SOCKET WELD FLANGE

Socket weld flanges are connected to pipes using a single fillet weld executed on the outer side of the flange (different from the slip-on flange type that requires two welds).

According to ASME B31.1, to execute a flanged connection using a socket weld flange, the pipe shall be at first inserted in the socket of the flange until it reaches the bottom of the flange, then it should be lifted by 1.6 mm and finally welded.

This gap shall be left to allow proper positioning of the pipe inside the flange socket after the solidification of the weld.

Socket Weld Flanges are used for small-size and high-pressure piping that do not transfer highly corrosive fluids.

This due to the fact that these flange types are subject to corrosion in the gap area between the end of the pipe and the shoulder of the socket.

Socket-Weld Flanges has a female socket in which the pipe is fitted. Fillet welding is done from outside on the pipe. Generally, it is used in small bore piping and only suitable for low pressure and temperature application.

Socket-Welded Flanges can be FF or RF
The cost of flange and fabrication is moderate.

socket weld flange cross section with weld detail

Socket weld flange dimensions are covered in ASME B16.5 – which covers Pipe Flanges and Flanged Fittings for size NPS ½” to 24” for above NPS 26” to 60” it should be as per ASME B16.47. Socket weld flanges are available only up to 3″ NPS Size.

During a dimensional inspection of socket weld flange, you should check for

Outer & Inner Diameter of body
Bolt Circle & Bolt Hole Diameter
Depth of the socket
Length of the Hub and
Straightness and alignment of the bolt hole

Class 150 Socket Neck Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Flange Length	RF Dia.	RF Height	Socket Depth	PCD	Socket Bore	No of Bolts	Bolt Size UNC	Machine Bolt Length	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
		A	B	C	D	E	F	G	H	J
1/2	15	90	9.6	30	14	34.9	2	10	60.3	22.2	4	1/2	50	55	5/8	M14	0.8
3/4	20	100	11.2	38	14	42.9	2	11	69.9	27.7	4	1/2	50	65	5/8	M14	0.9
1	25	110	12.7	49	16	50.8	2	13	79.4	34.5	4	1/2	55	65	5/8	M14	0.9
1 1/4	32	115	14.3	59	19	63.5	2	14	88.9	43.2	4	1/2	55	70	5/8	M14	1.4
1 1/2	40	125	15.9	65	21	73	2	16	98.4	49.5	4	1/2	65	70	5/8	M14	1.4
2	50	150	17.5	78	24	92.1	2	17	120.7	61.9	4	5/8	70	85	3/4	M16	2.3
2 1/2	65	180	20.7	90	27	105	2	19	139.7	74.6	4	5/8	75	90	3/4	M16	3.2
3	80	190	22.3	108	29	127	2	21	152.4	90.7	4	5/8	75	90	3/4	M16	3.7

Class 300 Socket Neck Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Flange Length	RF Dia.	RF Height	Socket Depth	PCD	Socket Bore	No of Bolts	Bolt Size UNC	Machine Bolt Length	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
		A	B	C	D	E	F	G	H	J
1/2	15	95	12.7	38	21	34.9	2	10	66.7	22.2	4	1/2	55	65	5/8	M14	1.2
3/4	20	115	14.3	48	24	42.9	2	11	82.6	27.7	4	5/8	65	75	3/4	M16	1.4
1	25	125	15.9	54	25	50.8	2	13	88.9	34.5	4	5/8	65	75	3/4	M16	1.4
1 1/4	32	135	17.5	64	25	63.5	2	14	98.4	43.2	4	5/8	70	85	3/4	M16	1.8
1 1/2	40	155	19.1	70	29	73	2	16	114.3	49.5	4	3/4	75	90	7/8	M20	2.7
2	50	165	20.7	84	32	92.1	2	17	127	61.9	8	5/8	75	90	3/4	M16	3.2
2 1/2	65	190	23.9	100	37	105	2	19	149.2	74.6	8	3/4	85	100	7/8	M20	4.6
3	80	210	27	117	41	127	2	21	168.3	90.7	8	3/4	90	110	7/8	M20	5.9

Class 600 Socket Neck Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Flange Length	RF Dia.	RF Height	Socket Depth	PCD	Socket Bore	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
		A	B	C	D	E	F	G	H	J
1/2	15	95	14.3	38	22	34.9	7	10	66.7	22.2	4	1/2	75	5/8	M14	1.3
3/4	20	115	15.9	48	25	42.9	7	11	82.6	27.7	4	5/8	90	3/4	M16	1.4
1	25	125	17.5	54	27	50.8	7	13	88.9	34.5	4	5/8	90	3/4	M16	1.8
1 1/4	32	135	20.7	64	29	63.5	7	14	98.4	43.2	4	5/8	95	3/4	M16	2.3
1 1/2	40	155	22.3	70	32	73	7	16	114.3	49.5	4	3/4	110	7/8	M20	3.2
2	50	165	25.4	84	37	92.1	7	17	127	61.9	8	5/8	110	3/4	M16	4.1
2 1/2	65	190	28.6	100	41	105	7	19	149.2	74.6	8	3/4	120	7/8	M20	5.9
3	80	210	31.8	117	46	127	7	21	168.3	90.7	8	3/4	125	7/8	M20	7.3

Class 1500 Socket Neck Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Flange Length	RF Dia.	RF Height	Socket Depth	PCD	Socket Bore	No of Bolts	Bolt Size UNC	RF Stud Length	Hole Size	ISO Stud Size	Weight in kg
		A	B	C	D	E	F	G	H	J
1/2	15	120	22.3	38	32	34.9	7	10	82.6	22.2	4	3/4	110	7/8	M20	1.8
3/4	20	130	25.4	44	35	42.9	7	11	88.9	27.7	4	3/4	115	7/8	M20	2.3
1	25	150	28.6	52	41	50.8	7	13	101.6	34.5	4	7/8	125	1	M24	3.7
1 1/4	32	160	28.6	64	41	63.5	7	14	111.1	43.2	4	7/8	125	1	M24	4.1
1 1/2	40	180	31.8	70	44	73	7	16	123.8	49.5	4	1	140	1 1/8	M27	5.5
2	50	215	38.1	105	57	92.1	7	17	165.1	61.9	8	7/8	145	1	M24	9.8
2 1/2	65	245	41.3	124	64	105	7	19	190.5	74.6	8	1	160	1 1/8	M27	16.4
3	80	265	47.7	133	N/A	127	7		203.2	N/A	8	1 1/8	180	1 1/4	M30	21.8