What is TMT Bar?

TMT bars or Thermo-Mechanically Treated bars are high-strength reinforcement

bars having a tough outer core and a soft inner core. The very first step of the
manufacturing process involves passing the steel wires through a rolling mill stand.
Thereafter, these rolled steel wires are again passed through the Tempcore water
cooling system. While passing the wires through the water cooling system, the
water pressure is optimised. The sudden quenching and drastic change in
temperature toughen the outer layer of the steel bar, thus making it super tough
and durable. Once this process is over, the TMT bars are subject to atmospheric
cooling. This is done in order to equalise the temperature difference between the
soft inner core and the tough exterior. Once the TMT bar cools down, it slowly
turns into a ferrite-pearlite mass. The inner core remains soft giving the TMT bar
great tensile strength and elongation point. This design is unique to the TMT bars
and gives superior ductility to the bars. Also, this unique manufacturing technique
and the absence of Cold stress make this bar corrosion-resistant and boost its
weldability.

Higher elongation of TMT bar improves the bend/re-bend properties or the TMT
bars, thus making it safe from natural calamities such as an earthquake. The
special ribbed design of the TMT bars form a stronger bond with the concrete or
cement, thus, provides additional support and strength to the building structure
and improves their longevity and durability. This prevents the collapse of a building
during an earthquake and ensures the longevity of the structure.

NEED OF TMT BARS :

From homes and multi-storeyed buildings to flyovers and bridges, TMT bars
provide high strength to the structures. TMT bars are able to withstand any amount
of load. These improves the safety and longevity of the structure and secures it
from any damages.

AVAILABLE GRADES OF TMT BARS :

1. TMT BARS or Deformed Bars (8 mm- 50 mm dia.) Grade available: Fe-415/
500/ 550 & Fe-415D, Fe500D, Fe 550D, Fe 600
2. TMT/ Deformed Bars, Corrosion Resistance Bars (8 mm - 50 mm dia.)
Grades available: Fe-415/ 500/ 550 & Fe-415D, Fe500D, Fe 550D, Fe 600
QUALITY STANDARD OF TMT BARS :
Various international standards, viz. IS:1786 Grade Fe415/ Fe500/ Fe550 / Fe
600 / Fe 415D/Fe 500 D/ Fe 550 D / Fe 500 S of BIS of India, ASTM A615 Grade
60 of the USA, BST 500 of DIN 488 of Germany, BS 444 Grade 460 of Great
Britain,among others.

Strength
TMT Bars are available in Fe: 415 /500 /550/ 600 & Fe-415D, Fe500D, Fe 550D,
Fe 600 and Fe500SD, Fe 550SD grade which are much stronger than
yesteryears' conventional Bars and give upto 20% stronger concrete structure
with same quantity of steel.

Elongation
More strength with higher elongation is one of the unique features of TMT Bars. It
makes a concrete structure not only sound but safe also from earthquake related
natural calamities.

Bend Properties
Due to unique feature of greater elasticity in TMT Bars, it provides a very good
bending/ re-bending option during application in construction.

Corrosion Resistant
TMT Bars provides very good corrosion resistance due to it’s controlled chemistry
of raw material inputs, which provides a longer life concrete structure.

Fatigue Resistant
The unique feature of TMT Bar is its high Fatigue Resistance on dynamic loading
on account of the high strength of the surface layer.

Weld-ability
TMT Bars with low carbon equivalent content can be used for butt/ lap and other
weld joints without reduction in strength at the weld joints.
APPLICATION OF TMT BARS :
These bars can be used for general concrete reinforcement in building, bridges
and various other concrete structure. They are highly recommended for use in
high- rise building because of the saving of steel through higher strength. TMT
Bar, the new generation high strength ribbed reinforcement bar is different from
traditional bars in its method of manufacture and consequently, in its combination
of properties.

