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Hot-dip galvanizing (HDG) offers outstanding durability and corrosion resistance, making it the preferred option for various industries. The excellent qualities of the materials come from their protective zinc coating. This coating performs best when applied to steel, creating a mutually beneficial bond between the two substances. The thickness of the coating on hot-dip galvanized materials may vary due to several factors determining the final coating thickness.
As hot-dip galvanizing experts, Enze knows how to ensure your materials receive a coating that is the proper thickness for your project. We adhere to the ISO 1461 standard for the thickness range of all hot-dip galvanizing.
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ToggleThe term “hot-dip galvanizing thickness” indicates the thickness of the zinc coating after the material is removed from the hot zinc bath. Before being immersed in the bath, the steel undergoes a preparation process to ensure that the surface is metallurgically clean, facilitating the adherence of the zinc. The thickness is determined by the amount of zinc that remains bonded to the steel after it comes out of the bath.
A single standard defines the standard for hot dip galvanized(HDG) coatings on iron and steel articles; the hot-dip galvanizing standard for iron and steel articles is (BS) EN ISO 1461. This standard has exceptions for thicker coatings. The previous British standard, BS 729, has been replaced by (BS) EN ISO 1461.
The thickness of the hot dip galvanized coating is a crucial factor that determines its resistance to corrosion and its durability. A thicker coating will last longer in given circumstances. However, the coating’s thickness is affected by several factors, including the surface situation, chemical composition, steel geometry, and the zinc bath’s temperature and composition. Therefore, it is essential to understand how to specify, measure, and control the coating thickness to ensure the best performance.
Several factors influence the thickness of the galvanized coating. These include:
1. Material: The thickness of the zinc coating is influenced by several factors, one of which is the material itself. The original steel’s thickness and composition will determine the coatings’ thickness. Thicker steel with higher silicon content in the composition will result in the thickest zinc coatings. When standard hot-dip galvanizing procedures are followed, the steel will naturally end up with a coating that meets the minimum required thickness without requiring extra effort.
2. Surface: The steel surface’s condition affects the coating’s adhesion and quality. Rough surfaces may lead to uneven coatings, while smooth surfaces can result in uniform coatings.
3. Zinc bath: The temperature and composition of the zinc bath influence the reaction rate and the formation of the pure zinc layer. Higher temperatures increase the reaction rate and decrease coating thickness, while lower temperatures have the opposite effect. Similarly, higher aluminum content enhances the pure zinc layer formation, and lower aluminum content has the opposite effect.
4. Geometry: The shape and dimensions of the steel affect immersion time and zinc drainage. Thick or large pieces need longer immersion, while thin or small pieces need shorter immersion. Complex shapes may result in uneven coatings, while simple ones produce uniform coatings.
Enze offers expert advice on the best galvanized steels for your projects.
There are benefits to having a greater hot-dip galvanizing thickness. The thicker the zinc coating, the longer the expected lifespan of the material. Some environments may require a thicker coating to withstand extreme conditions. Your materials will suit their intended tasks if they meet the minimum thickness requirements outlined in ISO 1461.
The best approach is to utilize a magnetic thickness gauge, which provides a straightforward and rapid measurement of the coating’s thickness without damaging the galvanized material.
With over 15 years of experience, Enze’s team ensures cost-efficient steel projects. We offer hot-dip galvanizing services and carefully preserve material integrity to deliver reliable products for tough conditions.