ASTM A350 LF2 Blind Flanges Manufacturer
As a leading ASTM A350 LF2 blind flanges manufacturer, we specialize in providing low temperature carbon steel flanges designed for use in high-pressure and low-temperature systems. Our ASTM A350 LF2 blind flanges are crafted from low-temperature carbon steel, offering superior strength, durability, and corrosion resistance in critical industrial applications.
What is ASTM A350 LF2 Blind Flange?
ASTM A350 LF2 refers to a specification for low-temperature carbon steel flanges, including blind flanges, designed for use in piping systems that operate in environments with temperatures as low as -50°F to +100°F (-46°C to +38°C). These flanges are widely used in industries such as oil and gas, chemical processing, and petrochemical, where safety, reliability, and performance are paramount.
A blind flange is a type of flange used to close the end of a piping system. It is a flat, round plate with bolt holes for securing the flange to a pipeline. Blind flanges are critical in preventing flow through a pipeline or vessel, ensuring that systems are securely sealed for maintenance, repairs, or during temporary shutdowns.
Key Features of ASTM A350 LF2 Blind Flanges:
- Material Composition: Made from low-temperature carbon steel per ASTM A350 LF2 standards, these flanges provide excellent strength, ductility, and resilience at low temperatures.
- Low-Temperature Performance: Designed specifically for cryogenic temperatures, ASTM A350 LF2 blind flanges can operate efficiently in environments ranging from sub-zero temperatures to moderate heat.
- Corrosion Resistance: The LF2 material is known for its ability to withstand corrosion, making it ideal for use in marine environments, chemical plants, and refineries.
- High Strength: With a tensile strength of 70,000 psi (485 MPa), these flanges can handle high-pressure systems without risk of failure.
- Durability: ASTM A350 LF2 blind flanges are durable and designed for long-term service, reducing the need for frequent replacements.
Download the ASTM A350 Latest EDITION PDF

ASTM A350 LF2 Chemical Composition
| C | Si | Mn | P | S | Cr | Mo | Ni | Al | Sn | Cu | |
| Min | 0.15 | 0.60 | 0.015 | ||||||||
| Max | 0.22 | 0.30 | 1.35 | 0.02 | 0.015 | 0.30 | 0.12 | 0.40 | 0.035 | 0.01 | 0.40 |
ASTM A350 LF2 Blind Flange MECHANICAL PROPERTIES
| Tensile | Result |
| RP 0.2% | 36,000 PSI MIN |
| RM | 70,000 – 95,000 PSI |
| Elongation | 22% |
| Reduction of area | 30% |
| HBW10/3000 | Max 187 BHN |
| KCV @ -46 DEG C | 20J min Ave, 16J min single |
A350 LF2 Blind Flange Specification
- Dimension : ASME B16.5 / B16.47 A& B.
- Size: ½” to 60” (DN15 to DN1500)
- Pressure ratings: 150# to 2500#
- Impact tested at –46°C (Charpy V-notch)
- NACE MR0175 / ISO 15156 compliance for sour service
- EN 10204 3.1 / 3.2 certificates available
ASTM A350 LF2 Blind Flanges – Heat Treatment
Normalization or Normalization followed by tempering
A typical ITP Inspection and Test Plan for ASTM A350 LF2 Blind Flanges
| Stage | Activity | Requirement/Standard | Type of Check | Acceptance Criteria | Inspector | Document Reference |
| 1 | Raw Material Verification | ASTM A350 LF2 | Certificate Review | Chemical & Mechanical per spec | Manufacturer / QC | Mill Certificate (MTC) |
| 2 | Visual Inspection (Raw Material) | Internal Standard | Visual | No defects, cracks, damage | QC | Inspection Report |
| 5 | Forging Process | ASTM A350 | Process Control Check | As per forging procedure | QC | Forging Log |
| 3 | Heat Treatment | As per ASTM A350 / Client Spec | Temperature & Time Log | Normalized / Tempered as required | QC | HT Report |
| 6 | Final Machining | ASME B16.5/B16.47 | Measurement | Tolerances within limits | QC | Dimensional Report |
| 4 | Dimensional Inspection | ASME B16.5 / B16.47 / Drawing | Measurement Tools | As per drawing | QC | Dimensional Report |
| 7 | Mechanical Testing | ASTM A350 | Tensile, Yield, Elongation | Min. Yield 250 MPa, etc. | Lab / QC | Mechanical Test Report |
| 8 | Charpy V-Notch Impact Test | ASTM A350 at –46°C | Destructive Test | Min 27 J avg (3 samples) | Lab / Third Party (if TPI) | Impact Test Report |
| 9 | Non-Destructive Testing (Optional) | Client Requirement | UT / MT / PT | As per ASME / Client standard | NDT Level II / TPI | NDT Reports |
| 10 | Final Visual and Dimensional Check | ASME B16.5 / Drawing | Visual, Measurement | Surface finish, dimensions OK | QC / Client / TPI | Final Inspection Report |
| 11 | Marking & Stamping | ASTM A350 / ASME B16.5 | Visual | Proper heat/lot marking | QC | Marking Record |
| 12 | Documentation Review & Compilation | Project Requirement | Review | All docs present and signed | QA/QC | Dossier / Data Book |
| 13 | Packing & Dispatch Inspection | Client/Project Spec | Visual / Verification | Packing list, labels, protection | QC / Client | Packing List, Dispatch Note |

Looking for a reliable manufacturer of ASTM A350 LF2 Blind flanges? We specialize in producing high-quality carbon steel flanges designed for low-temperature service, meeting ASTM A350 LF2 specifications NACE MR 0175 compliance.
Does NACE MR-0175/ISO 15156 specifies the Hardness requirement for ASTM A350 Grade LF2 material?
NACE MR0175/ISO 15156 does not dictate the hardness requirements that may be present in other standards. The standard does define material requirements and use limits as they relate to environmental cracking in the presence of H2S. ASTM A350 LF2 requires the hardness to be 197 HB maximum and this meets the requirements for carbon steel forgings in NACE MR0175/ISO 15156-2. Please refer to Clause A.2.1 and the sub-clauses beneath it for carbon and low alloy steels.
Contact us to receive a Sample MTC for ASTM A350 LF2 Weld neck Flanges.
⬇️Download ASTM A350 LF2 specification
⬇️Download ASTM A350 Standard Latest Edition (PDF)