SECTION WEIGHT CHART OF TMT BARS

FEATURES OF DIFFERENT TMT BARS

PRODUCED BY SECONDARY PRODUCERS :
Features of Fe 415 grade TMT Bars are as follows:

MECHANICAL PROPERTIES CHEMICAL PROPERTIES

0.2% Proof Stress / YS Tensile Strength Elongation C S P S&P
% (%) (%) (%) (%)
(N/mm²) Max. (N/mm2)Min
485.0 14.5 0.30 0.060 0.060 0.110
415.0

Fe-415 D: The D variety of TMT bars were introduced by BIS in their latest
armament in the year 2008. This category of TMT Bars demonstrates higher
tensile strength and ductility on and above normal grade TMT bars. D variety TMT
bars are manufactured through special category of billets and critically controlled
thermal treatment during manufacturing process. The best part of D variety TMT
bars are these are the ideal product for earthquake resistance and totally free of
mechanical fatigue.

Features of Fe 415D grade TMT Bars are as follows:

MECHANICAL PROPERTIES CHEMICAL PROPERTIES

0.2% Proof Stress / YS Tensile Strength C S P S&P
Elongation% (%) (%) (%) (%)
(N/mm²) Max. (N/mm2)Min
415.0 500 18.0 0.25 0.045 0.045 0.085

Fe 500 Grade : Fe 500 grade TMT Bars were introduced as an one step up
technological marvel over conventional Fe 415 grade product . The superior tensile
strength in Fe 500 TMT bars resulted in approximately 17% lesser consumption in
steel in construction.

Features of Fe 500 grade TMT Bars are as follows:

MECHANICAL PROPERTIES CHEMICAL PROPERTIES

0.2% Proof Stress / YS Tensile Strength C S P SP
Elongation% (%) (%) (%) (%)
(N/mm²) Max. (N/mm2)Min
500.0 545.0 12.0 0.30 0.055 0.055 0.105

Fe-500 D: The D variety of TMT bars were introduced by BIS in their latest
armament in the year 2008. This category of TMT Bars demonstrate higher tensile
strength and ductility on and above normal grade TMT bars.D variety TMT bars
are manufactured through special category of billets and critically controlled
thermal treatment during manufacturing process. The best part of D variety TMT
bars are these are the ideal product for earthquake resistance and totally free of
mechanical fatigue.
Features of Fe 500 D grade TMT Bars are as follows:

MECHANICAL PROPERTIES CHEMICAL PROPERTIES

0.2% Proof Stress
Tensile Strength C S P S&P
/ YS
Elongation% (%) (%) (%) (%)
(N/mm2)Min
(N/mm²) Max.
500.0 565.0 16.0 0.25 0.040 0.040 0.075

Fe 550 Grade & Fe 600 Grade: Fe 550 grade & Fe 600 grade TMT Bars were
introduced to further increase the technical excellence of TMT bars and propensity
of consumption of steel in construction projects drastically got reduced due to
much higher tensile strength and load bearing capabilities of these technologically
superior grade of TMT bars .Gradually the structural engineer fraternity is inclining
towards these high end TMT Bars.

Features of Fe 550 & Fe 600 grade TMT Bars are as follows:

Grade Fe- 550

MECHANICAL PROPERTIES CHEMICAL PROPERTIES

0.2% Proof Stress / YS Tensile Strength C S P S&P
Elongation% (%) (%) (%) (%)
(N/mm²) Max. (N/mm2)Min
550.0 585.0 10.0 0.30 0.055 0.050 0.100

Grade Fe- 550 D

MECHANICAL PROPERTIES CHEMICAL PROPERTIES

0.2% Proof Stress / YS Tensile Strength C S P S&P
Elongation% (%) (%) (%) (%)
(N/mm²) Max. (N/mm2)Min
550.0 600.0 14.5 0.25 0.040 0.040 0.075

Grade Fe- 600

MECHANICAL PROPERTIES CHEMICAL PROPERTIES

0.2% Proof Stress / YS Tensile Strength C S P S&P
Elongation% (%) (%) (%) (%)
(N/mm²) Max. (N/mm2)Min
 600.0 660.0 10.0 0.30 0.040 0.040 0.075

Reinforcement bars of wire rods are used in conjunction with cement concrete to
build up a reinforced concrete structure which has a much higher strength.
However, corrosion of reinforcement bars arises due to the presence of chloride
ions in the concrete, and cement which contains calcium hydroxide produces
calcium carbonate in the presence of carbon dioxide and moisture in the
environment. The formation of calcium carbonate lowers the pH value of Steel thus
making it more prone to corrosion. The corroded products are detrimental because
they are more voluminous and exert pressure in the concrete leading to cracking.
To protect steel from corrosion CRS TMT was introduced to prolong the longevity
of RCC structure.

