Stub Ends for Flanged Joints

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Author: Projectmaterials
Posted: September 20, 2017
6 Comments

What is a stub end and why should it be used? Stub ends are buttweld fittings that can be used (in combination with a lap joint flange) alternatively to welding neck flanges to make flanged connections. The use of stub ends has two advantages: it can reduce the total cost of flanged joints for piping systems in high material grades (as the lap joint flange does not need to be of the same material of the pipe and the stub end but can be a lower grade); it speeds up the installation process, as the lap joint flange can be rotated to facilitate the alignment of the bolt holes. Stub ends are available in short and long pattern (ASA and MSS stub ends), in sizes up to 80 inches.

STUB END APPLICATION

A stud end and a lap joint flange can be used together as an alternative way to make a flanged connection than welding neck flanges.

The two devices to be combined, in this case, are:

The stub end, which is essentially a piece of pipe, with one end flared outwards and the other prepared to be welded to a pipe of the same bore size (NPS = nominal pipe size), material and wall thickness. The most widely used fabrication tool for stub ends is the flaring machine, which is able to flare the end of the pipe and then cuts it to length.

A Lap Joint Flange, which is used to actually bolt the two lengths of pipe together.

BENEFITS OF LAP JOINT STUB ENDS

The use of stub ends has these two advantages:

Reduces the overall cost of the flanged joint

Generally, the lap joint flange is of a lower grade than the material of the stub end and the pipework, thus saving the total weight of high-grade material used for the flanged joint.

Example:

For an SS316 pipe, instead of using a full 316 welding neck flange, a combination of an SS316 stub end and a carbon steel lap joint flange would do the same exact job, but the total weight of SS316 material would be lower, and the cost as well.

Essentially, stub ends allow to minimize the weight of high-grade material in stainless, duplex, and nickel alloy piping, saving costs. Of course, the bigger the diameter and the class of the flanges, the higher the saving!

Facilitates the installation of the flange

The lap joint flange can be rotated on the pipe and simplify the alignment of the bolt holes of the mating flanges

It shall be noted that stud ends are becoming popular also in high-pressure applications (whereas they were used for low-pressure applications only in the past).

STUB END TYPES

Stub ends are available in three different types, named “Type A”, “Type B” and “Type C”:

The first type (A) is manufactured and machined to match standard lap joint backing flange (the two products have to be used in combination). The mating surfaces have an identical profile to permit a smooth loading of the flare face
Stub ends type B are have to be used with standard slip-on flanges
Type C stub ends can be used either with lap joint or slip-on flanges and are manufactured from pipes

SHORT/LONG PATTERN STUB ENDS (ASA/MSS)

Stub ends are available in two different patterns:

the short pattern, called MSS-A stub ends
the long pattern, called ASA-A stub ends (or ANSI length stub end)

Short and long pattern stub ends — Short pattern (MSS) and long pattern stub ends (ASA)

STUB END FINISH

Stub ends can be ordered with different ends finishing:

Beveled Ends
Squared Ends
Flanged Ends
Grooved Ends
Threaded Ends (Male Only)

STUB END MATERIALS

ASTM	Grade	UNS Equivalent
A234 WPB Carbon Steel	B	K03006
A403 Stainless Steel	304/304L	S30403
	304H	S30409
	316/316L	S31603
	316H	S31609
	317L	S31703
	904L	N08904
	309S/H	S30908
	310S	S31008
	321	S32100
	6XN	N08367
	20CB	N08020
	347	S34709
	254SMO	S31254
A815 Duplex /Super Duplex	2205	S31803/S32205
	Zeron 100	S32760
	2507	S32750
	410	S41000
A366 Nickel Alloys	HC22	N06022
	HB-3	N10675
	HG3	N06985
	HX	N06002
	HC2000	N06200
	HC276	N10276
	NCI	N06600
	NC	N04400
	N	N02200
	NL	N02201
	NCMC	N06625
	NICMC	N08825
	NIC10	N08810
	NIC11	N08811

STUB ENDS DIMENSIONS

The chart shows the MSS and ANSI stub end dimensions in inches.

