building materials - ferrous and non-ferrous

8/18/2019 building materials - ferrous and non-ferrous

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FERROUS METALS: STEEL ANDSTEEL ALLOYS

UNIT I


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Introduction to Ferrous Metals : Iron ore and Steel / Steel

Alloys - Defnition, Properties and Uses

- Manuacture o Iron ore

- Types o Iron ore : their properties and uses

1. Pig Iron

2. Wrought Iron

. !ast Iron

Steel

- Manuacture, !asting, "eat Treat#ent, Mechanica$ Treat#ent,

Process o %tee$

- Mar&et 'or#s o %tee$, 'ire Protection o %tee$

UNIT 1 –FERROUS METALS : STEEL AND STEEL ALLOYS


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Meta$s can +e either ferrous or nonferrous.

Ferrous #eta$s contain iron hi$e non-errous #eta$s do not.

oth errous and non-errous #eta$s are di!ided into pure

"etals and alloys#

A $ure "etal is an ele"ent - eg iron, copper, go$d -una$$oyed

not #i/ed0 ith another su+stance.

An alloy is a "i%ture of t&o or "ore ele"ents eg, iron

and car+on0 to #a&e another #eta$ ith particu$ar properties eg

stee$0. 'errous #eta$s'errous #eta$s contain iron. (/a#p$es are

cast iron, #i$d stee$, #ediu# car+on stee$,

high car+on stee$, stain$ess stee$, and high

speed stee$.

on-errous #eta$s

on-errous #eta$s do not contain iron.

%o#e co##on non-errous #eta$s are

a$u#inu# , copper, inc, tin, +rass copper

3 inc +rone co er 3 tin .


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ORES:

)n ORE is a type o roc( that contains "inerals &it) i"$ortant ele"ents

includin* "etals#

)n ore is a roc& that contains enough o the #eta$ or #eta$ co#pound to #a&e it

econo#ic to e/tract the #eta$. Thus Iron ores are rocks and minerals from

which metallic iron can be economically extracted.

+LASSIFI+ATION OF IRON ORES:

The ores o iron are c$assed according to the iron

#inera$ hich is predo#inant. The iron content o the

#ain ores are as o$$os:

,# Ma*netite -Fe.O0 1 2342567

8# 9ae"atite -Fe8O.0 1 2367

.# Li"onite -8Fe.O.#.98O01 367 it is

)ydrated )ae"atite7

# Iron $yrite -FeS.0 1 267 and

5# Siderite -Fe+O.0 1 36E;TRA+TION OF IRON FROM T9E ORES

9eatin* the ores in the presence o a reducing agent i$$ resu$t in the

or#ation o !5 or !52,

li


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=I> IRON

The crude impure ir on hich is e/tracted ro# iron ores 6

?asic "aterial for "anufacture of cast iron 7&rou*)t iron and

steel#

Manufacturin* =rocess:

,# Dressin*

8# +alcination And Roastin*

.# S"eltin*

. The iron ore is dressed +y crushing it

to a+out 78 ## cu+es.

. The i#purities are &noc&ed o9 and the

ore is then calcined-)eatin* in

$resence of air for o%idation0 to drie

o9 #oisture.

. The ca$cined ore is s"elted

separate the #eta$ ro# ore0in blast

furnace 'ig0

. The #o$ten #eta$ is tapped ro# theBLAST F!"A"#$

The #o$ten #eta$ is tapped ro# the urnace and is cast in the


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Alternati!e Met)ods Of Manufacturin* =rocess:

1. ($ectric ;eduction 'urnace

2. *o %hat $ast 'urnace

. %ponge Iron Process

=I> IRON +LASSIFI+ATION:


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=RO=ERTIES OF =I> IRON :

•"ard and +ritt$e ,

•Me$ts easi$y

•"ardened +ut cannot +e te#pered and #agnetied.

•!o#pressie strength is high +ut is ea& in tension

and shear.

•Does not rust and cannot +e rieted or e$ded

• Too di=cu$t to +end

Uses :

Pig iron is #ost suita+$e or #a&ing colu"ns7


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+AST IRON:

Manufacturin* =rocess:

Pig iron is re#e$ted ith $i#estone >u/0 and

co&e and refned in !upo$a urnace.

Poured into #ou$ds o desired sie and shape.

The product is &non as +ast Iron containing

a+out 2?@A o car+on in to or#s,

1. the compound #$%$"TIT$ ( COMBINED

CARBON )—state of che#ica$ co#+ination

2. as Free +ar


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=ES OF +AST IRON:

+astin* is a #anuacturing process +y hich a $iuid #ateria$ is usua$$y poured into a #o$d,

hich contains a ho$$o caity o the desired shape, and then a$$oed to so$idiy. The so$idifedpart is a$so &non as a casting, hich is eEected or +ro&en out o the #o$d to co#p$ete the


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T&'$S (F #ASTI")*

+. Sand #astin, ino$es

pouring #o$ten #eta$ into

a caity in a #ass o

pac&ed sand.

