Buttweld Fittings Dimensions

Buttweld fittings are widely used in piping systems, primarily connecting two pipe sections through welding. They are primarily used in high-pressure piping systems and other high-pressure applications requiring high-pressure resistance and precise dimensions. These fittings are meticulously designed to ensure stable and leak-tight connections, playing a vital role in various industrial environments. They are used in industries such as petrochemicals, pharmaceuticals, healthcare, power generation, aerospace, defense, fire protection, metallurgy, shipbuilding, natural gas, nuclear power, and environmental protection.

Buttweld Fitting Standards

ASME B16.9: This is an internationally recognized standard established by the American Society of Mechanical Engineers (ASME). It covering factory-manufactured buttweld fittings, including elbows, tees, reducers, caps, and more. This standard specifies detailed technical requirements for pipe fitting dimensions, tolerances, pressure ratings, and other parameters, making it one of the most widely used standards globally.

ASME B16.28: This standard primarily addresses small-radius welded elbows.

GB/T 12459: This is a Chinese national standard similar to ASME standards, specifying dimensions, tolerances, and technical requirements for welded seamless steel pipe fittings.

GB/T 13401: This standard specifies the dimensions, tolerances, and technical requirements for welded steel pipe fittings.

EN 10253: This is the primary European standard for buttweld fittings, divided into several parts, such as EN 10253-2 and EN 10253-4.

DIN 2605 / DIN 2615 / DIN 2616 / DIN 2617: German standards for elbows, tees, reducers, and pipe caps.

Types of Buttweld Fittings

Fitting Type	Function Description	Common Types / Angles	Application Fields	Features & Notes
Elbow	Change the flow direction in a pipeline	90°, 45°, 180° Long Radius, Short Radius	Oil, Gas, Chemical, Power, etc.	Used to change flow direction; available in LR and SR types
Tee	Distribute or combine flow	Equal Tee, Reducing Tee	Branch piping layout	Connects branch pipelines; simple structure, easy installation
Cross	Connect multiple pipeline directions	Equal Cross, Reducing Cross	Chemical, Firefighting, Complex piping	Complex structure, stress-concentrated; requires proper installation layout
Reducer	Connect different pipe diameters	Concentric Reducer, Eccentric Reducer	Flow control, pump inlet, horizontal piping	Eccentric prevents fluid accumulation; concentric used for vertical piping
Cap	Close the end of a pipeline	Hemispherical, Elliptical	Pipe ends, test lines, reserved pipelines	Easy to install, ideal for sealing or testing ends
Stub End	Used with lap joint flange for easy disassembly	Long Stub End, Short Stub End	Food, Pharmaceutical, Stainless Piping Systems	Reusable; suitable for systems that require frequent disassembly

Buttweld 90°+45°+180° Elbow Dimensions

Nominal Size		Outside Diameter at Bevel	Center to End			Center to Center		Back to Face
Nominal Size		Outside Diameter at Bevel	90° Elbows		45° Elbows	180 Returns
DN	NPS	OD	A		B	O		K
DN	NPS	OD	LR	SR	LR	LR	SR	LR	SR
15	1/2	21.3	38		16	76		48
20	3/4	26.7	38		19	76		51
25	1	33.4	38	25	22	76	51	56	41
32	1 1/4	42.2	48	32	25	95	64	70	52
40	1 1/2	48.3	57	38	29	114	76	83	62
50	2	60.3	76	51	35	152	102	106	81
65	2 1/2	73.0	95	64	44	190	127	132	100
80	3	88.9	114	76	51	229	152	159	121
90	3 1/2	101.6	133	4、89	57	267	178	184	140
100	4	114.3	152	102	64	305	203	210	159
125	5	141.3	190	127	79	381	254	262	197
150	6	168.3	229	152	95	457	305	313	237
200	8	219.1	305	203	127	610	406	414	313
250	10	273.0	381	254	159	762	508	518	391
300	12	323.8	457	305	190	914	609	619	467
350	14	355.6	533	356	222	1067	711	711	533
400	16	406.4	610	406	254	1219	813	813	610
450	18	457.0	686	457	286	1372	914	914	686
500	20	508.0	762	508	318	1524	1016	1016	762
550	22	559.0	838	559	343	1676	1118	1118	838
600	24	610.0	914	610	381	1829	1219	1219	914
650	26	660.0	991	660	406
700	28	711.0	1067	711	438
750	30	762.0	1143	762	470
800	32	813.0	1219	813	502
850	34	864.0	1295	864	533
900	36	914.0	1372	914	565
950	38	965.0	1448	965	600
1000	40	1016.0	1524	1016	632
1050	42	1067.0	1600	1067	660
1100	44	1118.0	1676	1118	695
1150	46	1168.0	1753	1168	727
1200	48	1219.0	1829	1219	759

