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Carbon Steel Long Weld Neck Flanges Manufacturer and Supplier in India
Carbon steel long weld neck flange or LWN flange or extended weld neck flange is a short flange with a long length of straight cylindrical hub (barrel) made by forging, which replaces the standard short flange and the pipe nipple, and is a kind of flange used in pipes. These are mostly used for butt welding directly to pressure vessel shells, heat exchanger nozzles, reactors, and high-pressure process equipment, they offer critical structural reinforcement, high bending moment resistance, and smooth stress distribution. Solitaire Overseas manufactures and supplies high-quality carbon steel long weld neck flanges in every grade of ASTM A105, A350 LF2, and ASTM A694, with pressure ratings ranging from Class 150 to Class 2500, and conforms to ASME B16.5 specifications.
Technical Data
Specifications of Carbon Steel Long Weld Neck Flanges
| Specification Parameter | Details |
|---|---|
|
Material Specifications |
ASTM A105, A694, A350 / ASME SA105, SA694, SA350 |
|
Dimensional Standards |
ANSI/ASME B16.5, B16.47 Series A & B, B16.48, BS 4504, BS 10, EN 1092, DIN, etc. |
|
Standard Types |
ANSI Flanges, ASME Flanges, BS Flanges, DIN Flanges, EN Flanges, etc. |
|
Size Range |
1/2″ (15 NB) to 48″ (1200 NB) |
|
Class / Pressure Rating |
150#, 300#, 600#, 900#, 1500#, 2500#, PN6, PN10, PN16, PN25, PN40, PN64, etc. |
|
Flange Face Type |
Flat Face (FF), Raised Face (RF), Ring Type Joint (RTJ) |
Chemical Compositions of Carbon Steel Long Weld Neck Flanges
| Grade | Carbon (C) max | Manganese (Mn) | Phosphorus (P) max | Sulfur (S) max | Silicon (Si) | Micro-Alloying / Other Elements |
|---|---|---|---|---|---|---|
|
ASTM A105 |
0.35% |
0.60 – 1.05% |
0.035% |
0.040% |
0.10 – 0.35% |
Cu: 0.40% max, Ni: 0.40% max, Cr: 0.30% max, Mo: 0.12% max |
|
ASTM A350 LF2 Class 1 |
0.30% |
0.60 – 1.35% |
0.035% |
0.040% |
0.15 – 0.30% |
Cu: 0.40% max, Ni: 0.40% max, Cr: 0.30% max, Mo: 0.12% max |
|
ASTM A694 Grade F60 |
0.26% |
1.40 max |
0.025% |
0.025% |
0.15 – 0.35% |
V, Nb, Ti additions controlled per manufacturer specification |
Mechanical Properties of Carbon Steel Long Weld Neck Flanges
| Grade | Tensile Strength (MPa) | Yield Strength, min (MPa) | Elongation, min (%) | Hardness, max (HBW) | Charpy V-Notch Impact Test |
|---|---|---|---|---|---|
|
ASTM A105 |
485 min |
250 |
22% |
187 HBW |
Not required by default standard |
|
ASTM A350 LF2 Class 1 |
485 – 655 |
250 |
22% |
197 HBW |
$-46^\circ\text{C}$:20J avg, 16J min |
|
ASTM A694 Grade F60 |
515 min |
415 |
20% |
235 HBW |
As specified by purchase order / API 6A PSL |
