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u-‘ i'lllll-

TH ESIS

 

This is to certify that the
thesis entitled

EFFECT. O! m ADDI'HOIS 0F ACTIVE
W ON nu: DEMOLI- GOIIPOSITIOI’,’ IIGROSTBUCTURE

AND PHYSICAL PROPERTIES OF 018! IRON

presented by
Alan Ullah Khan

has been accepted towards fulfillment
of the requirements for

~

J.§.___'degree chal Wearing

 

THE EFFECI‘S OF LADIE ADDITIONS OF ACTIVE

METALS ON THE PHYSICAL PROPERTIES, MICRO-

STRUCTURE AND CHEMICAL COMPOSITION OF
CAST IRON

By
mam ULLAH mm

A THESIS

Submitted to the School of Graduate Studies of
Michigan State College of Agriculture and
Applied Science in partial fulfillment
of the requirements for the degree

of

IvE-S'EEI‘. 0 SCIENCE

Department of Metallurgical Engineering

1951

THESIS

 

ACKNOWLEDGEMENTS

The author is deeply grateful to Professor
Howard L. Vomochel, for his generous and painstaking
work for guiding and helping in the laboratory and
for many helpful suggestions and much useful in-
formation given during the preparation of this thesis.
The author also desires to acknowledge his app-
reciation for information and other assistance given by
many people of the metallurgical Engineering Department

of Michigan State College during the course of this
investigation.

268405

TABIE OF CONTENTS

Introduction . . . . . . . . . . . . . 1
Survey of Literature . . . . . . . . . 4
Experimental Procedure . . . . . . . . 5
Actual Data . . . . . . . . . . . . . . 10
Discussion of Results . . . . . . . . . .27
Summary and Conclusions . . . . . . . . 36

Bibliography . . . . . . . . . . . . . 38

INTR ODUCT ION

The technique of inoculating cast Iron has been
known to the foundrymen for the past fifteen years.
Although some work has been done in this field, it is
still far from complete. Occasionally a new 'inoculatent
has been discovered but no work has been done to show
the comparative effect as innoculents. New theories
have been presented but none has been able to explain all
the phenomenon of inoculation. -

Inoculation, as it is used today means addition of
small amounts of other metals or alloys to the ladle or
to the stream of metal flowing from the copula to bring
about different effects in graphite formation and dis-
tribution.

Ordinarily, fminoculated, low carbon, electric
furnace Cast Iron mierostruo tures consist of type D or
E or denderetic graphite with traces of ferrite, non
metallic inclusions of Pearlite background, as shown
in Fig. l. The Carbon Content of these Iron varies
between 2.6 to 3 percent and the Silicon between 1.25-
2.75 percent. During the solidification of the metal
the carbon which has a limited solubility in Iron starts
to leave the solution and solidifies as graphite flakes.

-2-

These flakes break the continuity of the structure,
thus their shape, size and distribution as a marked
effect upon the physical properties of grey cast Iron.

R. Schemdewind and C.D. D'Amieo5 have shown the
difference in Physical properties in iron having the
eeme amount of graphite but having a difference in the
size, shape and distribution of the graphite flake.

They have shown that irons with flakes randomly oriented
have the best physical properties but the same kind of

flakes if arranged in a lacey pattern around the primary
dendrites of austenite weaken the structure considerably.

Inoculation produces flakey graphite randomly
oriented which increases the strength of the iron as there
are no'continuous lines of weakness across the micro-
structure. The microstructure of flaky graphite ran-
domly oriented is shown in fig. 2. the microstructure
is also freer from ferrite which is formed by the under-
cooling of themetal during solidification.

Until recently inoculation has been regarded as
primarily a process of addition of silicon on various
high silicon alloys to the molten metal. Most important

of these alloys have been Ferro-silieon, Calcium-silicon

and Silicon-Manganese-Zinccnium.type. Although these
alloys'have been used extensively as late additions for
improving the physical properties during the past several
years, nothing has been available in the literature
regarding the relative effectiveness of these alloys or
regarding the mechanisn.of the process. In 1945 a general
program of research was initiated in the Engineering
Department at Michigan State College for the purpose of
determining the relative effectiveness of the various
innoculents and for the purpose of throwing some light
on the:mechanism of the process. Unpublished work by
Womochel, Harvy and McClune has indicated that Calcium
silicon is markedly more effective than Ferro silicon
as an innoculent. IData from.their work is presented in
Table no. 1 showing the different effects produced by
these two alloys when added to the ladle in amounts to
give the same silicon pick up.

the difference in the effects of the two alloys
suggests that the active metal, Calcium, plays an imp
portant role in the process and also suggests that other

active metals might be useful as innoculents.

SURVEY OF LITERATURE

Survey of the literature gives no information
on the effects of the active metals wdth.the exception
of the work done by Womochel, Harvey and McClune. Data
from.their work is presented in the following table:

 

Table 1 - Comparative effect of FeSi and CaSi
additions in grey Cast Iron.

~ %C sflSi Trans. Deflec. Ten. Chill
3 s x x s z s s
38.6 FeSi : 2.8 a 2.17 s 2905 s .261 3 51470 8 20 x
s s x z s 8 a :
3.6 CaSi : 2.84 s 2.21 s 3728 s .394 3 59200 x 8 s
s s s s z s x :

 

this marked difference in the relative effective-
ness of the two silicon alloys suggest that the active
metal content of the Calcium alloy is important in the

mechanism.cf inoculation.