Buttweld Tee & Cross Dimensions

Nominal Size		Outside Diameter at Bevel	Center to End
DN	NPS	OD1×OD2	C	M
15	1/2	21.3	25	25
20	3/4	26.7	29	29
25	1	33.4	38	38
32	11/4	42.2	48	48
40	11/2	48.3	57	57
50	2	60.3	64	64
65	21/2	73.0	76	76
80	3	88.9	86	86
90	31/2	101.6	95	95
100	4	114.3	105	105
125	5	141.3	124	124
150	6	168.3	143	143
200	8	219.1	178	178
250	10	273.0	216	216
300	12	323.8	254	254
350	14	355.6	279	279
400	16	406.4	305	305
450	18	547.0	343	343
500	20	508.0	381	381
550	22	559.0	419	419
600	24	610.0	432	432
650	26	660.0	495	495
700	28	711.0	521	521
750	30	762.0	559	559
800	32	813.0	597	597
850	34	864.0	635	635
900	36	914.0	673	673
950	38	965.0	711	711
1000	40	1016.0	749	749
1050	42	1067.0	762	711
1100	44	1118.0	813	762
1150	46	1168.0	851	800
1200	48	1219.0	889	838
1300	52	1321.0	965	914
1400	56	1422.0	1041	965
1500	60	1524.0	1118	1016
1600	64	1626.0	1194	1092
1700	68	1727.0	1270	1168
1800	72	1829.0	1320	1245
1900	76	1930.0	1422	1320
2000	80	2032.0	1499	1397

Buttweld Reducer Dimensions

OD1	OD2	END TO END
NPS	NPS	H
3/4	3/8 – 1/2	38
1	1/2 – 3/4	51
1 1/4	1/2 – 1	51
1 1/2	1/2 – 1 1/4	64
2	3/4 – 1 1/2	76
2 1/2	1 – 2	89
3	1 1/4 – 2 1/2	102
4	2 – 3 1/2	102
5	2 – 4	127
6	2 1/2 – 5	140
8	3 1/2 – 6	152
10	4 – 8	178
12	5 – 10	203
14	6 – 12	330
16	6 – 14	356
18	8 – 16	381
20	10 – 18	508
22	12 – 20	508
24	12 – 22	508
26	12 – 24	610
28	14 – 26	610
30	14 – 28	610
32	20 – 30	610
34	22 – 32	610
36	22 – 34	610
38	24 – 36	610
40	28 – 38	610
42	28 – 40	610
44	32 – 42	610
46	34 – 44	711
48	36 – 46	711
52	40 – 48	711
56	40 – 52	711
60	44 – 56	711

Buttweld Cap Dimensions

Nominal Size		Outside Diameter at Bevel	Length		Limiting Wall Thickness for Length E
DN	NPS	OD	E	E1	Limiting Wall Thickness for Length E
15	1/2	21.3	25	25	4.57
20	3/4	26.7	25	25	3.81
25	1	33.4	38	38	4.57
32	1 1/4	42.2	38	38	4.83
40	1 1/2	48.3	38	38	5.08
50	2	60.3	38	44	5.59
65	2 1/2	73.0	38	51	7.11
80	3	88.9	51	64	7.62
90	3 1/2	101.6	64	76	8.13
100	4	114.3	64	76	8.64
125	5	141.3	76	89	9.65
150	6	168.3	89	102	10.92
200	8	219.1	102	127	12.7
250	10	273.0	127	152	12.70
300	12	323.8	152	178	12.70
350	14	355.6	165	191	12.70
400	16	406.4	178	203	12.70
450	18	457.0	203	229	12.70
500	20	508.0	229	254	12.70
550	22	559.0	254	254	12.70
600	24	610.0	267	305	12.70
650	26	660.0	267
700	28	711.0	267
750	30	762.0	267
800	32	813.0	267
850	34	864.0	267
900	36	914.0	267
950	38	965.0	305
1000	40	1016.0	305
1050	42	1067.0	305
1100	44	1118.0	343
1150	46	1168.0	343
1200	48	1219.0	343

