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FAQs

What is Jindal Panther?

For the first time in history, JSPL has done product branding, and has forayed into retail with the launch of Jindal Panther™ TMT Rebars. These rebars are technically advanced thermo-mechanically treated and are different from the rest owing to the state-of–the art manufacturing HYQST technology from the leaders in the rebar production M/S MORGAN CONSTRUCTION COMPANY (NOW SIEMENS) of USA.

What is TMT?

Thermo Mechanical Processing, also known as Thermo-Mechanical Treatment (TMT), is a metallurgical process that integrates work hardening and heat treatment into a single process.

The quenching process produces a high strength bar from low carbon steel. The process quenches the surface layer of the bar, which pressurizes and deforms the crystal structure of the intermediate layers, and simultaneously begins to temper the quenched layers using the heat from the bar's core.

What is the need for TMT?

TMT steel bars compliments “Reinforced Cement Concrete” (RCC) which has become an integral part of every structure, be it a multi-storeyed building, a tunnel, a flyover, or a TV tower.With TMT, RCC can be moulded into any desired shape with which the steel rebars will gain the ability to withstand any load made to act upon them.These unnecessary forces can be developed by any live or dead load acting upon the structures thus causing loss of life and property.In order to secure the creations of mankind and to make them ever lasting for generations to come, the steel rebars should conform to the best in class quality standards.

What are the available grades and sizes of Jindal Panther™ TMT Rebars?

JSPL 500D high strength rebars conforms to IS 1786:2008, Fe 500D & Fe 550D, grade in normal EQR (Earthquake Resistant) & CRS (Corrosion Resistant) quality and Fe600 grade. JSPL TMT is available in 6-50(mm)(6,8,10,12,16,20,25,28,32,36,40,45,50), where 6-12 mm is available in coil as well as straight form.

What is HYQST?

High Yield Quenching and Self Tempering (HYQST) is an internationally renowned technology from Siemens, USA for manufacturing TMT Rebar which employs a special split style nozzle cooling process for producing fine grain multiphase composite Rebar, having superior strength and ductility.

How are Jindal Panther™ TMT Rebars produced?

Jindal Panther™ TMT Rebars are hot rolled from cast billets and are subjected to microprocessor controlled thermo-mechanical treatment in following three stages:

Step 1: Quenching
The hot rolled bar leaves the finishing mill stand at 1050 deg Celsius which is rapidly quenched by special split style nozzle cooling process. The quenching converts the billet's surface layer to martensite, which causes it to shrink. The shrinkage pressurises the core helping it to form the correct crystal structures, while the core remains hot and austenitic.

Step 2: Self Tempering
The bar leaves the quench box with a temperature gradient through its cross section and as the bar cools, heat flows from the bar centre to its surface and the bar heat and pressure correctly tempers an intermediate ring of martensite and bainite.

Step 3: Atmospheric Cooling
Finally, the slow cooling after quenching automatically tempers the austenitic core to ferrite and pearlite on the cooling bed , which now has a strong and tough , tempered martensite on the surface layer of the bar :an intermediate layer of tough martensite and bainite and a refined , ductile ferrite and pearlite core.

What are the USPs of Jindal Panther™ TMT Rebars?

The following points give Jindal Panther™ TMT Rebars an advantage over their competitors:

