Polyethylene (PE) coating indentation hardness inspection and its importance in pipeline corrosion protection

In many industrial fields, the transmission of pipelines is an indispensable part. In order to ensure the safe and efficient operation of pipelines, certain protective treatments are often required on the outside. Among them, polyethylene coating, as the main anti-corrosion material of pipelines, has received extensive attention. And the indentation hardness of the coating is one of the key indicators of its quality inspection. This article will explore in depth the inspection method of the indentation hardness of polyethylene coating and its importance in pipeline anti-corrosion.

First, the application background of polyethylene coating

Polyethylene, as a polymer material, has excellent corrosion resistance, water resistance and chemical resistance, and is a common material for modern pipeline corrosion protection. It can not only effectively prolong the service life of pipelines, but also reduce maintenance costs and ensure the safety of transportation media without pollution.

Second, the definition and importance of indentation hardness

Indentation hardness refers to the depth of indentation produced by external forces on the surface of a material, which can effectively reflect the hardness and compression resistance of the material. For polyethylene coatings, the indentation hardness is not only directly related to the wear resistance and corrosion resistance of the coating, but also to the overall service life and safety.

Third, polyethylene coating indentation hardness test method

In order to ensure the quality and performance of the coating, we use the following steps to determine the indentation hardness:

Materials and instruments: Use a professional indentation instrument with an indenter head of a metal rod with a bottom diameter of 1.8mm or a cross-sectional area of 2.5mm ^ 2. To ensure accurate measurement, the instrument needs to have a loading stress of 10MPa and a reading accuracy of 0.01mm. In addition, a thermostatic device is required to ensure a constant measurement temperature.

Measurement method: First, the test piece is placed at the measured temperature for 1 hour to achieve temperature equilibrium. Then, the indenter (without additional load) is slowly and carefully landed on the test piece, and the scale indicator is adjusted to the zero value within 5 seconds. After that, the additional load is applied to the indenter and held for 24 hours. After the measurement is completed, the value of the scale indicator is read, which is the indentation depth of the coating.

The results show that, typically, three specimens are selected for measurement and the results are averaged to represent the indentation hardness of the polyethylene coating in millimeters (mm).

In order to ensure the accuracy and reliability of the measurement, we also refer to the national standard GB/T 23257-2009 "Buried Steel Pipeline Polyethylene Anti-corrosion Layer" for operation.

IV. Conclusion

The measurement of indentation hardness of polyethylene coating is crucial to ensure the safety of pipelines and prolong the service life. Only when we ensure that the hardness and compression resistance of the coating meet the standards can we ensure its stability and durability in practical applications. With the development of modern industrial technology, the requirements for pipeline materials are also getting higher and higher. As an important means of anti-corrosion, the inspection of the indentation hardness of polyethylene coating is undoubtedly a key step in quality control.