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Non-Flat Products - The Indian Scenarioon-Flat Products - The Indian Scenario

Introduction

Steel has been regarded as the

most useful product for mankind. It

reaches every home, and has a wide

range of applications from a small

pin to the manufacture of

automobiles, building of the railway

systems, ships, big construction

projects, housing, oil rigs, nuclear power stations an so on.

Steel is also eco-friendly.

Steel products are categorised into broad segments : Non-

flat (popularly known as Long products) and Flat products.

Finished steel Non-flat products include rounds, bars

including re-enforcement bars, wire rods, structural such as

angles, channels, joist / beams and railway materials in the

shape of rails, wheels and axles. All these products play a key

role in the growth of a country's more important sectors like

construction, power, oil and gas, engineering, railway an road

transportation, port, irrigation etc.

Profile of Non-flat Products

Bars and Rods comprise of plain

rounds / bars, cold-twisted deformed

bars (CTD bars), TMT Bars, with

innovations like THERMAX and

TEMPCORE bars.

In 2005-06, the share of bars and rods (including wire rods)

in the total production of carbon finished steel in India was

29.73 %, while its share in the total consumption of carbon

finished steel was 33.93 %. The consumption of bars and rods

increased by 13.26 percent in 2005-06 over the previous year.

The dominance of CTD bars

(Torsteel) since the early seventies of

the last century in India, was perhaps

due to the fact that most of the civil

engineers working in the construction

projects at that time did not bother to

check the vital parameters like yield

strength, ultimate tensile strength (UTS) or the elongation

capability of these materials while using the CTD bars in RCC.

It may be mentioned here that the industrially developed

countries had however, stopped using such CTD bars in the

mid-seventies of the last century.

Then came the era of Thermo Mechanically Tested (TMT)

bars which are even now being used by many civil engineers in

India, because they believe that these bars conform to the

specification Fe-415 as per IS:1768/1985 and these bars are

superior to CTD bars used earlier. However, these so-calledTMT bars available from numerous mills in India did not

guarantee a superior product. According to the technology

experts, these sub-standard TMT bars were very often found to2

have a yield strength of 350-390N/mm only on testing.

The basic requirements

of rebars today is low cost-

d e f o r m e d b a r s w i t h

guaranteed yield strength2

of 500N/ mm wi th

adequate ductility for theSeismic (earthquake prone)

zones.

THERMAX and TEMPCORE technologies were

developed by the mid-eighties of the last century to produce

reinforcing bars (rebars) that had far superior properties than

what were available in the ordinary CTD bars and the so called

TMT Bars. These processes were introduced to target the

prevalent global demand for low cost rebars at that time, with a2

strength of 400 to 500N/mm and good ductility so that

adequate safety was ensured while using these products in

Seismic zone as well as to effect savings in the steel used.

These QUENCHED and TEMPERED rebars were found to be

a far superior product to the CTD bars and the ordinary TMT

bars used by the civil engineers.

Nearly 55 to 60 percent of India fall under the Seismic

Zones 3, 4 and 5. Effective January, 2006, the BS : 4449 / 20052

with yield strength of 500N/ mm has been specified for use in

the Seismic Zones of India. The new high ductility grade 500C

as per BS : 4449/2005 has the following parameters :

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Characteristic Grade - C

*Min.

Admissible

*Max.

Admissible

Yield strength Re,MPa 500 485 650

Stress Ratio (Rm/Re) > 1.5 to 7.5 6.0 NA

The bar as it leaves the

rolling mill is guided through

specially designed proprietary

THERMAX PIPES, wherein

the surface temperature of 950-0

1000 C is brought down

drastically in a short period of about one second by intensive

and uniform water cooling. The temperature of the core

remains largely unaffected.

The pre-determined cooling of the bar periphery

transforms the peripheral structure into martensite and then

annealed through the heat available at the core. The peripheral

and core temperature difference finally equalises at about0

600 C and the resultant bar structure is of tempered martensite

at the periphery and of fine-grained ferrite pearlite at the core.

Usually, the resultant soft core forms about 65-75 percent of

the area (depending upon the minimum yield strength desired)

and the rest is hardened periphery.

The Thermax products exhibits high yield point, surface

hardness, toughness, ductility and weldability.

The brand name Thermax is derived from thermal

exchange and this exchange is the key to this process. Thermax

bars saves steel consumption by 15 to 19 percent as compared

to the conventional CTD bars.

