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STEEL Most popular and effective building material.

Steel is an alloy made by combining iron and other

elements, the most common of these being carbon.

Intermediate stage between wrought iron and cast iron

wrought iron – Carbon content: not greater than

0.15%

steel - Carbon content: 0.15% to 1.5%

cast iron - Carbon content :2% to 4%

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VARIETIES OF STEEL Based on carbon content

Mild steel – 0.15 to 0.25%

Medium carbon steel - 0.25 to 0.6% ( rail

wheels)

High carbon steel - 0.6 to 1.5%

Increase in carbon content

Increase strength

Decrease ductility

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MANUFACTURING PROCESS

Hot rolling*temperature above recrystallization temperature

*by rolling hot steel in semi solid state (900 to 12500)

Cold rolling*temperature below recrystallization temperature

* rolling sheets from sheets, plates or flats in rolling machines or by press breaking

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MILD STEEL

Carbon content – 0.25% (max)Sulphur – 0.055%Phosphorous - 0.055% ( I.S. 226: 1969)

Dark bluish colour It is tough, elastic than cast iron and wrought

iron. It is malleable and ductile.

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PROPERTIES OF MILD STEEL

Can be magnetized permanently Readily forged, riveted and bolted Easily hardened or tempered Malleable and ductile Specific gravity 7.8 Melting point – above 1400°C

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USES OF MILD STEEL Used as steel reinforcements (mild steel

round bars) Mild steel tubes are used in construction Mild steel sheets are used for roof coverings Used in manufacture of various tools,

machinery and other equipments

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Steel is used structurally in two ways

Reinforcement steelStructural steel

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REINFORCEMENT STEEL9

REINFORCING STEEL Concrete – weak in tension – strong in

compression Steel – strong in tension Steel bars embedded in concrete –

reinforcement Develops good bond with concrete

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TYPES OF REINFORCEMENT BARS

Mild steel and medium tensile steel / Plain steel bars Round sections Mild steel / medium tensile steel / plain steel

bars Plain steel bars – 5mm to 32mm Designated as Fe250 Yield strength – 250 N/mm2

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High yield strength deformed bars (HYSD)/ TOR steel Cold twisted deformed bars Tor steel bars – longitudinal ribs in the form of

continuous helix Develop high bond strength due to interlocking

with concrete Mean diameters – 5mm to 40mm Designated as Fe415, Fe500, Fe550

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ADVANTAGES OF TOR STEEL

Good bonding capabilities High yield strength Saving in reinforcement cost Better structural properties Bars can be welded End hooks not essential

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STRUCTURAL STEEL SECTIONS / MARKET FORMS OF STEEL

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STRUCTURAL STEEL SECTIONS:

Angle sections Channel sections I-sections T-sections Flat sections Steel plates Corrugated sheets Round bars Square bars

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STRUCTURAL STEEL SECTIONS

Rolled steel bar section:• Indian Standard Round Bars (ISRO):

Designated as ISRO 10 (round bars having diameter 10mm)

Available in diameter varying from 6mm to 25mm.

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• Indian Standard square bars (ISSQ): Designated as ISSQ 10 (square bars of size

10mm) Used for grillwork, handrails for staircases

etc.

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Rolled Steel Plate Section ( ISPL):• Designated as ISPL 500 x 5 (500mm width and

5mm thickness)• Used for construction of water tanks and other

storage structures, built up beams, columns, base plate for foundations etc.

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Rolled Standard Sheet Sections (ISSH):• Plates having thickness less than 5mm.• Designated as ISSH 1800 x 600 x 4

(sheet having length 1800mm, breadth 600mm and thickness 4mm).

• Used for construction of boxes and vehicle bodies.

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Indian Standard Strips (ISST):• Mainly used as beedings.• Designated as ISST 100 x 2 (steel strip with a

width of 100mm and thickness 2mm).

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Indian Standard Flats (ISF):• Designated as ISF 10 x 3(flat of width

10mm and thickness 3 mm).• Available in suitable widths varying from

10mm to 400mm• Thickness varying from 3mm to 40mm.• Used for steel grillwork for windows and

gates.

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Rolled Steel Tubes:• Inner diameter varying from 15 to

150mm.• Thickness varying from 2 to 5.4mm.• Efficient structural sections for formwork

and trusses

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Rolled Steel Angle Sections (ISA)• Designated as ISA and width and length of

legs• Available as

Equal angle sectionsi. Two legs will be equal in lengthii. Available in sizes varying from 20mm x

20mm x 3mm to 200mm x 200mm x 25mm

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Unequal angle sectionsi. Two legs will be unequal in length.ii. Available in sizes varying from 30mm x

20mm x3mm x 3mm to 200mm x 150 mm x 18mm

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Bulb angle sections

• Extensively used in structural steel works like roof trusses, and as connecting members for different structures.

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Rolled steel Tee sections:• Resembles the alphabet T• Consists of web and flange• Designated by overall dimensions and

thickness.• Available in sizes varying from 20mm x 20mm

x 3mm to 150mm x 150mm x 10mm.• Widely used as members of the steel roof

truss and form built – up sections.

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• Different types available are: Indian Standard Normal Tee (ISNT) Indian Standard Heavy Tee (ISHT) Indian Standard Short Tee (ISHT) Indian Standard Junior Tee (ISHT)

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Rolled Steel Channel Sections:• Consists of a web and two equal flanges.• Designated by height of web and width of

flange• Available in sizes varying from 100mm x

45mm to 400mm x 100mm.• Widely used for beams and columns.

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• The different types available are: Indian Standard Junior Channel (ISJC) Indian Standard Light Channel (ISLC) Indian Standard Medium Channels

(ISMC)

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Rolled Steel I – Sections

• Known as rolled steel joists or beams.

• Consists of two flanges connected by a web.

• Designated of overall depth and width of flange.

• Available in sizes varying from 75mm x 50mm to 600mm x210mm.

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• Different types are: Indian Standard junior beam (ISJB) Indian Standard Light Beam (ISLB) Indian Standard Medium Beam (ISMB) Indian Standard Wide Flange Beam (ISWB) Indian Standard Heavy Beam (ISHB)

• Strongest and most economical of all sections• Used as columns, purlins in trusses and

grillage foundations.

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Built –up sections:• Composed of a combination of available basic sections like plates,

angles, channels etc.• For increased strength and stability• Different sections are joined by welding or riveting

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TYPES OF BUILT – UP SECTIONS

Two angles back to back Two channels I-sections with top and bottom plates Plate girder Built up column sections

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LIGHT GAUGE SECTIONS Made from steel sheets of uniform thickness

– process in cold state Coated with zinc or aluminium Thickness normally less than 2mm Yield stress ranging from 250MPa to 550 MPa. Normally have stiffening lips on flanges Intermediate stiffeners in wide flanges and

webs

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Plain C section Lipped C section Swage beam SFS C section

Multichannel Multibeam Zed section Zeta section

Ultrazed section

ADVANTAGES OF LIGHT GAUGE SECTIONS

Lightness High strength and stiffness Ease of fabrication and mass production Fast and easy erection and installation High strength to weight ratio Substantial elimination of delays due to

weather Formwork not needed Uniform quality

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THANK YOU

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