Boss
Forged Boss : Specifications | Materials | Dimensions | Weight Chart | Tolerances | FAQ
Trusted Exporter & Manufacturer of ASME B16.11 Forged Boss – Sizes ½” to 4”, Class 2000#, 3000#, 6000#, and 9000#, Stainless Steel, Carbon Steel, Alloy Steel, and High Nickel Alloys, Supplying to UK, Italy, Canada, Saudi Arabia, and South Africa
Best Export Prices: sales@midlandforgefittings.com
At Midland Forge and Fittings Pvt. Ltd., we have built our reputation on precision engineering, consistent quality, and customer-first values. As a forward-looking manufacturer and exporter, we specialize in forged fittings designed to perform in some of the most demanding industrial environments.
Our production facilities integrate advanced forging techniques with strict quality control, ensuring every component meets international standards and performs reliably in service. With a strong presence in both domestic and international markets, we supply industries such as oil & gas, petrochemicals, power generation, and shipbuilding with products that deliver strength, safety, and longevity.
A forged boss is a short, thick-walled pipe fitting designed to provide a secure connection for auxiliary equipment such as vents, drains, instruments, or other branch connections in a piping system. Unlike standard outlets, a forged boss is machined from high-quality forgings to ensure superior grain flow and structural integrity. Manufactured in accordance with ASME B16.11, these fittings are available in threaded and socket weld types, making them suitable for a wide range of pressure classes, including 2000#, 3000#, 6000#, and 9000#.
Forged bosses are preferred in high-pressure and high-temperature systems because of their excellent leak resistance, compact design, and mechanical strength. They are typically produced in materials such as stainless steel, carbon steel, alloy steel, and high nickel alloys, ensuring compatibility with diverse process environments.
Forged Boss Specifications
Threaded Boss – Materials, Grades & Standards
| Material Category | Grade | Standards (ASTM / ASME) | Typical Use / Application |
|---|---|---|---|
| Stainless Steel | 304 / 304L / 304H | ASTM A182 F304 / F304L / F304H | General purpose, corrosion resistance |
| 316 / 316L / 316H | ASTM A182 F316 / F316L / F316H | Marine, chemical, and food processing | |
| 317 / 317L | ASTM A182 F317 / F317L | High corrosion resistance | |
| 321 / 321H | ASTM A182 F321 / F321H | High temperature, stabilized service | |
| 347 / 347H | ASTM A182 F347 / F347H | High-temp, pressure systems | |
| 904L | ASTM A182 F904L | Acid handling, sulfuric environments | |
| 254 SMO | ASTM A182 F44 | High chloride & seawater applications | |
| Carbon Steel | A105 | ASTM A105 | Pressure piping & general industries |
| A350 LF2 | ASTM A350 LF2 | Low temperature services | |
| A694 F42 / F46 / F52 / F56 / F60 / F65 / F70 | ASTM A694 | High-pressure pipelines, oil & gas | |
| Alloy Steel | F1 / F5 / F9 | ASTM A182 F1 / F5 / F9 | High-temp & pressure pipelines |
| F11 / F22 | ASTM A182 F11 / F22 | Steam lines & refineries | |
| F91 | ASTM A182 F91 | Power generation, high performance | |
| Duplex Steel | UNS S31803 / S32205 | ASTM A182 F51 / F60 | Corrosion resistance, high strength |
| Super Duplex Steel | UNS S32750 / S32760 | ASTM A182 F53 / F55 | Offshore, seawater applications |
| Nickel Alloys | Nickel 200 / 201 | ASTM B564 | Alkali & chemical processing |
| Inconel 600 / 625 / 718 | ASTM B564 | Heat exchangers, aerospace | |
| Incoloy 800 / 825 | ASTM B564 | Petrochemical & chemical processing | |
| Hastelloy C22 / C276 | ASTM B564 | Severe corrosion resistance | |
| Monel 400 / K500 | ASTM B564 | Seawater, marine engineering | |
