ASME B16.9 Carbon Steel Butt Weld Fittings

ASME B16.9 carbon steel butt welded pipe fittings have multiple advantages and play important roles in connecting, turning, and reducing in industrial pipeline systems.

What is Butt Weld Fittings

Butt weld fittings are an important type of pipe fittings in industrial pipeline systems, which are connected to pipelines through welding to achieve functions such as turning, reducing, branching, and end sealing of pipelines.

During the welding process of welded pipe fittings, it is necessary to perform bevel treatment on the ends of the fittings and pipes, and then use welding technology to connect them to the pipes. This connection method can not only effectively avoid medium leakage, but also reduce pressure loss in the pipeline system and improve the operating efficiency of the pipeline system.

Introduction to ASME B16.9 Standard

The ASME B16.9 standard (Download) is a standard specification developed by the American Society of Mechanical Engineers (ASME) for forged steel butt welded pipe fittings manufactured in factories. This standard has been widely recognized and applied worldwide, providing a unified technical basis for the design, manufacturing, inspection, and acceptance of butt welded pipe fittings.

Material	ASTM A234 WPB
Standard	ASME/ANSI B16.9, ASME B16.28, ASME B16.49,MSS-SP-43
Size	1/8"- 48″(DN6-DN1200)
Types	Butt Weld Elbow、Tee、Cross、Reducer、Cap、Stub End
Thickness	Sch 5s, Sch 10s, Sch 40s, Sch 80s, Sch 160s, Sch XXS

Scope

The ASME B16.9 standard applies to butt welded fittings with nominal sizes ranging from 1/2 inch (DN15) to 48 inches (DN1200), covering various common pipe specifications. At the same time, this standard is applicable to welded fittings made of various materials such as carbon steel, alloy steel, and stainless steel, which can meet the needs of different industrial environments.

Types of Buttwelding Fittings

According to ASME B16.9 standard, butt welded pipe fittings mainly include various product types such as butt welded elbows, butt welded tees, butt welded tees, reducers, butt welded pipe caps, and flanged short sections. These different types of butt welded pipe fittings each have unique structures and functions, which can meet different installation requirements in pipeline systems.

Specification of ASME B16.9

The ASME B16.9 standard provides strict specifications for the manufacturing process, dimensional tolerances, material properties, inspection methods, and marking requirements of forged steel butt welded pipe fittings.

Overall dimensions: Key dimensions for various types of fittings are specified, such as end outer diameter, center to end distance, wall thickness, etc.

Tolerance: specifies the manufacturing deviation allowed for the above dimensions.

Pressure rating: defines the working pressure of the pipe fittings at different temperatures and materials.

Testing: may include inspection and testing requirements for materials or finished pipe fittings, such as non-destructive testing, pressure testing, etc.

Marking: specifies the information that must be marked on the pipe fittings, such as standard number, material grade, size, pressure rating, etc., for easy identification and traceability.

Types and Dimension of Carbon Steel Butt Welded Fittings

ASME B16.9 offers a wide variety of carbon steel butt weld fittings, each with specific size specifications to meet the installation needs of different piping systems.

ASTM A234 WPB Carbon Steel Butt Weld Elbow (45 °/90 °/180 °/LR/SR)

Butt weld elbow is the most widely used type of carbon steel butt welded pipe fittings in ASME B16.9, mainly used to achieve pipeline turning.

According to the different bending angles of elbows, they can be divided into three common types: 45 ° elbows, 90 ° elbows, and 180 ° elbows;

According to different bending radii, it can be divided into long radius elbows (1.5D LR) and short radius elbows (1D SR);

In terms of size, the nominal size range of butt welded elbows is from 1/2 inch (DN15) to 48 inches (DN1200), and their outer diameter and wall thickness are designed and manufactured according to the corresponding pipeline standards (such as ANSI B36.10).