The physical properties of the Thermax bars used in the

Indian construction sector are shown below :

Minimum Yield Strength 500N / mm2

Minimum Tensile Strength 10% more than YS Subject to 560N/mm2

Stress Ratio (TS/YS) 1.1 (Generally 1.15 to 1.35)

Minimum A5 Elongation (%) 16 (Generally 18 to 22)

Weldability Consistent with Industry Requirement

SAIL's Dugrapur and Bhilai Steel Plants, Rathi Udyog,

Kalyani Steels, Ramsarup, Kolkata, Besco, Kolkata, Beekay,

Jamshedpur, MSP, Orissa and about 50 other steel plants / units

in India have adopted Thermax technology raising the capacity

of this technology in the country to over 2 Mtpy.

This is a special heat

treatment process wherein the

heat treatment is done from the

heat of the rolling process

itself. Beginning with blooms,

which are heated in a Re-

Heating Furnace, rolled

through a sequence of rolling stands and progressively reduced

to a final shape and size of the reinforcing bar.

As the hot rolled bar emerges from the finishing stand of

the bar mill, it is rapidly cooled. The Quenching process, by a

special water spray system, converts the surface layer of the

bar to a hardend structure called 'Martensite' while the core

remains 'Austenitic'.

The second stage of 'Tempering' begins as the bar leavesthe water cooling section. In this stage, the heat flows from the

core to the surface layer, transforming it into a structure called

'Tempered Martensite', while the core continues to stay in

'Austenitic' state.

The third and the final stage takes place on the cooling bed.

Here the austenitic core is transformed to a ductile 'Ferrite

Pearlite' core. The finished bar has a grain structure comprising

of a tough outer layer of 'Tempered Martensite' and a ductile

'Ferrite Pearlite'. The combination of these two factors gives

excellent yield strength to the bar along with superior ductility

and weldability.Tata Steel, RINL's Vizag Steel Plants and many more

producers have adopted the 'Tempcore' technology. The two

ISP's are producing rebars at par with the new specification BS

: 4449/2005. The Tempcore process saves steel consumption

by 16-18 percent as compared to the ordinary CTD bars.

Galvanised coating provide important advantages for the

protection of reinforcing bars. It has been found by researchers

that the corrosion resistance of galvanised steel reinforcement

to be superior to uncoated steel, while the bond strengths of

galvanised and block steel are not significantly different.

The benefits of galvanised reinforcement are as follows :

a) Protection of steel during storage and construction prior to

placing the concrete.

b) Diminished effect of variations in concrete quality.

c) Safeguards against poor workmanship, especially

misplacement of reinforcement, poor compaction and

inadequate curing.

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d) Delayed initiation of corrosion and the onset of cracking.

e) Reduced likelihood of surface staining.

f) Increased structural life of concrete, particularly where

chloride contamination is likely.

The galvanised rebars have been successfully used in :

i) Immersed or buried elements subject to ground water

effects and tidal fluctuations.

ii) Coastal and marine structures.

iii) Transport infrastructure including bridge decks, roads

and crash barriers.

iv) High risk structure in aggressive environments.

Galvanised reinforcement has been used in many countries

abroad and has been found to be cost effective. In India, some

big structures have been constructed using galvanised rebars.

About 350,000 tonnes of stainless non-flat products are

being used in India of which stainless steel rebars have a

noticeable share. Stainless steel rebars in India are used in :

Architectural applications

All stainless railway coaches

Coal wagons

Grate bars in the sintering machines of steel plants.

AISI 316 LN developed by Alloy Steel Plant, Durgapur to

with stand Seismic effects.

Wire Rods play a

significant role, both in the

industrial and construction

sectors of the economy. In

the industrial sector, wire

rods have sophisticated uses

in atomic vessels, airport

hangers and runways,

railway steepers, automotive tires, cycle tires, armouring of

submarine cables, cables and conductors in power sector,

components, spares and ancillaries of auto industry etc.

In the construction sector, wire rods offer social benefits in-

terms of construction of dwelling houses, hospitals,

construction of educational institutions, stay wire bridges and

in the development of transport facilities.

Wire Drawing Units, Bright Bar Units, hardware and

fastener units and other industries in India consume about 2.5

Mtpy of wire rods at present. Wire rods have multifarious uses.