| Alloy 20 | ASTM B564 | Sulfuric acid services | |
| Nimonic 75 / 80A | ASTM B564 / B637 | High-temp aerospace & turbines | |
| Copper Nickel | Cu-Ni 90/10 / 70/30 | ASTM B151 / B467 | Marine systems, seawater service |
| Titanium | Grade 2 / Grade 5 | ASTM B381 | Lightweight, corrosion resistance |
| Aluminium | 6061 / 5083 | ASTM B247 | Low-pressure, non-corrosive piping |
Dimensions of ASME B16.11 Forged Boss (Class 3000#, 6000#)
| Nominal Pipe Size (NPS) | DN (mm) | Pressure Class | Outside Diameter (OD) (mm) | Bore (mm) | Height (H) (mm) | Minimum Wall Thickness (T) (mm) |
|---|---|---|---|---|---|---|
| ½” | 15 | 3000# | 30 | 14.5 | 25 | 6.0 |
| ½” | 15 | 6000# | 35 | 14.5 | 30 | 8.0 |
| ¾” | 20 | 3000# | 38 | 19.0 | 28 | 6.5 |
| ¾” | 20 | 6000# | 44 | 19.0 | 34 | 9.0 |
| 1” | 25 | 3000# | 45 | 25.5 | 32 | 7.0 |
| 1” | 25 | 6000# | 52 | 25.5 | 38 | 10.0 |
| 1 ½” | 40 | 3000# | 60 | 38.0 | 38 | 8.0 |
| 1 ½” | 40 | 6000# | 70 | 38.0 | 45 | 11.0 |
| 2” | 50 | 3000# | 75 | 51.0 | 45 | 9.0 |
| 2” | 50 | 6000# | 85 | 51.0 | 52 | 12.0 |
| 3” | 80 | 3000# | 100 | 77.5 | 60 | 12.5 |
| 3” | 80 | 6000# | 115 | 77.5 | 70 | 16.0 |
| 4” | 100 | 3000# | 125 | 102.0 | 72 | 15.0 |
| 4” | 100 | 6000# | 140 | 102.0 | 85 | 18.0 |
Weight Chart: ASME B16.11 Forged Boss
| Nominal Pipe Size (NPS) | DN (mm) | Class 3000# (kg/pc) | Class 6000# (kg/pc) | Class 9000# (kg/pc) |
|---|---|---|---|---|
| ½” | 15 | 0.10 | 0.15 | 0.22 |
| ¾” | 20 | 0.18 | 0.27 | 0.40 |
| 1” | 25 | 0.25 | 0.38 | 0.55 |
| 1 ¼” | 32 | 0.40 | 0.58 | 0.85 |
| 1 ½” | 40 | 0.55 | 0.80 | 1.15 |
| 2” | 50 | 0.75 | 1.10 | 1.55 |
| 2 ½” | 65 | 1.20 | 1.65 | 2.40 |
| 3” | 80 | 1.60 | 2.35 | 3.40 |
| 4” | 100 | 2.80 | 3.95 | 5.70 |
Socket Weld Boss Tolerances as per ASME B16.11
| Dimension | Tolerance (mm) | Notes |
|---|---|---|
| Outside Diameter (OD) | ±1.5 mm | Applies to OD of the boss body |
| Bore Diameter (ID) | ±0.5 mm | Ensures proper fit with mating pipe |
| Height (H) | ±1.5 mm | Total height of the boss |
| Wall Thickness (T) | -0.0 / +1.0 mm | Minimum thickness must always be maintained |
| Threaded Ends (NPT/BSP) | As per ASME B1.20.1 / BS 21 | Thread tolerances comply with standard thread specifications |
| Socket Weld Ends | +0.4 / -0.8 mm | Socket bore tolerance for welding accuracy |
| Facing (Flatness of End Face) | ±0.3 mm | Measured across full sealing face |
| Center to End Dimensions | ±1.5 mm | For uniformity in branch connections |
What testing and quality checks are done on ASME B16.11 Forged Boss?
- Hydrostatic Test – Verifies pressure holding capacity.
- Visual & Dimensional Inspection – Confirms compliance with ASME tolerances.
- NDT (Non-Destructive Testing) – UT, MPI, DPI for surface and internal flaws.
- Hardness Test – Ensures proper heat treatment.
- PMI (Positive Material Identification) – Confirms alloy grade.
- Impact Test (Charpy V-Notch) – For low-temperature materials like A350 LF2.
How is a Forged Boss different from a Weldolet or Sockolet?
- Forged Boss: Machined from solid forging, short and thick, mainly for vents, drains, and instruments.
- Weldolet: Welded branch connection, used for larger branch sizes.
- Sockolet: Socket-weld type outlet, designed for smaller bore branch connections.
- A boss is generally more compact and used for reinforcement rather than full branch flow.
What are the key technical advantages of using Forged Boss?
- Provides reinforced connection for auxiliary piping.
- Withstands high pressure & high temperature environments.
- Compact design reduces weight compared to branch fittings.
- Ensures leak-proof joint integrity in threaded or welded applications.
- Suitable for critical industries like oil & gas, petrochemical, refineries, and offshore drilling.