1. Material Requirements

1.1 Base Material

The ductile iron grade shall comply with EN-GJS-500-7 (EU standard) or QT500-7 (Chinese standard).

In the metallographic structure, the nodularity shall be ≥90%, and the graphite ball size shall be Grade 6-8 (per ASTM A247).

1.2 Chemical Composition

1.3 Harmful Elements Control

The total content of harmful elements such as lead (Pb), chromium (Cr), and tin (Sn) must be <0.1%.

2 Mechanical Properties

2.1 Strength and Elongation

Tensile strength ≥500 MPa (per ISO 6892-1).

Yield strength ≥300 MPa (per ISO 6892-1).

Elongation ≥7% (gauge length 50mm).

2.2 Hardness Testing

Brinell hardness 130~180 HBW (per ISO 6506-1).

3Dimensions and Tolerances

3.1 Diameter and Wall Thickness

Outer diameter tolerance: ±1.0% for DN80~DN600, ±1.5% for ≥DN700 (per EN 545).

Wall thickness tolerance: ±(0.1t + 0.5 mm), where t is the nominal thickness (per ISO 2531).

3.2  Length Requirements

Standard length 6 meters, tolerance ±50 millimeters.

4Surface Treatment and Coating

4.1 External Anti-Corrosion Coating

Zinc coating ≥130 g/m² (spray or hot-dip, per ISO 8179-1).

Bitumen coating thickness ≥70μm, free from bubbles and peeling.

4.2 Lining Material

Cement mortar lining thickness ≥3mm, pH value 9~11 (per ISO 4179).

Epoxy coating dry film thickness ≥250μm, adhesion test passed (per ISO 2409).

5Inspection and Testing

5.1 Non-Destructive Testing (NDT)

Ultrasonic testing (UT) full-body scan, defect depth <5% of wall thickness (per EN 10308).

Radiographic testing (RT) spot-check on welds, compliant with ISO 4998 Class B.

5.2 Pressure Testing

According to ISO2531-1998/2009 standard, each ductile iron pipe needs tested by on-line hydraulic pressure.

6Marking and Documentation

6.1 Pipe Marking

Laser marking: Production date, batch number, standard code (e.g., EN 545).

6.2 Shipping Documents

Material Test Certificate (MTC), inspection report, packing list, certificate of origin.

7 Packaging and Shipping

7.1 Anti-Rust Packaging

Pipe end protection: Sealed with plastic end caps.

Moisture-proof film wrapping the entire pipe.

7.2 Shipping Requirements

Bulk shipping or container loading: according to the order quantity and the destination port of transport conditions for the choice of transport mode, while need to choose container transport of the order that most of time will use  the pipes of effective length of 5.7 meters.

Export to EU requires compliance with CE marking and PED 2014/68/EU directive.