Dimension of 90 Deg and 45 Deg Elbow

BW 90 LR/SR Elbow			BW 45 LR Elbow
ASME B16.9
Nominal Size		Outside Diameter at Bevel	Center to End
			90°  Elbows		45°  Elbows
DN	NPS	OD	A		B
			LR	SR	LR
15	1/2	21.3	38		16
20	3/4	26.7	38		19
25	1	33.4	38	25	22
32	1 1/4	42.2	48	32	25
40	1 1/2	48.3	57	38	29
50	2	60.3	76	51	35
65	2 1/2	73.0	95	64	44
80	3	88.9	114	76	51
90	3 1/2	101.6	133	89	57
100	4	114.3	152	102	64
125	5	141.3	190	127	79
150	6	168.3	229	152	95
200	8	219.1	305	203	127
250	10	273.0	381	254	159
300	12	323.8	457	305	190
350	14	355.6	533	356	222
400	16	406.4	610	406	254
450	18	457.0	686	457	286
500	20	508.0	762	508	318
550	22	559.0	838	559	343
600	24	610.0	914	610	381
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

Dimension of 3D and 180 Deg Elbow

          

BW 90 3D Elbow			BW 45 3D Elbow			BW 180 LR/SR Return
ASME B16.9
Nominal Size		Outside Diameter at Bevel	Center to End		Center to Center		Back to Face
			90°     Elbows	45°          Elbows	180                                                                                        Returns
DN	NPS	OD	A	B	O		K
			3D	3D	LR	SR	LR	SR
15	1/2	21.3			76		48
20	3/4	26.7	57	24	76		51
25	1	33.4	76	31	76	51	56	41
32	1 1/4	42.2	95	39	95	64	70	52
40	1 1/2	48.3	114	47	114	76	83	62
50	2	60.3	152	63	152	102	106	81
65	2 1/2	73.0	190	79	190	127	132	100
80	3	88.9	229	95	229	152	159	121
90	3 1/2	101.6	267	111	267	178	184	140
100	4	114.3	305	127	305	203	210	159
125	5	141.3	381	157	381	254	262	197
150	6	168.3	457	189	457	305	313	237
200	8	219.1	610	252	610	406	414	313
250	10	273.0	762	316	762	508	518	391
300	12	323.8	914	378	914	609	619	467
350	14	355.6	1067	441	1067	711	711	533
400	16	406.4	1219	505	1219	813	813	610
450	18	457.0	1372	568	1372	914	914	686
500	20	508.0	1524	632	1524	1016	1016	762
550	22	559.0	1676	694	1676	1118	1118	838
600	24	610.0	1829	757	1829	1219	1219	914
650	26	660.0	1981	821
700	28	711.0	2134	883
750	30	762.0	2286	964
800	32	813.0	2438	1010
850	34	864.0	2591	1073
900	36	914.0	2743	1135
950	38	965.0	2896	1200
1000	40	1016.0	3048	1264
1050	42	1067.0	3200	1326
1100	44	1118.0	3353	1389
1150	46	1168.0	3505	1453
1200	48	1219.0	3658	1516

ASME B16.9 Tee (BW Tee)

ASME B16.9 carbon steel butt welded tees are used to branch pipelines, allowing the pipeline system to transport media from the main pipeline to the branch pipeline. According to the different structural forms of tees, they can be divided into two types: equal diameter tees and reducing diameter tees.

The nominal size of the three ports of the equal diameter tee is the same, while the nominal size of the main port of the different diameter tee is larger than that of the branch port.

The nominal size range for butt welded tees is also from 1/2 inch (DN15) to 48 inches (DN1200), and the outer diameter and wall thickness of the main and branch pipes also follow the corresponding pipeline standards.

ASME B16.9 Dimensional for Butt Welded Tee

Nominal   Size		Outside Diameter at Bevel	Center to End
DN	NPS	OD	C	M
15	1/2	21.3	25	25
20	3/4	26.7	29	29
25	1	33.4	38	38
32	1.1/4	42.2	48	48
40	1.1/2	48.3	57	57
50	2	60.3	64	64
65	2.1/2	73.0	76	76
80	3	88.9	86	86
90	3.1/2	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	457.0	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	762
1100	44	1118.0	813	813
1150	46	1168.0	851	851
1200	48	1219.0	889	889

Concentric/Ecc Reducers

Butt welded reducers, also known as reducing pipes, are used to connect pipes of different diameters. They are divided into two types: concentric reducers (CONC) and eccentric reducers (ECC).