Pressure Classes of Carbon Steel Long Weld Neck Flanges
| Pressure Class | Maximum working pressure at -29 to 38 C (psig) | Maximum working pressure at -29 to 38 C (bar) |
|---|---|---|
|
Class 150 |
285 psig |
19.6 bar |
|
Class 300 |
740 psig |
51.0 bar |
|
Class 600 |
1,480 psig |
102.1 bar |
|
Class 900 |
2,220 psig |
153.2 bar |
|
Class 1500 |
3,705 psig |
255.3 bar |
|
Class 2500 |
6,170 psig |
425.5 bar |
Dimensions Chart of Carbon Steel Long Weld Neck Flanges
| Nominal Pipe Size (NPS) | Outside Diameter of Flange (O) | Thickness of Flange Min (C) | Diameter of Raised Face (R) | Hub Diameter at Base (A) | Diameter of Bore (B) | Length Through Hub (H−9") | Length Through Hub (H1−12") | Bolt Circle Diameter (BC) | Number of Bolts (n) | Diameter of Bolt Holes (d) |
|---|---|---|---|---|---|---|---|---|---|---|
|
1/2" |
95.5 |
14.3 |
34.9 |
38.1 |
12.7 |
228.6 |
304.8 |
66.7 |
4 |
15.8 |
|
3/4" |
117.5 |
15.9 |
42.9 |
47.6 |
19.1 |
228.6 |
304.8 |
82.5 |
4 |
19.0 |
|
1" |
124.0 |
17.5 |
50.8 |
54.0 |
25.4 |
228.6 |
304.8 |
88.9 |
4 |
19.0 |
|
1-1/4" |
133.5 |
19.1 |
63.5 |
63.5 |
31.8 |
228.6 |
304.8 |
98.4 |
4 |
19.0 |
|
1-1/2" |
155.5 |
20.6 |
73.0 |
69.8 |
38.1 |
228.6 |
304.8 |
114.3 |
4 |
22.5 |
|
2" |
165.0 |
22.2 |
92.1 |
82.5 |
50.8 |
228.6 |
304.8 |
127.0 |
8 |
19.0 |
|
2-1/2" |
190.5 |
25.4 |
104.8 |
100.0 |
63.5 |
228.6 |
304.8 |
149.2 |
8 |
22.5 |
|
3" |
209.5 |
28.6 |
127.0 |
117.5 |
76.2 |
228.6 |
304.8 |
168.3 |
8 |
22.5 |
|
3-1/2" |
228.5 |
30.2 |
139.7 |
133.4 |
88.9 |
228.6 |
304.8 |
184.1 |
8 |
22.5 |
|
4" |
254.0 |
31.8 |
157.2 |
146.0 |
101.6 |
228.6 |
304.8 |
200.0 |
8 |
22.5 |
|
5" |
279.5 |
34.9 |
185.7 |
177.8 |
127.0 |
228.6 |
304.8 |
234.9 |
8 |
22.5 |
|
6" |
317.5 |
36.5 |
215.9 |
206.4 |
152.4 |
228.6 |
304.8 |
269.9 |
12 |
22.5 |
|
8" |
381.0 |
41.3 |
269.9 |
260.3 |
203.2 |
228.6 |
304.8 |
330.2 |
12 |
25.5 |
|
10" |
444.5 |
47.6 |
323.9 |
320.7 |
254.0 |
228.6 |
304.8 |
387.3 |
16 |
28.5 |
|
12" |
520.5 |
50.8 |
381.0 |
374.6 |
304.8 |
228.6 |
304.8 |
450.8 |
16 |
31.8 |
|
14" |
584.0 |
54.0 |
412.8 |
425.4 |
355.6 |
228.6 |
304.8 |
514.3 |
20 |
31.8 |
|
16" |
647.5 |
57.2 |
469.9 |
482.6 |
406.4 |
228.6 |
304.8 |
571.5 |
20 |
35.1 |
|
18" |
711.0 |
60.3 |
533.4 |
533.4 |
457.2 |
228.6 |
304.8 |
628.6 |
24 |
35.1 |
|
20" |
774.5 |
63.5 |
584.2 |
587.3 |
508.0 |
228.6 |
304.8 |
685.8 |
24 |
35.1 |
|
24" |
914.5 |
69.9 |
692.2 |
701.6 |
609.6 |
228.6 |
304.8 |
812.8 |
24 |
41.2 |
Weight Chart of Carbon Steel Long Weld Neck Flanges
| NPS (Inches) | DN (mm) | Flange OD (mm) | Class 150 LWN Weight (H=9") [KGS] | Class 150 LWN Weight (H=12") [KGS] | Class 300 LWN Weight (H=9") [KGS] | Class 300 LWN Weight (H=12") [KGS] |
|---|---|---|---|---|---|---|
