SLIP ON FLANGE

WELD NECK VS SLIP ON FLANGE

Flanged joints made with slip-on flanges are, in the long run, a bit more fragile than connections made with welding neck flanges (in similar service conditions). This seems due to the following facts:

a welding neck flange features a tapered hub, absent in a socket weld flange, which distributes the mechanical stress between the pipe and the flange more evenly
a welding neck joint as only one welding area instead of two (socket weld flange).

Another advantage of the welding neck flange is that it can be connected either to pipes and fittings, whereas socket weld flanges suit pipes only.

A slip-on flange is connected to the pipe or the fittings by two fillet welds, one executed inside and one outside the cavity of the flange.

The bore size of a slip-on flange is larger than the outside diameter of the connecting pipe, as the pipe has to slide inside the flange to be connected by the execution of a fillet weld.

Slip-On flange has a hole with matching outside diameter of pipe from which pipe can pass. The flange is placed on pipe and fillet welded from both inside and outside. Slip-On Flange is suitable for low pressure and temperature application.

This type of flange available in large size also
It can be FF or RF
The cost of flange and fabrication is moderate.

Slipon raised face (SORF) flange Cross section with weld detail

Slip on 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.

During a dimensional inspection of slip on flange, you should check for

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

Class 150 Slip-on Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Flange Length	RF Dia.	RF Height	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
1/2	15	90	9.6	30	14	34.9	2	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	69.9	27.7	4	1/2	50	65	5/8	M14	0.9
1	25	110	12.7	49	16	50.8	2	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	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	98.4	49.5	4	1/2	65	70	5/8	M14	1.4
2	50	150	17.5	78	24	92.1	2	120.7	61.9	4	5/8	70	85	3/4	M16	2.3
2 1/2	65	180	20.7	90	27	104.8	2	139.7	74.6	4	5/8	75	90	3/4	M16	3.2
3	80	190	22.3	108	29	127	2	152.4	90.7	4	5/8	75	90	3/4	M16	3.7
3 1/2	90	215	22.3	122	30	139.7	2	177.8	103.4	8	5/8	75	90	3/4	M16	5
4	100	230	22.3	135	32	157.2	2	190.5	116.1	8	5/8	75	90	3/4	M16	5.9
5	125	255	22.3	164	35	185.7	2	215.9	143.8	8	3/4	85	95	7/8	M20	6.8
6	150	280	23.9	192	38	215.9	2	241.3	170.7	8	3/4	85	100	7/8	M20	8.6
8	200	345	27	246	43	269.9	2	298.5	221.5	8	3/4	90	110	7/8	M20	13.7
10	250	405	28.6	305	48	323.8	2	362	276.2	12	7/8	100	115	1	M24	19.5
12	300	485	30.2	365	54	381	2	431.8	327	12	7/8	100	120	1	M24	29
14	350	535	33.4	400	56	412.8	2	476.3	359.2	12	1	115	135	1 1/8	M27	41
16	400	595	35	457	62	469.9	2	539.8	410.5	16	1	115	135	1 1/8	M27	54
18	450	635	38.1	505	67	533.4	2	577.9	461.8	16	1 1/8	125	145	1 1/4	M30	59
20	500	700	41.3	559	71	584.2	2	635	513.1	20	1 1/8	140	160	1 1/4	M30	75
24	600	815	46.1	663	81	692.2	2	749.3	616	20	1 1/4	150	170	1 3/8	M33	100