-5-
'EXFERIMENTAL PROCEDURE

The general procedure was as follows: To melt
dawn 200#flheat in indirect arc rocking furnace to the
following composition:

Carbon 2.8 -3.0 percent Silicon 2.0-2.5 percent

manganese 0.9-1.0 percent Sulphur 0.05-0.068 percent

Phosphorous 0.06-0.1 percent

‘Metal was tapled to pairs of 50# ladles. hotel in
one ladle was treated in each case‘with active metal and
the iron from.the two ladles poured into chill test
specimen and standard 1.2 inch LS.T.M. transverse test
bar.moulds.

ihe metal from the untreated metal served as a control
or blank for determining the effect of the active metal.
‘ihe metals used in this experiment were Calcium, Sodium,
Magnesium and Aluminium. “
Preparation of rest Bar Mbulds: the.moulds were made
from Lake Michigan sand with oil and cereal binder.
Moulds were washed with a commercial non-graphitic

core wash. his diameter of the bars were approximately

1.2 inches.

Charge and Chargigg Practice: A typical charge is

tabulated in the following table:

Mays Pig 125#

Ingot Iron 2'7}

Steel Strip 25#

Silveny Pig 25#

Fern-Manganese l.‘7#

Iron Sulphide 110 grams.

A Detroit indirect arc rocking furnace with
silminite lining was used during this investigation.
the capacity of the furnace was 250#. Silveny pig
was first placed on the bottom of the furnace. It
was covered with ingot iron and steel strip. Pig
was finally placed over the steel strip. Ferromanganese
and iron sulphide were added to the furnace men iron
was partially molten. ‘me tapping temperature for all
hosts was zesoor and was poured at 2600 to 2650°F.
Method of Inoculation: Provision was made to weigh the
ladle during pouring. Fifty# of metal was tapped in
each ladle. Additions of Calcium and Sodium were made
by means of an inoculating bar about ten feet long. Each
end of which carried a cage in which inoculent was placed.
A guard was provided for the inoculater. A quick

check was made for the temperatures by optical pyrometer

after the ladles were poured and skimmed. The cage
containing the inoculent was then plunged below the
surface by manipulating the opposite end of the bar.
An orange flame was produced of a violent nature.
Sodium addition was tried in the same way but the
moment sodium comes in contact with molten metal it
explodes. Part of the metal was thrown out of the
ladle in the form of mist. Magnesium additions cause
a white glare with splatter more violent than Calcium.
The Aluminium and Magnesium additions were made by
dropping the metal through a tube suspended above the
ladle on to the molten cast iron as opposed to the Sodium
and Calcium additions which were made by plunging and
holding them beneath the surface. Aluminium does not
glow or spatter when added to the ladle.
Casting Procedure 3 Part of a steel bar was melted in
the untreated ladle to compensate for the addition of
about one halfl 36‘ of steel in the treated ladle by the
melting of the cages. One rectangle chill test and
five vertical arbitration bars-mould were poured from
each ladle. Increasing amounts of inoculating agent
were added to the successive group during the experiment.
The rectangle chill tests were obtained by pouring

3 7/8" by 2 1/4" by 7/8 " section.
A Cast Iron chill block was placed inside the mould
adjacent to 2 1/4 by 3/8” ‘i‘aoe.
Chemical Analysis: Samples for chemical analysis were
obtained by drilling the chill test half way across the
length. Great precautions were taken to eliminate any
external source of addition of Silicon and carbon.

Carbon determinations were made by the combustion
method. Sulphur by the combustion of Silicon by the
perchloric acid method. The accuracy of the methods
was checked by running standard samples.
Tiansverse Strength and Deflection: A hand operated
Olsen lester was used to break the bars. A dial guage
was set up to record the deflection midway between the
supporting end. The supporting ends were eighteen
inches apart and the lead was applied at the midpoint.
me transverse test data is tabulated in Tables
He. 2.3.4.5 and 6.
Chill Test: Rectangular chilled test specimen
3 7/8 by 2 1/4' by 7/8” size were moulded. One of
the 2 1/4' by 7/8' faces was poured in contact with
cast iron. chill placed inside the mould. The clean
chill included the white iron fracture only while

the total chill included both the white and mottled
fracture.

The chill test data is tabulated in Table 7.
Hardness Test: Brinell.hardness samples were taken
adjacent to the fracture of each bar and about 5/4?
thick. The Brinell hmpressions were made after they
‘were grounded on both sides. A.three thousand Kg.
load on a ten millimeter steel ball was utilized. The
test results are tabulated in Table 8.
macroscopic Examinations: Samples for macroscopic
examinations were cut from.the test bars adjacent to
the fracture. The samples were l/4' thick and rep-
resented more than half the cross-section. They were
polished and etched with two percent nital. ’As the
structure did not contain any extraordinary constituent.
only the amount of ferrite and graphite distribution
were recorded.

The result is tabulated in Table 9.