  • Weight/unit length: Jindal Panther™ TMT Rebars are rolled in negative tolerance zone promising same strength than similar TMT of the same sectional properties.
  • Bond Strength: Jindal Panther™ TMT Rebars have uniform and precise parallel rib pattern, ensuring excellent bonding with concrete, which provides superior strength to the buildings.
  • Dimensions: Jindal Panther™ TMT Rebars have close dimensional tolerance, superior surface finish, standard weights, lengths as mentioned in the standards and uniform & precise rib pattern.
  • Bendability: Jindal Panther™ TMT Rebars have high elongation which means that the TMT bars are capable of absorbing large amount of energy by plastic deformation before undergoing failure by fracture – a boon for ductile constructions in the seismic zones.
  • Weld-ability: Jindal Panther™ TMT Rebars have low carbon equivalent and is directly related to hydrogen induced cold cracking which is the most common weld defect for steel. Higher concentration of carbon and other alloying element tend to increase hardness and decrease weld-ability.
  • Corrosion Resistant: Jindal Panther™ TMT Rebars have minimum or negligible residual stresses in order to prevent any chance of rusting. And also by micro-alloying with small amount of Cr and Cu besides low C content, coupled with the state-of-the-art rolling technology , which imparts excellent corrosion resisting properties in the TMT bars.
  • Earthquake Resistance: Jindal Panther™ TMT Rebars have high UTS/YS ratio which signifies that steel is capable of elongating to a large extent when loaded beyond yield point as in the situation of an earthquake. It is with this view that some of the international specifications stipulate fairly high values for the UTS / YS ratio
  • Durability & Strength: Jindal Panther™ TMT Rebars have very low level of Sulphur and Phosphorous as they reduce the strength of the material and make them brittle. Excess level of S can lead to hot shortness wherein the melting point of steel gets lowered, thus making steel more prone to failure under extreme high temperature conditions. Excess level of P can lead to cold shortness wherein the steel undergoes brittle fracture while working in extremely cold condition and thus becomes more prone to cracking.
  • Cost Savings: Jindal Panther™ TMT Rebars have high UTS/YS ratio and high elongation which results in lesser consumption of the similar TMT of the same sectional properties but with low UTS/YS ratio and lesser elongation. As per studies TMT with high strength saves about 10-12% than corresponding lesser strength TMT.
  • Process Route: Jindal Panther™ TMT Rebars are produced using the superior and clean steel billets produced at JSPL, Raigarh through the BF+DRI-EAF-LRF-CCM route with highly controlled steel chemistry with very low levels of sulphur and phosphorus (less than 0.035%), and very low levels of inclusion and tramp elements.

Why Jindal Panther™ TMT Rebars should be preferred over other TMTs?

Jindal Panther™ TMT Rebars are produced using the superior and clean steel billets produced at JSPL, Raigarh through the BF+DRI-EAF-LRF-CCM route with highly controlled steel chemistry, very low levels of sulphur and phosphorus (less than 0.035%), and very low levels of inclusion and tramp elements. Our Steel making and TMT manufacturing process has to pass through strict quality control norms in our laboratories, which are NABL (National Accreditation Board of Laboratories) certified, which confirms the purity and quality in Jindal Panther™ TMT Rebars.

Can Jindal Panther™ TMT Rebars be bought in pieces?

Jindal Panther™ TMT Rebars are sold in retail shops only in pieces.

What is the advantage of buying Jindal Panther™ TMT Rebars in pieces?

Jindal Panther™ TMT Rebars in pieces offer you the following advantages:

  • Guaranteed weight in each piece.
  • Procure exact pieces as recommended by designer/architecture.
  • Avoids wastages in sites as exact number of pieces is purchased.
  • Guarantees customer satisfaction by reduction in delays and reduces labour cost.
  • Jindal Panther™ TMT Rebars are delivered to the customers at free of cost.

What is the misconception about the reddish colour of the superior quality of Jindal Panther™ TMT Rebars?

Often due to the interaction of the rebar with moisture and air, the surface of the rebar develops a reddish colour which is being misunderstood as corrosion. In fact, reddish rebar can be used for construction without any hesitation, as long as they are in proper physical shape, weight and strength.

How does Jindal Panther™ TMT Rebars result in cost saving?

Jindal Panther™ TMT Rebars are manufactured in a world class state-of-the-art rolling mill ensuring excellent yield strength exceeding the values mentioned in the standard IS-1786 and resulting in material saving of 14-15% compared to the TMT manufactured by the secondary producers. The Steel consumption depends on the strength of the rebar. Higher the strength, lower will be the consumption.

What are the special mill features that make Jindal Panther™ TMT Rebars superior?

The Present mill consists of the modern state-of-art-design and has the following special features to ensure superior surface finish, close dimensional tolerances and physical properties of the products:

  • HYQST technology, most advanced technology in India.
  • Hot/ cold billet charging facility.
  • Billet weighing facility.
  • Walking beam type reheating furnace-Ensures uniform heating of billets.
  • High pressure water de-scaling facility-Ensures scale free TMT bars.
  • Single strand high speed continuous mill arranged in V-H.
  • Quick roll change carpet in finishing group of stands.
  • Inter stand tension control rolling MTC (Minimum Tension Control).
  • Facilities of convertible stands to allow slit rolling for smaller size re-bars.
  • Online rapid water quenching unit for production of thermo-mechanically treated high strength Bars (TMT bars).
  • Facilities of two nos. 6 stand high speed finishing block NTM (NO-TWIST MILL) for smaller cross-sections-for superior surface finish & dimensional accuracy.
  • High speed discharge facility RES (ROTARY ENTRY SYSTEM) at cooling bed entry side for bars coming from 6-stand finishing block.
  • Automatic bundling & tying facilities for rolled product in straight length.
  • Level-2 mill automation and control.
  • Use of patented ‘Oval-Round Pass’ design ensures a higher reduction ratio providing better internal soundness in the rebars. The Mill is equipped with automatic shears for head/tail cropping, dividing, sampling or scrapping, and cutting-to-length, at various stages.

