM A403 / B366 | High chloride environments | |
| Carbon Steel | A234 WPB / WPC | ASTM A234 | Pressure piping & general piping systems |
| A420 WPL6 | ASTM A420 | Low temperature services | |
| Alloy Steel | A234 WP1 / WP5 / WP9 | ASTM A234 | High-temp & pressure pipelines |
| A234 WP11 / WP22 | ASTM A234 | Steam lines & refineries | |
| A234 WP91 | ASTM A234 | Power generation, high performance | |
| Duplex Steel | UNS S31803 / S32205 | ASTM A815 / A790 | Corrosion & high strength use |
| Super Duplex Steel | UNS S32750 / S32760 | ASTM A815 / A790 | Offshore, seawater applications |
| Nickel Alloys | Nickel 200 / 201 | ASTM B366 / B162 | Alkali & chemical processing |
| Inconel 600 / 625 / 718 | ASTM B366 | Heat exchangers, aerospace | |
| Incoloy 800 / 825 | ASTM B366 | Petrochemical & chemical processing | |
| Hastelloy C22 / C276 | ASTM B366 | Severe corrosion resistance | |
| Monel 400 / K500 | ASTM B366 | Seawater, chemical industries | |
| Alloy 20 | ASTM B366 | Sulfuric acid services | |
| Nimonic 75 / 80A | ASTM B366 / B637 | High-temp applications | |
| Copper Nickel | Cu-Ni 90/10 / 70/30 | ASTM B466 / B467 | Marine systems, seawater service |
| Titanium | Grade 2 / Grade 5 | ASTM B363 | Lightweight, corrosion resistance |
| Aluminium | 6061 / 5083 | ASTM B361 | Low-pressure, non-corrosive piping |
Dimensions of End Cap
| Nominal Pipe Size (NPS) | Outside Diameter (D) | Length (H) |
|---|---|---|
| 1/2″ | 21.3 mm (0.84″) | 25 mm (1.00″) |
| 3/4″ | 26.7 mm (1.05″) | 25 mm (1.00″) |
| 1″ | 33.4 mm (1.31″) | 38 mm (1.50″) |
| 1 1/4″ | 42.2 mm (1.66″) | 38 mm (1.50″) |
| 1 1/2″ | 48.3 mm (1.90″) | 38 mm (1.50″) |
| 2″ | 60.3 mm (2.38″) | 38 mm (1.50″) |
| 2 1/2″ | 73.0 mm (2.88″) | 51 mm (2.00″) |
| 3″ | 88.9 mm (3.50″) | 64 mm (2.50″) |
| 4″ | 114.3 mm (4.50″) | 64 mm (2.50″) |
| 5″ | 141.3 mm (5.56″) | 76 mm (3.00″) |
| 6″ | 168.3 mm (6.63″) | 89 mm (3.50″) |
| 8″ | 219.1 mm (8.63″) | 102 mm (4.00″) |
| 10″ | 273.0 mm (10.75″) | 127 mm (5.00″) |
| 12″ | 323.9 mm (12.75″) | 152 mm (6.00″) |
| 14″ | 355.6 mm (14.00″) | 165 mm (6.50″) |
| 16″ | 406.4 mm (16.00″) | 178 mm (7.00″) |
| 18″ | 457.2 mm (18.00″) | 203 mm (8.00″) |
| 20″ | 508.0 mm (20.00″) | 229 mm (9.00″) |
| 24″ | 609.6 mm (24.00″) | 267 mm (10.50″) |
Weight Chart: ASME B16.9 Buttweld Cap (SCH 40 / STD)
| Size (Inches) | Cap (kg) |
|---|---|
| ½” | 0.08 |
| ¾” | 0.12 |
| 1″ | 0.20 |
| 1½” | 0.60 |
| 2″ | 0.90 |
| 3″ | 2.30 |
| 4″ | 4.00 |
| 6″ | 8.50 |
| 8″ | 14.00 |
| 10″ | 22.00 |
| 12″ | 32.00 |
| 14″ | 43.00 |
| 16″ | 58.00 |
| 18″ | 74.00 |
| 20″ | 95.00 |
| 24″ | 130.00 |
| 26″ | 150.00 |
| 28″ | 170.00 |
| 30″ | 200.00 |
| 32″ | 225.00 |
| 36″ | 280.00 |
| 40″ | 340.00 |
| 42″ | 370.00 |
| 44″ | 400.00 |
| 48″ | 455.00 |
End Cap Pipe Fitting Tolerances as per ASME B16.9
| Fitting Type | Parameter | Tolerance | |
|---|---|---|---|
| Up to 4” NPS | Above 4” NPS | ||
| Cap | Outside Diameter at Bevel | ±1.6 mm (1/16″) | ±1.6 mm (1/16″) |
| Center-to-End (A, B) | ±1.6 mm (1/16″) | ±3.2 mm (1/8″) | |
| Wall Thickness | -12.5% (no positive tolerance) | ||
| Ovality | Shall not exceed 1% of specified OD | ||
What is a Buttweld End Cap used for in piping systems?
A buttweld end cap is used to permanently seal the end of a pipe, effectively closing it off from flow. Its main purposes include:
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Safety: Prevents fluids, gases, or debris from escaping the pipeline.
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System Isolation: Allows sections of a pipeline to be isolated during maintenance, testing, or future expansion.
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Pressure Containment: Suitable for high-pressure systems where a secure, leak-proof seal is essential.
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Durability: Being a butt-weld fitting, it creates a continuous metal joint with the pipe, providing high structural integrity and long-term reliability.
How is a Buttweld End Cap different from a threaded cap?
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Connection Type: A buttweld end cap is welded directly to the pipe, forming a permanent, leak-proof joint, whereas a threaded cap screws onto the pipe and can be removed or reused.
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Pressure & Temperature Resistance: Buttweld caps provide superior strength and reliability in high-pressure and high-temperature applications, while threaded caps are typically suited for lower-pressure systems.
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Durability & Safety: Welding ensures long-term integrity and reduces the risk of leaks, making buttweld caps ideal for critical systems in oil & gas, petrochemical, and power generation industries.
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Maintenance: Threaded caps allow easier access for maintenance or modifications, whereas buttweld caps require cutting or grinding to remove.
Do Buttweld End Caps require special welding procedures?
Yes, buttweld end caps require proper welding procedures to ensure a strong, leak-proof connection:
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Standards Compliance: Welding should follow ASME (or other applicable) standards to meet industry safety and quality requirements.
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Qualified Welders: Only certified welders should perform the welds to guarantee proper technique and joint integrity.
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Material & Thickness Considerations: The material grade and wall thickness of the pipe and end cap determine the appropriate welding method—commonly TIG, MIG, or SMAW.
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Pressure Integrity: Correct welding ensures the joint can withstand operating pressures and temperatures, preventing leaks, cracks, or system failures.
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Inspection & Testing: Post-weld inspections, such as visual inspection, radiography, or ultrasonic testing, are often required to verify weld quality.