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Manufacturing Process

Precision-Crafted
TMT Bars

The high-quality Fe 550 TMT bars manufactured at NSPL are crafted through a tried, tested and perfected methodology to ensure absolute consistency in quality and reliability. Our team is constantly innovating to ensure that each bar is made as efficiently and quickly as possible.

Due to this extensive process, each of our steel bars have greater strength, ductility, bendability and weldability.
The raw material for our steel bars is processed in our in-house induction furnaces. Once the raw material has been melted inside the furnace, the molten metal is separated from the slag.

At this point, we purge the molten product inside a ladle furnace to achieve the desired chemical composition. During this process, we add micro-alloying materials to fix the inherent chemistry of the molten metal.
Molten metal from the ladle refining furnace is poured into a nearby tundish, which then pours the liquid into a mould located underneath. This process is used to cast a predetermined length of metal, transforming the molten metal mix into a solidified form. New molten metal is continuously supplied to the mould at a precise rate to keep up with the solidifying process.

Our advanced continuous casting machine helps in achieving improved yield, cost efficiency, productivity, and quality.
Once the solidifying billets exit the continuous casting machine, they enter a secondary cooling chamber. Here, the semi-finished billets are sprayed with water to achieve complete solidification. This process is important for maintaining the shape of the solidified billets, improving their quality in the long run.

Next, the solidified metal strands are reheated again in our reheating furnace. This is done to recrystallize the metal, improving quality and reducing material losses. The recrystallization process is very important because the metal strands can then be processed in the rolling mill without destroying the bonding.
The recrystallized metal billets are transported to a cutting-edge rolling mill using conveyors. Here, they are processed using the internationally accepted roll pass design, which makes for higher strength and elongation. This fully automatic process ensures a greater degree of uniformity throughout the length of each bar.

Our state-of-the-art rolling mill technology comprises a roughing mill of two 18” stands, four intermediate mills, four pre-finishing mills, and a finishing mill of six 12” stands. All the stands have individual DC motors to maintain total automation.
After the steel rebars leave the finishing mill with the desired size, they enter a water cooling chamber where they’re subjected to a quenching process. We have an Evcon Turbo machine which employs a unique method for quenching and self-tempering the ribbed steel bars. This treatment is completed in 3 successive stages:

  • As soon as the steel rebars leave the final mill stand, they are rapidly cooled to ensure surface hardening.
  • Once the quenching operation is completed, the surface layer of each bar undergoes a tempering process with the help of the residual heat left in its core.
  • The third stage takes place when the steel bars lie on a cooling bed, where they are subjected to rapid air cooling.
Coating Process

The Science Behind Our Coating

Shot Blasting

Surface contaminants such as grease and oil are removed by solvent cleaning. This is followed by shot blasting, which removes rust and scales, leaving a clean, rough finish

Bars are pre-heated to stand-alone FBE of 225°C to 245°C. They are then passed through a coating booth in which electrically charged epoxy powder is applied using electrostatic spray guns. As soon as the epoxy particles settle on the hot bar, they melt and flow into the anchor profile. Also, the hot powder particles form cross-linked polymer chains which give the coating its properties. The coated bars, after curing at high temperatures, are then gradually cooled down. Surface contaminants such as grease and oil are removed by solvent cleaning. This is followed by shot blasting, which removes rust and scales, leaving a clean, rough finish

Heating

Surface contaminants such as grease and oil are removed by solvent cleaning. This is followed by shot blasting, which removes rust and scales, leaving a clean, rough finish Bars are pre-heated to stand-alone FBE of 225°C to 245°C. They are then passed through a coating booth in which electrically charged epoxy powder is applied using electrostatic spray guns. As soon as the epoxy particles settle on the hot bar, they melt and flow into the anchor profile. Also, the hot powder particles form cross-linked polymer chains which give the coating its properties. The coated bars, after curing at high temperatures, are then gradually cooled down. Surface contaminants such as grease and oil are removed by solvent cleaning. This is followed by shot blasting, which removes rust and scales, leaving a clean, rough finish

Quoting

Surface contaminants such as grease and oil are removed by solvent cleaning. This is followed by shot blasting, which removes rust and scales, leaving a clean, rough finish Bars are pre-heated to stand-alone FBE of 225°C to 245°C. They are then passed through a coating booth in which electrically charged epoxy powder is applied using electrostatic spray guns. As soon as the epoxy particles settle on the hot bar, they melt and flow into the anchor profile. Also, the hot powder particles form cross-linked polymer chains which give the coating its properties. The coated bars, after curing at high temperatures, are then gradually cooled down. Surface contaminants such as grease and oil are removed by solvent cleaning. This is followed by shot blasting, which removes rust and scales, leaving a clean, rough finish

Quenching

Surface contaminants such as grease and oil are removed by solvent cleaning. This is followed by shot blasting, which removes rust and scales, leaving a clean, rough finish Bars are pre-heated to stand-alone FBE of 225°C to 245°C. They are then passed through a coating booth in which electrically charged epoxy powder is applied using electrostatic spray guns. As soon as the epoxy particles settle on the hot bar, they melt and flow into the anchor profile. Also, the hot powder particles form cross-linked polymer chains which give the coating its properties. The coated bars, after curing at high temperatures, are then gradually cooled down. Surface contaminants such as grease and oil are removed by solvent cleaning. This is followed by shot blasting, which removes rust and scales, leaving a clean, rough finish

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