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We Maintain Better than BIS Standards to Ensure Our TMT Bars Can Handle Cyclic Loads Extremely Well

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Kamachi Sponge & Power Corporation Limited is part of the Kamachi Group, with business interests in a wide spectrum of industries including steel manufacturing and processing, granites, energy, imports and exports. Foun-ded in 1978, Kamachi Sponge & Power Corporation is involved in the processing, trading and supplying of a wide array of sponge iron, raw coal, iron ore, corrosion resistant steel bar, mild steel billet and TMT bars. In an exclusive interaction with The Masterbuilder, Vinod Kothari, Managing Director threw light on various aspects related to their range of TMT bars.

Excerpts:

Please tell us about the technology behind your products

Kamachi TMT bars are manufactured in a fully automated mill that is sourced from MWE, Germany to ensure unmatched consistency across the entire spectrum of production. The importance of this mill can be gauged from the fact that other than Primary Producers, no Secondary Producer of steel in south India owns this technology.

The below are the high-lights of the technology we use:

–        Pressurized Descaler: Scaling interferes with bonding between steel and cement. If not removed, it forms a thin layer on the TMT bar. Our manufacturing process ensures that scaling formed during heating of billet is removed with pressurized 230 Bar Descalers. This ensures scale free rolling compared to loop mills as they do not have these facilities.
–        German Mill: We deploy 100% automatic German rolling mill.
–        Computer Controlled: All our processes are 100% computer controlled. The entire 1200 mt per day mill floor can be operated by 2 engineers.
–        H-V mill: We use the Horizontal and Vertical combination mill as this is critical to reduce the billet evenly in the rolling process. Perfect weight tolerances are easily achieved with this technology.
–        Online Heating: Temperature at which bars are rolled holds key to improve the mechanical strength of TMT bars. At our facility, the billets temperatures are monitored and heated through induction heaters whenever necessary. This ensures that no billet is ever rolled at wrong temperatures.
–        Notching Robotic: We use imported Robot Notching machines supplied by Sparkonix (India), which ensures 100% uniform rib height, distance and pattern.
–        Tension Free Rolling: Looper Boxes en-sure that our TMT bars are rolled tension free. If Looper Boxes are not installed it may result in damage to the TMT bar at various places during production and the same cannot be detected by the naked eye.
–        Automatic 72 mtr Cooling Bed: TMT bars are formed by self tempering of steel bars. The core heat dissipates outside on the cooling bed. At Kamachi, the cooling bed is elevated at 5 mtr levels and hence ensures 360O cooling.
–        Robot Testing: Most advanced spectro machines are used at Kamachi.Our quality testing machine results are printed directly and cannot be tampered with.
–        Temperature Control: Automatic pyrometers test and relay billet temperatures relay data to computers. This is just one of the 1000 automation checks our billets pass through.
–        Hot Charging: At our facility the billets are produced in Concast and Hot rolled in Rolling mill. This saves reheating and avoids scaling. The billets are of 12 mtrs length and 160 * 160mm India this ensures 4 times better quality.
–        Thermex Technology: Only when passed through a patented process such as Thermex, Tempcore or Hyqst the TMT bar is accepted internationally. At our facility the Thermex QST process ensures proper formation of cores.
–        Cut to Customized Length: An engineer can save time by specifying customized lengths for their projects. We have the facility to deliver TMT bars that are precision cut by computers upto 25 mtrs in a single length. Manual cutting cannot achieve this accuracy.
–        Auto Counting Packing Bundling: Our TMT bars are auto counted, packed and bundled. Even the bending process is done through machines and is metal tagged. Our bundles are theft proof and ensure peace of mind. These facilities are hardly found in semi automatic plant.

What ensures that TMT bars are resistant to earthquakes and corrosion?

TMT bars have a ferrous Perlite core (soft) and tempered Martensite (Hard) exterior. In layman terms, the core allows mild tilting and the exterior brings it back to its original position during an earthquake. This formation is ensured by the TMT process. Hence, only an internationally accepted QST technology such as Thermex, Tempcore or Hyqst should be used. How-ever, if the steel bar is not perfect, no amount of German process can improve its strength. Hence, the combination of a V-H mill technology with Thermex process is adopted to ensure utmost earthquake protection.

TMT bars which denote ‘D’, like Fe-500D, where D stands for Ductility are designed for better earthquake resistance than ordinary TMT bars. Lower levels of Sulphur + Phosphorus are ensured to achieve this.

