Carbon Steel, Low-Temperature & High-Yield Pipeline Flanges
Carbon steel covers most piping by volume: A105 for general service, A350 LF2 and LF3 where impact toughness is needed at low temperature, and A694 high-yield grades matched to API 5L line pipe.
Teshi Group manufactures carbon steel flanges and fittings in all three families, normalised where required and supplied with EN 10204 3.1 certificates, Charpy results for low-temperature grades and IBR certification when specified.
Carbon & low-temp steel — grades, chemistry and properties
Grades and ASTM / ASME specifications
| Grade | Forged flanges & fittings | Butt weld fittings | Plate | Pipe |
|---|---|---|---|---|
| A105 / A105NUNS K03504 · W.Nr. ~1.0460 | ASTM A105 (N = normalised) | ASTM A234 WPB | ASTM A516 Gr 70 / IS 2062 | ASTM A106 Gr B / API 5L |
| A350 LF2 Cl.1UNS K03011 · W.Nr. ~1.0566 | ASTM A350 LF2 Cl.1 | ASTM A420 WPL6 | ASTM A516 Gr 70 | ASTM A333 Gr 6 |
| A350 LF3UNS K32025 · W.Nr. — | ASTM A350 LF3 | ASTM A420 WPL3 | ASTM A203 | ASTM A333 Gr 3 |
| A694 F42 – F70UNS — · W.Nr. — | ASTM A694 F42 to F70 | MSS SP-75 WPHY 42–70 | — | API 5L X42 – X70 |
Chemical composition (weight %, maximum unless a range is given)
| Grade | C | Mn | Si | P | S | Ni |
|---|---|---|---|---|---|---|
| A105 / A105N | 0.35 | 0.60–1.05 | 0.10–0.35 | 0.035 | 0.040 | — |
| A350 LF2 Cl.1 | 0.30 | 0.60–1.35 | 0.15–0.30 | 0.035 | 0.040 | — |
| A350 LF3 | 0.20 | 0.90 | 0.20–0.35 | — | — | 3.3–3.7 |
| A694 F42 – F70 | 0.26 | 1.60 | — | 0.025 | 0.025 | — |
Mechanical properties (minimum, room temperature)
| Grade | Tensile strength | Yield strength (0.2 %) | Elongation | Note |
|---|---|---|---|---|
| A105 / A105N | 485 MPa (70 ksi) | 250 MPa (36 ksi) | 22 % | Max 187 HB |
| A350 LF2 Cl.1 | 485 MPa (70 ksi) | 250 MPa (36 ksi) | 22 % | Charpy at −46 °C |
| A350 LF3 | 485 MPa (70 ksi) | 260 MPa (38 ksi) | 22 % | Charpy at −101 °C |
| A694 F42 – F70 | — | — | — | Yield = grade number in ksi (F52 = 52 ksi / 360 MPa) |
Values are minimums and limits from the governing ASTM / ASME specifications, summarised for convenience. The current edition of the specification takes precedence; confirm requirements against your project specification.
Where it is used
- General refinery, process and utility piping (A105N)
- LNG, ammonia and low-temperature service (LF2, LF3)
- Oil and gas transmission pipelines (A694)
- Steel plant water, air and gas mains
- Boiler and steam service with IBR certification
Testing & certification
- Normalising where specified (A105N)
- Carbon equivalent limit (e.g. CE ≤ 0.43) when the project specifies it
- Charpy V-notch impact testing for LF grades
- Hardness, dimensional and visual inspection
- IBR certification when specified
Carbon & low-temp steel products we manufacture
All products
01OEM manufacturerWeld Neck Flanges
ASME B16.5 · ASME B16.47
02OEM manufacturerBlind Flanges
ASME B16.5 · ASME B16.47
03OEM manufacturerSlip-On Flanges
ASME B16.5 · EN 1092-1 Type 12
04OEM manufacturerButt Weld Elbows
ASME B16.9 · ASME B16.25
05OEM manufacturerButt Weld Tees
ASME B16.9 · ASME B16.25
06OEM manufacturerWeldolets & Sockolets
MSS SP-97 · ASME B16.11
Industries and projects
Steel & Metals
Where Carbon & low-temp steel is specified
ViewIndustryOil & Gas
Where Carbon & low-temp steel is specified
ViewIndustryPower Generation
Where Carbon & low-temp steel is specified
ViewProjectsMega-projects & EPC supply
Project BOQs, shutdowns and annual rate contracts
ViewGrade data sheets
Other materials
FAQ
Carbon & low-temp steel: common questions
What is the difference between A105 and A105N?
A105N is A105 supplied in the normalised condition, which refines the grain and improves toughness. Many project specifications require A105N.
At what temperature is A350 LF2 impact tested?
A350 LF2 Class 1 is Charpy impact tested at −46 °C (−50 °F); LF3 is tested at −101 °C (−150 °F).
What does F52 mean in ASTM A694?
The number is the minimum yield strength in ksi: A694 F52 has a minimum yield strength of 52 ksi (360 MPa), matching API 5L X52 line pipe.
Which fittings match A694 flanges?
High-yield butt weld fittings to MSS SP-75 WPHY 42–70 are matched to A694 flanges and API 5L X-grade pipe.
Carbon steel grade data sheets
Carbon steel overview →Chemical composition, mechanical properties and PDF data sheet for each grade.
Ready to build to spec?
Share your drawing, bill of materials or technical requirements with the Teshi team.