Class 300 Slip-on Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thick.	Hub OD	Flange Length	RF Dia.	RF Height	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
1/2	15	95	12.7	38	21	34.9	2	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	82.6	27.7	4	5/8	65	75	3/4	M16	1.4
1	25	125	15.9	54	25	50.8	2	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	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	114.3	49.5	4	3/4	75	90	7/8	M20	2.7
2	50	165	20.7	84	32	92.1	2	127	61.9	8	5/8	75	90	3/4	M16	3.2
2 1/2	65	190	23.9	100	37	104.8	2	149.2	74.6	8	3/4	85	100	7/8	M20	4.6
3	80	210	27	117	41	127	2	168.3	90.7	8	3/4	90	110	7/8	M20	5.9
3 1/2	90	230	28.6	133	43	139.7	2	184.2	103.4	8	3/4	95	110	7/8	M20	7.7
4	100	255	30.2	146	46	157.2	2	200	116.8	8	3/4	95	115	7/8	M20	10
5	125	280	33.4	178	49	185.7	2	235	144.4	8	3/4	110	120	7/8	M20	12.7
6	150	320	35	206	51	215.9	2	269.9	171.4	12	3/4	110	120	7/8	M20	17.7
8	200	380	39.7	260	60	269.9	2	330.2	222.2	12	7/8	120	140	1	M24	26
10	250	445	46.1	321	65	323.8	2	387.4	277.4	16	1	140	160	1 1/8	M27	36
12	300	520	49.3	375	71	381	2	450.8	328.2	16	1 1/8	145	170	1 1/4	M30	52
14	350	585	52.4	425	75	412.8	2	514.4	360.2	20	1 1/8	160	180	1 1/4	M30	75
16	400	650	55.6	483	81	469.9	2	571.5	411.2	20	1 1/4	165	190	1 3/8	M33	86
18	450	710	58.8	533	87	533.4	2	628.6	462.3	24	1 1/4	170	195	1 3/8	M33	113
20	500	775	62	587	94	584.2	2	685.8	514.4	24	1 1/4	185	205	1 3/8	M33	143
24	600	915	68.3	702	105	692.2	2	812.8	616	24	1 1/2	205	230	1 5/8	M39	216

Class 400 Slip-on Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thickness	Hub OD	Flange Length	RF Dia.	RF Height	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
1/2	15	95	14.3	38	22	34.9	7	66.7	22.2	4	1/2	75	5/8	M14	1.3
3/4	20	115	15.9	48	25	42.9	7	82.6	27.7	4	5/8	90	3/4	M16	1.5
1	25	125	17.5	54	27	50.8	7	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	98.4	43.2	4	5/8	95	3/4	M16	2.3
1 1/2	40	155	22.3	70	32	73	7	114.3	49.5	4	3/4	110	7/8	M20	3.2
2	50	165	25.4	84	37	92.1	7	127	61.9	8	5/8	110	3/4	M16	4.1
2 1/2	65	190	28.6	100	41	104.8	7	149.2	74.6	8	3/4	120	7/8	M20	5.9
3	80	210	31.8	117	46	127	7	168.3	90.7	8	3/4	125	7/8	M20	7.3
4	100	255	35	146	51	157.2	7	200	116.1	8	7/8	140	1	M24	11.8
5	125	280	38.1	178	54	185.7	7	235	143.8	8	7/8	145	1	M24	14.1
6	150	320	41.3	206	57	215.9	7	269.9	170.7	12	7/8	150	1	M24	20
8	200	380	47.7	260	68	269.9	7	330	221.5	12	1	170	1 1/8	M27	31
10	250	445	54	321	73	323.8	7	387.4	276.2	16	1 1/8	190	1 1/4	M30	42
12	300	520	57.2	375	79	381	7	450.8	327	16	1 1/4	205	1 3/8	M33	59
14	350	585	60.4	425	84	412.8	7	514.4	359.2	20	1 1/4	210	1 3/8	M33	82
16	400	650	63.5	483	94	469.9	7	571.5	410.5	20	1 3/8	220	1 1/2	M36	107
18	450	710	66.7	533	98	533.4	7	628.6	461.8	24	1 3/8	230	1 1/2	M36	130
20	500	775	69.9	587	102	584.2	7	685.8	513.1	24	1 1/2	240	1 3/4	M39	157
24	600	915	76.2	702	114	692.2	7	812.8	616	24	1 3/4	265	1 7/8	M45	232

Class 600 Slip-on Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thickness	Hub OD	Flange Length	RF Dia.	RF Height	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
1/2	15	95	14.3	38	22	34.9	7	66.7	22.2	4	1/2	75	5/8	M14	1.3
3/4	20	115	15.9	48	25	42.9	7	82.6	27.7	4	5/8	90	3/4	M16	1.4
1	25	125	17.5	54	27	50.8	7	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	98.4	43.2	4	5/8	95	3/4	M16	2.3
1 1/2	40	155	22.3	70	32	73	7	114.3	49.5	4	3/4	110	7/8	M20	3.2
2	50	165	25.4	84	37	92.1	7	127	61.9	8	5/8	110	3/4	M16	4.1
2 1/2	65	190	28.6	100	41	104.8	7	149.2	74.6	8	3/4	120	7/8	M20	5.9
3	80	210	31.8	117	46	127	7	168.3	90.7	8	3/4	125	7/8	M20	7.3
4	100	275	38.1	152	54	157.2	7	215.9	116.1	8	7/8	145	1	M24	16.8
5	125	330	44.5	189	60	185.7	7	266.7	143.8	8	1	165	1 1/8	M27	29
6	150	355	47.7	222	67	215.9	7	292.1	170.7	12	1	170	1 1/8	M27	36
8	200	420	55.6	273	76	269.9	7	349.2	221.5	12	1 1/8	190	1 1/4	M30	52
10	250	510	63.5	343	86	323.8	7	431.8	276.2	16	1 1/4	215	1 3/8	M33	77
12	300	560	66.7	400	92	381	7	489	327	20	1 1/4	220	1 3/8	M33	91
14	350	605	69.9	432	94	412.8	7	527	359.2	20	1 3/8	235	1 1/2	M36	105
16	400	685	76.2	495	106	469.9	7	603.2	410.5	20	1 1/2	255	1 5/8	M39	150
18	450	745	82.6	546	117	533.4	7	654	461.8	20	1 5/8	275	1 3/4	M42	182
20	500	815	88.9	610	127	584.2	7	723.9	513.1	24	1 5/8	285	1 3/4	M42	232
24	600	940	101.6	718	140	692.2	7	838.2	616	24	1 7/8	330	2	M48	332

