Carbon Steel Forged Flanges Manufacturer and Supplier

A carbon steel forged flange is a pipe connection component shaped from a heated steel billet under compressive force, built to ASME B16.5 and ASME B16.47 across pressure Class 150 through 2500, in grades such as ASTM A105 and ASTM A694. Forging gives the flange a continuous, oriented grain structure that runs with the shape of the part rather than being cut across it, which is what gives a forged flange its strength and reliability compared to a plate cut or cast alternative. Solitaire Overseas manufactures and supplies the full range of carbon steel forged flanges with full mill test certification, and hydrostatic testing, ultrasonic testing or third party inspection can be arranged on request.

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Carbon Steel Forged Flanges Specifications

Parameter	Specification
Standard	ASTM A105, ASTM A694, ASME B16.5, ASME B16.47, MSS SP44
Size Range	NPS 1/2 inch to 24 inch, forged route
Pressure Class	Class 150, 300, 600, 900, 1500, 2500
Facing	Raised Face, Flat Face or Ring Type Joint
Construction	Forged from billet, free forged or die forged
Testing	Hydrostatic test, ultrasonic test, third party inspection on request
Certification	Mill Test Certificate EN 10204 3.1, 3.2 on request

Chemical Composition of Carbon Steel Forging Flanges

Grade	C max	Mn	P max	S max	Si
A105	0.35	0.60 to 1.05	0.035	0.040	0.10 to 0.35

ASTM A694 is a property based specification rather than a fixed composition specification. The standard sets the required tensile strength, yield strength and elongation for each sub grade (F42 through F70), and the manufacturer selects alloy additions to meet those properties, so chemistry for a specific A694 heat is confirmed on the mill test certificate for that production lot.

Forged Carbon Steel Flanges Mechanical Properties

Grade	Tensile Strength min	Yield Strength min	Elongation min (%)
A105	485 MPa (70 ksi)	250 MPa (36 ksi)	22
A694 F60	586 MPa (85 ksi)	415 MPa (60 ksi)	18
A694 F70	655 MPa (95 ksi)	485 MPa (70 ksi)	17

Pressure Class Reference CS Forged Flanges

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

Class 150 Forged Flanged Dimensions

Nom. Pipe Size	O	T	TJ	R	X
½	3.5	0.38	0.44	1.38	1.19
¾	3.88	0.44	0.5	1.69	1.5
1	4.25	0.5	0.56	2	1.94
1¼	4.62	0.56	0.62	2.5	2.31
1½	5	0.62	0.69	2.88	2.56
2	6	0.69	0.75	3.62	3.06
2½	7	0.81	0.88	4.12	3.56

Applications of Carbon Steel Forged Flanges

Oil and gas pipelines and wellhead piping
Refinery and petrochemical process units
Power generation, steam and boiler feed lines
High pressure gas transmission pipelines
Hydraulic and metering skids
Offshore platform piping

Frequently Asked Questions

Q: What is a carbon steel forged flange?

A: It is a flange shaped from a heated steel billet under compressive force, rather than cast in a mould or cut from flat plate, giving it a continuous grain structure and higher strength for a given size and grade.

Q: How is a forged flange manufactured?

A: A billet is cut to size, heated, upset into a rough blank, then die forged or free forged into near final shape, cooled under controlled conditions and machined to final dimensions, bore, bolt holes and facing.

Q: What is the difference between a forged flange and a cast flange?

A: A forged flange has a continuous, oriented grain structure and no molten pour stage, so it avoids porosity and inclusion defects and carries higher tensile strength. A cast flange is poured into a mould, which is lower cost but generally limited to lower pressure, non critical service.

Q: What is the difference between a forged flange and a plate flange?

A: A forged flange is shaped under heat and compressive force, giving it better strength and fatigue resistance, suited to Class 150 through 2500. A plate flange is cut and machined from flat steel plate, which is lower cost and suited to Class 150 and 300 general piping.

Q: What grades of carbon steel are used for forged flanges?

A: ASTM A105 is the standard forged grade. ASTM A694, in sub grades F42 to F70, is used for high pressure oil and gas transmission. ASTM A350 LF2 is used for low temperature forged service.

Q: What pressure class are forged flanges available in?

A: Solitaire Overseas supplies carbon steel forged flanges from Class 150 through Class 2500 per ASME B16.5 and ASME B16.47.

Q: What size range do forged flanges come in?

A: The forged route is generally practical up to about NPS 24 inch. Larger diameters are more commonly produced by plate rolling and welding or by casting.

Q: What is the lead time for forged flanges?

A: Lead time depends on size, class, grade and testing requirements. Share your specification sheet with our sales team for a project specific delivery schedule.