What are the advantages of superior Rib Patten in the Jindal Panther™ TMT Rebars?

Jindal Panther™ TMT Rebars have a precise and uniform parallel rib pattern engraved through computer controlled notch making machines which results in excellent bond strength with concrete.

Jindal Panther™ TMT Rebars have parallel ribs with excellent bond strength as compared to the ‘X’ rib pattern, which has a very low fatigue life and reduces bond strength with the concrete to a great extent.

Consistency of rib pattern is uniform and guaranteed in each bar as the finishing mill stand pass is not over used ,thus ensuring utmost quality product delivered to the customers.

Owing to the precise and uniform parallel rib design Jindal Panther™ TMT Rebars have superior mechanical properties as compared to the ordinary rebars in the market. Parallel Ribs on Jindal Panther™ TMT Rebars are produced by high speed finishing block called NTM (NO TWIST MILL) which is ultra-heavy duty block and uses TC (TUNGSTEN CARBIDE) rings which give Close dimensional tolerance, superior surface finish, uniform & precise parallel rib pattern to the rebars.

What are the advantages of using Jindal Panther™’s CRS (corrosion Resistance steel) rebars?

Advantages of using JSPL CRS Rebars:

  • Longer Life.
  • High yield strength coupled with good ductility and bendability.
  • No extra precaution required in material handling and transportation.
  • No maintenance required during fabrication.
  • More suitable under poor workmanship conditions at site.
  • No extra precaution during welding.
  • Can be bent and re-bent around very small mandrels.
  • Fatigue tests show that it can be used as a reinforcement material in the seismic zones.

What is the advantage of De-scaling the Billets before rolling?

Jindal Panther™ TMT Rebars are produced by complete descaled billets with the help of high pressure Descaler (working at 230 bar pressure and having a flow of 330 litres per minute) placed at the exit of the reheating furnace. This eliminates the possibility of rolled–in-scale in the finished rebar.

Descaling ensures uniform development of martensitic rim depth of up to 25% of the diameter in the finished rebar after quenching which ensures high strength and ductility in the finished rebar. As the yield strength increases with the rim thickness, it reduces the hardness from the outer surface reducing the brittle nature of the rebar as more the hardness, more will be the brittleness.

When rebars are manufactured without descaling, the scales get rolled in with the product and during mechanical working peels off from the surface of the rebar , it makes the rebar surface more prone to corrosion.

What is Carbon Equivalent and how does it enhances the weldability of Jindal Panther™ 500D TMT?

Carbon Equivalent is the measure of the tendency of the weld to form martensite on cooling and suffer brittle fracture. It is directly related to hydrogen induced cold cracking which is the most common weld defect for steel. Higher concentration of carbon and other alloying element tend to increase the hardness and decrease the weldability. TMT process can produce the desired yield strength with steel of relatively lower carbon equivalent by adjusting the on-line heat treatment parameters.

CARBON EQUIVALENT WELDABILITY
Up to 0.35 Excellent(JSPL’S CE)
0.36-0.40 Very good
0.41-0.45 Good
.46-0.50 Fair
Over 0.500 Poor

Jindal Panther™ TMT Rebars are conforming to chemistry which strictly follows a narrow band. We maintain a very low level of carbon content leading to excellent weldability.

How does low level of Sulphur and Phosphorous makes Jindal Panther™ TMT Rebars superior in quality? Lower the level of sulphur and phosporous, more is the strength of steel.

We maintain a very low level of Sulphur and Phosphorous as compared to the other primary producers, thus keeping the harmful impurities in steel to the lowest level by using our state-of-the-art steel making and steel refining technology.

Effect of Sulphur & Phosphorous:

Phosphorous Excess level of P can lead to cold shortness wherein the steel undergoes brittle fracture while working in an extremely cold condition and hence becomes more prone to cracking.
Sulphur Excess level of S can lead to hot shortness wherein the melting point of steel gets lowered, which lowers the steel strength and makes it makes it more prone to failure under extreme high temperature conditions.

What are the chemical and mechanical properties of Jindal Panther™ TMT Rebars?

