Carbon Steel Socket Weld Flanges | ASME B16.5

Q: What is the maximum size available for socket weld flanges?

Standard ASME B16.5 socket weld flanges are commonly available up to NPS 4, while custom dimensions up to 24 inches may be supplied for utility lines, subject to manufacturer specifications.

Q: How does socket weld flange fatigue performance compare to weld neck?

Socket weld flanges generally offer better fatigue performance than slip-on flanges, but lower fatigue strength than weld neck flanges with full-penetration butt welds. Actual performance depends on design and operating conditions.

Q: Are low-temperature grades like ASTM A350 LF1 and LF2 available?

Yes, Solitaire Overseas can supply low-temperature carbon steel socket weld flanges in ASTM A350 LF1, LF2, and LF3 grades, subject to availability and specified Charpy impact testing requirements.

Q: What is the difference between socket weld and threaded flanges?

Socket weld flanges are joined to pipes by welding, while threaded flanges connect through matching pipe threads without welding.

Q: Are socket weld flanges suitable for corrosive service?

Socket weld flanges are generally not recommended for severely corrosive service because the internal socket crevice can trap fluid and promote crevice corrosion.

Premium Carbon Steel Socket Weld Flanges Manufacturer in India

The carbon steel socket weld flange (also known as the SW flange) comes with a socket counterbore which receives the pipe before making a single fillet weld at the outer hub. Socket weld flanges have been mainly designed for small diameter and high pressure piping systems due to their higher fatigue strength and internal smooth flow properties. Solitaire Overseas is a premier socket weld flange manufacturer in India, supplying precision-engineered SW flange ASME B16.5 units in ASTM A105, A350 LF2, and A694 grades to oil and gas, power generation, and chemical processing plants worldwide.

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Technical Data

Specifications Chemical Composition Mechanical Properties Pressure Class Class 150 Dimensions Class 300 Dimensions Class 150 Weight Chart Class 300 Weight Chart

Specifications of Carbon Steel Socket Weld Flanges

Feature / Parameter	Standard Specification
Standard Specifications	ASME B16.5, BS 3293, DIN 2633, MSS SP-44, AWWA C207, JIS B2220
Size Range	NPS 1/2" to 4" (DN15 to DN100) standard for high-pressure SW; custom up to 24" (DN600) for specialized utility runs
Pressure Ratings	Class 150, Class 300, Class 600, Class 900, Class 1500 (PN6 to PN100)
Primary Material Grades	ASTM A105, ASTM A350 LF1 / LF2 / LF3, ASTM A694 F42 through F70
Flange Facings	Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ)
Surface Coating	Anti-rust oil, black paint, transparent varnish, hot-dip galvanized

Chemical Compositions of Carbon Steel Socket Weld Flanges

Material Grade	C (Max)	Mn	P (Max)	S (Max)	Si	Cr	Ni	Mo
ASTM A105	0.35	0.60–1.05	0.035	0.040	0.15–0.30	0.30	0.40	0.12
ASTM A350 LF1	0.30	0.60–1.35	0.035	0.040	0.15–0.30	0.30	0.40	0.12
ASTM A350 LF2	0.30	0.60–1.35	0.035	0.040	0.15–0.30	0.30	0.40	0.12
ASTM A694 F42–F70	0.26	1.40	0.025	0.025	0.15–0.35	—	—	—

Mechanical Properties of Carbon Steel Socket Weld Flanges

Material Grade	Tensile Strength (MPa)	Yield Strength (MPa)	Elongation (%)	Hardness (HBW Max)
ASTM A105	485 Min	250 Min	22 Min	187
ASTM A350 LF1	485–655	250 Min	22 Min	197
ASTM A350 LF2	485–655	250 Min	22 Min	197
ASTM A694 F42	415 Min	290 Min	20 Min	235
ASTM A694 F52	450 Min	360 Min	20 Min	235
ASTM A694 F60	515 Min	415 Min	19 Min	235
ASTM A694 F65	535 Min	450 Min	19 Min	235
ASTM A694 F70	565 Min	485 Min	18 Min	235

Pressure Class Reference at Ambient Temperature per ASME B16.5

Class	Approximate Rating at Ambient (psi)	Approximate Rating at Ambient (bar)
150	285	20
300	740	51
600	1480	102
900	2220	153
1500	3705	255
2500	6170	425

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Class 150 Socket Weld Flange Dimensions Chart

Nominal Size (NPS)	Outer Diameter (O)	Flange Thickness (C)	Bore Diameter (B)	Socket Diameter (D)	Socket Depth (J)	Approx. Weight (kg)
1/2" (DN15)	89 mm	11.2 mm	15.8 mm	22.2 mm	9.5 mm	0.5 kg
3/4" (DN20)	98 mm	12.7 mm	20.8 mm	27.6 mm	11.0 mm	0.7 kg
1" (DN25)	108 mm	14.3 mm	26.6 mm	34.2 mm	12.7 mm	0.9 kg
1-1/4" (DN32)	117 mm	15.9 mm	35.1 mm	42.9 mm	14.3 mm	1.2 kg
1-1/2" (DN40)	127 mm	17.5 mm	40.9 mm	49.0 mm	15.9 mm	1.5 kg
2" (DN50)	152 mm	19.1 mm	52.5 mm	61.7 mm	17.5 mm	2.4 kg
2-1/2" (DN65)	178 mm	22.3 mm	62.7 mm	74.2 mm	19.0 mm	3.6 kg
3" (DN80)	190 mm	23.9 mm	77.9 mm	90.2 mm	20.6 mm	4.3 kg
4" (DN100)	229 mm	23.9 mm	102.3 mm	115.6 mm	23.8 mm	6.1 kg