-10-

 

 

Table 2- Actual Data

8 8
8 Addition 9; .2; percent 9319133. 8
8 8
8 Specimen 8 Load 8Deflecticn8 Specimnn 8 Load 8Deflectien8
8 8 8 8 8 8 8
8 13931 8 2647# 8 .265" 8 T901 8 3098#8 .292“ 8
8 T932 8 2570# 8 .228' 8 T902 8 2868#8 .268“ 8
8 T933 8 2691# 8 .247' 8 T903 8 3000 8 .291" 8
8 T934 8 2699# 8 .242" 8 T904 8 2831 8 .269" 8
8 8 8 8 8 8 8
8 8 8 8 8 8 fi_8
8 8
8 " 8
8 Addition of .44 percent Calcium. 8
8 ' 8
8 T935 8 2689# 8 .260" 8 T905 8 3262#8 .339" 8
8 T937 8 2718# 8 .270' 8 T906 8 2898#8 .269“ 8
8 T938 8 2640# 8 .252" 8 T907 8 3345#8 .374" 8
8 T939 8 2662# 8 .252' 8 T908 8 3178#8 .318" 8
88 8 8 8 8 8 8

 

 

 

L!

.6

O

 

a 11 -

Table 3- Heat No. 10

Addition of .63 percent Calcium

 

 

 

 

 

8 8
8 Specimen 8Lgad 8 Deflection8 Specimen8 Load 8Def1ection8
8 8 8 ' 8 8 8 8
8 T1031 82280 8 .192' 8 T1001 8 2980 ‘8 .3043 8
8 T1032 8222 8 .196' 8 T1003 8 3170 8 .3333 8
8 T1033 82245; 8 .182" 8 T1003 8 3120 8 .358' 8
8 T1034 82245 8 .198' 8 T1004 8 3075 8 .312" 8
8 T1035 82340# 8 .210' 8 T1005 8 3060 8 .310" 8
8 8 8 8 8 8 8
8 8 8 8 8 8 8
8 8
8 8
8 Addition of .87gpercent Calcium. 8
8 8
8 T1036 82150 8 .187 8 T 1006 8 3275 8 .397 8
8 T1037 82180 8 .188 8 T1007 8 3180 8 .358 8
8 T1038 82180 8 .190 8 T1008 8 3230 8 .387 8
8 T1039 82315 8 .200 8 T1009 8 3290 8 .367 8
8 T10310 82245 8 .187 8 T10010 8 3200 8 .375 8
8 8 8 8 8 8 8
8 8 8 8 8 8 8

-12..

Table 4- 'Heat 11

Addition of 0.68Apercent Calcium

 

 

 

8 8
8 Specimen 8 .Load 8Deflection8 Specimen8 Load.8Deflecticn8
8 8 # 8 ' 8 8 # 8 ' 8
8 T1131 8 2290 8 .251 8 T1101 8 2890 8 .346 8
8 T1132 8 2240 8 .247 8 T1102 8 2940 8 .359 8
8 T1133 8 2390 8 .271 8 T1103 8 2975 8 .359 8
8 T1134 8 2145 8 .216 8 T1104 8 2880 8 .328 8
8 T1135 8 2400 8 .264 8 T1105 8 3125 8 .366 8
8 8 8 8 8 8 8
8 8 8 8 8 8 8
8 8
8 8
8 Addition of l.11_percent Calcium. 8
8 w 8
8 T1136 8 2270 8 .243 8 T1101 8 2770 8 .287 8
8 T1137 8 2190 8 .232 8 T1102 8 2780 8 .283 8
8 T1138 8 2225 8 .244 8 T1103 8 2780 8 .292 8
8 T1139 8 2115 8 .203 8 T1104 8 2280 8 .204 8
8 TllBlO 8 - 8 - 8 T1105 8 2610 8 .239 8
8 8 8 8 8 8 8
8 8 8 8 8 8 8

 

C.

e!

.1 .I

Table 5-

Addition of .55 percent Sodium

- 13 -

Heat 12

 

 

8

8

8 Specimen
1;

8

8 T1231
8 T1232
8 T1233
8 T1234
8 T1235
8

 

2100
2215
2020
2165
2335

1

 

8
Deflection88pecimen
inch 8 g
8
.180 8 T1281
.192 8 T1282
.155 8 T1283
.185 8 T1284
.210 -

2430
2420
2340
2320

.225
.222
.208
.204

 

8
8 Load 8Def1ection8
nch

I.

 

-14-

Table 6-

Heat 13

Addition of 1.1 percent W

 

 

 

 

 

8 8 8 8 8 8 8
8 Specimen 8 Load 8Def1ection8 Specimen 8 Load 8Def1ection8
8 8 8 8 8 8 8
8 8 8 8 8 8 8
8 T1331 8 2210 8 .176 8 T13Hl 8 2395 8 .206 8
8 T1332 8 2155 8 .172 8 T12M2 8 2270 8 .186 8
8 T1333 8 2160 8 .169 8 T13M3 8 2295 8 .190 8
8 T1334 8 - 8 - 8 T13KA 8 2320 8 .182 8
8 T1335 8 2200 8 .173 8 T1338 1 2220 8 .194 8
L. 8 8 8 8 8 8
8 8 8 8 8 8 8
8 ' 8
8 Addition of 1.1 percent Aluminium 8
8 8
8 T1336 8 2220 8 .189 8 T1346 8 2650 8 .239 8
8 T1337 8 2180 8 .172 8 T13A7 8 2430 8 .200 8
8 T1338 8 2265 8 .179 8 T13A8 8 2110 8 .162 8
8 T1339 8 2270 8 .189 8 T1349 8 2365 8 .200 8
8 Tl3310 8 2315 8 .186 8 T13A10 8 - 8 - 8
8 8 8 8 8

Os

- 15 .

