Wilson Steel and Timber.pptx

7/31/2019 Wilson Steel and Timber.pptx

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is an alloy made by combining iron and otherelements, the most common of thesebeing carbon. Steel is the general name given to alarge range of iron alloys.


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There are three major types ofsteel: carbon steels, alloy steels, andstainless steels. All three types of steel havetheir own uses, ranging from appliances to

structural support in buildings.


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Steels containing 0.2% C to 1.5% C are known ascarbon steel. They are of three types.Low Carbon Steel

It contains 0.2% carbon.Uses:Sheets, wires, pipes.

Mild Carbon SteelIt contains 0.3% to 0.7% carbon.Uses:Rails, boilers, plates, axles, structures.

High Carbon SteelIt contains 0.7% to 1.5% carbon.

Uses:Surgical instruments, razor blades, cutlery, spring.


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There are three types of alloy steel.

Mn-SteelIt contains 10%-18% Mn.Uses:Rail tracks, armor plate, safe.

Si-SteelIt contains 1% to 5% Si.Uses:Permanent magnet.

Ni-SteelIt contains 2% to 4% Ni.Uses:

Gear, shaft, cable.

It contains 14% to 18% chromium and 7%to 9% nickel.

UsesCar accessories, watch case, utensils,cutlery.


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Stainless steels resistance to corrosion and staining, low

maintenance and familiar lustre make it an ideal material for manyapplications. Steel construction has so many advantages: the strengthto weight ratio is excellent, metals join easily, efficient shapes areavailable, etc.

For most larger buildings, metals are a key element of the

structural system. Steel beams and columns, steel joists, steel studs,aluminium framing are a few examples of metal construction. A wiseSuperintendent understands not only how to erect the structure, butalso the basics of how the structural system works and the ways inwhich it fails


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Density is the measurement of how muchmatter there is per unit volume of an object. Giventwo objects of the same size, but differentdensities, the denser object will be heavier than theless dense object. For example, a block of lead ismore dense than a block of aluminium. Steeltypically has a density between 7.75 to 8.1 megagrams per cubic meter.


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Elastic modulus is a measurement that describes howmuch stress you can subject an object to before it deformspermanently (as opposed to deforming elastically, whenthe object reverts back to its original state once the stressis removed). The higher this value, the more elastic it is.Steel typically has an elastic modulus between 190 to 210gigapascals.


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Poisson's Ratio when an object is stretched, thelength of the object increases, while the thickness of theobject decreases. The ratio between the contraction andelongation of an object (or expansion to shortening) isknown as Poisson's Ratio. The lower this number, the lessan object will shrink in thickness when stretched (or growin thickness when contracted). Steel typically has aPoisson's Ratio of 0.27 to 0.3.


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Melting Point the melting point of an objectrefers to the temperature at which the object can besubjected or heated to before it begins to melt.Stainless steel typically has a melting point between1,371 to 1,454 degrees Celsius, which correlates toapproximately 2,500 to 2,649 degrees Fahrenheit.However, there is no such acceptable range for carbonand alloy steels, due to the extreme variance in theircomposition.


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When an object is stretched, there is a certain point

where the object begins to thin out drastically before itrips apart at those locations. This is known as "necking"and it occurs at a maximum applied stress called thetensile stress. An object with a higher tensile stress canwithstand more stress before it begins to neck. Stainlesssteels have accepted tensile stress values between 515

to 827 megapascals; carbon steels have accepted tensilestress values between 276 and 1882 megapascals; andalloy steels have accepted tensile stress values between758 and 1882 megapascals.


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Yield Strengthwhen an object deforms and is able to revertback to its original state, this is known as elastic, or non-permanent,deformation. After a certain amount of stress applied to an object,the object can no longer deform elastically and starts to deformplastically, or permanently. The maximum amount of stress that anobject can withstand before plastically deforming is known as theyield strength. Stainless steels have accepted yield strengths

between 207 to 552 megapascals; carbon steels have acceptedyield strengths between 187 to 758 megapascals; and alloy steelshave accepted yield strengths between 366 to 1793 megapascals.


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Properties Carbon Steels Alloy Steels Stainless Steels

Density (1000 kg/m3) 7.85 7.85 7.75-8.1

Elastic Modulus (GPa) 190-210 190-210 190-210

Poisson's Ratio 0.27-0.3 0.27-0.3 0.27-0.3

Thermal Expansion (10-6/K) 11-16.6 9.0-15 9.0-20.7

Melting Point (C) 1371-1454

Thermal Conductivity

(W/m-K)24.3-65.2 26-48.6 11.2-36.7

Specific Heat (J/kg-K) 450-2081 452-1499 420-500

Electrical Resistivity (10-

9W-m)130-1250 210-1251 75.7-1020

Tensile Strength (MPa) 276-1882 758-1882 515-827

Yield Strength (MPa) 186-758 366-1793 207-552

Percent Elongation (%) 10-32 4-31 12-40

Hardness (Brinell 3000kg) 86-388 149-627 137-595


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TYPE: Wide FlangeSYMBOL: WDESCRIPTION: Flange surfaces are parallel; flange thickness isnot necessarily equal to the web thickness.


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Many buildings use steel wide flangebeams as lintels in larger masonryopenings that have a plate welded to the

underside to carry the exterior wythe ofbrick


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TYPE: Bearing PileSYMBOL: HPDESCRIPTION: Flange surfaces are parallel; flangeand web have equal thicknesses.


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They are used as bearing piles for foundation projects suchas bridges and industrial facilities or as anchoring piles forquay or excavation walls.


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TYPE: American Standard BeamSYMBOL: SDESCRIPTION: The inner flange surface is sloped.


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American Standard steel beam is called S-shape has wide flanges at the top andbottom with a narrower section below. It isused in axial loads such as holding uproofs or floors.


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TYPE: Wide FlangeSYMBOL: C

DESCRIPTION: Standard AISC flangeshave sloped inner flange surfaces.


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Wide Flange beams can be usedfor cross bracing, which is utilizedto reinforce building structureswhen diagonal supports intersect.The common uses for cross bracing

include bridges (for side supports)along with structural foundations.This method maximizes the weightof the load a structure is able tosupport


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TYPE: TeeSYMBOL: WT,ST,MTDESCRIPTION: WT shapes are cut from a

wide flange.ST shapes are cut fromAmerican Standard Beams.MT shapes arecut from non-standard I-shapes.


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are primarily used in the fabrication of steel trusses. havetraditionally been used in parking structures. Over the pastdecade, tees have been integrated into the building envelope for

use in floor and roof systems.


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TYPE: Hollow Steel Section,Steel TubeSYMBOL: HSS,TSDESCRIPTIONEither nomenclature is

acceptable; however, HSS is morecommon.


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HSS is a cold formed welded steel tube used forwelded or bolted construction of building, bridges and

other structures and a wide variety of manufacturedproducts.


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TYPE: AngleSYMBOL: LDESCRIPTION: Angles come in equal leg

or unequal leg sizes. The diagram at leftshows an unequal leg.


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TYPE: PipeSYMBOL: PipeDESCRIPTION:


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TYPE: PlateSYMBOL: PL or BarDESCRIPTION: Very small plates can also

be called bars.


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Wilson Steel and Timber.pptx

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