Will Silicon Steel Sheets Rust When Packaged in Ordinary Plastic Bags?

Silicon steel sheets are a core material in industries such as motors, transformers, and new energy equipment. Many companies simply wrap them in ordinary plastic bags during turnover, warehousing, or export, thinking that sealing them is sufficient. However, silicon steel sheets packaged in ordinary plastic bags are very prone to rusting.

Why is rust prevention for silicon steel sheets so crucial?

Although silicon steel sheets have an insulating coating, they are still steel at their core. As with any steel, there is always a risk of oxidation. This is especially true for the edges, cuts, and stacked end faces after stamping, which are often exposed metal areas and extremely sensitive to moisture and oxygen. More importantly, silicon steel sheets have very high requirements for surface condition. Even slight rust can affect not only appearance but also stacking quality and magnetic properties, and in severe cases, even overall machine efficiency. In our long-term cooperation with motor customers at CVCI, we have found that many quality problems are not caused by errors in the production process, but rather by uncontrolled environments during storage and transportation. Especially for exports to Southeast Asia, the high temperature and humidity, coupled with long transportation cycles, mean that irreversible oxidation can occur within weeks if rust prevention measures are inadequate. Therefore, for silicon steel sheets, rust prevention is never an option, but a fundamental requirement.

Why can't ordinary plastic bags prevent rust?

Ordinary plastic bags are merely a physical barrier; they neither absorb moisture nor provide active corrosion protection. The bag already contains air, which inherently contains moisture. When environmental temperature changes, such as high temperatures during the day and low temperatures at night, the moisture in the air inside the bag condenses into water droplets. This phenomenon is very common during sea freight or long-distance transportation. Once these water droplets adhere to the edges or cuts of the silicon steel sheets, oxidation begins. More importantly, the interior of an ordinary plastic bag creates a relatively closed, humid space, preventing moisture from escaping and accelerating corrosion. In cases encountered by CVCI, customers have found water droplets on the inner walls and yellowed edges of the silicon steel sheets upon unpacking—this is almost a typical scenario. Therefore, it can be clearly stated that ordinary plastic bags can only prevent dust, not rust.

Why Use Professional Rust-Proof Packaging – VCI Film For Steel?

Since ordinary plastic bags are insufficient, what's a more reasonable approach? The answer is to use professional VCI Film For Steel. The biggest difference between VCI rust-proof film and ordinary plastic bags is that it's not just a wrapping material, but an active protective material. The film contains volatile corrosion inhibitors, which are slowly released within a sealed space, actively adsorbing onto the metal surface to form a molecular-level protective layer, thereby blocking the reaction of moisture and oxygen with the metal. In other words, it doesn't simply isolate, but actively intervenes in the corrosion process. For materials like silicon steel sheets that are sensitive to edges and cuts, this protection method is more reliable. During the research and development of VCI rust-proof film, CVCI adjusts the formula according to the characteristics of different steels, transportation cycles, and climatic environments, and conducts continuous testing and optimization. Our rust-proof film products have been exported to many countries and regions for a long time, accumulating extensive application experience, especially in the high-humidity environments of Southeast Asia. These real-world examples are more convincing than laboratory data.

A Multi-Layer Rust-Proof Approach is More Reliable Than a Single Material

In actual export projects, sometimes using only one layer of rust-proof film is not enough. The truly reliable approach is to establish a multi-layered rust prevention system. The silicon steel sheet itself is wrapped with VCI Film For Steel, directly protecting the metal surface; an outer layer of desiccant or moisture-absorbing material further reduces overall ambient humidity; and for palletized transport, it can be completely sealed. This approach maintains a high safety margin even with extended transport times or drastic temperature changes. When designing rust prevention solutions for clients, CVCI doesn't simply sell a roll of film, but conducts a comprehensive assessment considering the transport route, storage conditions, and destination climate. We possess stable production capacity and continuous R&D investment, enabling us to provide more tailored solutions for different application scenarios, rather than single-specification products.

Many companies only begin to prioritize rust prevention after customer complaints. However, rust prevention is actually a measure with low upfront investment and high returns. Once silicon steel sheets rust, it can require manual polishing at best, and in severe cases, the entire batch may need to be returned, increasing costs and damaging the company's reputation. In contrast, establishing a scientific rust-proof packaging system at the manufacturing stage has a very limited cost component. CVCI's long-standing philosophy is that rust prevention is an integral part of the supply chain, not an add-on to packaging. Because of our long-term focus on the research and development and production of rust-preventive materials, our products are consistently exported and stably used in humid and hot regions. We understand the challenges that real-world transportation environments pose to materials.

Ordinary plastic bags cannot control internal humidity and lack active corrosion protection. Under temperature fluctuations or high humidity, condensation easily forms, leading to rust. In contrast, using professional VCI Film For Steel, combined with a multi-layered rust-prevention approach, truly reduces warehousing and transportation risks. This difference is particularly pronounced when exporting to high-humidity regions such as Southeast Asia.

Welcome to discuss and visit

CVCI has long focused on the research and development and production of rust-preventive materials. Our products have been exported to many countries and regions, and we have accumulated rich application experience in humid and hot climates. If you are looking for a more reliable solution for exporting silicon steel sheets or other metal materials and addressing rust-preventive packaging issues, please feel free to contact us to discuss your specific needs. We also warmly welcome you to visit the CVCI factory to learn about our production capabilities, R&D system, and real-world application cases. Many rust prevention problems are actually not complicated as long as the right method is chosen.