탄소강 - kemco.or.krkemco.or.kr/up_load/blog/탄소강.pdf · 3-4. 일반탄소강의분류...
TRANSCRIPT
-
Chapter 3.
(Fe3O4,Fe2O3)
+
+Fe2O3+C Fe+CO + Q
CO CO2
+ 4%
+ P, S
+ Fe2O3
(Casting)
) Continuous Casting
) Ingot Casting
Blast Furnace( )
< >Steel Making
< >
)
)
) Slab( )
,
Annealing
-
3-1.
1) (Iron-Making Process)
(50% ) Al2O3, SiO2
(CaO, Al 2O3, SiO2 ) Slag .
Slag Fe .
2) (Steel making)
: , ( .) : , ,
) (Converting)
+
+Cokes
O2
Slag
Molten iron
Blast Furnace( )
Fe2O3
Fe3O4 + C( ) Fe + CO, CO 2
FeO
Fe2O3
Fe3O4 + CO( ) Fe + CO, CO 2
FeO
.
Steel Case
ironO 2
O 2+Fe FeO 3
O 2+C CO, CO 2
O 2+S SO 2, SO3
O 2+P P 2O5
Slag
Molten iron
Fe+C+S+P
( )
Ni, Cr, Mo .
-
)
3) Ladle
) ingot .
) ( ) : , .
O2 Argon Gas ,
S Mn( ) MnS : .
Fe2O3 Si, Al( ) Fe + SiO2 Al 2O3Slag .
Fe-C Si, Mn .
4) (Casting)
(Ingot casting) (Continuous Casting) : . .
Arc
-
3-2.
1) (Ingot casting)
: .( )
2) (Continuous Casting)
: , , .
: , .
-
3-3. Ingot Structures ( )
) Capped Steel
) Killed Steel
Si, Al
Fe2O3 + Si, Al Fe + Al2O3, SiO2
. CO, CO2 .
, , ex) Steel Can (Deep drawing, )
) Rimmed Steel
Capped Steel Killed Steel )
(Shrinkage)
Fe2O3+C Fe+ CO , CO 2 Gas .
Cap
Gas hole: gas . CO, CO2 Gas Mold
Gas .
, ( )
ex) , H
-
3-4.
: Fe-C-Mn-Si
, .
KS : SxxC
AISI : 10xx
ex) S45C : Plain steel with 0.45wt% Carbon.
Carbon .
= 1045
0.45wt% Carbon.
3-5.
Fe-C-Mn-Si
Mn : Max. 1.0% ( )
Si : Max. 0.3% ( )
S : Max. 0.05%
P : Max. 0.04%
S + Fe FeS : 1188 Melting Point
Grain-boundary .
: , : 1200
Grain-boundary FeS .
Mn FeS MnS(Grain ) .
Si Fe 2O3 .
Fe2O3 + Si Fe + SiO 2
P Fe3 P
Grain-boundary .
P .
Grain-boundary
FeS
-
3-6. ,
Ingot Ingot
2, 3 ( H2SO4 )
H 2SO4+Fe2O3 .
ferrite( )
:Fe2O3 BaOFe2O3 SrO
: Fe2O3 ZnOFe2O3 NiOFe2O3 MnO
Coling
)
)
Annealing (H 2+CH4 +N)
Gas
-
3-7.
. ( Carbon )
) Plate :
) strip :
: Press , Deep drawing
: (Fommoability)
: Carbon 0.03 0.12%
Martensite .
Quenching and Tempering .
65% (0.06% C)
-
Annealing
) Box Annealing
Grain Size .
) Continuous Annealing
Grain Size .
( .)
, , ,
.
Annealing
Temper Rolling (1 2%)
.
.
-
3-8. Quench-aging( )
Deformation-aging( )
1) Quench-aging .
, -Cabide .
700 200 6
Fe-0.13%C {110}
.
y [0 1 0]
z [0 0 1]
x [1 0 0]
-Cabide
-
2) Deformation aging of plain carbon steel
: annealing ( 200 )
.
(a) . Skin ( )
.
. (Ludus band)
.
(b) - .(
.)
Carbon .
Carbon .
Carbon Stress
. : Yield drop
-
.
.
: .
Carbon
Carbon dislocation .
: dislocation Carbon .
Temper rolling
carbon , .
:
: .( )
( 3/4)
-
3-9.
1) 0.1 0.25% : , Q+T .
2) 0.25 0.55% :
3) 0.55 1.0% : , , + W, Mo, Ni .
,
: 30 40 kg/mm 2
2 .
Q+T : 40 100 kg/mm 2
Tempering ,
,
-
(a) (b) (c) (d) AISI 1040
(a) 871 1 ; ;
. (b) 871
1 ; 691 24 ; +
. (c) 843 1 ;
. (d) (c) 538
4 ; (c) .
.
-
3-10. ( .)
+Nb, Ti, V Carbon NbC, TiC, VC Carbide .
: , Carbide .
Nb-
NbC
NbC (
.)
35kg/mm2 56kg/mm2 Nb-
Austenite
.
.
-
.
) .
) Grain-boundary .
) .
) .
) . ,
Grain Size .
3-11. 2 ( Dual Phase Steel)
ferrite( ) Martensite( )
2 (0.065C, 1.5%Mn) -
; 760
.
.