The Problem of Anticorrosive Coating Material on Steel Tube Surface

1. The Function of Protective Coating

In order to prevent rust, the outer surface of the steel pipe is normally coated. The corrosion of the surface of the steel pipe will not only affect the actual use effect but also influence the quality and appearance. Therefore, the coating techniques of the steel pipe have a great impact on the quality of the steel pipe product.

2. The Requirements of Protective Coating

According to the standards of the American Petroleum Institute, steel tubes need to be corrosion-free for three months, so the anti-corrosion time of the coated steel tubes needs to meet the requirements of this standard. However, nowadays, users have higher requirements for the antirust period of steel tubes. Many users require that steel tubes can be stacked outdoor for 3 to 6 months without rusting. In addition to the requirements of antirust period, many customers also have certain requirements for the appearance quality of the coating, which is mainly reflected in the need for a smooth and clean surface after the steel pipe is coated. The anti-corrosion coating needs to be evenly distributed on the surface of the steel pipe, without leakage or dripping, and they can not affect the appearance quality.

3. Common Problems of Anti-Corrosion Coating Materials

It is concluded that common problems of the anti corrosion coating materials can be roughly divided into three types: non-uniform coating, sagging of film, and blister of coating.

• Non-uniform coating

The basic manifestation of this kind of problem is the non-uniform distribution of the coating on the surface of the steel tubes. For example, some parts are too thick, and some parts are too thin or even not coated with oil. Under this circumstance, the coating area that is too thick will exceed the standard, resulting in waste; and the coating area that is too thin or uncoated will reduce the corrosion resistance of the steel pipe and cause rust.

• Sagging of film

The sagging of coating film refers to the situation where the paint sags and solidifies on the surface of the steel pipe like water droplets. The occurrence of this phenomenon usually does not directly affect the corrosion-resistance, and can also ensure the required corrosion-resistance of the steel tubes. However, from an aesthetic perspective, the steel tubes with coat sagging normally look rough and non-uniform, which directly affects the appearance of the steel tubes.

• Blistering of the coating film

As air enters the paint, bubbles may get formed in the coating of the steel tubes. These bubbles have different sizes according to the specifications of the steel tubes. The shape of the larger bubble is similar to the bubble on the protective cover of some household appliances, and pressing the bubble with your hand will burst it. The anticorrosive foaming phenomenon not only affects the appearance of the steel pipe, but also makes the entire surface of the steel pipe appear rough and not smooth, and the destruction of bubbles will reduce the standard of the coating film thickness, reduce the anti-corrosion ability, and cause corrosion of the steel pipe where the bubbles are located.

All of the above mainly introduce the function and requirements of anticorrosive coating materials and common problems of coating materials. It is believed that through reading, everyone can have a better understanding of coating materials. If you want to know more about coating materials, please continue to follow our news!