Class 150 Stainless Steel Weld Neck Flange

The Class 150 stainless steel weld neck flange is a forged flange designed for low-pressure piping systems where strength, reliability, and corrosion resistance are essential. Manufactured in accordance with ASME B16.5, this flange is widely used in oil & gas, chemical processing, power generation, marine, and industrial piping systems.

Why Choose a Weld Neck Design?

Compared with slip-on or threaded flanges, the stainless steel weld neck flange is engineered for applications where strength, alignment, and long-term reliability are critical.

Key structural advantages include:

•Long tapered hub reduces stress concentration

•Butt weld connection ensures full penetration and strength

•Smooth bore alignment minimizes turbulence and erosion

•Better performance under pressure fluctuation and thermal cycling

What is Class 150 Weld Neck Flanges?

Class 150 Weld Neck Flanges are designed for medium-pressure systems with maximum pressure up to 285 psi at 100°F. They feature a long tapered hub that gradually transitions to the pipe wall, reducing stress and ensuring durability. Compared to higher classes like Class 300, Class 150 flanges are more suitable for standard industrial piping where moderate pressure is required.

Class 150 WN Flange Dimensions

Nominal Pipe Size		A	B	C	D	E	F	G	H	I	J
inch	mm	mm	mm	mm	mm	mm	mm	mm	Holes	mm	mm
1/2	21.30	88.90	15.70	11.20	47.80	21.30	30.20	35.00	4	15.70	60.45
3/4	26.70	98.60	20.80	12.70	52.30	26.70	38.10	42.90	4	15.70	69.85
1	33.40	108.0	26.70	14.20	55.60	33.50	49.30	50.80	4	15.70	79.25
11/4	42.20	117.3	35.10	15.70	57.15	42.20	58.70	63.50	4	15.70	88.90
11/2	48.30	127.0	40.90	17.50	62.00	48.30	65.00	73.15	4	15.70	98.60
2	60.30	152.4	52.60	19.10	63.50	60.45	77.70	91.90	4	19.10	120.7
21/2	73.00	177.8	62.70	22.40	69.85	73. 15	90.4	104.6	4	19.10	139.7
3	88.90	190.5	78.00	23.90	69.85	88.90	108.0	127.0	4	19.10	152.4
31/2	101.6	215.9	90.20	23.90	71.40	101.6	122.2	139.7	8	19.10	177.8
4	114.3	228.6	102.40	23.90	76.20	114.3	134.9	157.2	8	19.10	190.5
5	141.3	254.0	128.3	23.90	88.90	141.2	163.6	185.7	8	22.40	215.9
6	168.3	279.4	154.2	25.40	88.90	168.4	192.0	215.9	8	22.40	241.3
8	219.1	342.9	202.7	28.40	101.6	219.2	246.1	269.7	8	22.40	298.5
10	273.0	406.4	254.5	30.20	101.6	273.0	304.8	323.8	12	25.40	362.0
12	323.8	482.6	304.8	31.75	114.3	323.8	365.3	381.0	12	25.40	431.8
14	355.6	533.4	To be specified by the Purchaser	35.10	127.0	355.6	400.1	412.7	12	28.40	476.3
16	406.4	596.9		36.60	127.0	406.4	475.2	469.9	16	28.40	539.8
18	457.2	635.0		39.60	139.7	457.2	505.0	533.4	16	31.75	577.9
20	508.0	698.5		42.90	144.5	508.0	558.8	584.2	20	31.75	635.0
24	609.6	812.8		47.80	152.4	609.6	663.4	692.1	20	35.10	749.3

ASME B16.5 & ASME B16.47 Weld Neck Flange

Item	ASME B16.5 Weld Neck Flange	ASME B16.47 Weld Neck Flanges
Nominal Pipe Size (NPS)	1/2” – 24”	26” – 60”
Pressure Class	150, 300, 400, 600, 900, 1500, 2500	75, 150, 300, 400, 600, 900
Typical Class 150 Use	Standard piping	Large-diameter pipelines
Flange Face Type	RF, FF, RTJ	RF, FF
Design Feature	Thick hub & flange body for stress distribution	Optimized weight for large OD pipelines
Dimensional Control	Precise class 150 weld neck flange dimension	Optimized dimensions for large bore pipelines
Typical Industries	Oil & gas, chemical, refinery, power plants	Power generation, offshore, marine, chemical
Material Options	SS304 / SS304L, SS316 / SS316L, Carbon Steel (CS), Alloy Steel (A182 F11/F22), Nickel Alloy (Inconel/Hastelloy), Low Temperature Steel (LF2)	Same as B16.5, commonly SS304L, SS316L, CS, Alloy Steel, Nickel Alloy
Material Application	General piping, chemical, marine, high temperature/high pressure, low temperature	Large pipelines, offshore, chemical, marine, high temperature/high pressure

The Science of Material: SS304L and 316L Flanges

Property	SS304L Flange	SS316L Flange
Chemical Composition (%)	C ≤0.03, Cr 18–20, Ni 8–13, Mn ≤2, Si ≤1	C ≤0.03, Cr 16–18, Ni 10–15, Mo 2–3, Mn ≤2, Si ≤1
Tensile Strength	485–620 MPa	485–620 MPa
Yield Strength	≥170 MPa	≥170 MPa
Elongation	≥30%	≥30%
Reduction of Area	≥50%	≥50%
Corrosion Resistance	Good in freshwater and general chemical environments	Superior to 304L, resistant to chlorides, seawater, and aggressive acids/bases
Typical Applications	Chemical piping, boilers, food industry	Seawater equipment, chemical processing, pharmaceutical and petrochemical industries

Typical Applications by Industry

•Oil and gas pipelines

•Chemical and petrochemical plants

•Power generation and utility systems

•Water treatment and desalination

•HVAC and general industrial piping

Quality Control and Inspection

•Dimensional inspection

•Chemical composition analysis

•Mechanical property testing

•Optional NDT: UT, RT, PMI

22 12 月, 2025