Our last blog described the TMT steel bars and its importance as reinforcement for the construction of commercial buildings. More specifically, it described the standard IS 1786:2008 that every reinforced steel bar should conform to. The IS standard defines certain guidelines that must be followed when manufacturing the reinforced steel bar.
In reinforcement of steel bars, splicing technique is generally used to produce a single large reinforced steel bar by joining two similar length reinforced bars and wiring them.
The current construction of building structures is dominated by reinforced steel. Reinforced steel bars are preferred for their unmatched tensile strength which the concrete is weak to provide and ductility factor, that helps to withstand the load of the structure. There are different grades and different diameters (mm) of the reinforced bars in the current market namely Fe 415, Fe 500, Fe 550 and Fe 600.
Reinforced steel bars have played a major role in the rise of the construction sector by evolving with the demands of the construction sector to provide safer buildings. The use of steel bars as reinforcement started from the 19th century. The rising demands led to the innovation of technologies that refined steel reinforced bars, used for constructing structures.
Part-I of this blog explained the current reinforcement steel trend in India, the TMT steel reinforced bar, the different grades and which grades are preferred. It also explained the most important factor of TMT steel bar which is Ductility. How is it compromised for higher strength. In this blog, the shift towards value-added reinforced steel is explained
Reinforced steel bars or rebars has become the preferred standard for construction of building structures, bridges and many other commercial structures. The most popular among them is the Thermo Mechanically Treated ( TMT) reinforced bars. About 35% of the total steel production in the country was accounted by the reinforced steel industry. Usage of high strength TMT steel rebars has ensured rapid growth within the construction sector.
This is two of the most used TMT bars when it comes to building homes in India and the average homeowners have a tough time getting their heads around to knowing their difference. So let’s begin with basics itself. Fe stands for Iron, the numbers 500 and 415 is their tensile strength and the ”D” stands for ductility. Here the word signifies the extra ductility which is generally not found in Fe 500. So why would steel companies go to the trouble of making a new grade of TMT bars instead of just promoting Fe 415? In this blog, we will try to find an answer for this conundrum.
First things first, these TMT bars are completely different due to the differences in their manufacturing process. It is where they are used is where the confusion arises. Fe 415 is a fan favourite among the average homeowner and Fe 500 is the choice for home contractors, this is mainly due to their combination of strength and ductility. Fe 500D seems to solve the problem of choosing between either strength or ductility. Fe 500 is perfect medium and small-sized commercial buildings as well as homes, and the Fe 500D can be used to construct both them, the versatility gives the Fe 500D an advantage of over Fe 500 but not over Fe 415.
Fe 415 is naturally more ductile than Fe 500D, while Fe 500D may seem like a combination of strength and ductility, it actually compromises between them. With Fe 415 homeowners get more ductility which can withstand earthquakes and other natural disasters. Fe 415 with its superior ductility can be made into shapes such as columns, slabs and other shapes. Fe 415 can be easily bent without needing the use for any bar bending and bar cutting machines as well. This significantly reduces the cost associated with building a home.
While TMT stands for ‘Thermo Mechanical Treatment’, the name is basically their process of protection and HYSD means ‘High Yielding Strength Deformed’ which is their main characteristic when compared with other rods. HYSD bars can be further divided into Torsed / twisted steel (TOR Steel Bars) and Cold Twisted Deformed Steel Bars (CTD Steel Bars).