FAQ

What is Kamachi TMT?

What are the available grades and sizes of Kamachi TMTTM Re-bars?

Kamachi TMTTM Re-bars conform to IS 1786:2008. They are available in Fe500, Fe500D and Fe550D grade under regular earth quake resistant & CRS (Corrosion Resistant) varities. Kamachi TMT™ Re-bars are available in 8 to 40 mm sizes

What is Thermex Technology?

THERMEX Quenching & Self-Tempering Technology is offered by H&K Rolling Mill Engineers Pvt. Ltd. under exclusive & perpetual rights from M/s Hennigsdorfer Stahl Engineering Gmbh, Germany.

Thermex Re-bars have a tempered martensite periphery with fine grain of ferrite pearlite at the core.

The search for a process better than CTD led to the development of THERMEX Technology - a Quenching & Self Tempering (QST)process; and the first choice world wide.

benefits of the Thermex Re-bars primarily on account of

  • Superior product with consistent properties
  • High strength combined with high ductility
  • Better corrosion resistance
  • Better resistance to high temperatures, as in the case of fires
  • Easy manufacture of different strengths of Re-bars from nearly the same steel grades
  • Saving of 10-20% in steel consumption when using Thermex 500 in place of CTD Re-bars
  • Better fatigue resistance
  • Better weldability
  • Easy and less construction time
  • Lastly, an ideal choice for seismic zones due to excellent ductility properties. This is of great importance for India because nearly 60% of the country falls in the high seismic hazard category.

How are Kamachi TMTTM Re-bars produced?

Kamachi TMTTM TMT Re-bars are hot rolled from concast route billets and pass through one of the most advance rolling technologies imported from The MWE Magdeburger Walzwerk Engineering GmbH. Unique slit technology ensures that minimum of 3 bars of 8mm size are produced at a time. This is possible, only if the billets are of the finest quality. The two steps involved in manufacturing of Kamachi TMT Re-bars are :

  • Step 1: Quenching
    The hot rolled bar leaves the finishing mill stand at 950 deg Celsius which is rapidly quenched by split style nozzle cooling process. This cools the re-bars to around 500 deg celcius and converts the surface layer to martensite, which causes it to shrink, pressurizing the core to form the required crystal structures, while the core remains hot and austenitic.
  • Step 2: Self Tempering and Atmospheric Cooling:
    As the bar leaves the quenching box with a consistent temperature gradient across its cross section, it cools and heat flows from the center to its surface. Parallelly, the bar heat and pressure forms an intermediate ring of martensite. Finally, the cooling bed built at 5mtr level above ground ensures even atmospheric cooling from all sides to achieve a tempered martensite periphery with fine grain of ferrite pearlite at the core.

What are the USPs of Kamachi TMTTM Re-bars?

The following points give Kamachi TMT™ Re-bars an advantage over their competitors:

  • BETTER CORE. BETTER STEEL
    Made from internationally patented German technology that ensures superior core formation for best quality TMT re-bars. Kamachi TMT Re-bars have tempered martensite periphery with fine grain of ferrite pearlite at the core.
  • EVERY BAR TESTED AND TRACKED
    Each TMT bar can be backtracked to the specific heat and the quality of superior billets that it was rolled from. That and our hi-tech automatic monitoring system ensure complete peace of mind.
  • UNMATCHED CONSISTENCY UNRIVALLED STEEL.
    Advanced slit technology with low rolling time allows production of three 8 mm bars at the same time with the same consistency. This is possible only if the billets are of the highest quality
  • PRIME RAW MATERIAL. PREMIUM TMT.
    TMTTM Re-bars are produced clean steel billets in house via the DRI + LRF route with computer controlled processes for consistent steel chemistry. They are the hot rolled with both German Rolling Mill and German TMT technology unlike regular bars with none or part of these facilities.
Some of the other features :
  • Cost Savings: Kamachi TMTTM Re-bars save more than 10% of steel consumption compared to ordinary bars. This is made possible due to the higher strength of the bars which lead to lesser steel requirements for a given area.
  • Earthquake Resistance: During earthquakes, the structure receives severe shock / impact loading. The area under the engineering ‘stress – strain’ curve represents the energy absorbed by the steel before it fractures. As stress is first inflicted on the re-bar before passing on to other materials, Kamachi TMT™ Re-bars come with high UTS/YS ratio signifying its ability to handle this extreme stress and hence protecting the integrity of the structure.
  • Durability: Kamachi TMTTM Re-bars have lower levels of Sulphur and Phosphorous than stated in IS standards. Excess levels of Sulphur leads to “hot shortness” wherein the melting point of steel is lowered, leading to failure under extreme high temperature conditions. Excess level of Phosphorus leads to cold shortness wherein the steel becomes brittle under extremely cold conditions and leads to cracking.
  • Bond Strength: Kamachi TMTTM Re-bars provide uniform and precise parallel rib patterns created by computer controlled notch machines to assure excellent bonding with concrete.
  • Bendability: Kamachi TMTTM Re-bars provide higher than Indian Standards elongation enabling absorption of high stress levels without which the bar would fail due to fracture. This is particularly essential for constructions in the seismic zones.
  • Weld-ability: Kamachi TMTTM Re-bars contain low carbon equivalent and is directly related to hydrogen induced cold cracking which is the most common weld defect for steel.
  • Corrosion Resistant: Kamachi TMTTM Re-bars are produced with specific chemistry to handle corrosion. By adding special alloys like Chromium, Copper and Silicon, the bars can withstand longer compared to ordinary grades.