With respect to the second part of your question, not all TMT bars are necessarily resistant to corrosion. Only High Corrosion Resistant Marine (HCRM) can withstand corrosion due to the addition of corrosion fighting Nickel, Copper and Chrome. Al-though the cost of these bars is higher than regular Fe-500 bars, the lifecycle of the product recovers this easily.  Our HCRM bars are widely used in bridges and high rises, particularly near coastal area as the presence of these elements is higher than ordinary HCRM bars.

What determines the tensile strength of a TMT bar?

The tensile strength of a bar is created in the rolling mill and enhanced by the QST process.

Is there any difference in making billets and numbers of Ribs to make the tensile strength of steel with uniform consistency?

Rib formation is related to Rolling and not billets. Billets define the chemical parameters of a TMT Bar. To ensure maximum consistency, virgin material like DRI is best suited. Billets made from scrap cannot match these.

The rib formation on a bar is controlled first on the notching machines. These notching machines need to be computer controlled to ensure even height, distance, length of lugs and prominent side ribs to ensure best reinforcement to cement. The tensile strength of the bars is controlled in the rolling parameters.  Uniform consistency is achieved only through automation as multiple parameters like Temperatures, rolling speed, Number of stands are  inter-related.

Do you conduct regular test on the tensile strength of your TMT bars?

Yes. UTM (Universal Testing Machine) connected to Automated Software are installed which enables rigorous testing of tensile strength. However, please note that cyclic loading tests are not part of the latest IS 1786:2008 guidelines. The parameters mentioned in BIS are relevant to handle cyclic loading. We maintain better standards, hence can confirm that our TMT bars handle cyclic loading better than regular TMT Bars. If clients require a particular load parameter to be tested on the bar, the same can be done.

Any plans for Readyfix steel to prevent wastage and ensure ready availability of material?

Ready Made steel market is yet to mature and presently we are not planning to venture in to the same. However, we are already specialists in Special Length Steel. As per engineer’s requirement, TMT bars can be cut to accurate measurements up to 25 meters. This coupled with large production base of 1200 m.t per day ensures ready availability.

 

 

What are the benefits of using Fe-500 TMT bar. Are there any price differences when compared to Fe-415 ?

Fe-415 evolved as a standard for TMT bars when they were introduced. Today, that has been replaced by Fe-500. The idea is to reduce the consumption of steel while retaining the same area of construction. Assume this, two buildings with same foundation space. One is of 2 floors and the other of 6. Fe-500 bars are best suited as they can be used in lesser quantities and cost wise, are at par.

As for as a prices are concerned there is no price difference between an Fe-415 and a Fe-500 bar!

Please tell us about the performance of your steel rebars at elevated fire temperatures.

Thermal efficiency of a TMT bar is majorly dependent on its chemical content of Sulphur. Excess of these elements cause Hot Shortness. During high temperatures, high levels of sulphur forms iron sulphide which causes the steel to crack rather than deform. This phenomenon is controlled by adding manganese as it creates manganese sulphide whose melting point is higher.

In our TMT bars, Sulphur is well below and Manganese is added in higher levels than specified in BIS standards.

Please take us thru the behaviour of high quality TMT bars such as yours under cyclic loading.

Chances of failures are less in TMT bars which have a minimum of elongation of 14.5% as it accommodates the inelastic strains better during a cyclic loading situation like repeated earthquakes. Our TMT bars hence are well equipped to with-stand cyclic loading. To quote from SEF India “the behaviour with respect to ductility of rebar, against monotonic, repetitive and cyclic loading can be characterised by means of ultimate strain at fracture or total elongation. The requirement of minimum strain at fracture or minimum elongation is specified in codes”, At Kamachi, we maintain better than BIS standards to ensure fatigue caused under cyclic loads are well handled.

Can you thrown light on your CSR initiatives?

We have maintained a collective focus on several arenas of corporate sustainable growth, which leaves a positive impact on the human force, the environment and the society at large. As part of these initiatives the group works closely with the local community near our factory consisting of 10 villages and in and around Gummidipoondi Taluk, Tamil Nadu. Our focus is primarily on Education, Health & Hygiene, Sustainable Livelihood, Agriculture and Veterinary Development, Social Welfare, Infrastructure Development & Environment.

Lack of awareness on the benefits of using high quality TMT steel rebar is a major restraint.  How do you handle this situation?

We run a campaign called ‘Know your Steel’ where in engineers, dealers, college students, trainees and the general public are brought to our manufacturing  facility to explain the production process and benefits of using high quality TMT bars. We also regularly conduct engineering meets and participate in seminars to address this issue.

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