From the homes we live in to the offices, Steel bars are the backbone of our daily lives. The bridges, offices, houses, flyover, most modern structures gain their strength from TOP TMT steel bars interwoven through them. Without Strong & Flexi TMT bars, the current construction industry would doubtlessly be less robust and much more expensive.
WHY TMT BARS?
The strength of the TMT bars is specifically controlled while manufacturing to provide an optimum strength, ductility and toughness. These are widely used in general purpose like bridges and flyovers, concrete reinforcement structures, thermal and hydel power plants, dams, industrial structures, underground platforms in metro railway, high-rise buildings and rapid transport system. To yield high strength these TMT Bars are thermo-mechanically-treated by world’s best technology.
Now-a-days thermo-mechanically treated bars are preferred for any type of construction whether it is big or small because of their enhanced strength, workability, high ductility and malleability. The TMT bars were designed to support buildings during earthquakes and definitely to resist high temperatures, especially during fires. Best TMT bars come in various grades, which perform a range of rigidity and strength
FEATURES OF TMT BARS
- Enhanced strength combined with high ductility
- High thermal resistance
- Better ductility and malleability
- Earthquake resistant
- Significant savings in cost of steel
- Excellent weld ability without loss of strength particularly at welded joints
DIFFERENT GRADES OF TMT BARS
All grades of TMT bars are good for construction, but different steel grades suit different types of structures. They are as follows.
- Fe 600 : are for huge/enormous industrial projects
- Fe 550 : are for bridges and other slightly large-scale structures
- Fe 500 : are ideal for all types of commercial buildings
- Fe 415 : are good for houses
Fe 600 TMT bars are the strongest and sturdy steel bars available in the market so far. These bars boast yield strength of 600 N/mm² and an ultimate tensile strength of 660 N/mm². The elongation of these grades is 10 percent.
Fe 600 TMT bars are used for large-load, heavy-duty industrial construction projects. Metro projects, expressways, towers, plants, industrial zones and huge commercial properties are some examples of such construction projects.
Fe 550 grade TMT bars are the second strongest steel grades. It has minimum yield strength of 550 N/mm² and an ultimate tensile strength of 585N/mm². The elongation level of these grades is 10 percent.
Fe 550 grade TMT bars have higher tensile strength than the Fe 500. These are also used in a high-load capacity, broad range of large-format and industrial infrastructure development projects like underground structures and heavy bridges. These TMT bars are especially effective in marine and coastal environments.
Fe 500 is called market-standard TMT steel bars. This type of steel bar is used in a wide variety of construction projects. This type of bar has a minimum yield strength of 500 N/mm² and an ultimate tensile strength of 545 N/mm². The elongation level of these grades is 12 percent.
Commonly used in the construction of commercial structures with multiple stories, smaller bridges, and underground structures. Because of its anti-corrosion properties, this type of TMT bar is commonly used in coastal areas. It provides stability to high-rise construction projects. Another quality of this grade is to resist load better at the same time.
Fe 415 TMT steel bars are generally used in residential structures, building houses and small-scale construction projects due to their high uniform elongation. This type of bar has a yield strength of 415 N/mm² and an ultimate tensile strength of 485 N/mm². The elongation level of these grades is 14.5 percent.
Because of these characteristics, it makes these bars resistant to earthquakes. They are perfect for building homes in areas which are prone to seismic activities. Presence of protective coating makes them resistant to corrosion and rust. Importantly it can be easily bent into the most complex shapes.
HOW THESE GRADES ARE DEFINED?
Different grades of steel bar vary yield strength, tensile strength, and elongation from one another. Thus we decide which bar is useful or suitable for a particular construction project.
Under the production process of these types of best steel bars, they are going through a process of rapid cooling while in their molten state. This process gives the steel bars a pliable core with a solid and hard surface. Their outer shell consists of a film coating, which protects them from rust and corrosion. Thus in turn, makes them great materials for using in building structures like bridges and high-rise residential buildings in humid places.
Water is sprayed at regular intervals on the molten irons, to cool rapidly. These intervals differ, thus giving different steel grades to the steel bars. These grades are designated by different characteristics. Different rigidity levels and yield strength of reinforcement are the characteristics which only define the grade.
“Fe” stands for “Ferrum”. Fe is the chemical symbol which indicates the presence of Iron in the TMT steel bar. Ferrum is the Latin word for the chemical element Iron. The highest is Fe 600 and the lowest grade is the Fe 415 bar. These TMT bars are graded according to the amount of withstand safely and without irreversible deformation. When the stress is applied within its yield point, the bar elastically deforms, but when this stress is removed, it returns to its original form or shape. The higher the steel grade lower bendable it is.
The yield strength is measured in Newtons per square millimeters or N/mm². For example, if a Fe 550-grade TMT bar provides yield strength of 550 N/mm², beyond that the bar may no longer be able to maintain its form.
WHY TMT BARS FOR CONSTRUCTION?
Before TMT bars came into the picture and ruled the market, cold-twisted deformed bars were used extensively for reinforcement in construction work. CTD or cold-twisted bars involve the process of cold twisting while TMT bars involve the hot treatment technology. During the manufacturing of CTD bars, they are being twisted in room temperature thus it was troubled with certain problems like inferior ductility, higher carbon content, low weld-ability and increased corrosion rate. Eventually TMT has dramatically taken over the low-cost reinforcement bars industry.
