Shipping exports sounds like a golden waterway to the global market, but there is also an invisible killer behind it that makes countless manufacturers headache - salt spray. The sea breeze is wrapped in fine salt grains, the humidity in the air is maintained at more than 80% all year round, and the deck surface temperature can easily soar to 60 ° C when the freighter sails near the equator, and then drop to about 15 ° C at night. This severe temperature difference and salt superposition is a continuous corrosive "storm" for metal parts. Many precision equipment, large structural parts, and standard fasteners are still as bright as new when they are packed, but it takes 30 to 60 days to cross the ocean. When they are in the hands of customers, they may already be covered with rust spots, blistering edges, and even coating peeling. If the customer says "unqualified quality" or even "rejected", the profit of the entire batch of orders can be reduced to zero.

In response to this pain point, Hank has launched the BS-400 series of anti-rust coatings, which are specially designed for marine transportation environments. To verify the reliability of this product during actual shipping, we conducted a rigorous test of salt spray resistance. The test was based on the ASTM B117 standard, which is the internationally accepted neutral salt spray test method. The experimental environment was set as 5% sodium chloride solution, the temperature was constant at 35 ° C, and the spray volume was uniform and continuous. We prepared three most common metal substrates: cold-rolled steel plates, cast iron parts, and galvanized bolts. The surface was treated with three different treatments: bare wood, ordinary anti-rust oil, and Hank BS-400 coating. All samples were placed in the same salt spray test chamber, and the surface condition was checked every 24 hours.

By the 24th hour of the test, the bare cold-rolled steel plate had visible pitting rust, which gradually spread on the surface, and you could feel fine rust particles on the touch. By the 48th hour, the rust area on the surface of the bare material exceeded 30%, and dark corrosion marks began to appear on the edges of the originally bright cast iron parts. Galvanized bolts showed a mixture of white rust and red rust at the root of the thread. Samples coated with ordinary anti-rust oil performed well in the first 24 hours, but by 48 hours, the oil film had shown signs of being penetrated by salt spray, and dark spots began to appear locally, especially at the sharp corners of the threads of the bolts. The oil film was seriously worn and slightly rusted. In contrast, the samples treated by the Hank BS-400 series still maintained the color they were originally painted for 48 hours, with no blistering, peeling, or rust spots on the surface. By wiping the surface by hand, the coating was complete and dense.

The test continued to advance to the 96th hour, which was the key node of this actual measurement. Under the continuous impact of water mist, the bare material had been completely covered by the rust layer, and the original processing lines could not be identified. With a light scrape with a blade, the rust layer fell off like puff pastry, completely losing its metal properties. Ordinary anti-rust oil samples had already appeared in a large range of "rust spot communities" at 96 hours. The anti-rust oil was emulsified and rinsed by salt spray, and lost its original adhesion. The original oily surface turned dry gray-brown, and many rust pits were up to 0.3 mm deep. Looking at the Hank BS-400 series again, all samples still did not rust. The most surprising is the cold-rolled steel plate, which is the most prone to rust, but because the BS-400 coating forms a continuous, non-conductive physical barrier, the chloride ions in the salt spray cannot always contact the metal substrate. Inspection of the coating section with high magnifying glass revealed that the BS-400 is tightly bonded to the metal surface, with no voids and no tilting at the edges. The coating, which is about 50 to 80 microns thick, acts like an invisible armor, completely isolating the salt particles and water vapor.

In order to evaluate the performance more scientifically, we did an adhesion test again, using the scratch method. The cross mesh was cut with a knife on the surface of the coating, and then pasted with special tape and torn off vertically. The result surprised everyone: the coating of the Hank BS-400 series did not fall off any debris at the edge of the scratch, the mesh area was complete and smooth, and the adhesion level reached the highest level of 5B. However, the ordinary anti-rust oil was physically adsorbed on the metal surface rather than chemically formed. After 96 hours of salt spray test, it almost lost its lubrication and protection ability, and the tape took away a large oil film as soon as it was pulled. This result means that the BS-400 series is not just an "oil", it can chemically bond with the metal surface to form an excellent anti-rust layer with excellent weather resistance.

So, why is the Hank BS-400 series able to perform so well in the salt spray test? We analyzed its film-forming mechanism. BS-400 uses a composite resin-based system, adding nano-scale corrosion inhibitors, special modified fillers, and anti-UV aids. When the coating is applied to the metal surface, the solvent evaporates, and the resin is cross-linked to form a three-dimensional network structure. The corrosion inhibitor forms a single-molecule protective layer on the metal surface, which can neutralize the trace amount of corrosive particles that penetrate to the interface. More importantly, the contact angle of BS-400 is designed to be greater than 110, and the water vapor rolls off in a bead shape on the surface of the coating, making it impossible to infiltrate and penetrate. The coating has a very low surface porosity after drying, and the chloride ion penetration rate is two orders of magnitude lower than that of ordinary anti-rust oils. We also verified its weather resistance. Under simulated sunlight exposure and alternating hot and cold cycles, it ran continuously for 1200 hours, and the color of the coating was only slightly lighter. There were no powder cracks or peeling.