The following table demonstrates the chemical and mechanical properties:

REBAR GRADE BIS FE 500 D JSPL 500 D  TYPICAL VALUES BIS FE 500 D CRS(AS PER CLAUSE 4.2,NOTE-3) JSPL FE 500 D CRS TYPICAL VALUES BIS FE 550 D JSPL 550 D TYPICAL VALUES BIS 600 JSPL 600 TYPICAL VALUES
% CARBON 0.25 0.20-0.25 0.15 0.11
0.15
0.25 0.22-0.25 0.3 0.25-0.28
% SILICON 0.15-0.25 0.15
0.25
0.15
0.25
0.15-0.25
% MANGANESE 0.90-1.00 0.80
1.00
0.95
1.05
0.75-0.80
% SULPHUR(MAX) 0.04 0.03 0.03 0.04 0.03 0.04 0.03
% PHOSPHOROUS(MAX) 0.04 0.03 0.12 0.1 0.04 0.03 0.04 0.03
% SULPHUR+PHOSPHOROUS(MAX) 0.075 0.055 0.125 0.075 0.055 0.075 0.055
% CARBON EQUIVALENT(CE) 0.42 0.31-0.36 0.42 0.42 0.31
0.41
0.42 0.41
% COPPER 0.35
0.40
% CHROMIUM 0.15
0.20
YIELD STRESS(N/mm2) MIN 500 525 500 525 550 575 600 610
% ELONGATION(MIN) 16 18 16 18 14.5 16 10 12
TENSILE STRENGTH(N/mm2) MIN 565 600 565 600 600 645 660 675
UTS/YS RATIO 1.13 1.15 1.13 1.15 1.08 1.12 1.1 1.2

What is the Stress-Strain curve? what is the importance of YS, UTS and Percentage Elongation?

Stress-strain curve is an extremely important graphical measure of the material’s mechanical properties

Yield stress: Is the stress a material can withstand without permanent deformation, Yield strength is usually stated as the stress at which a permanent deformation of 0.2% of the original dimension will result, known as the 0.2% yield stress.
OR
The stress at which a non-proportional elongation equals to 0.2 % of the original gauge length takes place (where gauge length is 5.65sqrt A.’A’ is the cross sectional area of the test piece).

Ultimate Tensile Strength: The maximum stress a material can withstand in a tensile test.
OR
The maximum load (force) reached in a tensile test divided by the effective cross sectional area of gauge length portion of the test piece.

Percentage Elongation: When a material is tested for tensile strength it elongates a certain amount before fracture takes place. The two pieces are placed together and the amount of extension is measured against marks made before starting the test which is expressed as a percentage of the original gauge length.

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

S.NO CHEMICAL ELEMENT EFFECT ON REBAR
CONTROLLING PROPERTY ACTUAL EFFECT
1 Carbon (C) Hardness, strength, weldability and brittleness Higher carbon contributes to the tensile strength of steel, resulting in higher load bearing capacity, while lower carbon content (less than 0.1% ) will reduce the strength. Higher carbon content ( 0.3% and above) makes the steel bar unweldable and brittle
2 Manganese(Mn) Strength and yield strength The manganese content in steel is not specified as per IS:1786-2008,however higher manganese content in steel increases the tensile strength and the carbon equivalent property
3 Sulphur (S) Present as an impurity in steel which increases its brittleness Presence of sulphur should be limited as per IS:1786-2008.Presence of high sulphur makes the bar brittle during twisting, as higher sulphur content leads to the hot shot problem during rolling
4 Phosphorus(P) Present as an impurity in steel which increases strength and brittleness Higher phosphorous content leads to increase in the strength and corrosion resistance properties, but leads to brittleness due to the formation of low euctoid phosphicles in the grain boundary. It also lowers the impact value at sub-zero temperature level(transition temperature)
5 Copper (Cu) Strength and corrosion resistance properties Being a pearlite stabiliser it increases the strength and corrosion resistance property
6 Chromium(Cr) Weldability and corrosion resistance Present as an impurity and influences carbon equivalent and increases the corrosion resistance property
7 Carbon Equivalent(CE) Hardness, tensile strength and weldability CarbonEquivalent is the measure of the tendency of the weld to form martensite on cooling and the suffer brittle fracture. It is directly related to hydrogen induced cold cracking which is the most common weld defect for steel. Higher concentration of carbon and other alloying element tend to increase hardness and decrease weldability

What are the quality testing facilities available for Jindal Panther™ TMT Rebars?


UTM (UNIVERSAL TESTING MACHINE) MACHINE (For conducting the destructive testing to measure YS, UTS and Elongation as per IS-1786:2008)

 


BAND SAW MACHINE (For cutting the Jindal Panther™ TMT Rebars with close finish to measure accurate weight/meter as per IS-1786:2008)

 


BENDING MACHINE (For conducting the bend test as per IS-1786:2008)

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