In harsh underground environments, the durability and corrosion resistance of pipelines directly determine the lifespan and safety of the entire water supply system. DINSEN ductile iron pipes are renowned not only for their high-strength ductile iron body but also for their rigorous and scientific dual-protective coating system—a zinc layer plus a finishing coating—that meets international EN545 standards. This system provides the pipelines with far superior corrosion protection, ensuring reliable operation for decades to come.
The zinc coating is the first line of defense against corrosion in ductile iron pipes. Through the electrochemical protection of the sacrificial anode, it actively protects the base iron from corrosion even if the coating is partially damaged.
We strictly adhere to EN545 standards, employing a precise weighing method to rigorously control the weight of the zinc coating: Sampling and Monitoring: Before zinc spraying, a rectangular test block measuring 500mm x 50mm is longitudinally attached to the pipe. This test block has a known, precise weight.
Precision Weighing: After zinc spraying and cleaning, the test block is weighed again using a high-precision balance with an accuracy of at least ±0.01 grams.
Scientific Calculation: The average weight of the zinc coating per unit area is calculated using the formula:
M = C * (M2 – M1) / A
- M: Average weight of zinc coating (g/m²)
- M1, M2: Weight of the test block before and after zinc spraying (g)
- C: Correction factor (typically 1-1.2), determined by DINSEN’s stringent quality plan, used to correct for differences between the test block and the pipe surface characteristics.
- A: Actual area of the test block (m²) Beyond the average value, we focus on uniformity.
DINSEN understands that weak points in localized corrosion protection are the source of risk. Therefore, we conduct visual inspections of the coating on test blocks. If the uniformity is poor, we cut a 50mm x 50mm sample from the lighter part and weigh it to determine the minimum local weight of the zinc layer, ensuring there are no weak points. In addition, we also use advanced technologies such as X-ray fluorescence to measure directly on the pipe body, achieving multiple verifications.
— The Second Layer of Protection: A Dense and Tough Finishing Coating —
The finishing coating (such as paint or polymer coating) above the zinc-rich layer forms a second physical barrier, isolating moisture, air, and chemicals, working synergistically with the zinc layer to achieve a “1+1>2″ protective effect.
How does DINSEN ensure film thickness? — Precise Measurement and Control Through Multiple Methods
We rigorously control the dry film thickness of the coating using any of the following methods:
Direct Measurement: Non-destructive measurement is performed directly on the coating using measuring sensors such as magnetic induction sensors.
Indirect Measurement with Test Blocks: Similar to zinc layer testing, test blocks are attached to the casting and coated simultaneously. After completion, the dry film thickness is measured using precision mechanical tools such as micrometers.
Test Plate Verification: Measurements are performed using steel or ductile iron test plates coated with the same process as the product.
According to standards, at least three measurement points are obtained for each casting. The average of these results represents the average coating thickness, while the lowest value among all results is considered the local minimum thickness. This reflects DINSEN’s commitment to quality standards.
For DINSEN, standards are merely the starting point for our quality. Through precise dual control of zinc coating weight and paint film thickness, we transform the abstract concept of “corrosion resistance” into measurable, verifiable, and traceable tangible data. This means: Longer lifespan: The superior dual-protection system significantly extends the service life of pipelines in complex underground environments.
Lower lifecycle costs: Reduced maintenance needs and replacement frequency bring maximum long-term economic benefits to our customers.
More reliable safety: Uniform and compliant coatings eliminate the risk of premature localized corrosion, ensuring safe water delivery.
Choosing DINSEN Ductile Iron Pipes is not just choosing a product, but also choosing a century-long commitment to quality and peace of mind.
Post time: Nov-19-2025
