An in-depth study: The importance of quenching in TMT bar manufacturing

TMT bars are thermo-mechanically manufactured. It involves intense heating of steel billets in blast furnaces followed by a rapid cooling treatment. This incredibly fast process of cooling that ultimately equips TMT bars with a unique microstructure- a hard outer layer combined with a soft ferrite core is known as quenching. TMT bar manufacturers all over the country aim to make their quenching process as efficient as possible as it is one of the critical factors that determine the high tensile strength, ductility, weldability and durability of these extremely modern reinforcement steel bars.

Improving the mechanical properties, quenching ensures the smooth transformation of steel billets into the final shape and size that we see after production. Thus, it is the primary task of effective quenching to alter the microstructure of these bars in manufacturing and enhance their properties before they are sent for self-tempering and atmospheric cooling.

In this article, we will be delving into the ins and outs of this seemingly complicated process to provide more clarity and make things simpler for you so that you can recognise its importance and benefits and realise why thermo mechanically manufactured (TMT) bars play such a pivotal role in the construction world.

The methodology of quenching

All TMT bar manufacturers are armed with pipes and jets just meant for the purpose of quenching. After heating, the rolled reinforcement steel bars are passed through these water jets and cooling pipes. It is here that the bars are supplied with a hard outer layer. Thus, how strong and durable a TMT bar is depends a lot on the manufacturer concerned- the more stringent the quality control is during quenching, the more effective the yield strength and ductility. 

When quenching surrounds the soft core with a hard outer layer, the ductility of these steel bars is also enhanced. They become immune to breaking under extreme loads and stress. TMT bars instead of breaking, bend due to their high ductility. Thus, without proper quenching, a manufacturer cannot produce earthquake-resistant TMT bars.  

In quenching, there is a lot of reliability on heat transfer. If the jets and pipes are incapable or not strong enough to transfer the heat away effectively, then there might be possible thermal stresses that lead to the formation of cracks on the outer surface. Besides, because quenching causes a transformation, a lot depends on the rate of cooling. If the force and speed of water are below par, then the rapid cooling that the outer structure needs and the slower cooling that the core demands will not be fulfilled. Thus, the cooling has to be strong, fast and controlled. 

Hence, every TMT bar manufacturer has to have adequate quenching systems, cooling pipes, nozzles and temperature regulators or monitoring systems (mandatorily fitted with sensors) to ensure consistency in terms of quality and reliability.

You May Read: From raw materials to finished product: A detailed look at Adukia Industries’ TMT bar manufacturing process

How does quenching impact TMT bars?

Here are some of the major ways in which the key properties of TMT bars benefit from the process of quenching:

• Improves tensile strength:

  Without this rapid cooling method, TMT bars would not be so unique. It is the microstructure of these bars that makes them stand out. Quenching ensures that bars have a tough layer outside while having an extremely soft core inside. Quenching despite transferring the heat away and causing these bars to undergo transformation, retains the high-temperature characteristics that the bars recently attained from intense heating in blast furnaces. This results in the bars getting equipped with an unmatched tensile strength that no other reinforcement bar in the industry has.

• High load resistance ductility:
  

  Because the core is soft, TMT bars are not very brittle. Hence they can bend without thermal strain. Thus, the chances of your steel bars cracking and breaking during construction or due to seismic activity are almost zero. Without quenching, the thermo mechanical treatment would not be complete and therefore, the high load resistance that TMT bars are known for would not be attained.

• Advanced corrosion resistance:

  The rapid cooling forms an extra protective layer of oxide on the outer layer of these bars. This prevents moisture and humidity in the air from depreciating their qualities.

• Increased reliability & longevity:
  

  We have already discussed how quenching contributes to the corrosion resistance, strength and ductility of TMT bars. All of these things are nothing but indicators of quality and reliability for household owners, architects, engineers, contractors and businesses.

Implementing stringent quenching procedures to create the best ultraMax TMT bars

Deploying state-of-the-art technology, Adukia Industries, one of the leading TMT bar manufacturers In India for decades is now the go-to option for all stakeholders in construction alike due to two primary reasons. Firstly, our distributorship is spread out all over the country thereby making sure that the problems of timely deliveries and reliability are avoided.  Secondly, we manufacture UltraMax TMT Bars – a low carbon content, high corrosion and earthquake-resistant reinforcement steel bar that is produced through the most stringent checks in heating, quenching, self tempering and atmospheric control.

The hallmark of excellence in terms of quality and reliability, we are committed to providing customers with maximum satisfaction for the right value of money.  Providing safer homes for the future, our commitment to efficiency and innovation continues to evolve and grow with time, making sure that we are always ahead of the curve meeting every demand that you can possibly have.