Foundry Trade Journal : with which is incorporated the iron and steel trades journal, Vol. 72, No. 1447

i m U M n & y

EST. 1902 T R A D E J O U R N A L

-UTISH ipULDING

"iER SH AM , KEN T.

WITH WHICH IS INCORPORATED T H E IR O N A N D S T E E L T R A D E S J O U R N A L

V O L . 73. N o . 1447. M A Y I I , 1944 r S in g le C o p y 6 d . B y P o st 8 Registered a t the G.P.O . os a Newspaper. Offices: 49, W e llin g to n Street, Strand, London, W .C .2 . L a n d 'o v c ^ s e a s f'2 ?/-°(P re[»a l(

I N V E S T I N „

MANSFIELD MOULDING SANE;

• P U L V E R IS E D R E A D Y F O R U S E I F R E Q U I R E ! ■

CHINE C° LTD

K E N T B O X E S T e le p h o n e s : S h e ffie ld 26311 (15 lin e s ) M a n s fie ld 37

* * S T E R L IN G F O U N D R Y S P E C IA L IT IE S L T D .. B E D F O R D

i

_

J P * “

Iłte E a k d d m /o p m m ł m R E F R A C T O R IE S -

HIGH A L U M I N A Plastic

F I R E B R I C K

a n d F O R R A M M I N G

FLUID R E F R A C T O R Y

F O R P O U R I N G

•nedstre t h e r m a l

F o r special shapes, M o n o lith ic lin in g s and re p a irs to co m b u s tio n cham bers, b o ile r tu r n a c e s , d e s tru c to rs , b rid g e w a lls , and e sp ecially t o furnace s now o p e ra tin g on c re o s o te p itc h . Engineers Services Available on Request.

DLAND M O N O L I T H I C F U R N A C E LI NI NG C O M P A N Y LI MI TED

. Narborouóh Z ? i o ~ 5

BLACK SEAM HOUSE • NARB 0 R 0 UGH • LEICESTE R

4ND TESTING

for Catalogue o f Testing M achines to I* _{~--r ■ ■} f=-~ — - _. ;T,:--:rr:_.

IS N O W V ITA L TO ALL FO U N D ERS TO EC O N O M ISE SAN D A N D M AKE B E TTER

t « % . .,v G S

T H E E V D C

E T K E S M E LTIN G C O M P A N Y LTD

T ~ J Ä W H . i- a M « r 1 1 e * G 1 1 n - M p r a T a n d e m W h i t e M e t a l s • G u n - M e t a f

B ro n z e and A lu m in iu m Ing o ts P h o s p h o r B r o n z e R o d s P h o s p h o r

C h i l l C a s t

C h l i t c a s t r n o s p n o r O I U I U C r . w u a T A N D E M W O R K S . M E R T O N A B B E Y , L O N D O N , S . W . I ( M it e h a m 2031)

2 FOUNDRY TRADE JO URNAL M A Y I I , 1944

R O T A R Y FURNACES

FIRED BY FUEL O IL

T O W N S GAS

“ PULVERITE ” OR

CREOSOTE PITCH

M IX TU R E

STEIN & A T K I N S O N L TD*

47, W O L S E Y R O A D ,

E A S T M O L E S E Y , S U R R E Y .

T E L E P H O N E S : T e l e g r a m i :

M O L E S E Y 3 11 1-2 M E T A S T E I N A . P H O N E . L O N D O N

£.6237

“ T M 6 0 S ” T W O -S T A G E C O M P R ESSO R

F .A .D .

— 516 c. f t . / m . t o 100 lb ./s q . in .

a t 720 r.p .m .

BRITISH

WAR PRODUCTION

is undoubtedly being greatly assisted by P N E U M A T IC PLA N T and the A IR C O M ­ PRESSOR illustrated is one of the many H O L M A N MODELS supplying the air.

C A M B O R N E - - E N G L A N D

P h o n e : G ra m s :

C a m b o r n e 2 2 7 5 A i r d r i l l , C a m b o r n e

1?« M A Y I I , 1944 FOUNDRY TRADE JOURNAL 3

"LITTLE COURT': PYRFORD COMMON,

W O K IN G , S U R R E Y .