 

 

Table 7- Data on Chill Test

8 8 8 8 8 8" 3
8 Blank — Chill 8 Treated 8 z Chill’Ratio 8
8 Specimen 8Tota1801ean8 Specimen8 add.8tota18clean8 a 8 5 .8
8 88/32-81/52": : 81/52"81/32"8 I 8 3 8
8 8 A. 8 3. 8 8 8 C 8 D 8 8 3
8 8 8 8 8 8 8 8 8 ‘13
8 8 8 8 8 8 8 8 8 3
8 T931-5 8 22 8 7 8 T901-5 80.21 817 85 8.79 8 .71 3
8 T936-10 8 l7 8 1 8 T9C6-10 80.44 8 4 81 8.23 81.0 2
8 8 8 8 8 8 8 8 8 3
8 T103l-5 8 31 8 9 8 T1001-5 80.63 811 83 8.35 8 .33 8
8 T1036-10 8 29 8 7 8 T1005-1080.87 8 3 8 .5 8.1028 .0718
8 8 8 8 8 8 8 8 8 8
8 TllBl-5 8 20 813 8 T1101-5 80.68 8 8 81.5 8.40 8..ll58
3 T1136-10 3 16 8 7 8 11106-1031e11 0 1 3 e5 3e062’ e0713
8 8 8 8 8 8 8 8 8 8
8 T1231-5 8 30 812 8 T12Sl-5 80.55 816.5 84.5 8.55 8 .3758
8 8 8 8 8 8 8 8 8 8
8 T1231-5 8 35 821 8 T12Ml-5 81.1 817.5 87.5 8.50 8 .3488
8 T1236-10 8 24 8 7 8 T13A6-1081.1 8 l 80 8.04180 8
8 8 8 8 8 8 8 8 8 8

 

&

 

Table 8-

-16.-

Brinell Hardness Data

 

8
Blank Specimen:

 

8 8
8 3.3.3. 8 Treated Specimen 8 3.3.3.
8 8 8 8

8 8 8 8

8 T931 8 205 8a T901 8 217
8 T932 8 217 8. T902 8 217
8 T933 8 217 8- T903 8 217
8 T934 8 214 :- T904 8 216
8 T935 8 207 8 T905 8 217
8 T936 8 - 8 T906 8 223
8 T937 8 207 8 T907 8 223
8 T938 8 212 8 T908 8 219
8 T939 8 209 8 T909 8 227
8 8 8 8

8 T1031 8 214 8 T1001 8 217
8 T1032 8 199 8 T1002 8 217
8 T1033 8 226 8 T1003 8 219
8 T1034 8 208 8 T1004 8 209
8 T1035 8 199 8 T1005 8 -
8 T1036 8 209 8 T1006 8 214
8 T1037 8 207 8 T1007 8 207
8 T1038 8 202 8 T1008 8 217
8 T1039 8 205 8 T1009 8 219
3 TlOBlO 8 223 8 T10010 8 199
8 8 8 8

 

- 17 -

Table 9- Data.on.Microscopic examination

T931-5
Abnormal structure. lots of

ferrite at the surface.
lacey graphite distribution

T936-10

Abnormal structure. same
as T931-5.

T1031-5

Abnormal structure

T1036-10

Abnormal structure

TllBl-5

Abnormal structure

W

mere massive ferrite and
abnormal graphite than
in Calcium treated iron.

T901-5

more normal structure.
ferrite at the surface.
less lacey graphite.
smaller cell size.

T906-10

Nermal structure. with
very little ferrite at
the surface. smaller
cell size. .

T1001-5

Smaller cell size and
normal structure with
little ferrite at the
surface.

W

Completely normal structure
and smaller cell size.

T1101-5

Smaller cell size. normal
structure.

T1106-10

.Almost completely normal
structure with no massive
ferrite. Smaller cell size.

F.
O
‘.
- C
I
.
~
. .- .
e
.
.-
. .
e
u
.I
.
,,

..

.4 — -.1»

9 I Q

 

d4...-

-18..

Table 9- Continued

T12Bl-5

Highly abnormal structure
with lacy graphite in some
areas. Shows lacy graphite
at surface with consider-
able ferrite

TISBl-S

Microstructure about like
other blank. Heats with
areas of large flakes and
abnormal granite.

11336-10

Less ferrite of somewhat
more normal than 8.1..
uminium treated iron.
Cell boundaries more
evident in this one than
in the aluminium treated

sample.

T12S1-5

Slightly less abnormal
than”: blank. Very little
graphite. Shows lacy
graphite at surface with
somewhat more ferrite

an n . More
ferrite in specimen
generally than in blank.
Smaller cell size.

TlSlfl-fi

Much more abnormal than
blank. Cell size smaller
and the boundaries much
less evident in this
sample.

T13A6-10

Appears to have more ferrite
and to be somewhat less
normal than the corres-
ponding blank. Cell

size is smaller.

-19-

Table 10- Data fr0m Carbon Determination

 

 

8 8 8 8 8 . 8
8 Blank 8 % Carbon 8 Treated 8 7! Carbon 8 Difference %8
8 Specimen 8 8 Specimen 8 8 8
L 8 8 8 8 8
8 8 8 8 8 8
8 T931-5 8 3.075 8 T901-5 8 3.040 8 .. .035 8
8 T936-10 8 3.090 8 T906-10 8 3.000 8 -.090 8
8 8 8 8 8 8
8 T1031-5 8 2.960) 8 T1001-5 8 2.800 8 -.160 8
8 T1036-10 8 2.995 8 T1006-10 8 2.830 8 -.165 8
8 8 8 8 8 8
8 TllBl-5 8 3.100 8 T1101-5 8 2.920 8 -.180 8
8 11136-10 8 3.085 8 TllC6-10 8 2.845 8 -.240 8
8 8 8‘ 8 8 8
8 T1231-5 8 2.900' 8 T12Sl-5 8 2.920 8 {.020 8
8 8 8 8 8 8
8 1‘13Bl-5 8 2.935 8 T13MI-5 8 2.940 8 {.005 8
8 Tl336-10 8 2.950 8 T13A6-10 8 2.900 8 -.050 8
8 8 8 8 8 8

 

I

-20..

