Knowledge About Stub End

 

Buttweld fitting: Stub End

A Stub End always will be used with a Lap Joint flange, as a backing flange; both are shown on the image below.

This flange connections are applied, in low-pressure and non critical applications, and is a cheap method of flanging.
In a stainless steel pipe system, for example, a carbon steel flange can be applied, because they are not come in contact with the product in the pipe.

 

 

Stub Ends are available in almost all pipe diameters. Dimensions and dimensional tolerances are defined in the ASME B.16.9 standard. Light-weight corrosion resistant Stub Ends (fittings) are defined in MSS SP43.

 

Dimensional Tolerances of Stub Ends MSS SP-43

Nominal Pipe Size	1/2 up to 2.1/2	3 to 3.1/2	4	5 to 8	10 to 18	20 to 24
Outside Diameter at Welding End (OD)	0.8	0.8	0.8	+ 1.6 – 0.8	+ 2.29 – 0.76	+ 3.05 – 0.76
Overall Length (F)	1.6	1.6	1.6	1.6	2	2
Outside Diameter of Lap (G)	+ 0 – 0.76	+ 0 – 0.76	+ 0 – 0.76	+ 0 – 0.76	+ 0 – 1.6	+ 0 – 1.6
Thickness of Lap (T)	+ 1.52 – 0	+ 1.52 – 0	+ 1.52 – 0	+ 1.52 – 0	+ 1.52 – 0	+ 1.52 – 0
Fillet Radius of Lap (R)	+ 0 – 0.76	+ 0 – 0.76	+ 0 – 1.6	+ 0 – 1.6	+ 0 – 1.6	+ 0 – 1.6
Wall Thickness (t)	Not less than 87.5% of Nominal Wall Thickness

Dimensional tolerances are in millimeters unless otherwise indicated.

Note:
MSS SP-43 only covers stainless steel buttweld fittings made for use with Schedule 5S and 10S pipe and Stub Ends suitable for use with Schedule 40S pipe, as defined in ASME B36.19. The dimensions and dimensional tolerances defined in MSS SP-43 are substantially the same as those in ASME B16.9 specifications from NPS 1/2 – NPS 24. Except with regard to the outside diameter at the bevel.

 

 

Dimensional Tolerances of Stub Ends ASME B16.9

Nominal Pipe Size	1/2 up to 2.1/2	3 to 3.1/2	4	5 to 8	10 to 18	20 to 24
Outside Diameter at Welding End (OD)	+ 1.6 – 0.8	1.6	1.6	+ 2.29 – 1.6	+ 4.06 – 3.05	+ 6.35 – 4.83
Overall Length (F)	1.6	1.6	1.6	1.6	2	2
Outside Diameter of Lap (G)	+ 0 – 0.76	+ 0 – 0.76	+ 0 – 0.76	+ 0 – 0.76	+ 0 – 1.6	+ 0 – 1.6
Thickness of Lap (T)	+ 1.52 – 0	+ 1.52 – 0	+ 1.52 – 0	+ 1.52 – 0	+ 1.52 – 0	+ 1.52 – 0
Fillet Radius of Lap (R)	+ 0 – 0.76	+ 0 – 0.76	+ 0 – 1.6	+ 0 – 1.6	+ 0 – 1.6	+ 0 – 1.6
Wall Thickness (t)	Not less than 87.5% of Nominal Wall Thickness

Dimensional tolerances are in millimeters unless otherwise indicated.

 

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