Isothermal Transformation of Austenite by Magnetic Permeability Method

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I30THBRKAL TajWSFORIUTIQB OF AUSEB&ITS BY MAGNETIC PSEMSASiLlfl METHOD

by

33283 A thesis Submitted t® the Departaent of M^talitargj ij& P a r t i a l # F a l f p ^ t ^ t of tbs RequireiiamtiV#for:#tli@ Deg^eaM of faster of Seleses* In JfeialXorglcal Snglxseering

MQHTiKA SCHOOL Of MIIiES Butte $ Moiitana Feb. U, 195Q

UMI Number: EP33456

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i TABLE

OF QOSTSHTS

mm iBtroduetiosi Ha&ure of I i a r o s t i g a t i w ^ . . . • * . * * * •

o . . . . . . *

.

1

Xmpm*tmm of Studj* . . . . • , * * . • . . . • • . . . . • •

2

History oi* the Process * * * * * « • * * • * * * . » » * • * «

2

Isottmraal Transforoaticci Brooe^s 1 Typieal Isothermal fr^mSoTimtxmi SigM£i&axim*

* * * . •

Diagram. . . . . . . . . . • • • • * •

BcrrLnr or Different Methods of Isothermal Studies *

• . • • • . * • • . .

9 13 16

Apparatus wad Materials Baals oJT S^-teetixm . . . . . . . . . . . . . . . . . . . . . .

18

AtEst^nltlsirig Furoae** . . . . . . . . . . . . . . . . . . . .

If

Qo«i)cb£ias«43sa^h Fornaoe * • « * « • « • * * « « . » * * » « » »

22

f r a m f o r m t i o i a Furna®* . . . . . . . . . . . • . . » • » . . •

22

M ^ n a t l c SOTieii* . . . . . . . . . . . . . . . . . . . . . . .

27

Jfttjdliary Equlp«wit # . . . . . . . . . . . . . . . . . . . . .

29

Mr%m i®r Bstdllag Spec&rens* . . . . . . . . . . . . . . . .

31

Preltolaai^f Work . . . . . . . . . . . . . . . . . . . . . . .

33

Saqperiamts ©n S t e e l X~916$* . . . . . . . . . . . . . . . . .

1*2

Isothermal f r a a a f e i ^ t i o a

1$

tea

. . . . . . . . . . . . . . . .

Essmlta of Ia¥#atigatl4rcn carbide i s given en page ? (diagram I) * I t MIX be seen from the diagram timt auatanite i s ccupletely atabla in t t e mm betawaa the OSS line {A3 *r Ao*) and the seUdta**

It

i s p a r t i a l l y stable l a the woe befetean A3 car Aot and % line and ecm~ plately unstable b e l ^ the Aj line* In actuiX prwtice* however* dne t@ fmi3^re of attaining eqaUiteiaam eooditioBS* t t e traaaforaatira tespirmtnree are found t o be slightly lower en coding arad higher m heating* flaws instead of t t e theoretical trmsfcrmti®n teiqpermtureii k% and A3 we

7

s. FERRJTE LIQUID SOLUTION

2800

LIQUID

SOLUTION

OF CARBOKI

\M I R O N

2t00 )-FERRITE

t-/\05TENlTE

240O LIQUID

AUSTENlTE 2200

(SOLID

SOLUTION V -

SOLUTION +

OP I R O N C A R B l D g

AO^TENlTE

IN \

IRON

2ooo

l^oo -

} 1200

\

1000-

PEARUTE

F E R R I T E -*- P E A R U T E

-t- C E M E N T I T E

a) o1

I

Ao.

_0-oo8

HI-

MYPOEUTECTOID

-L

J

L

0-5

0.35

l-O

STEELS

-L

l'|7 2-o PERCENT CARBON

*4-*-HYPERE.\jTECTOir> 1 STEEL5

DIAGRAM -

»[«< I

CAST i £ o N S -

I

THE IRON-CARBIDE EQUI&RIUM DIAGRAM

_L 5-Q

*4

8 have An md Aog^ $&d Arj and Acj^ the actual tranafonoation tesporaturaa found on cooling and heating*

This ia the f i r s t suggestion of t t e

ioflueaice of the tia© factor cm troraformtioji*

Obviously these tei^era-

tures Ar and jic