The centers of the two ends of the concentric head are on the same straight line, suitable for general pipeline variable diameter connections;

The centers of the two ends of the eccentric head are not on the same straight line, mainly used to prevent the accumulation of medium in the pipeline. It is commonly used in pump inlets, horizontal pipelines, and pipeline systems that require drainage.

The nominal size range of ASME B16.9 carbon steel concentric and eccentric reducers is from 1/2 inch (DN15) to 48 inches (DN1200), and the outer diameter and wall thickness of the large and small ends are designed according to the corresponding pipeline standards.

The size parameters of eccentric reducers are similar to those of concentric reducers, except for the difference in eccentricity in structure. The eccentricity is determined based on the nominal size and pipeline standards to ensure the smoothness of pipeline connections and the normal flow of media.

Dimensional of BW Reducer

Nominal Size				Outside Diameter at Bevel		Center to End
DN1	DN2	NPS1	NPS2	OD1	OD2	H
20	10-15	3/4	3/8-1/2	26.7	17.1-21.3	38
25	15-20	1	1/2-3/4	33.4	21.3-26.7	51
32	15-25	1 1/4	1/2-1	42.2	21.3-33.4	51
40	15-32	1 1/2	1/2-1 1/4	48.3	21.3-42.2	64
50	20-40	2	3/4-1 1/2	60.3	26.7-48.3	76
65	25-50	2 1/2	1-2	73.0	33.4-60.3	89
80	32-65	3	1 1/4-2 1/2	88.9	42.2-73.0	89
90	32-80	3 1/2	1 1/4-3	101.6	42.2-88.9	102
100	40-90	4	1 1/2-3 1/2	114.3	48.3-101.6	102
125	50-100	5	2-4	141.3	60.3-114.3	127
150	65-125	6	2 1/2-5	168.3	73.0-141.3	140
200	90-150	8	3 1/2-6	219.1	101.6-168.3	152
250	100-200	10	4-8	273.0	114.3-219.1	178
300	125-250	12	5-10	323.8	141.3-273.0	203
350	150-300	14	6-12	355.6	168.3-323.8	330
400	150-350	16	6-14	406.4	168.3-355.6	356
450	200-400	18	8-16	457.0	219.1-406.4	381
500	250-450	20	10-18	508.0	273.0-457.0	508
550	300-500	22	12-20	559.0	323.8-508.0	508
600	300-550	24	12-22	610.0	323.8-559.0	508
650	350-600	26	14-24	660	355.6-610.0	610
700	350-650	28	14-26	711	355.6-660.0	610
750	350-700	30	14-28	762	355.6-711.0	610
800	500-750	32	20-30	813	508.0-762.0	610
850	550-800	34	22-32	864	559.0-813.0	610
900	550-850	36	22-34	914	559.0-864.0	610
950	600-900	38	24-36	965	610.0-914.0	610
1000	700-950	40	28-38	1016	711.0-965.0	610
1050	700-1000	42	28-40	1067	711.0-1016.0	610
1100	800-1050	44	32-42	1118	813.0-1067.0	610
1150	850-1100	46	34-44	1168	864.0-1118.0	711
1200	900-1150	48	36-46	1219	914.0-1168.0	711
1300	1000-1200	52	40-48	1321	1016.0-1219.0	711
1400	1100-1300	56	40-52	1422	1016.0-1321.0	711
1500	1100-1400	60	44-56	1524	1118.0-1422.0	711

ASME B16.9 Butt Weld Cap 

The butt welded pipe cap is used to seal the end of the pipeline, preventing medium leakage and external impurities from entering the pipeline, and protecting the safe operation of the pipeline system. The nominal size range of ASME B16.9 carbon steel butt welded pipe cap is from 1/2 inch (DN15) to 48 inches (DN1200), and its outer diameter and wall thickness are consistent with the corresponding nominal size of the pipeline to ensure good connection with the pipeline.

