ASTM A694 covers high-strength carbon and alloy steel forgings for pipe flanges, fittings and valves in high-pressure transmission service. The grade number is the minimum yield strength in ksi: F52 has 360 MPa (52,000 psi) minimum yield, F70 has 485 MPa (70,000 psi). Sizes follow ASME B16.5 for NPS 1/2–24 and ASME B16.47 for NPS 26–60.
Mejor Steel is the export agent for the mills that make your material: one contract, one delivery date, and the mill named on the quotation. How we supply
We reply within one business day, Monday to Friday 09:00-18:00 CST. Or write to info@mejorsteel.com / WhatsApp.
Size range and specification
- Size range NPS 1/2 – NPS 60 (DN 15 – DN 1500)
- Classes Class 150 – 2500 to ASME B16.5; Class 75 – 900 to ASME B16.47 above NPS 24
- Types Weld neck, slip-on, blind, socket weld, threaded, lap joint and large-diameter flanges
- Facing Raised face (RF), flat face (FF), ring joint (RTJ)
- Heat treatment Normalized, or quenched and tempered, as required to reach the grade’s minimum properties
- Delivery standard ASTM A694 / ASME SA694, dimensions to ASME B16.5 / B16.47
How this grade is supplied
- Inspection Inspected by the producing mill’s own inspection department, independent of production. Third-party inspection — SGS, BV or TUV, or an inspector you send yourself — can be arranged at the mill or before shipment.
- Certificate A mill test certificate to EN 10204 3.1 showing the heat number, chemical composition and tensile results is standard. EN 10204 3.2, countersigned by the inspector you nominate, is available on request.
- Documents with the goods The mill test certificate and the packing list travel with the shipment, and the heat number is traceable from cast through to the finished flange.
- Packing Sea-worthy export packing with end and facing protection, stencilled with the size, class and heat number.
- MOQ One pallet or one truckload; mixed sizes and classes accepted.
- Lead time Counted from order confirmation. Stock sizes 5–10 days; mill run or non-stock 3–5 weeks. The delivery window is fixed on the quotation.
- How we supply Sourced through partner mills; the producing mill is named on the quotation.
ASTM A694 grades, yield and tensile requirements
| Grade | Yield strength, min | Tensile strength, min | Elongation, min |
|---|---|---|---|
| F52 | 360 MPa (52,000 psi) | 455 MPa (66,000 psi) | 20% |
| F60 | 415 MPa (60,000 psi) | 515 MPa (75,000 psi) | 20% |
| F65 | 450 MPa (65,000 psi) | 530 MPa (77,000 psi) | 20% |
| F70 | 485 MPa (70,000 psi) | 565 MPa (82,000 psi) | 18% |
Other grades in the A694 family (F42, F46, F48, F50, F56) fill the gaps below and between these values. Source: ASTM A694 / ASME SA694 tensile requirements. The standard is the governing document.
ASTM A694 chemical composition (heat analysis, %)
| Element | Requirement |
|---|---|
| Carbon, C | 0.26 max |
| Manganese, Mn | 1.40 max |
| Phosphorus, P | 0.025 max |
| Sulphur, S | 0.025 max |
| Silicon, Si | 0.15 – 0.35 |
The high-yield grades are micro-alloyed with niobium, vanadium or titanium within the limits of ASTM A694 Table 2 to reach the required strength while keeping the material weldable. Source: chemical composition requirements of ASTM A694. The standard is the governing document.
The grade number is the yield strength
The F number in A694 is not an arbitrary label: F52 means a minimum yield strength of 52 ksi (360 MPa), F65 means 65 ksi (450 MPa), and so on. The higher grades cost more because they need cleaner chemistry and a controlled heat treatment, not because the flange is a different shape. Choosing the right grade is a strength decision, not a size decision: match the flange to the pipe and the design pressure, and state the grade on the enquiry.
A105, A350 LF2 and A694 — which one on the drawing
| Specification | Strength level | Use |
|---|---|---|
| ASTM A105 | 250 MPa (36 ksi) yield | Standard forged carbon steel flange |
| ASTM A350 LF2 | 250 MPa (36 ksi) yield | Standard carbon steel flange for low-temperature service |
| ASTM A694 F52–F70 | 360 – 485 MPa (52 – 70 ksi) yield | High-yield flange for high-pressure transmission lines |
The point of A694 is strength: on a high-pressure pipeline, the flange must carry the same high yield as the API 5L X-grade pipe it joins, so the flange does not become the weak point of the joint.
Where high-yield flanges are used
A694 flanges appear wherever a line runs at high pressure and the design calls for a flange that matches the strength of high-yield pipe: gas and liquid transmission pipelines, compressor and pump stations, and wellhead and gathering systems. A flange ordered as A105 on a high-yield line is the classic mismatch — it is dimensionally identical but lower strength, and it has no business carrying the same pressure rating.
Ordering mistakes that cost a flange
- A105 ordered where the line calls for A694. The flange is dimensionally the same but lower strength; on a high-yield line it becomes the weak point.
- Grade left off. F52 and F70 are different strengths; writing only “A694” leaves the mill free to quote the cheapest grade.
- Grade confused with class. The class is the pressure rating; the F number is the material strength. Both are required.
- Impact requirement left off. A694 does not require a low-temperature impact test unless the project specifies one; if the line is sour or low-temperature, write the requirement on the order.
- Weldability not considered. The higher grades are micro-alloyed for weldability; state any carbon-equivalent or weld-procedure limit the project sets.
What to state on the enquiry
- Nominal size, pressure class and facing (RF / FF / RTJ).
- Flange type, and for a weld neck the pipe schedule.
- Material: ASTM A694 and the grade, for example F52, F60, F65 or F70.
- Certificate: EN 10204 3.1, or 3.2 with third-party countersignature.
- Quantity and destination port.
Typical applications
- Gas and liquid transmission pipelines
- Compressor and pump station flanges
- Wellhead and gathering systems
- High-pressure process and injection lines
Standards covered
Frequently asked questions
What does the F number mean in A694?
It is the minimum yield strength in ksi: F52 means 52 ksi (360 MPa), F65 means 65 ksi (450 MPa), F70 means 70 ksi (485 MPa). Higher grades are stronger, not larger.
What is the difference between A105 and A694?
A105 is a standard carbon steel flange with 36 ksi minimum yield. A694 is a high-yield forging family with 52 to 70 ksi minimum yield, specified for high-pressure transmission lines where the flange must match high-yield pipe.
Does A694 require an impact test?
Not unless the project specifies one. If the line is low-temperature or sour, write the impact or NACE requirement on the order so the material is tested to it.
Where to go next
- ASTM A105 Flange – the standard forged carbon steel flange
- ASTM A350 LF2 – the low-temperature carbon steel flange
- Pipe Flanges – flange types, classes and facings
- Get a Quote – send the grade, size, class and destination port
Need a price for a specific size and grade? Send the A694 grade, size, class, facing and the destination port. We reply with availability and pricing.