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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.
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