ASME B16.9 Dimensions of Buttwelding Pipe Cap

DN	NPS	OD	E	E1
15	1/2	21.3	25	25
20	3/4	26.7	25	25
25	1	33.4	38	38
32	11/4	42.2	38	38
40	11/2	48.3	38	38
50	2	60.3	38	44
65	21/2	73.0	38	51
80	3	88.9	51	64
90	31/2	101.6	64	76
100	4	114.3	64	76
125	5	141.3	76	89
150	6	168.3	89	102
200	8	219.1	102	127
250	10	273.0	127	152
300	12	323.8	152	178
350	14	355.6	165	191
400	16	406.4	178	203
450	18	457.0	203	229
500	20	508.0	229	254
550	22	559.0	254	254
600	24	610.0	267	305
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	---

Stub End

Stub End is a short pipe with a flanged structure, mainly used in conjunction with flanges to enhance the strength and sealing of the connection between pipes and flanges, while also facilitating the installation and disassembly of pipes. The nominal size range of ASME B16.9 carbon steel flanged short sections is from 1/2 inch (DN15) to 24 inches (DN600), with the same outer diameter and wall thickness as the corresponding pipeline specifications. The height and thickness of the flange are determined according to the flange standards and sealing requirements.

ASTM A234 Dimensions of Stub End

Nominal Size		OD of Cylinder		Length		Radius of Fillet		Diameter of Lap
DN	NPS	OD		F		R
		Max.	Min.	长型 Long Type	短型 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

ASME B16.9 Tolerance of Pipe Fittings

Nominal  Size		All Fittings		45°&90° Elbows & Tees, Crosses	3D Radius Elbows	180° Returns			Caps	Reducers & Lap Joint Stub Ends	Lap Joint  Stub Ends
DN	NPS	OD 3) 4)	ID 3)	A   B   C   M	A   B	O	K	U	E,  E1	H   F	G	R	t
15-65	1/2 -21/2	+1.6 -0.8	± 0.8	± 2	± 3	± 6	± 6	±  1	± 3	± 2	0  -1	0  -1	+1.6 0
80-90	3-31/2	± 1.6	± 1.6	± 2	± 3	± 6	± 6	±  1	± 3	± 2	0  -1	0  -1	+1.6 0
100	4	± 1.6	± 1.6	± 2	± 3	± 6	± 6	±  1	± 3	± 2	0  -1	0  -2	+1.6 0
125-200	5-8	+2.4 -1.6	± 1.6	± 2	± 3	± 6	± 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	0  -2	+3.2 0
500-600	20-24	+6.4 -4.8	± 4.8	± 2	± 3	± 10	± 6	± 2	± 6	± 2	0  -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	---	---	---	---	---	---	---	---	---

What is ASTM A234 WPB Standard

In ASME B16.9 carbon steel butt welded pipe fittings, ASTM A234 WPB material butt welded pipe fittings have been widely used in many industrial fields due to their excellent comprehensive performance.

What Means WPB?

ASTM A234 is a standard specification for forged carbon steel and alloy steel pipe fittings for medium temperature use developed by the American Society for Testing and Materials (ASTM), while WPB is a specific carbon steel material grade specified in the standard.

W "represents welding, indicating that the material of the pipe fittings is suitable for welding connections;

P "represents Pipe, indicating that this material is mainly used for the manufacturing of pipe fittings in pipeline systems;

B "is the grade designation of the material in ASTM A234 standard, representing specific chemical composition and mechanical performance requirements.

Material performance

ASTM A234 WPB material butt welded fittings have excellent mechanical and welding properties, high temperature and high pressure resistance, ensuring the structural stability of the pipeline system during operation.