 

 

 

Table 11- Data from.8ulphur Determination

8 8 8 8 8 A 8
8 Blank 8 %’Su1phur 8 Treated 8 %’Sulphur8 Difference:
8 Specimen 8 8 Specimen 8 8 8
8 8 8 8 8 A :8
8 8 8 8 8 8
8 T931-5 8 .063 . 8 T901-5 8 .062 8 -.001 8
8 T936-10 8 .066 8 T906-10 8 .057 8 -.009 8
8 8 8 8 8 8
8 T1031-5 8 .065 8 T1001-5 8 .056 8 -.009 8
8 T1036-10 8 .065 8 T1006-10 8 .058 8 -.007 8
8 8 8 8 8 8
8 TllBl-5 8 .063 8 T1101-5 8 .052 8 -.011 8
8 TllB6-10 8 .064 8 TllC6-10 8 .050 8,-.014 8
8 8 8 8 8 - 8
8 T1231-5 8 .057 8 T1281-5 8 .057 8 - 8
8‘ 8 8 8 8 8
8 T13Bl-5 8 .066 8 T12M1-5 8 .029 8 -.037 8
8 T1336-10 8 .068 8 Tl2A6-10 8 .067 8 -.001 8
8 8 8 8 8 8

 

-21..

 

 

Table 12- 3ata from.Silicon Determination

8 8 8 5' 8 8
8 Blank 8 Percent 8 Treated 8 Percent 8
8 Specimen 8 Silicon 8 Specimen 8 Silicon 8
8 8 8 8 8
8 8 8 8 8
8 T931-5 8 2.30 8 T901-5 8 2.29 8
8 T936-10 8 2.30 8 T906-10 8 2.30 8
8 8 8 8 8
8 T1031-5 8 8 T1001-5 8 8
8 T1036-10 8 8 T1006-10 8 8
8 8 8 8 8
8 T1131-5 8 2.28 8 T1101-5 8 2.31 8
8 T1136-10 8 2.25 8 TllC6-10 8 2.24 8
8 8 8 8 8
8 T1231-5 8 2.23 8 T1281-5 8 2.24 8
8 8 8 8 ‘ 8
8 T13Bl-5 8 2.26 8 T13Ml-5 8 2.26 8
8 T1336-10 8 2.26 8 T13A6-10 8 2.23 8
8 8 8 8 8

 

 

 

 

 

Table 13- Condensed Data on Transverse Test

8 8 8 88 8 8 8
8 Blank No. 8 Lead 8 Deflection88 Treated: Load 8Def1eotfion8
8 8 # 8 inches 88 No. 8 # 8 8
8 8 8 88 _ 8 8 8
8 8 8 88 ‘ 8 8 8
8 T931-5 8 2679 8 .251 88 T901-5 8 2988 8 .283 8
8 T936-10 8 2656 8 .261 88 T906-108 3261 8 .343 8
8 8 8 88 8 8 8
8 T1031-5 8 2288 8 .194 88T1001-5 8 3121 8 .335 8
8 T1036-10 8 2246 8 .192 88T1006-108 3265 8 .384 8
8 - 8 8 88 8 8 8
8 T1131-5 8 2360 8 .262 88T1101-5 8 3013 8 .361 8
8 T1136-10 8 2228 8 .239 88T1106-108 2776 8 .287 8
8 8 8 - 88 8 ' 8 8
8 T1231-5 8 2202 8 .196 88T12Sl-5 8 2396 8 .217 8
8 8 8 88 8 8 8
8 T13Bl-5 8 2188 8 .173 88T13M1-5 8 2333 8 .199 8
8 T1336-10 8 2280 8 .184 L8T13A6-108 2481 8 .213 8
8 8 8 88 8 8 8

 

 

 

 

 

Table 14- Comparative effects on the Physical
Ppoperties for same Car on and Silicon
PiEk up

8 8 8 8 8 8 8
8 Specimen 8Carbon 8Silicon8Transverse8Def1ec-8chill ratio8
8 8 8 8 8 tion 8tota18clean8
8 8 8 8 8 81/32'81/32"8
8 8 8 8 8 8 8 g__8
8 8 8 8 8 8 8 8
8 T1231-5 82.90 8 2.23 8 2202 8 .196 8 30 812 8
8 T1101-5 82.92 8 2.31 8 3013 8 .361 8 8 8 1.5 8
8 8 8 8 8 8 8 8
8 T1231-5 82.90 8 2.23 8 2202 8 .196 8 30 812 8
8 T12Sl-5 82.92 8 2.24 8 2396 8 .217 8 16.58 4.5 8
8 8 8 8 8 8 8 8
8 T1331-5 82.935 8 2.26 8 2188 8 .173 8 35 821 8
8 T13Ml-5 82.94 8 2.26 8 2333 8 .199 8 17.58 7.5 8
8 8 8 8 8 8 8 8
8 Tl2Bl-5 82.90 8 2.23 8 2202 8 .196 8 20 812 8
8 Tl3A6-10 82.90 8 2.23 8 2481 8 .213 8 1 8 0 8
8 8 8 8 8 8 8 8

 

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Photcmicregraph 1- 2% Hital etch. Showing
Abnormal structure with type D
gramite. (Blank for Magnesium
inoculation).

