Introduction of Galvanized Steel

Corrosion and repair of corrosion damage are multi-billion dollar problems. Estimates show metallic corrosion costs the United States approximately $297 billion annually, or about 3% of the national GDP. Although corrosion is a natural phenomenon, and can never be completely eliminated, utilizing adequate corrosion protection systems in harsh environments can drastically reduce the costs.

Manufacturing Process

• Planning and Design• Raw Material• Fabrication• Hot Dip Galvanization• Quality and Testing• Bundling and Loading

Planning and Design Planning of project was started when basic task of the project was received. For setting up about the main idea of project, several meetings were arranged among the team members. The Company has in-house design centres with a strong team of over 100 design experts in India and Americas who continuously develop innovative, construction friendly and cost- effective designs. It is equipped with the latest software like PLS Tower, PLS Pole, PLS CADD, AUTOCAD, MICROSTATION, BOCAD and Google Earth.

Raw Material The raw material used for manufacturing of self-supported power transmission towers are steel angle bars. It can be in different sizes and different profile types i.e. L, V, T-shape and flatangle bars iron netand other sheet metal.

FabricationThe raw material is issued from the storage the next and first operation of manufacturing are straightening and cutting of angle bars that are done with the presses. Before cutting the angle bars it needed to measure and have to do some marking according to required sizes. There are three presses in the factory which are used to cut different angle bars in different shapes and sizes and then material is sent to machine shop.

Flow Chart of Fabrication Process

Marking & Measurement

Straightening

Cutting Punching

Bending

Stamping Notching

• Marking and Measurement • Straightening• Cutting• Punching • Bending • Stamping• Notching

Raw Material

To galvanizationprocess

CNC Punching Machine Hot Treatment

Bending and Notching Machine Cutting Machine

Galvanization ProcessThe process of applying a protective zinc coating on iron or steel by passing the metal through a molten bath of zinc to prevent it from rusting. The steel is dipped into the molten zinc bath and held there until the temperature of the steel equilibrates with that of the bath.Temperature of molten bath is around 860°F(460°C).Zn+O₂=ZnOZnO+CO₂=ZnCO₃

Hot Dip Galvanization Process

• Degreasing- The product is dipped into hot alkali solution to remove contaminants such as dirt, grease, paint markings and oil.

• Rinsing- Alkali is removed by washing lightly with water.• Pickling- The product is dipped into a dilute solution of

HCL to remove rust.• Rinsing- HCL is removed by washing with water.• Fluxing- Zinc ammonium chloride is applied to remove

oxides and further formation of oxides on the surface of steel and promotes bonding of zinc to steel.

• Zink Bath-In this tank steel frames are diping in the hot melt Zink tank around 3-4 minutes according to the frame thickness.

• Rising Tank- This tank consist water. The material is dipped into it for cooking, cleaning after Zn coating.

Rising Tank

Zink Bathing

Quality & Testing The inspection of hot-dip galvanized steel is simple and fast. The two properties of the coating closely scrutinized are coating appearance and coating thickness. A variety of simple physical and laboratory tests may be performed to determine thickness, uniformity, adherence, and appearance.

Tower ErectionThe last operation after manufacturing is erection of simply supported towers. When the towers are transported to site, the foundation of tower is ready before the tower structure is unloaded. The foundation of the part is constructed by company's civil engineers who make the foundation ready two weeks before the erection of tower.

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