Epoxy coated TMT bar, one of the best TMT bars in India, are a highly corrosion resistant variant of steel bars which are protected by Fusion Bonded Epoxy coating. Commonly referred to as FBE coating it is widely used to protect concrete reinforcement bars, steel pipes, piping connections etc. used in construction.
FBE coatings are in the form of dry powder at normal atmospheric temperature. The powder is applied electrostatically to the surface of cleaned hot steel bars and cured to form a protective film after undergoing various chemical processes.
The epoxy coated bars last longer due to the protective film which prevents corrosive elements from coming into contact with the surface of the steel and thereby contribute to raising the quality of construction.
Advantages of Epoxy Coated bars:
The superior anti-corrosive property of epoxy coating extends the life of TMT bars and leads to much lower lifecycle costs over time.
The epoxy coated bar needs very low maintenance which helps to lower the labour costs significantly. These bars are also highly flexible and may be bent on a special mandrel during production to avoid causing damage to the epoxy coating.
One of the primary concerns of highway construction companies at present is to make environment friendly structures. Epoxy causes no harm to the environment and is a sustainable solution in this direction.
As per studies, structures built with epoxy last longer than similar structures made with black steel.
This is also a cost-effective solution as a very little is added to the overall cost of the structure to add epoxy coated bars.
This is a factory-based technique and therefore a greater degree of stringent quality checks may be applied to the process. The thickness of the coating also remains uniform through-out.
The epoxy coating has excellent adhesion and it form a lasting bond with the surface of the steel TMT bars.
The Fusion bonded Epoxy Coating acts as an insulator for electrochemical cells and creates a barrier of protection, sealing off the steel, preventing entry of chloride ions through it, which can cause further corrosion.
Process of manufacturing Epoxy TMT Steel Bars:
The epoxy coating is added to the steel bar under a rigorous procedure to ensure the best results with the following steps.
First the Surface of the TMT bar is cleaned to remove oil and grease using shot blast cleaning method. This type of cleaning technique is highly effective in removing rust, scales, slats and other undesirable elements from the surface of the steel. The resulting industrial grade surface is clean and a rough surface finish, ideal for application of the epoxy.
The TMT bars are then pre-heated using different methods. Of these the most efficient heating method is that of induction heating. For induction heating TMT bars are passed through a high frequency alternating current along with a magnetic field which heats according to the required FBE coating application temperature which is usually 225°C to 245°C.
Next the FBE powder is placed on the fluidisation bed and the heated TMT bar is passed through the coating booth fitted with electrostatic epoxy spray guns and the dry powder is sprayed on the heated TMT bars.
When the epoxy powder particles are released into a stream of electrically charged air, they are attracted to the grounded TMT bar. As soon as the epoxy particles are attracted to the grounded TMT bar they melt and flow into the anchor profile of the bar. At this point the heat also initiates a chemical reaction helping the epoxy powder molecules to form cross linked polymers which gives the coating its beneficial properties.
The final step to make the best TMT Bars in India consists of curing and cooling wherein the epoxy coated TMT bars are treated thermally at 225°C for a duration sufficient for fully cured coating.
The coated bars are then passed through a cooling tunnel and sprayed with water to cool them from where they are sent to the inspection rack for testing and inspection and quality checks to provide the best TMT Bars in India.
Method of manufacturing Epoxy TMT bars:
At Electrotherm steel, the method of manufacturing various grades of steel bars is of prime importance. We employ the world’s most advanced standards and state-of-the-art machinery to manufacture all our products and variants.
It is well known that steel produced from sponge iron is of the highest quality, hence ET TMT bars are produced from iron ore at the ET TMT’S world class facility following a stringent and streamlined production process.
For this purpose, iron ore is smelted in a blast furnace or a sponge iron kiln. The steel produced from the smelted iron ore is then processed in a steel melting shop from where it reaches the ladle refining furnace. The primary purpose of the ladle refining surface is to remove impurities like phosphorus and sulphur.
The purified steel is then forwarded to the billet caster where the billets are shaped and these billets are sent for rolling to the rolling mill. Here the billets are rolled into bars to and to give them the grooves for superior bonding with concrete. Once the rolling is complete the next step is the Thermex quenching system.
It is in the Thermex quenching system that the bars are finally tempered using temperature-controlled water systems. Here the bars are cooled and tempered by the water flow and they develop the variable structure which has a soft inner core and a hard-outer core. This leads to higher force resistance while maintaining ductility.
Once the bars have cooled, they are checked to ensure that they are free of defects and irregularities. This is done in the physical and chemical labs where both the physical structure as well as the chemical properties of the bars are examined to ensure that only the bars that meet all the quality checks reach the consumer.
Following the lab tests, the bars are certified and then moved on to storage and dispatch where they are stored or distributed.