It is also called hot dip galvanized and hot dip galvanized, and It is an effective way of metal corrosion protection, and it is mainly used for metal structure facilities in various industries. The steel after rust removal is immersed in molten zinc at about 500 degrees, so that the surface of the steel member is attached to the zinc layer, and then plays an anti-corrosive purpose. Hot galvanizing process: products pickling, water washing, auxiliary plating, drying, hanging, cooling, chemical cleaning, grinding, hot galvanizing, and so on. Hot-dip galvanizing is developed from a more old hot plating method. It has been one hundred and forty years Since France applied hot galvanizing to industry in 1836. However, in recent thirty years, hot galvanizing industry has been developing rapidly along with the rapid development of cold rolled strip. Over 90% of the wave beam steel guardrail is treated by hot dip galvanizing process, with corrosion resistance, scratch resistance, zinc thickness, long oxidation resistance and good antisepsis and anti-rust effect.
Cold galvanizing is also called galvanizing. The electrolysis device is used to remove the oil and acid from the pipe and then put it into the solution of zinc salt and connect the negative electrode of the electrolytic equipment. The zinc plate is placed on the opposite side of the pipe, the connection is connected to the cathode of the electrolytic equipment, and the directional movement of the current from the positive pole to the negative electrode will accumulate a layer of zinc on the pipe, and the cold plated pipe is first processed and then galvanized. The cold galvanized coating is mainly anti-corrosion through the principle of electrochemistry, so it is necessary to ensure that the zinc powder and the steel are fully touched and the electrode potential is poor, so the steel appearance processing is very important. In theory, galvanizing can reach or even exceed the thickness of zinc layer of hot-dip galvanizing. However, in general practice, the galvanized coating is all over thin and causes the anti-corrosion and anti-rust effect to be worse than the hot-dip galvanizing, the maintenance life is shorter, the anti scraping effect is poorer, but the relative cost is lower and the appearance is more beautiful and brighter than the hot galvanizing.
Spray molding is a surface treatment method to spray plastic powder on parts. The spray-paint is the electrostatic powder spray which we often mention, it uses electrostatic seizure to make the plastic powder charged, adsorbed on the exterior of the iron plate, and then after 180~220 degrees of baking, the powder is melted and attached to the metal appearance. The spray-paint products are used indoor, and the film appeared flat or matte effect.
Spray powder mainly has acrylic powder, polyester powder and so on. The advantages are no requirement for painter thinner, no pollution to the environment, and no harm to the human body; The appearance of coat is excellent and it has strong adhesion and mechanical strength; the curing time of spraying construction is short; The corrosion resistance and wear resistance of the coating can be higher than that of the primer; it does not need primer; the construction is simple, the workers' skill requirements are low; the cost is lower than the spray painting process; some construction occasions have now clearly put forward the necessity to use the electrostatic spray process; the electrostatic spray spraying process will not have flow phenomenon, which usually appears in the spray painting process. This kind of skill is applied to the wave guardrail. In general cases, there are 3 ways: 1. direct injection molding of steel plate 2. steel plate cold galvanized spray. 3. steel plate hot galvanized spray.
Dipping is a kind of plastic coating process, that is, coating plastic on the base (usually metal). For example, our daily clothes hangers, the handle of the pliers, the rubber sleeve on the scissors, all kinds of armrest and so on. According to whether heating is needed, it can be divided into hot dipping and cold dipping and according to the raw materials of dipping, it can be divided into liquid dipping and powder dipping. The impregnated plastic is a plastic film formed on the metal by heating the plastic powder evenly, or the heat soaking liquid is put into the metal to cover the metal after it is cooled. This technology has been widely applied to mould with low cost, simple processing and various shapes. This way can be used to handle the external form, but the cost is higher than that of the spray molding, and the effect is better, others are also used for silk screen products.
Cold spray zinc
A.Effect of cathodic maintenance
Cold spray zinc is different from general coatings. Its dry film contains more than 96% pure zinc, which can provide good cathodic protection for steel. Even in a very harsh environment, it can still maintain the appearance of steel for a long time. The anti-corrosion function is comparable with that of hot-dip galvanizing, even better.
B.Barrier maintenance effect
When the cold sprayed zinc coating is oxidized, it will create a layer of zinc salt in the appearance of coating to supply barrier maintenance. Adhesives with cold zinc spraying coating is supplied to guess an additional layer of barrier maintenance, then slow oxidation of zinc. Therefore, the anti-corrosion function of cold spray zinc coating is better than that of zinc spray (aluminum), hot-dip galvanizing and other zinc rich coatings.
These are commonly used in the daily production of road wave guardrails. The purpose is to prevent corrosion, anti-oxidation and beautify the environment in the final analysis, and to increase the natural life of the guardrails as far as possible without affecting the physical function of the data.