CRS TMT bars are produced with utmost care and with adequate addition of
corrosion resistance elements such as Copper, Chromium and Phosphorous. All
process controlled parameters are adhered to strictly at Steel Melting Shop and at
rolling mill. The international quenching technology of repute (TEMPCORE CRM-
Belgium) compliments the entire process to ensure the desired properties in CRS
TMT Bars.

AREAS OF USE OF CRS TMT :

 Highly humid and moist areas
 Marine atmosphere
 Bridges, dams, roofing prone to seepage of water
 Back water areas

CRS TMT BAR

Worldwide demand for Microalloyed low alloyed Re-bars generates majorly from
industries like Power, Oil and Gas extraction, Road & Bridge construction and Port
development. This is due to their improved strength-ductility, corrosion properties as
well as increased toughness.

CRS TMT Bar is produced by adding alloying elements like Cr, Cu, Ni, Mo and P,
either individually or in combination, to improve allied product properties. In the
Electric Furnace, corrosion resistant elements like phosphorus, copper/chromium
are added to the molten steel, while carbon and sulphur is reduced further through
 refining and deslagging. The microalloyed molten steel is then casted into billets
and rolled in a controlled quenching and tempering process to impart the desired
corrosion-resistant properties to the end product.

Corrosion Resistance Index (CRI)

Type of Test Non CRS TMT Re-bars CRS TMT Re-bars

Potentio Dynamic Test 1.0 2.35

Salt Spray Test 1.0 1.59

Sulphur Dioxide Test 1.0 1.68

Alternate Immersion Test 1.0 1.92

Advantages
1. No additional precaution required in material handling and transportation
2. No additional preparation for storage or working at site
3. No maintenance during fabrication
4. Workable at poor site conditions
5. Lifespan cost-benefit
6. No extra precaution during welding

CRS TMT Re-bars are ideal for

 Oil & Gas Exploration Sites
 Dams & Bridges
 Highways & Flyovers Construction
 Ports & Jetties
 Thermal & Hydel Power Station
 Industrial Structures
 Hazardous Area Construction
ADVANTAGES OF CRS BAR
 Longer life due to superior corrosion resistant
 High yield strength coupled with superior ductility and bendability
 No additional precaution required in material handling and transportation
 No extra operations required during fabrication
 Easy to weld
 Can be sent and re-bent using very small mandrel

Deterioration of reinforced concrete by corrosion of the carbon steel reinforcing

bars (Rebars) is a worldwide problem. The corrosion product (rust) occupies a
greater volume than the original steel bar and this creates a pressure which causes
cracking and subsequent bleeding of the surrounding concrete.

Corrosion of carbon steel rebars is greatly accelerated when chlorides are present
in the concrete (coupled with requisite moisture and oxygen levels to sustain the
corrosion reactions). This situation gets aggravated in constructions at the coastal
areas due to inherent extra salinity in its surroundings.

However, there is increasing interest in the use of reinforcing materials that have
inherently good corrosion resistance, thus minimizing the need for maintenance
and monitoring of the structure. Faced with the problems of costly repair /
replacement of important structures, the governing authorities are increasingly
demanding a greater emphasis on Life Cycle Costs for new construction projects,
as opposed to considering only the initial capital costs.

Billets manufactured from steel containing desired quantities of Copper and

Chromium / Copper and Phosphorus having inherent corrosion-resistant
properties are being used for hot-rolling of CRS TMT rebars. The bars then
undergo controlled quenching and tempering to impart the desired corrosion -
resistant properties to the end product.