-. ollow #astin, is used

or #a&ing co$u#ns and

pi$es.

/. 0ie #astin, is cheap or

co##ercia$ production.

!asting is done under

pressure.

1. #hilled #astin,

2. #entrifu,al castin,

3. 4ertical sand castin,


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=RO=ERTIES

1. !ast iron is hard and +ritt$e.

2. It can neither +e rieted nor e$ded.

. It is strong in co#pression F88 nG##20 +ut

@. Wea& in tension 178 G##20 and shear. Its specifc graity is

H.78.

7. It has lo& "eltin* $oint 1288c0 and is aected


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DEFE+TS :

,# +)ec(s7 Se*re*ation7 ?lo& 9oles And +oarse >rain originate during the

coo$ing o the castings.

• Irons ith high su$phur content are $ia+$e to hae s#a$$ crac&s running

transerse to $ongitudina$ a/is, ca$$ed Checks, due to !eate! sh!"nkae

and #ack of st!enth.

• $e!eat"on "s p!onounced "n high phosphorus iron

• B#o% ho#es a!e caused due to o! due to a h"h p!opo!t"on o su$phur.

• A coa!se o! open !a"n "n the "!on "s caused &' too s#o% coo#"n, o! due "t

ma' &e due to a ery high Phosphorus content.

8# S$on*y s$ots (the eae!ated fo!ms of open !a"ns) and

/. Lifts and shifts 5 due to misplacement of core

1. Scabbin, 5 when sand is hea6y and sticks to castin,2. Swellin, 5 when moulds are improperly rammed

3. oney combin, 5 6ent holes are insu7cient 8hence porous castin,

2# +old s)uts — fau#ts p#anes "n the meta# p!oduced &' the so#"d"cat"on of pa!t

of the cast"n

+eore the re#aining #o$ten #eta$ as run into p$ace B resu$t ro# $ac& o


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@ROU>9T IRON

*!ouht "!on cons"de!ed to &e pu!e "!on, "s p!oduced &'

!emo+"n the "mpu!"t"es of cast "!on.

It is #anuactured in re!erat +ars.

O$eration

s:

,# ReCnin*

8# =uddlin*

.# S)in*lin

*


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=RO=ERTIES

1. Wrought iron is ductile7 "allea


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USES :

1. ;oo coerings, riets, chains, orna#enta$ iron or&s such as gates, etc. are

#ade o rought iron.

2. ;a #ateria$ or #anuacture o stee$ ,+o$ts and nuts, horse shoe +ars, hand

rai$s, straps or ti#+er roo trusses, +oi$er tu+es, roofng sheets, e$ectro-

#agnets, etc.,

DEFE+TS :.# ery


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UNIT 1 –FERROUS METALS : STEEL AND STEEL ALLOYS

STEEL

- Manufacture7

- +astin*7 9eat Treat"ent7 Mec)anical Treat"ent7

=rocess of Steel

Mar(et For"s of Steel7 Fire =rotection of Steel

%tee$ is the #ost suita+$e +ui$ding #ateria$ a#ong #eta$$ic

#ateria$s.

There isnt Eust one su+stance ca$$ed stee$ ?

they are a a#i$y o a$$oys o iron ith car+on or arious

#eta$s.

5n the +asis o car+on content stee$ #ay +e c$assifed as under:


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MANUFA+TURIN> "et)ods:

The pro#inent stee$-#a&ing

processes are:

1. esse#er process

2. !e#entation process

. !ruci+$e process

@. 5pen "earth process

7. ($ectric %#e$ting process

F. Dup$e/ process

H. *int and Donait *.D.0

process

The "ost $ro"inent present-day stee$-#a&ing process is the

?esse"er $rocess as introduced in 1J7F.

Sc)e"atic Structural Steel Manufacturin*=rocess

?ESSEMER =RO+ESS


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?ESSEMER =RO+ESS

The pig iron is frst #e$ted in !upo$a urnace and sent to

esse#er conerter .

$ast o hot air is gien to o/idie the car+on.

Depending upon the reuire#ent, so#e car+on and

#anganese is added to the conerter and hot air is

+$asted once again.

Then the #o$ten #ateria$ is poured into #ou$ds to or#

ingots.

L#D# $rocess is #odifcation o the esse#er process in hich there in no contro$

oer te#perature. y this #ethod stee$ can +e #ade in hard$y 27 #inutes.

