In the global industrial grounding and lightning protection grounding fields, the choice of grounding materials directly determines the stability, service life and comprehensive cost of the grounding system. As a foreign trade earthing rod salesman, I have been deeply engaged in the industry for many years and have clearly witnessed a core trend: more and more multinational enterprises, engineering companies and purchasers are gradually abandoning traditional galvanized flat steel and turning to copper-plated flat steel as the core material of the grounding system. This choice is not accidental, but the comprehensive advantages of copper-plated flat steel in performance, cost, environmental protection and other aspects perfectly meet the needs of modern foreign trade projects for efficient, long-term and economic grounding solutions.
Galvanized flat steel was once the "mainstream choice" in the grounding field, and was widely used in various grounding projects due to its low initial purchase cost. However, with the upgrading of industrial technology, the tightening of global environmental protection standards, and the improvement of foreign trade projects' requirements for the reliability of grounding systems, many shortcomings of galvanized flat steel have become increasingly prominent, and it has gradually been difficult to meet the engineering needs of the new era. In contrast, copper-plated flat steel, as a new type of bimetallic composite material, combines the excellent electrical conductivity and corrosion resistance of copper with the high strength and easy construction characteristics of steel, which accurately solves the pain points of galvanized flat steel and has become a "new favorite" in the foreign trade market.
The huge gap in corrosion resistance is the core reason why enterprises choose copper-plated flat steel. Foreign trade projects cover all parts of the world. Whether it is coastal high-salinity areas, acidic soil in chemical parks, or humid and rainy tropical areas, grounding materials are facing severe corrosion tests. The surface zinc layer of galvanized flat steel is limited in thickness, usually only able to maintain a service life of 10-15 years, and the zinc layer is easily corroded and peeled off. Once damaged, the internal steel will rust quickly, leading to an increase in grounding resistance, failure of the grounding system, and then safety hazards such as equipment failures and lightning strike risks. Copper-plated flat steel, however, adopts electroplating or continuous casting technology to uniformly cover the surface of a special steel core with electrolytic copper with a purity of more than 99.9%. The average thickness of the copper layer is more than 0.25mm, which can form a firm molecular-level bond and will not fall off or crack even when bent 180 degrees. The corrosion resistance of copper is more than 3 times that of the galvanized layer. The patina formed on the surface can effectively isolate air and moisture, protect the internal steel core from corrosion, and the service life can reach more than 50 years. Even in highly corrosive environments, it can ensure the long-term stable operation of the grounding system and greatly reduce the later maintenance cost.
Better electrical conductivity and building a solid grounding safety barrier are another core competitiveness of copper-plated flat steel. The core function of the grounding system is to quickly discharge lightning and fault currents, and the electrical conductivity directly determines the grounding effect. At a temperature of 20℃, the resistivity of copper is only 17.24×10⁻⁶ (Ω•mm), while the resistivity of steel is as high as 138×10⁻⁶ (Ω•mm). The conductivity of galvanized flat steel is only 8.6% of that of copper, which is difficult to quickly discharge high-frequency lightning currents, easily leading to an increase in ground potential and an increased risk of side lightning strikes. With its high-purity copper surface layer, copper-plated flat steel has a conductivity of more than 20%. Under the action of high-frequency currents such as lightning currents, it will produce a skin effect, and its conductivity is close to that of pure copper, which can quickly conduct current into the ground, effectively avoiding safety accidents caused by lightning strikes and static accumulation. It is especially suitable for foreign trade projects with high requirements for electrical conductivity, such as power plants, substations, and communication base stations. At the same time, the resistance value of copper-plated flat steel is stable, which can maintain the grounding resistance in line with international standards for a long time, meet the grounding specifications of various projects around the world, and does not require frequent testing and maintenance.
The more advantageous comprehensive cost, which is in line with the long-term interests of foreign trade enterprises, is the key driving force for copper-plated flat steel to replace galvanized flat steel. Many foreign trade purchasers will initially be entangled in the slightly higher unit price of copper-plated flat steel, but from the perspective of long-term operation, the comprehensive cost of copper-plated flat steel is much lower than that of galvanized flat steel. On the one hand, copper-plated flat steel has better electrical conductivity, and under the same grounding requirements, the required dosage is less than that of galvanized flat steel, which can reduce the total amount of material procurement;