 

Showing

normal graphite pattern.

2% Nital etch.

Photomi crograph 2-

-26-

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’2

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‘ C
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Photomicrograph 3- 2% Nital etch. Showing abnormal
structure after Magnesium inoculation.

DISCUSSION 013‘ R33] LTS

W- Calcium decarbonizes the metal
as it is clear from Table 10. Increasing amount of
Calcium has brought about a corresponding decrease in
the Carbon content of the final inoculated metal. With
the addition of one percent of Calcium the Carbon has
decreased by 0.24 percent.
Mg. he apparently do not affect the carbon content

of the metal. It could not be said here with confid-
ence that sodium does not have any affect on Carbon.

as the amount of sodium ihich went into the metal was
very small for drawing any conclusions. It does have a
little effect but is very small as comparedotc the effect
of Calcium.

Sulphur- During the whole experiment the sulphur
content did not change very much. From Tables 11.

it is clear that Aluminium and Sodium do not affect

the sulphur content of. the final metal. Calcium does
have some effect on desulpherising.The sulphur decreased
0.014 percent by the addition of 1.11 percent of
Calcium to the charge.

Mesium- Magnesium disulpherises the metal consider-
ably. The addition of 1.1 percent of Mg reduces the
Sulphur content by 0.037.

Silicon- Silicon content was within close limits.

It varied between 2.23 to 2.30. Silicon content of

the final composition is not effected by inoculation.
Equivalent ladles have very little difference in Silicon
contents as such a comparison would be very accurate.
meme Strength and Deflection:

It is clear from Tables 2,3,and 4 that increasing
the amount of Calcium improved the transverse properties.
An addition of 0.21 percent Calcium showed the increase in
transverse load from 2679 to. 2988 pounds and the deflect-
ion increased from 0.251 to 0.283 inches.

Addition of 0.44 percent Calcium increased the
transverse load from 2288 to 3121 pounds and the deflect-
ion from 0.194 to 0.335 inches. Maximum increase in

the load was obtained by the addition of 0.87 percent
of Calcium (See heat T1039 in Tablets). The transverse
load increased from unto 31‘5pounds and the deflection
from 0.192 to 0.384 inches.

The effect seems to decrease by further increase of
Calcium. The cause may be due to the increase in
defects by the formation of Calcium Carbide , but the
holding time seems to have little effect on the difference
in the transverse properties.

The addition of 1.11 percent of Calcium reduced the
Carbon content by 0.24 percent. The transverse strength
increased from 2776 to 3265 pounds in heat No. 10. The
deflection also increased from 0.287 to 0.384 inches.

For good comparison Host No. 12 was proposed to
be inoculated by 0.55 percent and 1.1 percent Sodium,
but due to the explosion effect of Sodium inoculation
the latter additions were called off. Addition of 0.55
percent Sodium does increase the transverse load and
deflection but to a small extent as shown in Table 5.

The transverse load increased from 2202 to 2396 pounds.
The deflection increased from 0.196 to 0.217 inches.

It was also observed that sodium inoculation produces bars
with less defects and of uniform properties. In '
comparison with Calcium, Sodium has a lesser effect. In

fact Calcium is about twelve times as effective as Sodium.

-30-

Also, Sodium cannot be added by ordinary means.
Addition of 1.11 percent Magnesium has a very
small effect on the transverse properties. The Mag-
nesium inoculated bar had a transverse load of 2333#and
a deflection of 0.199 inches as compared to the non-
inoculated bar, of 2188 pounds and 0.173 inch respectively.
Aluminium additions have some inoculation effect.
The transverse load increased from 2280 pounds to
2481 pounds and the deflection increased from 0.184 to
0.213 inches. It was also observed that aluminium
inoculated bars have more defects. The defects are
probably due to the Aluminium oxide trapped during solid-
ification. Table 13 was prepared to show a clear picture
of the inoculating effects of these metals. Magnesium and
Aluminium slightly improve the physical properties, even
though more ferrite is found in the microstructure by
their addition. This may be due to the solid solution
effect of these inoculents in ferrite. Table 14 was
prepared to compare the physical properties for the same
Carbon and Silicon pick up. Calcium and Aluminium show
considerable increase in the physical properties but
Magnesium and Sodium do not have any appreciable effect.

Chill Characteristics:
Aluminium addition has the maximum effect in
.reducing the chill. Both clean and total chill were

 

reduced considerably. There was practically no clean
chill left by the addition of 1.1 percent Aluminium.
The total chill was reduced to about twenty-four times
in the treated iron. Calcium also reduced the chill
to a great extent. Increasing amounts of Calcium re-
duced the chill till 0.87 percent of Calcium was used,
after much no further reduction in chill was obtained by
further increase in the inoculent. Magnesium and
Sodium additions also reduced the chill but their effect
was small as compared to Aluminium and Calcium. Alum-
inium additions seem to be twice as effective as Calcium
from the data in Table '7. It is also clear from this
table that any addition of active metals reduces the chill
to some extent.
Ease of Inoculation:

Calcium inoculation produces a peculiar orange
flame. The Calcium addition causes some splattering
of the molten iron from the ladle. The reaction between

Calcium and molten metal is violent but it is not as

-32-

vigorous as those of Magnesimn and Sodium. Magnesium
has a violent reaction with molten Cast Iron and gives
out a white flame with much splatter. Sodium has

the most violent reaction with molten Cast Iron. It
explodes as soon as it comes in contact with the molten
metal. It throws the metal out of the ladle in the form
of a fine mist. It also produces black smoke.

