ASME B16.11 is a commonly used standard for forged pipe fittings provided by SSM to our customers.
ASME B16.11 is a standard established by the American Society of Mechanical Engineers (ASME) that covers dimensions, materials, pressure ratings, and tolerances for forged steel pipe fittings, including threaded and socket-weld fittings.
The ASME B16.11 standard is widely used in industries such as oil and gas, chemical processing, shipbuilding, power generation, and other sectors requiring high-reliability piping systems. It provides precise technical specifications for the manufacturing and inspection of fittings to ensure the safety and consistency of piping systems.
Scope of ASME B16.11
This Standard covers ratings, dimensions, tolerances, marking, and material requirements for forged fittings, both socket-welding and threaded.
Types of fittings covered by this Standard are shown in Table 6.
PRESSURE RATINGS
Fittings under this Standard shall be designated as Class 2000, 3000, and 6000 for threaded end fittings and Class 3000, 6000, and 9000 for socket-weld end fittings.
The schedule of pipe corresponding to each Class designation of fitting for rating purposes is shown in Table 7.
The minimum wall thickness for selected pipe, considering manufacturing minus wall thickness tolerance (typically 12.5%), shall not be less than the minimum wall calculation. The fitting is suitable for the application if the wall thickness of the selected pipe equals or is less than the ASME B36.10M Schedule No. or Wall Designation pipe wall thickness correlated with the fitting in Table 7 [see Note (1) in Table 7].
Nonstandard Pipe Wall Thickness.
Since ASME B36.10M does not include Schedule 160 nor Double Extra Strong thickness for NPS 1⁄8, 1⁄4, and 3⁄8, thevalues in Table 8 shall be used as the nominal wallthicknesses of the pipe for rating purposes.
SIZE AND TYPE
NPS, followed by a dimensionless number, is the designation for nominal fitting size. NPS is related to the reference nominal diameter, DN, used in international standards. The relationship is typically as follows:
Reducing Fitting Size
In the case of reducing tees and crosses, the size of the largest run opening shall be given first, followed by the size of the opening at the opposite end of the run. Where the fitting is a tee, the size of the branch is given last. Where the fitting is a cross, the largest side-outlet is the third dimension given, followed by the opening opposite. The line sketches, Fig. 1, illustrate how the reducing fittings are read.
| NPS | 1/8 | 1/4 | 3/8 | 1/2 | 3/4 | 1 | 1 1/4 | 1 1/2 | 2 | 2 1/2 | 3 | 4 |
| DN | DN 6 | DN 8 | DN 10 | DN 15 | DN 20 | DN 25 | DN 32 | DN 40 | DN 50 | DN 65 | DN 80 | DN 100 |
DIMENSIONS
DIMENSIONS OF FITTINGS IN U.S. CUSTOMARY UNITS
Unless otherwise noted, the dimensions without tolerances for socket-welding fittings given in Tables I-1 Dimensions are in inches.
The dimensions without tolerances for threaded fittings given in Tables I-2 is nominal values and subject to the designated manufacturing tolerances. Dimensions are in inches.
The dimensions without tolerances for threaded fittings given in Tables I-3 is nominal values and subject to the designated manufacturing tolerances. Dimensions are in inches.
The dimensions without tolerances for threaded fittings given in Tables I-4 is nominal values and subject to the designated manufacturing tolerances. Dimensions are in inches.
The dimensions without tolerances for threaded fittings given in Tables I-5 is nominal values and subject to the designated manufacturing tolerances. Dimensions are in inches.
TOLERANCES
The minimum wall thickness for selected pipe, considering manufacturing minus wall thickness tolerance (typically 12.5%)
Concentricity of Bores
The socket and fitting bores shall be concentric within a tolerance of 0.8 mm (0.03 in.) for all sizes. Opposite socket bores shall be concentric within a tolerance of 1.5 mm (0.06 in.) for all sizes.
Coincidence of Axes
The maximum allowable variation in the alignment of the fitting bore and socket bore axes shall be 1 mm in 200 mm (0.06 in. in 1 ft). The maximum allowable variation in alignment of threads shall be 1 mm in 200 mm (0.06 in. in 1 ft).
MATERIAL
Fittings shall be made of materials consisting of forgings, bar, seamless pipe, or seamless tubular products. These materials shall conform to the requirements for the WP seamless construction materials of ASTM Fitting Specifications A234, A403, A420, A815, or B366 or ASTM Forging Specifications A105, A182, A350, B462, or B564. Tees, elbows, and crosses shall not be made from bar stock.
MARKING
Each fitting shall be permanently marked with the required identification by raised lettering and/or stamping, electro-etching, or vibro-tool marking on the collar portion, raised pad, or raised boss portion of the forging. Cylindrical fittings shall be marked on the O.D. or end of the fitting in a location such that the marking will not be obliterated as a result of welding installation. The marking of bushings and plugs is not required by this Standard.
Specific Marking:
The marking shall include (but is not limited to) the following:
- (a) Manufacturer’s Name or Trademark
- (b) Material Identification. Material shall be identified in accordance with the marking requirements of either the appropriate ASTM Fitting or ASTM Forging Specifications.
- (c) Product Conformance. Fittings covered under para. 1.1.1 shall be marked with either the ASTM Fittings Specification material identification (e.g., “WP______”) or the symbol “B16” to denote conformance to this Standard. Fittings covered under para. 1.1.2 shall be marked with a supplementary suffix as follows:
- (1) For ASTM A234, A403, A420, and A815, suffix the material grade with “S58” (see ASTM A960 Supplementary Requirement S58).
- (2) For ASTM Fitting Specifications B366, suffix the material grade with “SPLD.”
- (3) For all ASTM Forging Specifications, suffix “B16” with “SPLD.”
- (d) Class Designation. 2000, 3000, 6000, or 9000, as applicable. Alternatively, the designation 2M, 3M, 6M, or 9M, as applicable, may be used where M stands for 1000.
(e) Size. The nominal pipe size related to the end connections.
Omission of Markings. Where size and shape of fittings do not permit all of the above markings, they may be omitted in the reverse order given above.
Weight Table
Why SSM is Your Trusted Supplier of Forged Pipe Fittings
Extensive Experience: With over 30 years of experience in the industry, SSM has a deep understanding of forged pipe fittings, ensuring reliable and high-quality products.
Strict Quality Standards: SSM adheres to internationally recognized standards like ASME B16.11, ensuring that all fittings meet rigorous quality and safety requirements.
Comprehensive Product Range: SSM offers a wide range of forged pipe fittings, including threaded and socket-weld fittings, to meet diverse customer needs across various industries.
If you have any more specific questions regarding ASME B16.11, feel free to ask!
FAQ
ASME B16.11 fittings are widely used in high-pressure and high-temperature applications. The standard ensures that fittings are manufactured to uniform dimensions, materials, and performance characteristics, which helps maintain safety and reliability in piping systems.
ASME B16.11 fittings are extensively used in industries such as oil and gas, chemical processing, power generation, shipbuilding, and other sectors that require reliable and durable piping systems.
The standard sets clear specifications for the manufacturing, testing, and inspection of fittings, ensuring they meet strict quality, dimensional, and mechanical property requirements. This guarantees consistent performance and safety in the applications where they are used.
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