Major-end-uses of such wire rods are as follows :

Wire Products End-Uses

Bearing Steel Wires Balls, Rollers, Bearings

Bright Bar WiresComponents, Spares and Ancillaries of

AutomobilesFlat Cable Armoured Wire Cables and Conductors in Power Sector.

Round Cable Armoured WirePower Sector, Armouring of Submarine

Cable

ACSR Single and Stranded Wire Overhead Power Transmission Line

Detonator Wire Explosives for Mining

Electrode Quality Wire Electrode Manufacture.

Galvanised WireBarbing, Fencing, Telephone / Telegraph

Sectors

Galvanised Steel Wire Rope

Strands

Stay in Telephone / Telegraphs Pales,

Railway Track Signals, Haulage Purposes.

Wires for Industrial Chains Industrial Chains for Industrial Sector.

Pre-Stressed Concrete Wire &

Strands

Construction of Bridges, Silos, Atomic

Reactor Vessels, Airport Hangers and

Runways, Railway Sleepers.

Tyre - Bead Wires Auto / Cycle Tyers.

Cold - Heading Quality Wires High Tensile Bolts, Rivets, Rails Etc.

Wire for Spring IndustryManufacture of Springs in General, Tiller

Springs, Galvanised Springs Etc.

Structural steel plays a vital

role in a country's economic

growth by providing essential

items for its infrastructural and

industrial development.

Structural steels have majorapplications in engineering fabrication, bridge girders,

transmission line towers, building columns, off share

construction, high rise buildings, wagon and railway coach

building, construction of large factory sheds, ship building,

fabrication of lock gates in irrigation projects, supporting

columns in coal mines, construction of sports sadia etc.

Structurals are grouped by sectional weight into heavy,

medium and light categories as follows :

Types of

StructuralsBeams / Joists Channels Angles

Heavy Above 200 x 100mm Above 200 x 75/76mm 150 x 150mm &above

Medium Above 125 x 70mm

From 125 x 65mm to

200 x 75/76mm or

200 x 100mm

From 100 x 100mm to

130 x 130mm

Light125 x 70mm

& BelowBelow 125 x 65mm Below 100 x 100mm

Besides the above, universal Beams are being produced by

RINL's Vizag Steel Plant and Jindal Steel & Power Ltd. (JSPL)

in the following sizes :

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VSP - I - Beams : 100 x 55mm to 180 x 91mm

H - Beams : 100 x 96mm to 120 x 114mm

JSPL - Parallel Beams : 200 x 100mm to 700 x 300mm

Universal Columns : Upto 400 x 400mm

In addition to the above, Z-type sheet pilling sections, theclosed structurals also has important end uses.

As mentioned before, all steel structural products have very

important end-uses. The major specifications of structurals

with their end-uses are mentioned below :

Specification Application

Industrial & Multi Story

Buildings

Road Bridge Composite

Constructions.

Utility Buildings & Car Parks.

Port & Harbours Jetties,

Warehouse Sheds.

Transmission Line Towers.

Technological Structures,

Off-Shore Drilling Rigs.

IS : 2062 / 1999, A-36

Decks and Platforms.

Railway Coaches and Wagons.

Structure for Electrification &

Underground Railways.

Material Handling System.

Conveyor Gallery.

Supporting Girders and Towers.

IS : 8850 / 91, Fe490 & 540

Railway materials are mainly

used by the Indian Railways and

a small quantity is used by

factory owners, and also for use

as railings, in culverts and small

bridges. Railway Materials

comprise of rails, crane rails,

wheel, axles, wheel sets, crossing sleeper bars, fish plates,bearing plate bars etc.

SAIL's Bhilai Steel Plant, who were producing 120 meter

long rails are now also producing 260 meter long rails, the

longest produced by any manufacturer in the world. Each 260

meter rail panel was manufactured by welding together four 65

meter long rails at the Flash Butt Rail Welding Plant of B.S.P.

The welding of long rails

into panels enables reduction

up to 70 percent in the

number of joints per track

kilometer. Bhilai rails nowmatch the cleanest steel in

the world with 72 percent of

rail heats having a hydrogen

content below one ppm and 28 percent below 1.6 ppm.

The Rail and Universal Beam Mill of Jindal Steel & Power

Ltd. (JSPL) is also producing 120 meter long rails. The

integrated Flash Butt Welding Unit will also help JSPL's Rail

Mill to produce long welded rails upto the length of 480 meter

in future. JSPL's Rail Mill is having continuous, automatic on-

line inspection facility including eddy current and ultrasonic

testing and use of lasers for straightness measurements.