The quality of the TMT bars varies across brands. When looking for the best quality TMT bars, we need to take note of the following characteristics:
- importantly the perfect balance of flexibility and strength
- must have higher yield strength
- must have high ultimate tensile strength
- should have a higher elongation percentage
- need to be highly weld-able
- highly resistant to earthquakes and corrosion
- should have lesser amount of sulfur, which makes the structures fire-resistant
CHOOSE THE RIGHT TMT BARS
These points should be kept in mind while looking for the best TMT bars India. For that, we need to approach the best dealer and also need to do a market survey and compare pricing before making any decision on top TMT bars.
Be aware of needs:
We must be clear about the construction requirements before starting to look for a TMT bar dealer. Recently the TMT bars are available in different grades. Particular grade is suitable for particular applications. For instance, small residential projects need TMT bars with specific properties, which definitely are different from the bars which are required for massive infrastructure projects. For an earthquake-prone zone, it requires TMT bars that would be more resilient and can absorb the shockwaves. Specific requirements decide the kind of TMT bars. Approach the best dealer, which helps to find the suitable product for the construction.
Explore the brands:
Since TMT bar steel rods are the core product of the construction, it must be high quality, and therefore buying the same from the top brands is a good decision.
We should never compromise on quality with any kind of construction materials. Need to explore the brands available in the market. The brand ensures the quality of those who invest in good quality raw materials that are used for manufacturing the bars. The bars which are made from scrapes and shoddy materials should be avoided. The brands using the latest manufacturing technology are the best brands. The bars would therefore guarantee anti-corrosive properties and earthquake-resistant properties. We need to opt for the best brand and check the latest TMT steel price.
Shyam Steel points out that the best TMT bars can protect a structure from fire, absorb extra energy in the event an earthquake happens, and can resist corrosion.
The right grade:
The TMT bars come in different grades. Previously we already mentioned a few grades of TMT bars. While choosing the top TMT Bar for your construction these sheet grades are important to know.
The TMT bars have different properties and different chemical composition. According to that they are categorized in grades. The Fe 415 grade TMT bars have a high ductility and are suitable for different projects. The Fe 600 grade TMT bar is the highest grade and has the highest tensile strength. So this type of category of TMT bars is used for big infrastructure projects.
Ductility: Special properties of TMT bars set them apart from the regular bars. TMT bars have a hard outer surface and a soft inner core, which make them stronger and also flexible. The ductile property allows them to bend when subjected to pressure, without developing any internal cracks. Due to the property it is most suited for earthquake prone areas.
Flexibility and bend-ability: The high-strength bars should have gone through a bend and rebend test. In this test, TMT bars are bent to 135 degrees and then these are kept submerged in boiling water for around half an hour. It is then re-bend to around 157.5 degrees. Bars which are manufactured with the proper combination of strength and flexibility should be able to bend easily. In this process the bars survive the cracks on the surface along the bends.
Strength: The strength of the bars tested using a Universal Testing Machine. To perform the test a TMT bar is positioned in between the UTM’s plates and pressure is applied to make sure it does not break before the yield point.
Chemical composition: The chemical composition of the TMT bars has to be observed with the IS Specification. A spectrometer is used to measure the chemical composition of the TMT bars. This chemical makeup needs to be right in order, so that it produces steel bars that are of the correct grade.
Elongation: Elongation is the percentage of stretch from the original length of the TMT bars to the point of failure. It shows how ductile the bar is. Elongation is very high in all the grades of the tmt bars. The requirement of elongation in the recent amendment is to IS: 1786 for earthquake resistance.
Weld-ability: It is defined on the basis of the presence of carbon in the bars. Steel with 0.15-0.3% carbon and up to 0.9% manganese possess good weld-ability. Steel with less than 0.2% carbon is ideal. If the impurities are kept low, these metals rarely show problems during the welding process. Steels with carbon more than 0.25% are prone to cracking in some applications.
Corrosion Resistance: Pre-welded meshes can be used to protect from corrosion. Moreover, the anti-corrosive properties make them ideal for being used in the humid areas also.
The knowledge about the properties of the steel bars should be followed while buying other steel products. The properties vary as per grades
Best TMT bars always come with the right certifications. The certifications are the indicators of the strength and properties of TMT bars. Always need to look for ISO certification, and OHSAS certification prior to buying the same. Exploring the market helps us to know that the bars have different properties. We need to be sure about getting the right products.
One thing is very important to get the right grade of TMT bars for a specific construction project. We need to identify the requirements and specifications of the construction project. On the basis of demand we need to choose the right TMT bars. In this process not only do we need to get TMT bars from the best manufacturers to ensure superior quality, but we also need to make sure you get the right grade of TMT bars for our specific construction project. It is important to buy from a reputable manufacturer to ensure the genuine and high-grade product.
All top TMT bars can be used for construction purposes, but different grades have different levels of bend-ability and strengths. Different types of construction projects need different stress strengths. It is very important to use top TMT bars that can provide an outstanding amount of support for the structure, given its size and its capacity.