Quality inspection standard of spiral steel pipe before delivery

Spiral steel pipes (SSAW) must undergo various tests before leaving the factory, ensuring they meet standard requirements. The quality inspection methods of spiral steel pipe are as follows.

Surface Inspection:

Visual inspection of welded joints to detect defects using tools like templates and magnifying glasses.

Physical Methods:

Non-destructive testing (NDT) methods such as ultrasonic, radiographic, penetrating, and magnetic testing.

Strength Inspection:

Hydraulic and pneumatic tests to verify weld tightness, with safety measures for the more sensitive pneumatic test.

Denseness Inspection:

Tests for weld imperfections, including kerosene, water-carrying, and water wash tests.

Hydrostatic Test: Each pipe undergoes a hydrostatic pressure test, calculated by P=2ST/D, with specific holding times.

NDT for Welds:

X-ray or ultrasonic inspections for repair and critical welds, with specific protocols for different fluid transportation pipes.

Product Classification

Based on inspection results, pipes are categorized as:

- Qualified Products: Meet all standards.

- Repaired Products: Can be repaired to meet standards.

- Scrap Products: Cannot meet standards even after repair.

Waste Management

Waste products are:

- Internal Waste: Detected within the factory.

- External Waste: Found post-delivery, causing significant economic loss.

To minimize external waste, batch-produced pipes should undergo heat treatment and rough processing sampling before factory dispatch to identify and address defects early.