Class 900 Slip-on Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thickness	Hub OD	Flange Length	RF Dia.	RF Height	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
1/2	15	120	22.3	38	32	34.9	7	82.6	22.2	4	3/4	110	7/8	M20	1.8
3/4	20	130	25.4	44	35	42.9	7	88.9	27.7	4	3/4	115	7/8	M20	2.3
1	25	150	28.6	52	41	50.8	7	101.6	34.5	4	7/8	125	1	M24	3.6
1 1/4	32	160	28.6	64	41	63.5	7	111.1	43.2	4	7/8	125	1	M24	4.1
1 1/2	40	180	31.8	70	44	73	7	123.8	49.5	4	1	140	1 1/8	M27	5.5
2	50	215	38.1	105	57	92.1	7	165.1	61.9	8	7/8	145	1	M24	11.5
2 1/2	65	245	41.3	124	64	104.8	7	190.5	74.6	8	1	160	1 1/8	M27	16.5
3	80	240	38.1	127	54	127	7	190.5	90.7	8	7/8	145	1	M24	12
4	100	290	44.5	159	70	157.2	7	235	116.1	8	1 1/8	170	1 1/4	M30	24
5	125	350	50.8	190	79	185.7	7	279.4	143.8	8	1 1/4	190	1 3/8	M33	38
6	150	380	55.6	235	86	215.9	7	317.5	170.7	12	1 1/8	190	1 1/4	M30	50
8	200	470	63.5	298	102	269.9	7	393.7	221.5	12	1 3/8	220	1 1/2	M36	78
10	250	545	69.9	368	108	323.8	7	469.9	276.2	16	1 3/8	235	1 1/2	M36	112
12	300	610	79.4	419	117	381	7	533.4	327	20	1 3/8	255	1 1/2	M36	148
14	350	640	85.8	451	130	412.8	7	558.8	359.2	20	1 1/2	275	1 5/8	M39	182
16	400	705	88.9	508	133	469.9	7	616	410.5	20	1 5/8	285	1 3/4	M42	193
18	450	785	101.6	565	152	533.4	7	685.8	461.8	20	1 7/8	325	2	M48	258
20	500	855	108	622	159	584.2	7	749.3	513.1	20	2	350	2 1/8	M52	317
24	600	1040	139.7	749	203	692.2	7	901.7	616	20	2 1/2	440	2 5/8	M64	608

Class 1500 Slip-on Flange Dimensions

Size in Inch	Size in mm	Outer Dia.	Flange Thickness	Hub OD	Flange Length	RF Dia.	RF Height	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
1/2	15	120	22.3	38	32	34.9	7	82.6	22.2	4	3/4	110	7/8	M20	1.8
3/4	20	130	25.4	44	35	42.9	7	88.9	27.7	4	3/4	115	7/8	M20	2.3
1	25	150	28.6	52	41	50.8	7	101.6	34.5	4	7/8	125	1	M24	3.7
1 1/4	32	160	28.6	64	41	63.5	7	111.1	43.2	4	7/8	125	1	M24	4.1
1 1/2	40	180	31.8	70	44	73	7	123.8	49.5	4	1	140	1 1/8	M27	5.5
2	50	215	38.1	105	57	92.1	7	165.1	61.9	8	7/8	145	1	M24	9.8
2 1/2	65	245	41.3	124	64	104.8	7	190.5	74.6	8	1	160	1 1/8	M27	16.4