		MSS Stub End			ANSI Stub End			Pipe OD			Pipe WT			Lap OD		Radius		Flange thk
NPS	Sch	Min	Nom	Max	Min	Nom	Max	Min	Nom	Max	Min	Nom	Max	Min	Max	Min	Nom	Min	Max
1/2″	05S	1.94	2	2.06	2.94	3	3.06	0.809	0.84	0.896	0.057	0.065	0.073	1.35	1.38	3/32	1/8	0.065	0.127
	10S										0.073	0.083	0.093					0.083	0.145
	40S										0.095	0.109	0.123					0.109	0.171
	80S										0.129	0.147	0.165					0.147	0.209
3/4″	05S	1.94	2	2.06	2.94	3	3.06	1.019	1.05	1.106	0.057	0.065	0.073	1.66	1.69	3/32	1/8	0.065	0.127
	10S										0.073	0.083	0.093					0.083	0.145
	40S										0.099	0.113	0.127					0.113	0.175
	80S										0.135	0.154	0.173					0.154	0.216
1	05S	1.94	2	2.06	3.94	4	4.06	1.284	1.315	1.376	0.057	0.065	0.073	1.7	2	3/32	1/8	0.065	0.127
	10S										0.095	0.109	0.123					0.109	0.171
	40S										0.116	0.133	0.15					0.133	0.195
	80S										0.157	0.179	0.201					0.179	0.241
1 1/4	05S	1.94	2	2.06	3.94	4	4.06	1.629	1.66	1.716	0.057	0.065	0.073	2.47	2.5	5/32	3/16	0.065	0.127
	10S										0.095	0.109	0.123					0.109	0.171
	40S										0.123	0.14	0.158					0.14	0.202
	80S										0.167	0.191	0.215					0.191	0.253
1 1/2	05S	1.94	2	2.06	3.94	4	4.06	1.869	1.9	1.965	0.057	0.065	0.073	2.85	2.88	7/32	1/4	0.065	0.127
	10S										0.095	0.109	0.123					0.109	0.171
	40S										0.127	0.145	0.163					0.145	0.207
	80S										0.175	0.2	0.225					0.2	0.262
2	05S	2.44	2.5	2.56	5.94	6	6.06	2.344	2.375	2.456	0.057	0.065	0.073	3.59	3.62	9/32	5/16	0.065	0.127
	10S										0.095	0.109	0.123					0.109	0.171
	40S										0.135	0.154	0.173					0.154	0.216
	80S										0.191	0.218	0.245					0.218	0.28
2 1/2	05S	2.44	2.5	2.56	5.94	6	6.06	2.844	2.875	2.966	0.073	0.083	0.093	3.9	4.12	9/32	5/16	0.083	0.145
	10S										0.105	0.12	0.135					0.12	0.182
	40S										0.178	0.203	0.228					0.203	0.265
	80S										0.242	0.276	0.311					0.276	0.338
3	05S	2.44	2.5	2.56	5.94	6	6.06	3.469	3.5	3.596	0.073	0.083	0.093	4.97	5	11/32	3/8	0.083	0.145
	10S										0.105	0.12	0.135					0.12	0.182
	40S										0.189	0.216	0.243					0.216	0.278
	80S										0.263	0.3	0.338					0.3	0.362
3 1/2	05S	2.94	3	3.06	5.94	6	6.06	3.969	4	4.096	0.073	0.083	0.093	5.47	5.5	11/32	3/8	0.083	0.145
	10S										0.105	0.12	0.135					0.12	0.182
	40S										0.198	0.226	0.254					0.226	0.238
	80S										0.278	0.318	0.358					0.318	0.38
4	05S	2.94	3	3.06	5.94	6	6.06	4.469	4.5	4.593	0.073	0.083	0.093	6.16	6.19	3/8	7/16	0.083	0.145
	10S										0.105	0.12	0.135					0.12	0.182
	40S										0.207	0.237	0.267					0.237	0.299
	80S										0.295	0.337	0.379					0.337	0.399
5	05S	2.94	3	3.06	7.94	8	8.06	5.532	5.563	5.683	0.095	0.109	0.123	7.28	7.31	3/8	7/16	0.109	0.171
	10S										0.117	0.134	0.151					0.134	0.196
	40S										0.226	0.258	0.29					0.258	0.32
	80S										0.328	0.375	0.422					0.375	0.437
6	05S	3.44	3.5	3.56	7.94	8	8.06	6.594	6.625	6.743	0.095	0.109	0.123	8.47	8.5	7/16	1/2	0.109	0.171
	10S										0.117	0.134	0.151					0.134	0.196
	40S										0.245	0.28	0.315					0.28	0.342
	80S										0.378	0.432	0.486					0.432	0.494
8	05S	3.94	4	4.06	7.94	8	8.06	8.594	8.625	8.743	0.095	0.109	0.123	10.59	10.62	7/16	1/2	0.109	0.171
	10S										0.13	0.148	0.167					0.148	0.21
	40S										0.282	0.322	0.362					0.322	0.384
	80S										0.438	0.5	0.563					0.5	0.562
10	05S	4.91	5	5.09	9.91	10	10.09	10.719	10.75	10.913	0.117	0.134	0.151	12.69	12.75	7/16	1/2	0.134	0.196
	10S										0.144	0.165	0.186					0.165	0.227
	40S										0.319	0.365	0.411					0.365	0.427
	80S										0.438	0.5	0.563					0.5	0.562
12	05S	5.91	6	6.09	9.91	10	10.09	12.719	12.75	12.913	0.137	0.156	0.176	14.94	15	7/16	1/2	0.156	0.218
	10S										0.158	0.18	0.203					0.18	0.242
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
14	05S	5.91	6	6.09	11.91	12	12.09	13.969	14	14.17	0.137	0.156	0.176	16.19	16.25	7/16	1/2	0.156	0.218
	10S										0.165	0.188	0.212					0.188	0.25
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
16	05S	5.91	6	6.09	11.91	12	12.09	15.969	16	16.18	0.144	0.165	0.176	18.44	18.5	7/16	1/2	0.165	0.227
	10S										0.165	0.188	0.212					0.188	0.25
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
18	05S	5.91	6	6.09	11.91	12	12.09	17.969	18	18.19	0.144	0.165	0.176	20.94	21	7/16	1/2	0.165	0.227
	10S										0.165	0.188	0.212					0.188	0.25
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
20	05S	5.91	6	6.09	11.91	12	12.09	19.969	20	20.24	0.165	0.188	0.212	22.94	23	7/16	1/2	0.188	0.25
	10S										0.191	0.218	0.245					0.218	0.28
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
24	05S	5.81	6	6.19	11.91	12	12.09	23.969	24	24.24	0.191	0.218	0.245	27.19	27.25	7/16	1/2	0.218	0.28
	10S										0.219	0.25	0.281					0.25	0.312
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
26	05S	5.81	6	6.19	11.81	12	12.19	25.969	26	26.24				29.19	29.25	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
28	05S	5.81	6	6.19	11.81	12	12.19	27.969	28	28.24				31.69	31.75	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
30	05S	5.81	6	6.19	11.81	12	12.19	29.969	30	30.24				33.69	33.75	7/16	1/2
	10S										0.273	0.312	0.351					0.312	0.374
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
32	05S	5.81	6	6.19	11.81	12	12.19	31.969	32	32.24				35.94	36	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.422
	80S										0.438	0.5	0.563					0.5	0.563
34	05S	5.81	6	6.19	11.81	12	12.19	33.969	34	34.24				37.94	38	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
36	05S	5.81	6	6.19	11.81	12	12.19	35.969	36	36.24				40.19	40.25	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
38	05S	5.81	6	6.19	11.81	12	12.19	37.969	38	38.24				42.69	42.75	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
40	05S	5.81	6	6.186	11.81	12	12.19	39.969	40	40.24				44.69	44.75	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
42	05S	5.81	6	6.186	11.81	12	12.19	41.969	42	42.24				46.94	47	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
44	05S	5.81	6	6.186	11.81	12	12.19	43.969	44	44.24				49.19	19.25	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
46	05S	5.81	6	6.19	11.81	12	12.19	45.969	46	46.24				51.19	51.25	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438		0.563					0.5	0.562
48	05S	5.81	6	6.19	11.81	12	12.19	47.969	48	48.24				53.19	53.25	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
50	05S	5.81	6	6.19	11.81	12	12.19	49.969	50	50.24				55.19	55.25	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
52	05S	5.81	6	6.19	11.81	12	12.19	51.969	52	52.24				57.19	57.25	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562
54	05S	5.81	6	6.19	11.81	12	12.19	53.969	54	54.24				59.44	59.5	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438		0.563					0.5	0.562
60	05S	5.81	6	6.19	11.81	12	12.19	59.969	60	60.24				65.44	65.5	7/16	1/2
	10S
	40S										0.328	0.375	0.422					0.375	0.437
	80S										0.438	0.5	0.563					0.5	0.562

