Charpy V-Notch impact testing for ASTM A350 LF2 CL1 flanges

ASTM A350 LF2 Class 1 (CL1) is a commonly used carbon steel material for forged flanges, fittings, and piping components in low-temperature applications. To ensure its performance and durability in extreme conditions, rigorous quality testing is required. One of the most critical tests for A350 LF2 CL1 flanges is Charpy V-Notch (CVN) impact testing, which evaluates the material’s toughness and ability to resist brittle fracture at low temperatures.

ASTM A350 Gr.LF2 Cl.1 ASME B16.5 C1 weld neck flange

Charpy V-Notch Testing Requirements for A350 LF2 CL1 Flanges

For the ASTM A350 LF2 CL1 flanges supplied to our Singapore client, the following Charpy impact testing requirements were specified:

Applicable Material Thickness: CVN testing is mandatory for flanges with a nominal thickness of 6mm or greater.

Test Temperature: The impact test must be conducted at minus 46°C (-51°F) to simulate the extreme conditions where the flanges will be used.

Energy Absorption Requirements:

The minimum average absorbed energy must be 27 Joules (J) across three specimens.

No single specimen should have an absorbed energy lower than 20J, ensuring uniform material toughness.

ASME B16.5 ASTM A350 LF2 C1.1 weld neck flanges

Reduction Factors for Sub-Size Specimens

In cases where standard-sized specimens cannot be tested, sub-size specimens are used, and energy requirements are adjusted accordingly:

7.5mm thick specimens: Energy values are reduced to 5/6 of the standard requirement.

5mm thick specimens: Energy values are reduced to 2/3 of the standard requirement.

These adjustments ensure that even smaller samples meet proportional impact resistance criteria.

Why Charpy Impact Testing is Essential for A350 LF2 CL1 Flanges?

Prevention of Brittle Fracture – Low-temperature environments increase the risk of material brittleness. Charpy testing ensures the flanges can withstand impact loads without sudden failure.

Compliance with International Standards – Many industry codes, including ASME, ASTM, and EN, require Charpy impact testing for materials used in cryogenic or sub-zero conditions.

Reliable Performance in Harsh Environments – A350 LF2 CL1 flanges are widely used in oil & gas, petrochemical, and offshore industries, where extreme temperatures and pressure fluctuations are common.

The Charpy V-Notch impact test is a crucial quality control measure for ASTM A350 LF2 CL1 flanges, ensuring they meet the required toughness for low-temperature applications. By conducting these tests at -46°C (-51°F) and meeting strict energy absorption criteria, we guarantee that our flanges provide high reliability, safety, and durability in critical pipeline systems.

If you want to know more about pipeline products,please feel free to contact us,email: sales@haihaogroup.com