Aluminium does not react with the molten metal
violently. There is no explosion, flame or splatter
during the inoculation procedure. It floats on top of
the metal and soon dissolves into the metal. During this
investigation, Aluminium was the easiest to be used as an
inoculant. Although it imparts a strange appearance to
the metal. During pouring the metal looks like an under-
coolubrass. It may be caused by Aluminium Oxide float-
ing on top of the metal.

Hardness: The Brinell hardness data is tabulated in
Table 8. for the first two heats. This data did not show
any significant change for comparing the effects of diff-
erent inoculants on their physical properties. The
variation of hardness was 14 B.H.N. for heat No. 9 and

2'? for heat No. 10. This difference does not lead to

any definite conclusion. It is generally understood
among grey iron Metallurgists that hardness is not
correlated with the other properties of Cast Iron. As
such the determination of B.H.N's for the hardness of
the rest of the specimens were discontinued.
Microstructure and graphite distribution:

Great difference in microstructure was observed
between the corresponding inoculated and uninoculated
specimen of Calcium heat. It has already been stated
that fa. change in matrix and graphite shape, size and
distribution greatly affects the physical properties of
the test bars. The same correlation was obtained
during this investigation. Inoculated specimen from
heat No. '9 showed an increase in normal graphite. The
cell size was smaller and the microstructure was less
denderetic than the corresponding blank. There was
quite a bit of ferrite and lacy graphite at the surface
of the test bars. The corresponding blank also had
dendretic structure and lacy graphite but in these
uninoculated bars the dendritic structure extended to
the center of the section. There was more massive ferrite
and abnormal graphite near the suface of the bar. In-
creasing amet nt of Calcium in heat No. 10 and 11 has

-34..

shown corresponding effect in producing normal graphite.
Specimen from Sodium inoculated iron showed slightly
less abnormal structure than the corresponding non-in-
oculated iron. There was smaller amounts of lacy
graphite throughout the specimen. The lacy graphite at
the surface was associated with somewhat more ferrite than
the blank. As a whole the sodium inoculated.iron had
more free ferrite than the blank. The blank had highly
abnormal structure with lacy graphite and more ferrite was
. associated with the lacy graphite at the surface. Blank
for Magnesium inoculated iron was shown to have the same
microstructure as other blanks. The flakes were larger
and there was abnormal graphite in the structure. Mag-
nesium inoculated iron had more abnormal structurewthan
blank. The cell bounderies were much less evident though
the cell size was smaller. There was more free ferrite
and lacy graphite than in the blank. This effect of
Magnesium on the microstructure may be attributed to the
reduction in the Sulphur content brought about by the
Magnesium addition. Reference to the table shows that
the inoculation reduced the Sulphur from 0.066 to 0.029

percent. Boyles 3 has shown that low sulphur irons

tend toward an abnormal structure and has stated that
0.025 S is necessary for a normal structure. Although
the Sulphur remaining in the treated iron expeads this
amount, it would appear desirable to control the Summr
content before reaching a final conclusion regarding the
effect of Mg. additions on the microstructure.

Blank for Aluminium treated showed abnormal structure,

with ferrite and lacy graphite. The cells were larger and
well defined. Ladle treated iron had smaller cell size
and the structure was more abnormal than blank.

From the microexamination it has become clear that
Calcium has the maximum effect in producing normal graphite.
Magnesium and Aluminium apparently have a negative effect
in promoting good graphite distribution. Their addit-
ions appear to make the iron more dendritic and increase
the amount of ferrite. Sodium has some inoculating
effect as it helps to produce normal graphite but it is
hard' to put into the ladle. It increases the amount

of ferrite and thus reduces the physical properties of
the metal.

SUMMARY AND CONCLUSIONS

An investigation has been carried out to determdne
the relative effects of Calcium, Aluminium, Magnesium

and Sodium as ladle inoculants for gray cast iron on its

chemical analysis, physical properties and microstructure.

The base iron has 8.3 to 3.0 percent Calcium, 1-0 to 1-5’
percent Silicon, 0.05 to 0.069 percent Sulphur, 0.61 to 1.0
percent Managnese and cue to 0-1. percent Phosphorous,
throughout the entire investigation. Comparisons were
based on the difference of the final chemical composition,
transverse strength and deflection, chill debth, micro-
structure and graphite distribution between inoculated and
uninoculated irons.

The conclusions drawn are as follows:

1- Calciwm is effective in improving the graphite
distribution and matrix structure when used as a
ladle addition in gray cast iron.

2- Magnesium and Aluminium additions to the ladle in
amounts of about one percent have an adverse effect
on graphite distribution and matrix structure. In
the case of Magnesiumpthis effect may be associated

with a reduction in sulphur content.

4-

10-

-57-

The addition of Calcium brings about an improve-

ment in the physical properties as evidenced from

the effect on the transverse strength.

An addition of about 0.87 percent Calcium seems to
have maximum inoculating effect.

Calcium decarbonizes the iron.

Calcium reduces the chill to a great extent but it

is less effective than Aluminium.