6 Responses

flosil bet says:

September 9, 2019 at 6:32 am

This is a very amazing blog and I’m very happy to read this blog.

Reply
Connor McDavid says:

December 12, 2019 at 5:21 pm

flosil bet this is a very amazing comment and I’m very happy to read this comment.

Reply
Rakesh D Dharia says:

February 15, 2020 at 12:55 pm

can i get the drawing / dimensions of 3″ nb ring type joint stub end?

Reply
RICARDO CAIANI says:

October 20, 2020 at 7:12 pm

What are the Standards that covers Stub ends bigger than 24″?

Reply
Iris Smith says:

November 25, 2022 at 2:10 am

It’s great to know that rotating the lap joint flange on the pipe makes it easier to line up the bolt holes on the matching flanges. My husband is an industrial worker. He wants to acquire a piece of machinery for his project that can be utilized to fortify the tube’s end. I’ll advise him to acquire rotating tube beading for the pipe for his project.

Reply
Kalikund Steel says:

November 29, 2022 at 11:34 am

Thank you for sharing this pipe fitting information with us it is very helpful for us. You may also go here.. Kalikund Steel & Engg Co, Stainless Steel Flanges manufacturer, SS Pipe Fittings Manufacturers in India, SS Pipe Fittings Manufacturer

Reply

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Stub Ends for Flanged Joints

STUB END APPLICATION

BENEFITS OF LAP JOINT STUB ENDS

Reduces the overall cost of the flanged joint

Facilitates the installation of the flange

STUB END TYPES

SHORT/LONG PATTERN STUB ENDS (ASA/MSS)

STUB END FINISH

STUB END MATERIALS

STUB ENDS DIMENSIONS

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