In addition to salt spray resistance, the environment at sea is often more complex during the actual export shipping process. When a cargo ship travels through the tropics, the deck cargo is exposed to high salt spray, strong ultraviolet rays and periodic rainfall for a long time. We also simulate the "hot and humid salt spray" alternating mode: first placed in an environment at 50 ° C and 95% humidity for 8 hours, then switched to a salt spray environment for 16 hours, for 5 consecutive cycles. This working condition is more severe than the pure salt spray test, because the expansion stress of the hot and humid heat will be superimposed on the salt spray corrosion. After the test, the samples of ordinary anti-rust oil had been severely emulsified and white, and the oil film was completely destroyed; while the surface of the Hank BS-400 series samples was still smooth as before, with only very slight salt crystals attached to the edges, which were restored to their original state after rinsing with water. During the entire cycle of testing, the coating did not produce any bubbles, and the metal substrate did not lose light or darken.

In order to ensure that the experimental results have reference value for actual production, we also tested the effect of pretreatment conditions of different types of substrates on the performance of BS-400. Brushing BS-400 directly on the steel plate with slight rust, and brushing BS-400 on the steel plate with sandblasted rust removal to Sa2.5 grade, after 72 hours of salt spray test, there is no rust. This shows that BS-400 has relatively loose requirements on the surface of the substrate and can tolerate a certain degree of residual rust and oxide scale, which is very friendly for quick treatment at the export site. It should be pointed out that if there is already a deep rust pit on the surface of the substrate, it is recommended to carry out simple grinding or phosphating treatment first, otherwise the corrosive medium may remain in the depth of the rust pit, and it may still expand slowly after long-term soaking. However, under normal trade conditions, especially on the surface of newly machined parts, the direct coating performance of BS-400 is sufficient to withstand all the risks of the shipping cycle.

We further made an economic comparison. The consumption of a set of ordinary anti-rust oil often needs to be applied with a very thick oil film during export by sea, about 80 grams per square meter, and it is easy to melt and flow when transported to tropical areas, requiring additional anti-rust paper and pe bag packaging. The Hank BS-400 series only needs to be brushed or sprayed with 30 to 40 grams per square meter, and a non-stick hand film layer is formed after drying, which not only saves material costs, but also saves customers the cleaning process after arriving at the port. Traditional anti-rust oil needs to be cleaned by workers with diesel oil or degreaser after arrival, which is not only time-consuming, but also generates a large amount of waste liquid. The BS-400 coating can be easily removed with weak alkaline cleaning agent, and can also be retained as a short-term anti-rust layer according to customer requirements. Many exporters have reported that after switching to BS-400, the packaging time has been shortened by 40%, and the landing inspection pass rate has increased to 100%.

What is more noteworthy is that the Hank BS-400 series has also passed the European Union RoHS and REACH environmental protection tests, does not contain chromate, lead, mercury and other harmful substances, does not pollute the goods, and does not release volatile organic compounds in storage. This makes it suitable for the export protection of high-standard products such as food machinery, electronic parts, medical apparatus, etc. There is a company that does large-scale numerical control machine tool exports. The order sent to Northern Europe before was due to the large wind and waves in the Atlantic Ocean during shipping, the cargo hold was flooded, and the surface of some bed guides was rusted. The customer asked for a 25% price reduction on the grounds of affecting the accuracy. Since switching to BS-400, not only has there been no rust on the same route and at the same time, but the original worry about water seepage on the guide rail joint surface has also been solved. Because the long-chain polymer film formed by BS-400 on the metal surface has good lubricity, it does not need to be removed before installation, but can play a role in assembling oil.

In the actual measurement, we also specially recorded the resumption of production of the samples after the salt spray test. The samples treated by Hank BS-400 were taken out of the test chamber, rinsed with water and left in a room temperature environment for two days. The surface was still dry and there was no moisture absorption and stickiness. The grid was drawn with a Baige knife, and it was found that the coating could continue to play a protective role. After another month, the metal under the coating was completely unchanged. This long-term protection ability is very suitable for those goods that need to be transferred to storage, inland river barging or even multiple ship changes after export. After two weeks of ordinary anti-rust oil transportation at sea, the oil film will absorb water vapor, forming a micro-battery, which will accelerate local corrosion. However, the hydrophobic properties of BS-400 make it immune to moisture in the air.

Therefore, we recommend that all exporters of metal products to overseas markets, especially those exporting to island countries, tropical coastal cities, and shippers who need to cross high salt spray waters such as the Red Sea and the Persian Gulf, should include salt spray resistance as a must-check item. The Hank BS-400 series provides multiple models from light corrosion protection to heavy corrosion protection, corresponding to different transportation cycles and storage requirements. For example, BS-401 is suitable for fast transportation within 30 days, BS-406 is suitable for long-term sea transportation over 60 days, and BS-410 also adds impact resistance, which is suitable for large open-air structural parts. When choosing, companies can make precise matches according to specific factors such as target ports, shipping schedules, weather seasons, etc.

This test confirmed the excellent performance of the Hank BS-400 series in 96 hours of continuous salt spray environment, which is beyond the one-way time of most international shipping routes. From cold-rolled steel plates to cast iron parts to galvanized parts, all are rust-free, no blistering, no peeling, and the adhesion is maintained at the highest level. It is not simply "wrapping" metal, but building a barrier against chloride ion intrusion at the molecular level. Export shipping is afraid of the collapse of trust, and the Hank BS-400 shows us that as long as the right product is used, no matter how far the sea route is, customers can receive a perfect "fresh" cargo. No matter how salty the sea breeze is, it will not corrode the determination of quality. In today's globalized supply chain that increasingly relies on ocean transportation, using the BS-400 to escort each product is the confidence for exporting companies to face long-distance delivery calmly. From today onwards, let the salt spray no longer be the nightmare of maritime exports, and let Hank BS-400 say for you: not afraid of rust, feel free to go.