Dimensions Chart of Class 300 Socket Weld Flange

Nominal Size (NPS)	Outer Dia (O)	Thickness (C)	Pipe Bore (B)	Socket Dia (D)	Socket Depth (J)	Hub Dia (X)	Approx. Weight (kg)
1/2" (DN15)	95 mm	14.3 mm	15.8 mm	22.2 mm	9.5 mm	38 mm	0.8 kg
3/4" (DN20)	117 mm	15.9 mm	20.8 mm	27.6 mm	11.0 mm	48 mm	1.2 kg
1" (DN25)	124 mm	17.5 mm	26.6 mm	34.2 mm	12.7 mm	54 mm	1.6 kg
1-1/2" (DN40)	156 mm	20.6 mm	40.9 mm	49.0 mm	15.9 mm	70 mm	3.2 kg
2" (DN50)	165 mm	22.3 mm	52.5 mm	61.7 mm	17.5 mm	84 mm	4.2 kg
3" (DN80)	210 mm	28.6 mm	77.9 mm	90.2 mm	20.6 mm	117 mm	8.1 kg

Weight Chart of Class 150 CS Socket-Welded Flanges

Class	Nominal Pipe Size (NPS)	Socket Weld
150 lb	½"	2
150 lb	¾"	2
150 lb	1"	2
150 lb	1¼"	3
150 lb	1½"	3
150 lb	2"	5
150 lb	2½"	8
150 lb	3"	9
150 lb	3½"	11
150 lb	4"	13
150 lb	5"	15
150 lb	6"	19
150 lb	8"	30
150 lb	10"	43
150 lb	12"	64
150 lb	14"	90
150 lb	16"	98
150 lb	18"	130
150 lb	20"	165
150 lb	22"	185
150 lb	24"	220

Weight Chart of Class 300 Carbon Steel Socket Welding Flanges

Class	Nominal Pipe Size (NPS)	Socket Weld
300 lb	½"	3
300 lb	¾"	3
300 lb	1"	3
300 lb	1¼"	4
300 lb	1½"	6
300 lb	2"	7
300 lb	2½"	10
300 lb	3"	13
300 lb	3½"	17
300 lb	4"	22
300 lb	5"	28
300 lb	6"	39
300 lb	8"	58
300 lb	10"	81
300 lb	12"	115
300 lb	14"	165
300 lb	16"	190
300 lb	18"	250
300 lb	20"	315
300 lb	22"	370
300 lb	24"	475

Applications and Industrial Uses of Carbon Steel Socket Weld Flanges

Oil and Gas Industry
Petrochemical Industry
Power Generation Industry
Chemical Processing Industry
Boiler Manufacturing Industry
Hydraulic Equipment Industry
Oil Refining Industry
Water Treatment Industry

Frequently Asked Questions

What are Carbon Steel Socket Weld Flanges?

Carbon Steel Socket Weld Flanges are pipe flanges made from carbon steel that connect pipes using a socket weld joint. They are commonly used in small-diameter piping systems that require strong, leak-resistant connections under pressure.

Why does the socket gap matter for thermal expansion?

A 1/16 inch (1.6 mm) gap prevents thermal expansion of the pipe from creating axial stress that could crack the fillet weld.

What is the maximum size available for socket weld flanges?

Standard ASME B16.5 socket weld flanges are stocked up to NPS 4", though custom dimensions up to 24" can be supplied for utility lines.

How does socket weld flange fatigue performance compare to weld neck?

Socket weld flanges offer about 1.5 times the fatigue resistance of slip-on flanges, but lower fatigue strength than full-penetration weld neck flanges.

Are low-temperature grades like ASTM A350 LF1 and LF2 available?

Yes, Solitaire Overseas stocks ASTM A350 LF1, LF2, and LF3 low-temperature carbon steel socket weld flanges with Charpy impact testing.

What is the difference between socket weld and threaded flanges?

Socket weld flanges are welded for a leak-tight, high-fatigue joint, whereas threaded flanges screw onto the pipe without welding.

What is the difference between socket weld and slip-on flanges?

Socket weld flanges receive the pipe into a counterbored socket and weld once externally, while slip-on flanges slide over the pipe and weld inside and out.

Are socket weld flanges suitable for corrosive service?

They are generally not recommended for severely corrosive service, as the internal socket gap can trap fluid and induce crevice corrosion.

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Carbon Steel Socket Weld Flanges Manufacturer and Supplier in India