Eye wash material and surface treatment

Stainless steel is often considered a durable and corrosion-resistant material, but it also has its limitations. One of the key reasons stainless steel resists corrosion is the presence of a thin, protective oxide layer known as a passivation film. This film forms naturally on the surface and acts as a barrier against chemical exposure. However, if this film is damaged—whether through mechanical abrasion, improper handling, or chemical exposure—the material's resistance to corrosion can significantly decrease. In some cases, rust spots may appear within three months, and over time, these spots can develop into holes, rendering the eyewash device inoperable.

Many eyewash manufacturers source stainless steel tubes from the market, process them by threading, and then polish the surfaces to make them look smooth and appealing. However, this polishing process can remove the critical passivation layer, leaving the material vulnerable to corrosion. Furthermore, once sold to customers, there is often no proper after-sales support, which leads to dissatisfaction and potential damage to the product’s performance over time.

Another issue arises when using stainless steel pipe fittings for eyewash accessories. Some components, such as eye wash nozzles, require bending at specific angles (like 113 degrees), while others, like pipettes with hand push handles, are bent at 90 degrees. These bending processes can introduce internal stresses into the material. If not properly addressed through heat treatment or stress relief techniques, these stresses can lead to premature failure when exposed to corrosive chemicals. Additionally, welding is commonly used during the manufacturing process, and the high temperatures involved can further induce internal stress in the stainless steel. If left untreated, these stresses can severely compromise the material's corrosion resistance, especially in 304 stainless steel, which is widely used in eyewash devices.

When it comes to corrosion resistance, foreign manufacturers often use materials like stainless steel or brass that are coated with ABS through an impregnation process. This method provides superior protection against chemical exposure. It's important to note that in China, many eyewash products are made using ABS spray technology, which only changes the appearance and does not offer real corrosion resistance. Unlike ABS impregnation, which involves soaking the material in powder and offers long-term protection, spray painting is merely a cosmetic solution. Some companies even use this technique to change the color of the eyewash without providing any meaningful anti-corrosion benefits. As a result, consumers should be cautious and understand the difference between actual corrosion resistance and superficial appearance improvements.

China Labor Insurance Network