What you need to know about quality inspection of large diameter ASME B16.47 flanges

Large-diameter flanges, such as ASME B16.47 welding neck (WN) and blind flanges, play a critical role in high-pressure and high-temperature pipeline systems. To ensure their reliability, strict quality inspection and testing are essential before shipment.

In this article, we will discuss the key aspects of ASME B16.47 flange inspection, including dimensional accuracy, surface defects, and non-destructive testing (NDT).

Weld Neck Flange RF ASME B16.47 Series A A105

Key Quality Inspection Points for Large-Diameter Flanges

1.Dimensional Tolerances and Flatness

Large flanges must meet precise dimensional tolerances to ensure proper sealing and alignment with pipeline connections. During inspection, we verify:

Outer and inner diameters to mach ASME B16.47 specifications

Bolt hole size and alignment to prevent installation issues

Flatness and warpage to avoid flange face misalignment

Why is flatness important?

If a flange face is not perfectly flat, it can cause leakage in high-pressure systems. We use dial gauges and precision measurement tools to check surface evenness.

2.Surface Quality: Preventing Rust, Scratches, and Damage

Flange surfaces must be smooth and free from defects to ensure proper sealing. Our inspection process includes:

• Checking for corrosion, scratches, pitting, or cracks
• Ensuring a smooth flange face to prevent gasket damage
• Applying anti-rust coatings for extended durability

ASME B16.47A A105N RF blind flange

How do we prevent defects?

All flanges are carefully handled, stored, and packed in wooden crates to avoid surface damage during transport.

Non-Destructive Testing (NDT) for ASME B16.47 Flanges

To ensure structural integrity, we conduct various non-destructive tests (NDT), including:

1.Ultrasonic Testing (UT)

✔ Detects internal defects such as voids or inclusions

✔ Ensures the flange has no hidden cracks or weaknesses

2.Magnetic Particle Inspection (MPI)

✔ Identifies surface and near-surface cracks

✔ Used mainly for carbon steel flanges like ASTM A105

3.Dye Penetrant Testing (DPT)

✔ Reveals fine surface cracks that may not be visible

✔ Suitable for stainless steel and alloy flanges

How Haihao Group Ensures Flange Quality?

At Haihao Group, we follow a strict inspection process to guarantee the highest quality:

✔ 100% dimensional and visual inspection before shipment

✔ Certified NDT procedures according to ASME standards

✔ Material verification tests to confirm chemical composition

✔ Precision machining for superior flatness and finish

Need high-quality ASME B16.47 flanges? Contact Haihao Group today for reliable and tested products! Email:sales@haihaogroup.com