Views:7 Author:Site Editor Publish Time: 2018-08-24 Origin:Site
Processing Of Metal Products
The processing of metalic products can be done in many ways. However, the most common ones are chrome plating, zinc plating, epoxy powder coating and powder coat over zinc plating
Chrome plating is an old technique that entails electroplating a layer of chromium onto a metal. It can be used for decorative purposes, increasing the hardness of the surface and to provide a corrosion resistant surface. When used for aesthetic purposes, the less expensive imitators are preferred.
Chrome plating process entails three stages; removing dirt and impurities on the surface, warming chrome so that it forms a solution and applying the plating current so that the required thickness is attained. During the process, etching solutions such as hydrochloric acid, sulfuric acid, hydrofluoric acid may be used to etch the alloy. Chromium plating comes in different variations depending on the surface to be plated.
Hexavalent chromium plating – where chromium trioxide is used as the main ingredient. It is ideal when you want to give the surface some hardness or could be used for decorative purposes.
Trivalent chromium plating- where one chromium sulfate is used as an ingredient and is suitably used in decorative plating.
• It gives the surface a great finish
• It reduces the chances of rusting
• It can be used for aesthetic purposes.
Zinc Plating Process
The process is popularly referred to as galvanization and is where a thin layer of zinc is deposited onto the metal to help provide a protective layer. When the outer layer of zinc coating oxidizes, it forms zinc oxide resulting into a silver-colored finish. The zinc plating can then be applied on steel parts to stop them from rusting when exposed to water and air.
The surface to be zinc plated must be prepared by having it cleaned before it is plated. The cleaning removes particulates, oxides, and grease that are deposited on metallic surfaces. This is done by bathing it in a weak acid solution. It ensures that particles don’t remain on the surface otherwise if they do, they create voids that results into spots on the parts that are unprotected.
The hot-dip galvanization method is used to apply the zinc on the surface. The metal is dipped into molten zinc containing a layer of a flux of zinc ammonium chloride solution which allows the surface to be coated in flux before it enters the molten zinc. After plating, the zinc is allowed to dry.
• It prevents rusting and lengthens the lifespan of steel products.
• Increases safety standards of steel and contributes to a better environment
• The higher resistance of zinc plated products reduces maintenance cost.
Hot dipped galvanizated wire container is an idea way for out door and wet area use with lower cost and longer life circle
Epoxy Powder Coating
Epoxy powder coating came on to the fore in 60’s where a new powder-based coating was required to address the challenges in performance resulting from the use of polymer-based coatings. Revolution in technology saw a combination of polyester and epoxies to form high performing coatings that are currently applied in many industries.
Just like the chemical production process, epoxy-based coating undergoes various stages of the manufacturing process before it can be used. The epoxy resin is heated to a molten state and released on a cooling steel belt where cooling takes place. It is then crushed and transformed into tiny flakes and packed. The solid resin is then be mixed with additives, hardeners, pigments, and fillers and the mixture milled and classified depending on the special mill.
Notice that epoxy coating is resistant to harsh chemicals and corrosion and so it is one of the best metal protectors. It is used to coat poles, pipelines, and pillars. It can also be used in steel bars that are used in concrete structures and in marine vessels.
Advantages of epoxy
• The cured surfaces are hardened and durable
• Epoxy coating is environmentally friendly since it is non-toxic.
• It is clean and easy to maintain.
• It is weather resistant and withstands high temperatures of up to 390 degrees Fahrenheit.
• It is impact resistant and cannot fracture, split or crack since it is strong and durable
• Epoxy coating is chemical resistant
• It is versatile and resilient.
Powder-Coating over Zinc Plated
Powder-coating a metal that has been zinc plated is a little bit challenging but if it is successful, it results in a product that is corrosion resistant. Notice that the zinc used in the process is an important factor since its concentration determines whether it works with powder or not. This process enables engineers to create high-quality steel component. It is a two-step process that starts by having the steel part galvanized with zinc. The layer is intended to provide a barrier protection which prevents oxidization. The second step entails applying a powder coating to the galvanized steel. It is then heat cured to bond the powder to the galvanized part. The powder protects both the steel and the galvanized layer.
• It provides exceptional color palette flexibility to designers
• The resultant product is durable