ASME B16.9 butt weld reducers are pipe fittings used to connect pipes of different diameters, serving as size transition components within piping systems. They enable fluid to smoothly transition from one pipe diameter to another, ensuring proper fluid conveyance while minimizing pressure loss.

Reducers typically feature a conical or eccentric conical structure. The conical shape may be concentric, where the center axes coincide, or eccentric, where the center axes do not align. Concentric reducers maintain a consistent centerline when pipe diameters change at both ends, making them suitable for applications with strict fluid flow direction requirements and limited installation space. ASME B16.9 reducers are widely used in pipeline systems across petroleum, chemical, natural gas, power, and metallurgical industries. They connect pipes of differing diameters or facilitate directional changes while conserving space.

Butt Weld Reducers Specification

Size	Seamless Butt Weld Fittings : 1/2″ – 10″
	Welded Butt Weld Fittings : 1/2″ – 48″
Dimensions	ASME/ANSI B16.9, ASME B16.28, MSS-SP-43, BS4504, BS4504, BS1560, BS10
Thickness	SCH10, SCH20, SCH30, STD SCH40, SCH60, XS, SCH 80, SCH 100, SCH 120, SCH 140, SCH 160, XXS available with NACE MR 01-75
Bending Radius	R=1D, 2D, 3D, 5D, 6D, 8D, 10D
Manufacturing process	Push, Press, Forge, Cast, etc.
Test Certificates	EN 10204/3.1B
	Raw Materials Certificate
	100% Radiography Test Report
	Third Party Inspection Report, etc

Concentric Reducer

The primary structural feature of concentric reducers is their concentric design. This configuration ensures that the fluid flow direction remains unchanged as it passes through the reducer, maintaining a relatively stable flow state. The defining characteristic of concentric reducers is the perfect alignment of their centerlines at both ends. Viewed from the side, it exhibits a symmetrical conical structure resembling a bell mouth or funnel. This design ensures a smooth transition for the fluid within the pipe, minimizing the generation of vortices and turbulence. This makes it particularly suitable for applications with stringent requirements for fluid flow.

Eccentric Reducer

An eccentric reducer is a pipe fitting used to connect two pipes of different diameters, with its two ends offset from each other. This offset is termed the eccentricity, meaning one side of the fitting is straight while the other tapers gradually at an angle. Unlike symmetrical concentric reducers, the eccentric design aids in controlling fluid flow, reducing turbulence, and preventing gas accumulation or cavitation within the piping system. It is commonly used in applications requiring consistent bottom or top liquid levels in pipelines.

Concentric and Eccentric Reducers

Concentric reducers and eccentric reducers are two common types of pipe fittings used for connecting pipes of different diameters in piping systems. However, due to their structural differences, their respective applications and advantages also vary.

Feature	Concentric Reducer	Eccentric Reducer
Structure	A symmetrical cone with aligned centerlines.	Centerlines are not aligned, with one side flat and the other inclined.
Primary Function	To maintain the pipeline’s centerline alignment.	To keep the pipeline’s bottom or top flat.
Application	Vertical pipelines, or horizontal pipelines where centerline alignment is required.	Horizontal pipelines, used to prevent liquid or gas accumulation.
Advantages	Simple structure, easy to install, lower cost.	Effectively prevents air pockets and liquid accumulation in the pipeline.
Disadvantages	Can lead to gas or liquid accumulation in horizontal pipelines.	More complex structure, higher cost, and requires careful orientation during installation.

ASME B16.9 Seamless and Welded Reducer

Seamless

Seamless reducers are typically manufactured by forming entire lengths of seamless stainless steel pipe through pressure or push forming. The advantage of this process lies in the absence of welds, resulting in higher overall strength and pressure resistance, making it particularly suitable for demanding environments requiring high pressure and temperature endurance. However, due to the use of solid pipe forming, the available size range is relatively limited, and wall thickness control presents greater challenges.

Welded

Welded reducers are produced by rolling stainless steel plates into a conical shape and then welding them together. This manufacturing method offers greater flexibility, making it especially suitable for producing large-diameter or non-standard-sized products, and it is typically more cost-effective. The primary drawback, however, is the presence of weld seams. Although these undergo rigorous inspection, they may be slightly inferior to seamless reducers in terms of pressure resistance and overall strength.

ASTM A403 Concentric Reducer

Chromium (Cr)

Provides the primary corrosion resistance and oxidation resistance; higher content yields better corrosion resistance.

Nickel (Ni)

Enhances material ductility and toughness, improves corrosion resistance, particularly against acidic media.

Molybdenum (Mo)

Significantly enhances resistance to chloride-induced pitting and crevice corrosion (e.g., seawater). Not present in 304.

Manganese (Mn)

Increases solid solution strength and improves machinability.

Silicon (Si)

Enhances oxidation resistance and improves fluidity.

