1. Significance of the surface treatments

In order to make the anti-corrosion coating achieve the ideal anti-corrosion effect and requirements, the surface treatment before coating is the top priority. Good surface treatment can improve the wettability of the coating, improve the adhesion between the coating and the substrate, and enhance the corrosion resistance of the coating, which is the meaning of surface treatment.

In the rust, oil, dust, invalid old paint film surface paint, whether it is time or money, is a great waste, like in the dust or oil on the desktop stick tape, do not clean up the dust or oil is not affixed, high grade surface treatment quality will extend the life of the paint.

2. Purpose of the surface treatment

1) for structure processing: strictly this belongs to the structure, but can't ah, some structure, can only leave the next step to coating processing, to have good anticorrosion effect, for the substrate itself must be certain processing, such as sharp Angle, sharp edge grinding, chamfer grinding round, splash removal, welding hole welding and manual welding flat.

2) Surface cleaning: in order to obtain good surface cleanliness of the substrate, it is very important to remove the substances that damage the coating on the surface, especially oxidized skin, rust, soluble salt, oil, moisture, etc.

3) Surface roughness: the surface roughness increases the coating and the substrate contact the surface, and has the effect of mechanical anastomosis, which improves the adhesion of the coating to the substrate.

3. Standard for surface treatment

1) GB 8923-88

2) ISO 8501-1：1988

3) SIS 055900：1967

4) SSPC／NACE

4. Common surface treatment methods

1. Handmade

Such as scraper, wire brush or grinding wheel. The rust and oxidation skin on the surface of the workpiece can be removed by hand, but the manual processing labor intensity is high, the production efficiency is low, and the cleaning is not thorough.

2. Chemical treatment

It is mainly to use the acidic or alkaline solution and the workpiece surface oxide and oil pollution chemical reaction, so that it is dissolved in the acidic or alkaline solution, in order to achieve the purpose of removing the workpiece surface rust oxide skin and oil. Chemical treatment is suitable for the cleaning of thin plates, but if the time control is not appropriate, even if the corrosion inhibitor, the steel may cause excessive corrosion phenomenon, and the chemicals are volatile, the cost is high, the chemical emission after treatment is difficult, if not properly, it will cause serious pollution to the environment.

3, the mechanical treatment method

It mainly includes steel wire brush roller polishing method, shot blasting method, shot blasting method and sandblasting method.

The polishing method is also the brush roller under the drive of the motor, and the brush roller is rotated in the opposite direction of the movement of the mill. The brushed iron oxide skin is washed off by a closed circulating cooling water flushing system.

Thiling cleaning method is a method that uses centrifugal force to accelerate the projectile and cast to the workpiece for rust cleaning. However, the flexibility of shot blasting is poor, limited by the site, and the blindness when cleaning the workpiece is some, and the dead corner is easy to clean up on the surface of the workpiece. The equipment structure is complex, vulnerable parts, especially the blade and other parts wear fast, maintenance time, high cost, one-time investment.

When the surface treatment by shot blasting method, the striking force is strong and the cleaning effect is obvious. But shot treatment of sheet workpiece, easy to make the workpiece deformation, and steel shot hit the workpiece surface (blasting or shot peening) make the metal substrate deformation, because of iron oxide and iron oxide without plasticity, broken after stripping, and oil film with material deformation, so the work with oil, shot, peening cannot completely remove oil.

At present, China's general sandblasting equipment is mostly composed of hinge dragon, scraper, the number one elevator and other original heavy sand conveying machinery. When using the sandblasting method, it is necessary to build a deep pit and waterproof layer to install the machinery. The construction cost is high, the maintenance workload and maintenance cost are great. A large amount of silicon dust produced in the sandblasting process can not be removed, which seriously affects the health of the operators and pollutes the environment.