Magnesium inoculation desulphurises the metal.

Sodium seems to promote normal graphilization to some
extent but it is very hard to inoculate. It ignites
with an explosion the moment it comes in contact with
molten metal.

Aluminium reduces the chill considerably. It was

the best chill reducer among the metals tried in this
investigation.

Calcium, Aluminium, Sodium and Magnesium do not have any
effect on the Silicon content of the final compos-
ition of the metal. All these inoculants reduce chill

to some extent.

BIBLI OGP—AHIY

Adams , ReRe
1942 Cast Iron Strength vs. Structure.
Trans. A.F.A., 50: 1063-1104. (14)

Alloy Cast Iron Handbook

Boyles , Ae
1938 The Formation of Graphite. Trans.A.F.A.
52: 1266-1271. (17)

Boyles,.A.
1947 The Structure of Cast Iron. American
Society for metals, Cleveland, Chic. (22)

Burgess, 0.0. and Bishop, RJI.
1944 Effect of inoculant on Cast Iron Preperties.
Trans. A.F.A., 52: 671-711. (16)

Gemstock, G.F. and Stankweather, E.Rt
1938 Comparative effects of late additions of titanium
and silicon on grey Cast Iron. Trans. A,F,A,,
46: 353-374. (20)

Creme, L.
1945 Opinions on Graphitization. Found , 73:102-
103, 248-258. (12)

Derge, C.
Deoxidation in Production of Modular Cast
Iron. Foundr , 79,4;3122-123. (25)

Dienher, A.H. '
1940 Ladle additions of graphite to ray Cast Iron.
American Foundryman, 2:2-5. (8% '

Finlayson,‘A.
1950 Diesel Engine Crankshaft cast in gray Iron.
Found , 78,9: 92-97,216-218,220. (30)

Flinn, KeAe and Reese, DeJe
1941 The Development of Control of'Engineering gray
-Dast Irons. _Trans. A.F.A., 49:559-608. (2)

Harvey, De Jo
1951 An investigation to determdne the manner
of Solidification and Transformation of
Medular Cast Iron. Thesis for*the degree
of Master of Science, Michigan State College,
p.53. (34)

Hurst, .T.E.
1945 Metallurgy of Iron and Steel for Casting.
F0 11nd ’ 73' A1183 90-91. 208. (13)

Loria, EeAw
1947 Reduction in chilling tendency through Silicon
Carbide inoculation of gray Cast Irons.
Amcrican Foundrymen Society, 55:301-308. (29)

Lorie, E.A.
1951 Chill control in Cast Iron. Found , 79:6:
l26-128,212-218. (24) ‘
Lorég, 0.1;. t d
1 39 ray Iron Me allurgical Practice. Penn 3:
67:26-27,74-76. (11)

MaOKan1e , JeTe
1944 Gray Iron Steel plus Graphite. Trans. A.F.A.
52:1266-1271. (17) ' .

Masearig Se Ce and Ladsay, R. We
1941 Some factors influencing the Graphitizing
Behavious of Cast Iron. Trans. A.E.A.
49: 953-992 . (6)

Massari, S.C. . '
1944 ‘White and Chilled Iron Casting. Amer.
Found an Societ , 52: 552-554. (25)

McClune, Norman C.
1949 Ferro-Sieicon, Calcium.Silicon end.Metallic
Calcium as ladle inoculants for gray Cast Iron.
Thesis for the degree of Master of Science,
Michigan State College. p.82 (23)

-40-

Metal Band Book, 1948 edition., American Society for
Meta-18.

McElween, R.G.
1938 Deoxidation and Graphite of Cast Iron.
Trans. AeFeLe 46,341-349e (19)

Schee, v.11. and Barlow, T.E.
1939 Copper Aluminimn Silicon Alloys for Addition
of Cast Iron. Trans. A.F.A. 47: 725-741. (33)

Schneble, A.W. Jr. and Chipman, .T.
1944 Superheating Gra Cast Iron. Trans. A.1‘.A.
52: 113-173. (15

Schneidwind, R and D'Amico, C.D.
1939 Influence of undercooling on graphite pattern
of Gray Cast Iron. Trans. A.F.A,, 47:831-854. (5)

Schneidewind, R. and McElwee, R.G.
1939 The Influence of Composition on the Physical
Properties of Gray Cast Irons. Trans. A.F.A,
47: 491-513. (1)

Timmons, G.A. and Crosby, V.A. ,
1941 Effect of Pouring temperature on the strength
and Microstructure of Gray Cast Irons. Trans.
A.F.A. 49: 225-255. (3) .

Varnish, 3.8.
1945 Cast Foundry Practice. Trans. A.F.A, 53:51 (10)

War Engineering Board. Foundry Process Control
Procedures. Society of Automotive Engineers,Inc.
New York. 145 (9)

Williams, A.E.
1948 Nickel Cast Iron. Engineer and Boiler House
Review, 63,6: 175 (26) “ “‘i ‘“

Williams , J.H.

1942 Ladle Metallur , Foundry Trade Journal
68:345-349. (7%y

Young, E.R., Crosby, V.A. and Henzig, A..T.
1938 Physical Properties of Cast Iron in Heavy
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Ziegler, ILA. and Northrup, H.W.
1939 Effect of Superheating on Castability and
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Carbon Contents. Trans. A.F.A., 47:620-553.(4)

80- 8 '54

M4317 1961-0
M5’77&

ROOM USE ONLY

 

 

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