|
1/2" |
15 |
88.9 |
1.8 kg |
2.3 kg |
2.4 kg |
2.9 kg |
|
3/4" |
20 |
98.6 |
2.4 kg |
3.1 kg |
3.2 kg |
3.9 kg |
|
1" |
25 |
108.0 |
3.2 kg |
4.1 kg |
4.1 kg |
5.0 kg |
|
1-1/4" |
32 |
117.3 |
4.1 kg |
5.3 kg |
5.2 kg |
6.4 kg |
|
1-1/2" |
40 |
127.0 |
5.2 kg |
6.8 kg |
6.8 kg |
8.4 kg |
|
2" |
50 |
152.4 |
7.8 kg |
10.1 kg |
9.4 kg |
11.7 kg |
|
2-1/2" |
65 |
177.8 |
11.2 kg |
14.5 kg |
13.8 kg |
17.1 kg |
|
3" |
80 |
190.5 |
13.8 kg |
17.9 kg |
17.2 kg |
21.3 kg |
|
4" |
100 |
228.6 |
19.5 kg |
25.4 kg |
26.5 kg |
32.4 kg |
|
6" |
150 |
279.4 |
31.0 kg |
40.3 kg |
44.2 kg |
53.5 kg |
|
8" |
200 |
342.9 |
49.5 kg |
64.4 kg |
71.8 kg |
86.7 kg |
|
10" |
250 |
406.4 |
72.0 kg |
93.6 kg |
108.5 kg |
130.1 kg |
|
12" |
300 |
482.6 |
108.0 kg |
140.4 kg |
158.0 kg |
189.6 kg |
Different Types of Carbon Steel Long Weld Neck Flanges
PN16 long weld neck
MSS SP-44 table e long weld neck
Long weld neck flange dimensions class 300
Grooved long weld neck EN 1092-1 Type 02
Forged integral puddle flange
AWWA C207 Class d reducing long weld neck
ASME B16.47 Series B Flat Face Long Weld Neck
ASME B16.47 Series A Integral Pipe Flange
ASME B16.5 RTJ Long Weld Neck Flange
ASME B16.5 Long Weld Neck Flange
ANSI B16.5 Slip On Integral Flange
Applications and Industrial Uses of Carbon Steel Long Weld Neck Flanges
- Oil and Gas Industry
- Petroleum Refining Industry
- Petrochemical Industry
- Power Generation Industry
- Chemical Processing Industry
- Natural Gas Processing Industry
- Fertilizer Manufacturing Industry
- Industrial Steam and Boiler Industry
Frequently Asked Questions
A long weld neck flange is a forged carbon steel flange featuring an extended straight barrel hub designed to serve as a self-reinforced nozzle connection on pressure vessels and tanks.
Standard weld neck flanges feature a short tapered hub for pipe welding, whereas long weld neck flanges have a longer straight hub that attaches directly to equipment wall shells.
They are used as process nozzles on pressure vessels, heat exchangers, reactors, tall distillation towers, and heavily insulated high-pressure piping systems.
Common standard barrel lengths are 9, 12, 16, and 18 inches, with custom lengths up to 48 inches manufactured to engineering order.
Primary grades include ASTM A105 for ambient/high-temperature service, ASTM A350 LF2 for low-temperature applications, and ASTM A694 (F42 to F70) for high-yield requirements.
Long weld neck flanges are produced across ASME B16.5 pressure ratings including Class 150, 300, 600, 900, 1500, and 2500.
Dimensional and tolerance requirements for sizes NPS 1/2 through NPS 24 are governed by ASME B16.5, while NPS 26 through 60 follow ASME B16.47.