ASTM A350 LF2 is carbon steel bought for what it can prove at low temperature. Chemically it sits close to A105, but it is tested for notch toughness, so the certificate carries Charpy impact results and not only tensile figures. Its heat-treatment condition follows ASME SA350 and the order; the order documented on this page was delivered quenched and tempered (Q+T), as its EN 10204 3.2 certificate 348229 states.
The flange shape still comes from ASME B16.5, EN 1092-1, DIN, GOST or a drawing; LF2 governs the grade, the heat-treatment condition and the test evidence. Because the impact test is run at a stated temperature, the enquiry has to give the service temperature or the test temperature the specification demands - that single figure decides whether the material can be offered at all.
This is the grade for cold service, gas processing, winterised pipelines and LNG-adjacent utilities. Documents are MTC 3.1 with the Charpy impact record where specified, the heat-treatment record, hardness and a dimensional report. Checks cover material verification, impact documentation, dimensions, marking and packing suited to cold-climate destinations.
Product family: Flanges
A350 LF2 flange RFQs are checked for low-temperature service, impact test requirements, heat treatment, MTC and inspection documents.
| Scope and rating | |
|---|---|
| Low-temperature focus | ASTM A350 LF2 is used when low-temperature service and impact-test evidence are part of the RFQ basis. |
| Standards and materials | |
| Standards / drawings |
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| Material grades |
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| Geometry, tolerance and inspection | |
| Shape scope | ASME, EN, DIN, GOST or drawing controls the flange geometry; LF2 controls grade, heat treatment and impact records. |
| Service review | Send service temperature, impact-test requirement, pressure class, material condition and certificate wording before quotation. |
| Critical documents | MTC 3.1, Charpy impact record when specified, heat-treatment record, hardness and dimensional report. |
| Inspection depth | Material verification, impact documentation, dimensional check, marking and packing for cold-service projects. |
| Reviewed before quotation |
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| Buying logic | |
| Best-fit RFQ | Best for low-temperature carbon steel flange requirements with impact-test expectations. |
| Buyer application | Cold service, LNG-adjacent utilities, gas processing, winterized pipelines and low-temperature pressure systems. |
Your standard, drawing revision and project specification govern.
For one order - WN flanges DN80 and DN100, Class 150, in A350 LF2 CL1 to ASME SA350/SA-350M (2021 edition), heat 6A06260, delivered Q+T - TÜV SÜD inspection certificate 348229 records Charpy V-notch results at −46 °C of 279 / 274 / 269 J (average 274 J) as delivered and, after simulated post-weld heat treatment, 266 / 255 / 242 J (average 254 J) for test set PWHT-1 and 216 / 258 / 257 J (average 244 J) for test set PWHT-2.
Evidence
Applies when
These values apply to this one order and heat 6A06260 only: A350 LF2 CL1 weld neck flanges DN80 and DN100, Class 150, Charpy-tested at −46 °C on full-size 10 × 10 × 55 mm specimens. The heat-treatment condition of an LF2 flange follows ASME SA350 and the order; this order was delivered quenched and tempered (Q+T), as page 1 of certificate 348229 states. A 3.2 certificate is arranged when the order calls for it: state the certificate type, impact test temperature and any PWHT condition in the RFQ.
Limits
These are one order's certified results for one heat - not typical, minimum or guaranteed values for A350 LF2 or for BLD flanges. Certificate 348229 covers that order only; it does not mean every BLD flange ships with a 3.2 certificate, and it does not certify BLD, its process or any other product. Another heat, grade, test temperature or heat-treatment condition has its own results on its own certificate.
Sources
Shown complete, all 11 pages in page order. Names, signatures, contact details, one face and one personal ID number are blacked out.
Every value above was checked against the linked documents on 2026-09-23.
Also known as
We confirm each step against your drawing or standard before we quote.
Material grade, heat number, certificate basis and substitution limits are checked against the A350 LF2 Flanges drawing or standard before procurement is released.
The forging route is selected around flange type, section thickness, bore allowance, hub or neck geometry and pressure-service requirements.
Heat treatment is planned with the required record package, mechanical testing basis and impact-test condition where low-temperature or alloy service applies.
Rough machining opens reference faces, bore, hub, neck or sealing-face stock needed to control allowance before final flange machining.
Final machining controls facing, bore, bolt pattern, groove, sealing surface and flange-table or drawing tolerances before dimensional inspection is issued.
Inspection covers dimensional report, MTC 3.1, PMI and required UT, MT or PT records before the release documents are matched to the purchase order.
Marking, packing and export documents are prepared by PO line item so the A350 LF2 Flanges shipment can clear customs and be identified at site receiving.
List document requirements in the first RFQ; they affect price and schedule.
Because the Charpy impact test is run at a stated temperature. The service temperature, or the test temperature your specification demands, is the single figure that decides whether the material can be offered at all.
As ASME SA350 and the order require. The order documented on this page was delivered quenched and tempered (Q+T), as its EN 10204 3.2 certificate 348229 states, so give the condition your specification calls for in the RFQ.
Chemically LF2 sits close to A105, but it is tested for notch toughness, so its certificate carries Charpy impact results and not only tensile figures.
Yes, when the order calls for it. The 3.2 certificate on this page reports two simulated-PWHT test sets next to the as-delivered set; state the certificate type, impact test temperature and any PWHT condition in the RFQ.
Email quote@bldforgedirect.com with standard, drawing, material, quantity and inspection requirements.