Buttweld Lap Joint Stud End Dimensions

Nominal Size		OD of Cylinder		Length		Radius of Fillet		Diameter of Lap
DN	NPS	OD		F		R		Diameter of Lap
DN	NPS	Max.	Min.	Long Type	Short Type	A	B max	G
15	1/2	22.8	20.5	76	51	3	0.8	35
20	3/4	28.1	25.9	76	51	3	0.8	43
25	1	35.0	32.6	102	51	3	0.8	51
32	1 1/4	43.6	41.4	102	51	5	0.8	64
40	1 1/2	49.9	47.5	102	51	6	0.8	73
50	2	62.4	59.5	152	64	8	0.8	92
65	2 1/2	75.3	72.2	152	64	8	0.8	105
80	3	91.3	88.1	152	64	10	0.8	127
90	3 1/2	104.0	100.8	152	76	10	0.8	140
100	4	116.7	113.5	152	76	11	0.8	157
125	5	144.3	140.5	203	76	11	1.6	186
150	6	171.3	167.5	203	89	13	1.6	216
200	8	222.1	218.3	203	102	13	1.6	270
250	10	277.2	272.3	254	127	13	1.6	324
300	12	328.0	323.1	254	152	13	1.6	381
350	14	359.9	354.8	305	152	13	1.6	413
400	16	411.0	405.6	305	152	13	1.6	470
450	18	462.0	456.0	305	152	13	1.6	533
500	20	514.0	507.0	305	152	13	1.6	584
550	22	565.0	558.0	305	152	13	1.6	641
600	24	616.0	609.0	305	152	13	1.6	692

Buttweld Fittings Tolerance

Nominal Size

All Fittings

45°&90° Elbows
& Tees, Crosses

3D Radius Elbows

180° Returns

Caps

Reducers & Lap Joint
Stub Ends

Lap Joint Stub Ends

NPS

OD 3) 4)

ID 3)

A B C M

A B

E, E1

H F

15 – 65

1/2 – 21/2

+1.6
-0.8

± 0.8

± 2

± 3

± 6

± 1

± 3

± 2

0
-1

+1.6
0

80 – 90

3 – 31/2

± 1.6

± 2

± 3

± 6

± 1

± 3

± 2

0
-1

+1.6
0

100

± 1.6

± 2

± 3

± 6

± 1

± 3

± 2

0
-1

0
-2

+1.6
0

125 – 200

5 – 8

+2.4
-1.6

± 1.6

± 2

± 3

± 6

± 1

± 6

± 2

0
-1

0
-2

+1.6
0

250 – 450

10 – 18

+4.0
-3.2

± 3.2

± 2

± 3

± 10

± 6

± 2

± 6

± 2

0
-2

+3.2
0

500 – 600

20 – 24

+6.4
-4.8

± 4.8

± 2

± 3

± 10

± 6

± 2

± 6

± 2

0
-2

+3.2
0

650 – 750

26 – 30

+6.4
-4.8

± 4.8

± 3

± 6

—

± 10

± 5

—

800 – 1200

32 – 48

+6.4
-4.8

± 4.8

± 5

± 6

—

± 10

± 5

—

1300 – 1500

52 – 60

+6.4
-4.8

± 4.8

± 5

—

1600 – 1700

64 – 68

+6.4
-4.8

± 4.8

± 5

—

1800 – 2000

72 – 80

+6.4
-4.8

± 4.8

± 5

—

Why Choose us?

ZIZI Company specializes in the design, manufacture, and supply of various types of buttweld fittings. Our products cover a wide range of materials, including carbon steel, stainless steel, duplex stainless steel, alloy steel, and nickel alloys, to meet the needs of different operating conditions. Our products are available in a wide range of sizes, from conventional small diameters to large diameters, and are suitable for harsh operating conditions such as high temperatures, high pressures, and strong corrosion.

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