CHEMICAL COMPOSITION OF CRS BAR

CHEMICAL COMPOSITION OF CRS MATERIAL (Cu / P Grade)

Elements composition
%C 0.15 (MAX.)
% Mn 0.50 (MIN.)
% Cu 0.30 (MIN.)
 %P 0.120 (MAX.)
% Cr Not required
REMARKS Ref. : IS:1786/2008, Clause no. 4.2, note 3
CHEMICAL COMPOSITION OF CRS MATERIAL (Cu /Cr Grade)

Elements composition
%C 0.15 (MAX.)
% Mn 0.50 (MIN.)
% Cu+ %Cr 0.40 (MIN.)
%P 0.120 (MAX.)
REMARKS Ref. : IS:1786/2008, Clause no. 4.2, note 3

PHYSICAL PROPERTIES OF CRS BAR

Grade Fe-415 Fe-415 D Fe-500 Fe-500 D Fe-550 Fe-550 D Fe-600

Yield
Strength
415 415 500 500 550 550 600
(N/mm2)
Min
10% more 12 % more 6% more 8% more 6% more
8 % more 10% more
than actual than actual than actual than actual than actual
than actual than actual
0.2 percent 0.2 percent 0.2 percent 0.2 percent 0.2 percent
Tensile 0.2 percent 0.2 percent
proof proof proof proof proof
Strength, proof proof
stress/Yield stress/Yield stress/Yield stress/Yield stress/Yield
(N/mm2) stress/Yield stress/Yield
Stress but Stress but Stress but Stress but Stress but
Min Stress but not Stress but not
not less not less not less not less not less
less than 545 less than 565
than 485 than 500 than 585 than 600 than 660
N/mm2 N/mm2
N/mm2 N/mm2 N/mm2 N/mm2 N/mm2
Elongation
14.5 18.0 12.0 16.0 10.0 14.5 10.0
(%) Min

WHAT IS RIB TECHNOLOGY?

1st to introduce India's innovative, patented designed ribs. It makes the home so
secure by creating strong bonding with the concrete, so that no threat can ever
bowl it out.
REASONS WHY TMT BARS ARE A MAJOR
FACTOR IN CONSTRUCTION:

 TMT bar are good during earthquake where it helps to withstand the shear force and
TMT bars have good expansion capacity. It holds the columns against failure during
earthquake.

 TMT bars have superior strength. These bars come in a variety of grades and are much
stronger than conventional bars. Compared to steel, TMT bars give extra strength to the
concrete structure. This feature makes them a cost-effective option for construction.

 TMT bars have unique bending ability. And that’s why it is ideal for any construction
work. It can be given any shape to meet the architectural and design needs of the
building.

 TMT bars are resistant to corrosion. This is an important feature as its anti-corrosive
properties ensure a longer life for the concrete structure.

 These bars are resistant to fatigue. This is yet another unique and important feature of
TMT bars. These bars can withstand any dynamic loading due to their excellent strength
of the surface layer. This makes TMT bars an essential choice for super strong buildings.

 TMT bars are resistant to earthquake. They have a soft ferrite-pearlite core and a high
strength outer layer. This makes them strong enough to withstand any seismic activity,
thus increasing the longevity and strength of the concrete structure.

 TMT bars can withstand high temperature and are pretty flexible to work with. That’s
another reason why it’s better to use TMT bars than other conventional bars.
Stainless Steel: Reasons Why It's Used
Widely in Construction Industry
Stainless steel is an important material finding a broad range of application
across many industries, especially the construction industry. It is primarily used
for construction purpose because it is highly resistant to corrosion and extreme
temperatures. That's the reason stainless steel is used for major construction
projects.

What is stainless steel?

Stainless steel refers to a group of corrosion-resistant steel alloys containing about

10.5% chromium. This chromium in the stainless steel reacts with the oxygen in
the atmosphere and produces a thin and inert layer of chromium-rich oxide on its
surface. Due to this layer, stainless steel is corrosion resistant. Unlike other
protective coatings such as paint or galvanising, this protective film of chromium -
rich oxide continues to protect the steel even if abrasion damages it. This film
tends to re-form even after being damaged.

Stainless steel is widely used for providing support and strength to the structure
and is extremely durable. However, from an architectural point of view, stainless
steel is also ideal for creating style. For any concrete structure, enhancements can
be easily made using stainless steel. Moreover, when constructing a building, it
needs a solid structure to support the entire building. Many important parts of a
building including wind posts, lintels, and masonry are made from stainless steel.
Stainless steel strips, steel wires, and steel plates are widely used to manufacture
these fixings. In construction, stainless steel is also used for:

 Flexible Design

Structural steel encourages design creativity. No matter how complex the design,
it can easily accomplish with the help of structural steel.