CHEMICAL	LIMITS	C	Mn	P	S	Si	Ni	Cr	Mo
ASTM A403 WP304	MIN						8.0	18.0
	MAX	0.08	2.00	0.045	0.030	1.00	11.0	20.0
ASTM A403 WP316	MIN						10.0	16.0	2.00
	MAX	0.08	2.00	0.045	0.030	1.00	14.0	18.0	3.00
ASTM A403 WP321	MIN						9.00	17.00
	MAX	0.08	2.00	0.045	0.030	1.00	12.00	19.00
ASTM A403 WP904L	MIN						23.00	19.00	4.000
	MAX	0.02	2.00	0.045	0.035	1.00	28.00	23.00	5.000

Tensile Strength: The maximum stress a material can withstand before breaking.

Yield Strength: The maximum stress a material can withstand before undergoing permanent plastic deformation.

Elongation: The percentage increase in length of a material at break, reflecting its plasticity and toughness.

MATERIAL	ASTM A403 WP304	ASTM A403 WP316	ASTM A403 WP321	ASTM A403 WP904L
T.S (MPA)	515 min	515 min	515 min	490 min
Y.S (MPA)	205 min	205 min	205 min	220 min
EL %	28 min	28 min	28 min	28 min

ASTM A234 WPB Concentric Reducer

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 Property

MATERIAL	T.S (MPA)	Y.S (MPA)	EL %	R/A %	HARDNESS
ASTM A234 WPB	415 min	240 min	22 min	30 min	197 max

ANSI / ASME B16.9 Reducer Dimensions

Concentric Reducer

OD1	OD2	END TO END	SCH 40 WEIGHT
NPS	NPS	H	KG
3/4	3/8 – 1/2	38	0.07
1	1/2 – 3/4	51	0.14
1 1/4	1/2 – 1	51	0.19
1 1/2	1/2 – 1 1/4	64	0.29
2	3/4 – 1 1/2	76	0.46
2 1/2	1 – 2	89	0.85
3	1 1/4 – 2 1/2	102	1.11
4	2 – 3 1/2	102	1.8
5	2 – 4	127	3.05
6	2 1/2 – 5	140	4.35
8	3 1/2 – 6	152	7.12
10	4 – 8	178	11.8
12	5 – 10	203	17.8
14	6 – 12	330	34.3
16	6 – 14	356	48.3
18	8 – 16	381	65.3
20	10 – 18	508	102
22	12 – 20	508	–
24	12 – 22	508	143
26	12 – 24	610	–
28	14 – 26	610	–
30	14 – 28	610	–
32	20 – 30	610	230
34	22 – 32	610	245
36	22 – 34	610	282
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

Eccentric Reducer

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

Eccentric Reducer Weight

Eccentric Reducer Weight Chart in kg
Nominal Size		SCH20	STD	SCH40	SCH80	SCH120	SCH160
DN	NPS
15	1/2		0.08	0.08	0.1
20	3/4		0.17	0.17	0.2
25	1		0.21	0.21	0.25		0.22
32	1 1/4		0.29	0.29	0.35
40	1 1/2		0.42	0.42	0.58		0.6
50	2		0.8	0.8	1.03		1.04
65	2 1/2		1.05	1.05	1.42		1.65
80	3		136	1.36	1.9
90	3 1/2		1.63	1.63	2.27		2.4
100	4		2.77	2.77	3.93		4.4
125	5		3.96	3.96	6		7.14
150	6		6.31	6.31	9.26		10.8
200	8	7.85	10.7	10.7	17.5	15	18.4
250	10	11.2	15.8	16.3	25.1	25.1	32.5
300	12	25.6	28.8	32.1	56.5	41.7	53.3
350	14	30.5	38.5	48.8	79	84.5	106
400	16	35.2	44.5	64.3	102	112	143
450	18	62.7	62.7	98.5	165
500	20	72.6	72.6		181
550	22	97	79.1	142	226
600	24	130	100

Concentric Reducer Weight

Concentric Reducer Weight Chart
DN	NPS	10S	20	STD	40	XS	80	160	XXS
20	3/4	0.1	/	0.1	0.1	0.1	0.1	/	/
25	1	0.1	/	0.2	0.2	0.2	0.2	/	/
32	1 1/4	0.1	/	0.2	0.2	0.3	0.3	0.2	/
40	1 1/2	0.2	/	0.3	0.3	0.4	0.4	/	/
50	2	0.3	/	0.4	0.4	0.6	0.6	0.6	1
65	2 1/2	0.5	/	0.8	0.8	1.0	1.0	1.0	/
80	3	0.6	/	1.1	1.1	1.4	1.4	1.7	1
90	3 1/2	0.7	/	1.4	1.4	1.9	1.9	/	/
100	4	0.8	/	1.6	1.6	2.3	2.3	2.4	/
125	5	1.4	/	2.81	2.8	4.0	3.9	4.4	/
150	6	1.9	/	4.0	4.0	6.0	6.0	7.1	8.6
200	8	2.8	/	6.3	6.3	6.0	9.3	10.8	12.6
250	10	4.6	7.9	10.7	10.7	9.3	17.5	18.4	17.9
300	12	7.0	11.2	15.8	16.3	14.5	25.1	32.5	29.3
350	14	14.0	25.6	28.8	32.1	21.0	56.5	53.3	41.7
400	16	17.5	30.5	38.5	48.8	37.1	79	106.0	/
450	18	21.5	35.2	44.5	64.3	48.8	102	143.0	/
500	20	36.0	62.7	62.7	98.5	58.5	165	/	/
550	22	38.0	72.6	72.6	/	80.4	181	/	/
600	24	47.5	97.0	79.1	142.0	93.8	226	/	/

How to Calculate The Weight of Steel Pipe Reducer?

