ASME B16.11 boss supplier, ASME B16.11 boss manufacturer from China! Contact us to get free quote and sample!
An ASME B16.11 boss is a compact, forged fitting designed to be welded directly onto a larger pipe or vessel surface to create a branched outlet. It falls under the ASME B16.11 standard, which governs forged steel fittings, including both socket-welding and threaded (screwed) types.
Key Structural Configurations
The standard outlines two main internal profiles for the connection side of a boss:
Socket Weld Boss: Features an internal bore matching the outside diameter of the branch pipe, along with a distinct internal shoulder (socket depth) where the pipe rests before being fillet-welded.
Threaded / Screwed Boss: Contains internal female threads-typically cut to ANSI/ASME B1.20.1 NPT (National Pipe Thread) parameters-allowing for direct, screw-in component installations.
Critical Dimension Parameters
The physical geometry of an ASME B16.11 boss varies based on two primary constraints: Nominal Pipe Size (NPS) and Pressure Class Rating. The standard size range typically spans from NPS 1/8 to NPS 4 (DN 6 to DN 100).
When interpreting an industrial dimension chart, you must look for several essential metric and imperial measurements:
Socket Bore Diameter (B): The precise internal machined diameter that accepts the male end of the incoming pipe.
Fitting Bore Diameter (D): The inner fluid pathway hole that dictates the volumetric flow capacity and must align properly with the main header hole extraction.
Minimum Socket Wall Thickness (C): The critical structural barrier that dictates pressure retention capacity.
Minimum Depth of Socket (J): The insertion depth required to guarantee proper alignment and structural stability prior to fillet welding.
Overall Height / Length (F or L): The total physical layout distance from the attachment weld face to the outermost face of the fitting.
asme b16.11 boss dimension
| Nominal size | Socket bore diameter | Bore diameter of fittings | Socket wall thickness | Body wall | Min. Depth of socket | Laying lengths | Laying lengths | End Wall thickness | Center to bottom of socket | |||||||||||||||
| DN | NPS | B | D | C | Gmin | Jmin | E | F | Kmin | A | H | |||||||||||||
| 3000 | 6000 | 9000 | 3000 | 6000 | 9000 | 3000 | 6000 | 9000 | 3000 | 6000 | 9000 | 3000 | 6000 | 3000 | 6000 | |||||||||
| Avg | Min | Avg | Min | Avg | Min | |||||||||||||||||||
| 6 | 1/8 | 10.9 | 6.1 | 3.2 | - | 3.18 | 3.18 | 3.96 | 3.43 | - | - | 2.41 | 3.15 | - | 9.5 | 6.5 | 16.0 | 4.8 | 6.4 | - | - | - | - | - |
| 8 | 1/4 | 14.3 | 8.5 | 5.6 | - | 3.78 | 3.30 | 4.60 | 4.01 | - | - | 3.03 | 3.68 | - | 9.5 | 6.5 | 16.0 | 4.8 | 6.4 | - | - | - | - | - |
| 10 | 3/8 | 17.7 | 11.8 | 8.4 | - | 4.01 | 3.50 | 5.03 | 4.37 | - | - | 3.20 | 4.01 | - | 9.5 | 6.5 | 17.5 | 4.8 | 6.4 | - | 37 | - | 9.5 | - |
| 15 | 1/2 | 21.9 | 15.0 | 11.0 | 5.6 | 4.67 | 4.09 | 5.97 | 5.18 | 9.53 | 8.18 | 3.73 | 4.78 | 7.47 | 9.5 | 9.5 | 22.5 | 6.4 | 7.9 | 11.2 | 41 | 51 | 9.5 | 11 |
| 20 | 3/4 | 27.3 | 20.2 | 14.8 | 10.3 | 4.90 | 4.27 | 6.96 | 6.04 | 9.78 | 8.56 | 3.91 | 5.56 | 7.82 | 12.5 | 9.5 | 24.0 | 6.4 | 7.9 | 12.7 | 51 | 60 | 11 | 13 |
| 25 | 1 | 34.0 | 25.9 | 19.9 | 14.4 | 5.69 | 4.98 | 7.92 | 6.93 | 11.38 | 9.96 | 4.55 | 6.35 | 9.09 | 12.5 | 12.5 | 28.5 | 9.6 | 11.2 | 14.2 | 60 | 71 | 13 | 16 |
| 32 | 11/4 | 42.8 | 34.3 | 28.7 | 22.0 | 6.07 | 5.28 | 7.92 | 6.93 | 12.14 | 10.62 | 4.85 | 6.35 | 9.70 | 12.5 | 12.5 | 30.0 | 9.6 | 11.2 | 14.2 | 71 | 81 | 16 | 17 |
| 40 | 11/2 | 48.9 | 40.1 | 33.2 | 27.2 | 6.35 | 5.54 | 8.92 | 7.80 | 12.70 | 11.12 | 5.08 | 7.14 | 10.15 | 12.5 | 12.5 | 32.0 | 11.2 | 12.7 | 15.7 | 81 | 98 | 17 | 21 |
| 50 | 2 | 61.2 | 51.7 | 42.1 | 37.4 | 6.93 | 6.04 | 10.92 | 9.50 | 13.85 | 12.12 | 5.54 | 8.74 | 11.07 | 16.0 | 19.0 | 41.0 | 12.7 | 15.7 | 19.0 | 98 | 151 | 21 | 30 |
| 65 | 21/2 | 73.9 | 61.2 | - | - | 8.76 | 7.62 | - | - | - | 7.01 | - | - | 16.0 | 19.0 | 43.0 | 15.7 | 19.0 | - | 151 | - | 30 | - | |
| 80 | 3 | 89.9 | 76.4 | - | - | 9.52 | 8.30 | - | - | - | 7.63 | - | - | 16.0 | 19.0 | 44.5 | 19.0 | 32.4 | - | 184 | - | 57 | - | |
| 100 | 4 | 115.5 | 100.7 | - | - | 10.69 | 9.35 | - | - | - | 8.56 | - | - | 19.0 | 19.0 | 48.0 | 22.4 | 28.4 | - | 201 | - | 66 | - | |
NOTE:
1) When the fittings are reducing, the shapes are the same as the ones of the straight fittings and dimensions of the reducing side (B, D) shall be produced according to the reducing sizes.
2) Full couplings can be concentric or eccentric.
3) Fittings with the mixed type of socket weld and thread are also available.