 It Improves the aesthetic appeal

Steel has a natural beauty, and the architects can easily expose this beauty in
the design of their structures for emphasising the grace, strength, and
transparency of the frame. No other material allows the application of degrees of
expression and creativity as structural steel.

 It is cost effective

The substitutes of stainless steel are extremely costly. So, without stainless
steel, there would be a rise in prices. Moreover, without stainless steel, it
would be a bit tough to produce aesthetically pleasing structures and
buildings that are resistant to corrosion.
Why Use Stainless Steel?

Stainless steel is widely used for construction purpose all over the globe. This is
because stainless steel offers a number of benefits such as:

 It is resistant to corrosion

 It is highly ductile and offers superior strength

 It has excellent high and low-temperature properties

 It is resistant to staining

 It has an aesthetic surface finish

 It is 100% recyclable
 Billets
Secondary Steel Industries produce a wide range of Continuously casted Billets in its
Steel Plant. The state-of-art technology of Concast AG Zurich imparts international
quality standards and ensures smooth and defect-free casting of billets.

The Billets produced can be broadly divided into Two main types i.e.

 M.S. Billets.
 Low Alloy Steel Billets (CRS Billets)

1. M.S. Billets are used for rolling of TMT Re-Bars and various other structural steel
products.
2. Low Alloy Steel Billets are used from rolling of CRS TMT Re-Bars.

Physical Properties

Description As per IS 2830

Bend (max.) 5 mm per meter

Camber (max.) 3mm per meter

Length 3 mt – 13 mt

Chemical Analysis as per B2830 : 2012

Designation %Carbon %Manganese

C15 0.12-0.18 + 0.30-0.60

C18 0.15-0.21 0.30-0.60

C20 0.17-0.23 0.30-0.60

C15 MMn 0.12-0.18 0.60-1.00

 Designation %Carbon %Manganese

C18 MMn 0.15-0.21 0.60-1.00

C20 MMn 0.17-0.23 0.60-1.00

C15 HMn 0.12-0.18 1.00-1.50

C18 HMn 0.15-0.21 1.00-1.50

C20 HMn 0.17-0.23 1.00-1.50

Chemical Analysis

Carbon Equivalent
Grade Sulphur Phosphorous
(CE)1

Max Max Max

A 0.05 0.05 0.42

B 0.045 0.045 0.41

C 0.04 0.04 0.39

Carbon equivalent based on ladle analysis = C + Mn/6 + Cr+Mo+V/5 + Nl+Cu/15

When steel is required in copper bearing quality, copper content is between 0.20 60
0.35 percent.

Features

The following are the Special features of Steel Billets: Best Steel Billets Manufacturer
India

 Excellent Surface Finish The Billets produced are free from any surface crack or
lamination. Magnetic particle test in order to identify any crack on the surface is done
on a regular basis as per its Quality Management Plan.
 Dimensional Tolerance: Billets are produced strictly in accordance to IS 2830 for
dimensional tolerance.
 No Internal Defects The Billets produced are free from any internal defects. Defects
such as piping blow-holes and pinholes are identified and segregated by Sulphur
Print Test.
 Excellent Corrosion Resistant property: The Special range of Billets known as CRS
Billets contain various corrosion resistant elements like copper, chromium and
phosphorous that impart corrosion resistance to the TMT Re-Bars rolled out of this
special type of Billets. The minimum CRE% (Cu% + Cr% + P%) is 0.50%

Quality Process
Dedication to quality can contribute to organization’songoing success, highly
marketable services and products. Quality Steel Companies incorporate quality at
every work stage, from conception to completion following a strict quality mandate in
order to always improve and provide value in everything thet do.
The entire quality control process adheres to 5 important things:

 Customer Satisfaction
 Organizational Performance
 Manufacturing Excellence
 Employee Contentment
 Social Responsibility

The quality control lab is furnished with advanced equipment like Universal Testing
Machine, Spectrometer, ICP, Leco, Bend and Rebend, Hardness Testing machine and
Microscope along with various other necessary devices. These are primarily used to
measure continuous quality improvement of the products from various angles at
various stages of production.