0.02466 × S ×[ (D+d)/2-S] × H / 1000

S: Wall thickness of Butt Weld Reducer

D: Outside diameter of the larger end

d: Outside diameter of the small end

H: End to end dimension

ASME B16.9 Standard

This Standard covers overall dimensions, tolerances, ratings, testing, and markings for factory-made wrought buttwelding fittings in sizes NPS 1/2 through NPS 48 (DN 15 through DN 1200).

Pressure Rating Designation

Class followed by a dimensionless number is the designation for pressure-temperature ratings. Standardized designations for flanges per ASME B16.5 referenced in this Standard are Classes 150, 300, 600, 900, 1500, and 2500.

Marking

Standard Marking Each fitting shall be permanently marked to show the following:

(a) manufacturer’s name or trademark

(b) material identification, either the ASTM or ASME grade designation

(c) schedule number1 or nominal wall thickness in mm

(d) size — the nominal pipe size (NPS) identification number related to the end connections shall be used

(e) compliance—see para. 4.4 for standard and special fitting marking

A manufacturer may supplement these mandatory markings with others, including a DN size designation, but confusion with the required marking shall be avoided.

Packaging

For large-sized or heavy carbon steel pipe reducers, individual packaging or bundling may not provide sufficient support. Therefore, they are typically stacked neatly on large wooden pallets. The wooden pallet provides a sturdy base platform that evenly distributes weight, preventing deformation of the pipe fittings due to uneven stress. Subsequently, forklifts can directly lift the pallets from the bottom, significantly improving loading/unloading efficiency while reducing damage risks associated with manual handling. Fittings of the same specification or batch are grouped together on a single pallet for easier inventory management. Before packaging, plastic pipe caps are installed on both ends of the fittings or they are wrapped with plastic sheeting to protect the beveled edges and inner walls from scratches and prevent dust or moisture ingress.

During packaging, the large and small ends are securely strapped to wooden pallets using steel or nylon strapping to prevent shifting or tipping during transit. This method is particularly suitable for long-distance shipping or export, offering superior protection against damage.

To learn more about carbon steel pipe reducers, please click

Advantages 

Integrally formed with no welded seams, eliminating risks associated with welding defects.

High strength and superior pressure resistance, suitable for demanding operating conditions.

Smooth inner walls with natural transitions minimize turbulence and pressure loss.

Excellent corrosion resistance, commonly manufactured from stainless steel grades such as 304/316L.

Widely applied in petroleum and natural gas, chemical, power generation, offshore engineering, and pharmaceutical industries.

Application

Oil and gas pipeline systems

Chemical and petrochemical plants

Power and nuclear power plant pipelines

Marine engineering and shipbuilding

Pharmaceutical and food processing industries

Water treatment and environmental engineering

Heating and air conditioning (HVAC) systems

Industrial piping for high-pressure, high-temperature, and corrosive media

ASME B16.9 Reducers Manufacturers & Supplier

We are a professional reducer manufacturer, offering high-quality stainless steel, carbon steel, and alloy steel reducers, including concentric reducers and eccentric reducers. Additionally, we produce various butt weld fittings and forged fittings, manufactured strictly in accordance with international standards such as ASME, ANSI, DIN, EN, and GB to ensure dimensional accuracy and reliable performance. Our pipe fittings are widely used in industries such as oil and gas, chemical, power generation, marine, and pharmaceutical, meeting diverse pipeline connection requirements across various operating conditions. Leveraging premium materials, advanced production techniques, and stringent quality control, we provide comprehensive pipe fitting solutions—including reducers, tees, elbows, reducers, and custom fittings—empowering customers to build safe and efficient pipeline systems.

Exported Countries

We Export Reducer to Saudi Arabia, United Arab Emirates, Qatar, Bahrain, Oman, Kuwait, Jordan, Cyprus, Singapore, Malaysia, Indonesia, Thailand, Vietnam, South Korea, Japan, Sri Lanka, Maldives, Bangladesh, Cambodia, Argentina, Bolivia, Brazil, Venezuela, Colombia, Ecuador, Guyana, Paraguay, Uruguay, United States Of America, Canada, Mexico, Panama, Jamaica, Bahamas, Denmark, Norway, Germany, France,Italy, United Kingdom, Spain, Belgium, Greece, Czech Republic, Portugal, Hungary, Albania, Austria, Finland, Ireland, Croatia, Malta, Nigeria, Algeria, Angola, South Africa, Egypt,  Europe, Africa, Asia, North America, South America, Middle East.etc,Italy, United Kingdom, Spain, Belgium, Greece, Czech Republic, Portugal, Hungary, Albania, Austria, Finland, Ireland, Croatia, Malta, Nigeria, Algeria, Angola, South Africa, Egypt,  Europe, Africa, Asia, North America, South America, Middle East.etc