Chemical composition

CHEMICAL

LIMITS

C

Mn

P

S

Si

Cr

Mo

Ni

Cu

Cb

V

ASTM A234 WPB

MIN

0.29

0.10

MAX

0.30

1.06

0.050

0.058

0.40

0.15

0.40

0.40

/

0.08

Mechanical properties

MATERIAL	T.S (MPA)	Y.S (MPA)	EL %	HARDNESS
ASTM A234 WPB	415 min	240 min	22 min	197 max

Advantages and Disadvantages of BW Fittings and SW Fittings

In industrial pipeline systems, butt welded pipe fittings and socket welded pipe fittings are two commonly used types of pipe fittings, which have significant differences in structure, connection methods, performance characteristics, and applicable scenarios, and each has its own advantages and disadvantages.

Structure and Connection Method

The end of the welded pipe fittings adopts a groove form, which forms a continuous weld connection with the pipeline through welding, and the strength of the welded joint is relatively high;

Socket welded pipe fittings have a socket, and after the pipe is inserted into the socket, it is welded at the gap between the socket and the pipe to form a fillet weld connection.

Advantage

Advantages of BW Fittings

Good sealing performance: The welding joint between the welded pipe fittings and the pipeline is a continuous weld seam, which can effectively prevent medium leakage.

Excellent mechanical performance: The strength of welded joints can withstand high pressure, temperature, and vibration loads, improving overall stability and safety.

Wide applicability: Welded pipe fittings are suitable for pipeline systems in high-pressure and high-temperature environments, with nominal sizes ranging from 1/2 inch to 48 inches, and can meet the needs of different industrial fields.

Advantages of SW Fittings

Easy installation: The installation process of socket welding fittings is relatively simple, and the pipeline only needs to be inserted into the socket and welded, resulting in high installation efficiency.

Easy maintenance: In some small pipeline systems, if replacement of fittings is required, the disassembly and replacement of socket welding fittings are relatively easy, which can reduce maintenance workload and costs.

Disadvantage

Butt Wedl Fittings

Difficulty in installation

High requirements for installation environment

Socket Weld Fittings

Poor sealing performance

Limited mechanical properties

High flow resistance

narrow scope of application

ASTM A234 VS ASTM A403

ASTM A234 and ASTM A403 are both material standards for forged pipe fittings developed by the American Society for Testing and Materials. There are certain differences between the two in terms of application scope, material type, performance requirements, etc., and they are suitable for different industrial scenarios.

Scope

The ASTM A234 standard is applicable to carbon steel and alloy steel butt welded pipeline fittings, mainly used in pipeline systems at room temperature, covering various types such as butt welded elbows, tees, tees, pipe caps, reducers, and flanged short joints;

The ASTM A403 standard is applicable to austenitic stainless steel butt welded fittings, mainly used in pipeline systems with high corrosion resistance requirements. It also covers various types of butt welded fittings such as butt welded elbows, tees, crosses, pipe caps, reducers, and flanged short joints.

Material

The ASTM A234 standard mainly includes carbon steel and alloy steel materials. Common grades of carbon steel materials include WPB, WPC, etc., while alloy steel grades include WP1, WP5, WP9, WP11, WP22, WP91, etc. Different grades of materials have different chemical compositions and mechanical properties to meet the needs of use under different temperature and pressure conditions;

The ASTM A403 standard mainly includes austenitic stainless steel materials, with common grades including WP304, WP304L, WP316, WP316L, WP321, WP347, etc. These materials have excellent corrosion resistance, can resist the erosion of various corrosive media, and also have good high-temperature strength and oxidation resistance.

Application

ASME B16.9 carbon steel butt welded pipe fittings play an indispensable role in multiple industrial fields due to their strict quality standards, diverse product types, and adaptability to different working conditions. The specific application scope is as follows:

Petrochemical industry

Natural gas transportation industry

power industry

Metallurgical industry

Municipal Engineering and Other Fields

ASME B16.9 carbon steel butt welded pipe fittings have become key components in industrial pipeline systems due to their strict standard specifications, comprehensive product types, excellent performance, and wide applicability, providing solid guarantees for production safety and efficient operation in various industries.