Quality Management

The entire Quality Management passes through four levels:

 Inspection
 Control
 Assurance
 Total Quality Management (TQM)
Inspection Process

Purpose: To conduct an inspection, testing, identification, and traceability of materials

and products in various stages of production in accordance with the applicable IS
specifications and customer requirements.
Scope: The process covers inspection, testing, identification and traceability of the
product from receipt stage, in-process inspection and final inspection till dispatch.

Procedure:

Direct Reduced Iron Unit (D.R.I.): The sized iron-ore is tested for its Fe content and
coal for its ash content and is then charged to D.R.I plant. The finished product of DRI
plant i.e. sponge iron is then tested for its Fe content and chemical composition and
is identified by day wise production.

The conforming material is taken to SMS plant for charging and in case of non-
conformation, the material is sent to rejection yard.

Steel Melting Shop (SMS): In the SMS plant the material is melted at about 1700 C
in an Electric Arc Furnace. The slag is removed automatically in the Arc furnace to
achieve precision control of chemistry of the molten metal. The hot molten metal is
checked for its chemical composition. Depending upon the composition required,
various ferroalloys are added to it. The molten steel with requisite chemical
composition from Electric Arc Furnace is sent to the continuous casting unit for casting
billet.

Continuous Casting Machine (CCM): The billets thus produced are first visually
inspected for the surface condition and then tested for its chemical composition. If any
surface discontinuity is observed in the material it is then sent to SMS unit for recycling.
The tested billet is then sent to the Rolling Mill raw material yard with a proper batch
number.

Rolling Mill: The Billets are then taken for production in the Rolling Mill. During the
production process, inspection is done at various stages. The non-conforming
products are identified and segregated properly for recycling. The finished product is
then subjected to final inspection (visual inspection & physical property) and a Lot
Number is allotted to it before being stored in the finished product yard.
Quality Assurance

The next level quality assurance includes inspection, correction, and investigation to
find the cause of the problems, and take action to prevent errors from re-occurring.

Total Quality Management

TQM or Total Management is designed to create a comprehensive and all-

encompassing module which aides in achieving Manufacturing Excellence. Every
element of this term speaks of an important aspect.

Total: Made up of the whole.

Quality: Degree of excellence of a product or service

Management: The art and science of planning, controlling, directing…. therefore,

TQM is the art and science of managing the whole to achieve excellence.
Plan: Establish the objectives and process necessary to deliver precise results, in
accordance with the Customer’s requirements and the organization’s policies.

Do: Implement the process.

Check: Monitor and measure processes and products against policies, objectives,
and requirements of the product to ensure strict adherence to them and detailed
reporting of the results.

Act: Take action to continuously improve process performance.

 TMT Facts

Important Facts on TMT Bar

TMT bars are one of the most important construction materials that are widely used
for building earthquake-resistant structures. The ribbed TMT bars from the best TMT
Bar Manufacturers provide better reinforcement to any concrete structure, thus,
minimizing damages during any seismic activities. Let’s take a look at a few quick facts
about TMT bars:

The true strength of TMT bar lies in the optimum balance between Toughness and
Flexibility (Elongation). Choosing the Best TMT bars are one of the most important
facts when it comes to choosing the right building materials.

 TMT bars are been used in all constructional projects which made from the latest
technological process and comes with high strength.

 With the new edge, technological innovation TMT bars are being produced with the
latest technology called ‘Thermex’. In this process after the final rolling, it subjected
to sudden cooling. It makes the bars strong optimally to its level and also the core
become soft.

 Due to high ductility bars are being produced in the number of grades which are Fe:
415, Fe: 500 and Fe: 550. These bars are being used in the construction of buildings,
bridges, various types of plants, Concrete Structural base etc.

 New edge TMT bars are earthquake resistant and it can be used in all type of
construction projects due to its extremely bending ability. It can be broadened to
match up exactly how you want it to be for your constructional structure.

 TMT bars are fully corrosion resistant, rust resistant and these bars are mandatory
to be used in coastal and humid tract. It intensifies the durability for the longer period.

 Thermo Mechanically Treated Bars are fire and heat defiant and it helps to prevent
any hazard.

 TMT bars have high weld-ability for which these being used for weld joints by
keeping the construction structure unchanged.

 Manufacturing process of a TMT bar save 20% of the steel than the usual. Hence,
the production cost becomes even lower.