In O$en)eart) $rocess a$so &non as %ie#ens-Martin process, the stee$ produced

is #ore ho#ogeneous than +y esse#ers.

The e$ectric process is cost$y +ut no ash or s#o&e is produced.

The +ruci


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• Mi$d stee$ Also known as low carbon or soft steel.

• It is ductile8 malleable9 tou,her and more e$astic than rought iron.Mi$d stee$ can +e orged and e$ded, di=cu$t to te#per and harden.

• It rusts uic&$y and can +e per#anent$y #agnetised.

•

The properties are: %p. gr. N H.8, u$ti#ate co#pressie and tensi$estrengths J88?1288G##2 and F88?J88G##2.

• Mi$d stee$ is used in the or# o ro$$ed sections, reinorcing +ars, roocoerings and sheet pi$es and in rai$ay trac&s.

• ard stee$ The carbon content in hi,h carbon steel 6aries from:.22 to +.2:;.

•

It is also &non as hard stee$. It is tougher and #ore e$astic than #i$dstee$. It can +e orged and e$ded ith di=cu$ty.

• Its u$ti#ate co#pressie and tensi$e strengths are 178 G##2 and 1@88?2888 G##2, respectie$y. Its %p. gr. is H.K8.

• "igh car+on stee$ is used or reinorcing ce#ent concrete and prestressedconcrete #e#+ers.

• It can ta&e shoc&s and i+rations and is used or #a&ing too$s and #achineparts.

• The carbon content in hi,h tensile steel is :.35:.


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• MARET FORMS OF STEEL:

• )C*( %(!TI5%

•

!")(* %(!TI5%• !5;;UC)T(D %"((T%

• (OP)D(D M(T)*

• '*)T );%

• I-%(!TI5%

• P*)T(%

• ;I(D-T5;%T((* );%

• ;5UD );%• %U);( );%

• T-%(!TI5%


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• +AUSES OF +ORRISON:

'o$$oing are the 'actors hich are responsi+$e or causing corrosionespecia$$y to reinorcing +ars in concrete:

• !ongested reinorce#ent in s#a$$ concrete sections,

•

(/cessie ater-ce#ent ratio,• I#proper construction #ethods,

• Inadeuate design procedure,

• Inco#p$ete superising sta9 or contractor,

• Initia$$y rusted reinorce#ent +eore p$acing concrete,

• Insu=cient coer to stee$ ro# the e/posed concrete suraces,

• Per#ea+i$ity o concrete hich depends on arious actors such as ater-ce#ent ratio, sie o aggregate, curing, grading o aggregates, etc.

• Poor oranship,

• Presence o #oisture in concrete,

• Presence o sa$ts,

•

Type o at#ospheric conditions surroundings the region o concrete,• Uneua$ distri+ution o o/ygen oer the stee$ surace,

• Wea& and porous coer +$oc&s hich are tied direct$y to thereinorce#ent or stirrups, etc.


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• ')!T5;% I'*U(!IC !5;;5%I5:

The corrosion is in>uenced +y the o$$oingactors:

• $o ho$es, inc$usions and trapped gases,

• !he#ica$ nature o the #eta$,

• Distri+ution o secondary phases,

• (ddy e$ectric currents,• Interna$ structure o #eta$,

• ature o engineering app$ication,

• Presence o dust, dirt or other oreign #atter,

• %urace f$#,

• Wor&ing conditions or eniron#ent $i&ete#perature, concentration o stresses, etc.


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• =REENTION OF +ORROSION OF STEEL IN +ON+RETE:

• The stee$ is #ost $ia+$e to corrosion and hence, the study o stee$corrosion is o para#ount i#portance. To #ini#ie the chances odee$op#ent o corrosion o stee$ in concrete, the o$$oing preentie#easures #ay +e ta&en:

• )oiding heai$y congested reinorce#ent especia$$y at the intersectiono +ea#s and co$u#ns6

• )oiding the stee$ to co#e into contact ith +ric&s soi$. Wood and otherporous non-a$&a$ine #ateria$s6

• )oiding the use o #ateria$s hich acce$erate the process o corrosioni.e. aggregates ith high sa$t contents, ater containing sa$ts, etc.6

• !$eaning the reinorce#ent ith ire-+rush to re#oe the rust sca$es+eore p$acing o concrete6

• Maintaining a high degree o oranship6

• Proper structura$ design ith due proision o coer6

• Proiding cathodic protection to reinorce#ent +y so#e suita+$e #ethod6

• Proide surace coatings ith paints, tars, aspha$ts, etc.6• Use o high ua$ity and i#per#ea+$e concrete6

• Using stone pe++$es in p$ace o +ad$y #ade coer +$oc&s6

• Using the correct ater-ce#ent ratio6 etc.

building materials - ferrous and non-ferrous

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