Both BSP and JSPL are producing rails to IRS : T-12/96

grade 880 specifications with tensile strength of 880 Mpa

(min) and elongation of 10 percent.

Wheels, axles and wheel sets

conform to the Indian Railway

Specifications IRS : R-16/95, IRS

:R-19/93 and IRS : R-34/99

respectively with the hydrogen

content varying from less than 3

ppm to less than 2.5 ppm.

Category wise Production of Non-flatProducts in India

The category wise production of Non-flat steel products in

India between 2002-03 and 2005-06 are furnished in Table-1.

CategoryProduction of Non-flat Products

in India% Growth

2002-03 2003-04 2004-05 2005-06 05-06/04-05

Bars & Rods 10696 11140 11827 13243 11.97

Structurals 2323 2999 3046 3525 15.73

Rly. Materials 893 939 1007 1013 0.60

Total Non-flat

Products13912 15078 15880 17781 11.97

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The growth in production of Non-flat products in 2005-06

was 11.97 percent over the previous year. In case of flat

products the same was 10.71 percent. Increased activity in the

construction sector might have influenced the healthy growth

of Non-flat Products during 2005-06.

Imports & Exports of Non-FlatProducts

Imports and Export figures for Non-flat Products areshown in Table - 2.

Years Bars & Rods Structurals Rly. Materials Total

Import Export Import Export Import Exports Import Export

2002-03 103 515 47 35 --- --- 150 550

2003-04 71 499 17 64 --- --- 88 563

2004-05 150 179 83 61 2 --- 235 240

2005-06 375 387 99 89 --- --- 474 476

It is observed that India has been a net exporter of Non-flat

products during the above period, though marginally in 2004-

05 and 2005-06. The high imports of these products during

2005-06 were due to the increased constructional activity in

the country, which had resulted in a higher consumption of

these products.

Apparent Consumption of Non-flat

ProductsThe apparent consumption of Non-flat products in India

between 2002-03 and 2005-06 are presented in Table 3.

Category Apparent Consumption of Non-flat Products

2002-03 2003-04 2004-05 2005-06

Bars & Rods 10337 10713 11739 13296

Structurals 2420 3015 3049 3523

Rly. Materials 882 930 1007 998

Total Non-flat

Products13639 14658 15795 17817

It is evident from the above table that the average yearly

growth of consumption in respect of total flat products has

been 10.21 percent. During the above period, the same for Bars

and Rods, Structurals and Railway Materials have been 9.54

percent, 15.19 percent and 4.38 percent respectively. The

growth in consumption of total non-flat products at 12.80

percent in 2005-06 over the previous year was due to the

increased constructional activity in the country.

The percentage share of total non-flat products in the total

consumption of Finished Steel during 2005-06 was 45.47 as

against 54.53 percent in case of Flat products.

Non-flat and Flat Product Consumption

Pattern

Some steel experts are of the opinion that, flat products

play a vital role in the economic development of a country. As

economy matures, the purchasing power of the people

increases, resulting in enhanced demand for automobiles and

consumer goods as well as an increased use in infrastructural projects. These experts also maintain that the use of flat

products in India should go over 60 percent of total finished

steel consumption in the country.

However, the other group of experts say that the present

proportion of flat to non-flat products consumption is heavily

tilted towards flat products in India. They point out that China

is a developing country with a per capita steel consumption of

194 kg's and its proportion of long products to flat products is

presently 60 percent to 40 percent.

India, with a per capita steel consumption of about 34 kg's,

is predominantly an underdeveloped country having no

meaningful infrastructure. These experts hold that the

proportion of non-flat products in the total finished steel

consumption should go up from the present level of 45 percent

to at least 48-50 percent for the rapid economic development of

the country.

Infrastructure, Construction andConsumption of Non-Flat Products

The share of Non-flat

p r o d u c t s i n t h e t o t a l

consumption of finished steel

in India during 2005-06 hasbeen 45.47 percent.

Construction sector plays

a very significant role in the

development of infrastructural projects. Construction

component in any infrastructural project has a share of 70

percent on an average. According to experts, the cost of steel

used (mostly Non-flat products) in any construction project

has been found to be 25-30 percent on an average.

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