steel materials.pptx

8/20/2019 Steel materials.pptx

1/10

Steels are generally classified on various criteria’s

1. Amount of carbon

2. Amount of alloying elements

3. Amount of de oxidation

4. Grain coarsening characteristics

5. ethod of manufacture

!. "e#th of hardening

$. Grades of Steels chosen by the vehicle ma%er

Classification of Steels


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1&'o( )arbon Steels * C < 0.3%&

+& ,hey are Soft in nature- "uctile -alleable- igh toughness- /asily (elded- 'o( hothardness tem#erature - 0on hardenable by using heat treatment

+& roducing nails- rivets- gears and also used in construction of structures- buildings

2&edium )arbon Steels * C 0.3% - 0.6%&

+& ,hey are not as ductile as that of lo( carbon steels - not as hard as high carbon steels-

little (ear resistance and relatively high hot hardness.

+& Automobiles for the manufacturing of axles- loc% (ashers- s#rings- (heels s#o%es- cran%

#ins- cylinder liners and for ma%ing form dies

3&igh )arbon Steels or ,ool Steels * C 0.6% - 2.0%&

+& ,hey are having igh hardness -igh (ear resistance -igh hardenability- rittle in nature

and 'o( toughness. ardness can be im#roved by heat treatment.

+& orging dies for forging industry- drills- and other machine sho# com#onents

+& ltrahighcarbon steels * C 1.25% - 2.0% & 6 ,hese are thermo mechanically #rocessed to

#roduce microstructures that consist of ultrafine- e7uiaxed grains of s#herical-

discontinuous #roeutectoid carbide #articles

Classified based on amount of Carbon


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1&'o( alloy steels *8 of alloying elements #resent in the steels < 10%&

+& ighstrength lo(alloy *S'A& steels or micro alloyed steels

2&igh alloy steels *8 of alloying elements #resent in the steels > 10%&

Element Symbol ercenta!e "d#anta!es

Aluminium Al 9.:5 ; 1.39 Alloying element in nitriding steels

ismuth i


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1&Bimmed steels

+& A lo(carbon steel containing sufficient iron oxide to give a continuous evolution of carbonmonoxide (hile the ingot is solidifying- resulting in a case or rim of metal virtually free of

voids. Sheet and stri# #roducts have very good surface 7uality.

+&


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1&)oarse grained steels

+& @hen a coarse grain siDe is s#ecified-


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1&)old rolled steels or cold (or%ed steels

Steels that has been sha#ed by rolling e7ui#ment (ithout the a##lication of heat. ormed by#lastic deformation of the material- causes flattening giving steel higher levels of strength.

2&ot rolled steels

Steel is heated above its recrystalliDation tem#erature and rolled into a sha#e by a series of

rollers. ,he higher the tem#erature to (hich a metal is heated- the higher its ductility.

Classified based on metod of manufacture

Cold rolling in a tandem rolling mill . he rolling

mill consists of !-" stands having four high

configurations #two large back-up rolls and two

small work rolls$.

"nnealin! results in recrystalliDation of the steel

Grain structure and in stress relief.


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1&)old rolled steels

)old rolled carbon steels are available in t(o classes6 )lass 1- for a##lications (heresurface a##earance is of #rimary im#ortance- and )lass 2- generally for unex#osed

a##lications. )old rolled carbon steels are #roduced in four #rinci#al 7ualities6 )ommercial

Fuality *)F&- "ra(ing Fuality *"F&- "ee# "ra(ing Fuality *""F&- and /xtra "ee# "ra(ing

Fuality */""F&. ormability increases in the follo(ing order6 )F- "F- ""F- and /""F. ,he

/""F steels are also called


8/103H2H1! =

(ot rolled steel $s. Cold rolled steel

(ot )olled Steels Cold )olled Steels

)ost 'ess manufacture cost igh manufacture cost

inish Bough- bluegrey finish- Bounded corners Shiny- bluegrey surface- s7uare corners

inished#roducts

roduce variety of sha#es such as < beam'imited to fe( sha#es- mostly flat- round-s7uare and variations of those

lexibility lexible but more (or% can cause crac%s sed for detailed (or%s

rocess ,ime 'ess manufacturing time ore manufacturing time

,em#erature at 1999 deg at 59 deg

,hic%ness I 9.91 inches- or even more than that 'ess than 9.91 inches

,olerancesinished material (ill have loosertolerances because it reconfigures itselfduring the cooling #rocess.

inished materials (ill have more #recisedimensional tolerance

*reatments

Steel has layers of oxidiDation #revents thechemicals.


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Classified based on det of ardenin!

"e#th of ardening is the degree to (hich steel ac7uires a martensitic structure in

a layer of some thic%ness u#on hardening.


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399 !99 :99 1299 1599

19

29

39

49

59

!9

9

* o t a l E l o n ! a t i o n . % /

*ensile Stren!t a/

" u c t i l e

'o( igh ltra

-(S

SS

(

Cn

(S4"

*)

1& Standard Steels

+ )ommercial steel *)S&

+ "ra(ing steel *"S&

+ "ee# dra(ing steel *""S&

+ /xtra dee# dra(ing steels */""S&

+

steel materials.pptx

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