Why Kamachi TMTTM Re-bars are preferred over other brands?

Kamachi TMT Re-bars has been awarded the Indian Power Brand for 2013.

Kamachi TMT bar is also the fastest growing tmt bar brand in Southern India

While every company produces the same quality tmt bars, only Kamachi TMT Re-bars can assure every single piece produced maintains the same quality. This is ensured by installing the state of the art; DCS and PLC controlled production facilities. Test certificate is provided with every bar which can be cross checked at any government-accredited lab for quality verifications.

Also, Kamachi TMTTM Re-bars are made in South India’s first and only integrated factory dedicated for TMT Re-bar manufacturing only. Right from processing Virgin iron ore from the mines: creating billets: hot charging and rolling along with the Thermo Mechanical Treatment happens in a single quality controlled atmosphere to ensure that every bar bearing the Kamachi Trade mark, matches its claim of unbeatable quality.

How does Kamachi TMTTM Re-bars result in cost saving?

Fe500 Cost Effective:

For every 1 ton of Fe 500 re-bars, 1.2 MT Fe 415 has to be used, hence,

Grade Cost /MT (landed at Site) Qty (in MT) Value
Fe 500 46500=00 1 46500=00
Fe 415 45500=00 1.2 54600=00
Savings 8100=00

Total savings in Rs. 8100=00

Total Savings in % 17%

How to identify Kamachi TMTTM Re-bars?

Every Kamachi TMTTM Re-bars is embossed with “Kamachi 500” along with the size/section and the ISI logo.

What are the special mill features that make Kamachi TMTTM TMT Re-bars superior?

The State of the art German Mill Technology ensures unique features to ensure quality consistency in every bar. For perspective, we can produce more than 5 crore TMT bars a year!

  • Thermex technology. Internationally patented and leader in TMT processes.
  • Hot / cold billet charging facility.
  • Online billet weighing facility to ensure perfect lengths
  • Online Induction reheating ensures uniform heating of billets and maintains exact temperatures for perfect rolling of bars
  • High pressure online water de-scaling facility ensures premium finished and scale free TMT bars.
  • Advanced Vertical/ Horizontal Stands mill and loopers ensure automized and tension free rolling
  • Unique slit technology to allow slit rolling for smaller size re-bars.
  • Automatic Bundling and weighing unit ensures consistency in packaging.
  • Level-2 mill automation and control.
  • Flying shears and cold shears ensures standard and non- standard size order execution

What are the chemical and mechanical properties of Kamachi TMTTM Re-bars?

Chemical Properties
Elements (Maximum %) IS:1786 500 Kamachi TMT 500 IS:1786 500D Kamachi TMT 500D Kamachi CRS
Carbon 0.30% Max 0.25% Max 0.25% Max 0.22% Max 0.15% Max
Sulphur 0.055% Max 0.050% Max 0.040% Max 0.035% Max 0.04% Max
Phospharus 0.055% Max 0.050% Max 0.040% Max 0.035% Max 0.1% Max
Sulphur + Phospharus 0.105% Max 0.100% Max 0.075% Max 0.070% Max
Manganese 1% Max
Chromium 0.42% Max
Copper 0.5% Max
Silicon 0.45% Max
Mechanical Properties
Parameter Unit IS:1786 500 Kamachi TMT 500 IS:1786 500D Kamachi TMT 500D
Yield Stress N/mm2 500 540 500 545
Tensile Strength N/mm2 545 580 565 595
Elongation % 12 20 16 20

What is the influence of different chemical ingredient in steel on the properties of rebar?

Influence of different chemical ingredients in steel on properties of rebars
Carbon (C) Hardness, strength, weldability and brittleness Higher carbon contributes to the tensile strength of steel, that is, higher load bearing capacity and vice versa. Lower carbon content less than 0.1 percent will reduce the strength. Higher carbon content of 0.3 percent and above makes the steel bar unweldable and brittle
Manganese(Mn) Strength and yield strength The manganese content in steel is not specified as per IS: 1786. However higher manganese content in steel increases the tensile strength and also the carbon equivalent property.
Sulphur (S) Present as an impurity in steel which increases its brittleness Presence of sulphur should be limited as per IS:1786. Presence of higher sulphur makes the bar brittle during twisting, as higher sulphur content brings the hot shot problem during rolling.
Phosphorus(P) Present as an impurity in steel which increases strength and brittleness Higher phosphorus content contributes to the increase in strength and corrosion resistance properties but brings brittleness due to the formation of low euctoid phosphicles in the grain boundary. Also lowers the impact value at sub zero temperature level (transition temperature).
Copper (Cu) Strength and corrosion resistance properties Being a pearlite stabiliser, it increases the strength and corrosion resistance property
Chromium(Cr) Weldability and corrosion resistance Present as an impurity from the scrap and influences carbon equivalent; weldability and increases corrosion resistance property
Carbon Equivalent(CE) Hardness, tensile strength and weldability This property is required to set the cooling parameters in TMT process and a slight variation in carbon equivalent may alter the physical properties. In case of CTD bars, carbon equivalent has a maximum limit of 0.42 percent but there is no lower chemical composition and physical properties of raw materials are withinlimit prescribed. As such, as long as the specified limits, the variation in carbon equivalent as in the case of TMT bars

Ref : internet and sefindia