Telephone:-BYFLEET 3IOO Telegrams:-IRONOBRIT,PHONE,WOKING.*

*3

— j t . . . mnrlp o f raw m aterials in short supply cwing to[w ar conditions are advertised - -— — - - ^ - - s.-: as an indication that they are necessarily available for export

4 FOUNDRY TRADE JOURNAL M A Y I I , 1944

B r i t i s h M o u l d i n g M a c h i n e C ^o . L ^{t d} .

M A Y I I , 1944 FOUNDRY .TRADE JOURNAL

you are having trouble w ith production from your CORE BLOW ING MACHINES

you experience objectionable FUMES when c a s t in g ...

you wish to IMPROVE THE FINISH of your castings

n i

.... j

THE FORDATH ENGINEERING C L

t e l e p h o n e:

WESt BROMWICH 0549 f2 LIMES*

HAMBLET WORKS WEST BROMWICH

'mETALIICAL' WEST BROMWICH

6 FOUNDRY TRADE JO URNAL M A Y I I , 1 9 4 4

PR O D U C TIO N PR O D U C TIO N PR O DUCTIO N

in these gain this The main o b je c t o f nearly every fo u n d r y

p r o d u c tio n . S te rlin g Boxes w il l help t o

lightness enables m oulders t o p u t dow n m ore moulds per day. T h e i r accuracy reduces th e n u m b e r o f wasters. T h e i r d u r a b ili ty prevents stoppage o f w o r k due t o breakage o f boxes.

• • s

All kinds and sizes o f castings in all kinds o f metal are made in Sterling Boxes.

Telephone B E D F O R D 5338-9 Telegram s STE R FLA S K , B E D F O R D

days is increased

o b je c tiv e . T h e ir

M A Y I I , 1944 FOUNDRY TRADE JOURNAL

c o r e s

P n e u le c S t o v * Z b ^ * * * O f 4

for a ^ h g ’b L a* ? ect

cupolas Royer sand mixers

L B C

core and mould jarr rollover sand preparing sand mixing mills rotary sand dryers T->_ T_ drying stoves machines plants sand disintegrators portable mould dryers

.E C L IM IT E D - M qfekinq R o a d - S m eth w ick - N e a r BIR M ING H A M

FOUNDRY TRADE JOURNAL M A Y I I , 1944

M ost U n fo rtu n a te !

T h e in c re a sin g u se o f scrap in th e s te e l-f o u n d ry j u s t c a n ’t b e h e lp e d th e s e days.

S o m e n a tio n a lly -e c o n o m ic a lly -m in d e d ste e l m a k e rs (m o re p o w e r to th e ir elb o w s !) are u sin g p ra c tic a lly 1 0 0 % scrap fo r a larg e n u m b e r o f castin g s. T h is , o f co u rse, is ju s t w iz a rd — p ro v id e d th e castin g s o n ly begin as sc ra p . U n fo rtu n a te ly , to o m an y o f ’e m also en d as scrap . T h a t ’s w h e re S o d iu m C a rb o n a te c o u ld h av e m ad e all th e d ifferen ce. A p a rt fro m th e n ecessity o f c o n tro llin g th e excessive s u lp h u r p ic k -u p r e s u lta n t fro m u sin g a h ig h p e rc e n ta g e o f sc ra p , th e a p p lic a tio n o f S o d iu m C a rb o n a te p ro d u c e s a far b e tte r q u a lity ste e l w ith im p ro v e d d u c tility an d m a c h in in g q u a litie s. I t ’s m o s t u n fo r tu n a te if y o u a re a d d in g

to y o u r scrap w ith ste e l castings re je c te d a fte r m u c h tim e an d m o n ey h a s b e e n lo st a n d c o stly to o ls p o ssib ly d a m a g e d in th e ir p ro d u c tio n — p a rtic u la rly w h e n th is s ta te o f affairs is so easily g u a rd e d a g ain st b y th e u se o f th e S o d iu m C a rb o n a te p ro cess.

I M P E R I A L C H E M I C A L I N D U S T R I E S L I M I T E D

cnm u

m a y I I . 1944 FOUNDRY TRADE JOURNAL !9

B u tto n .

9 9

REDUCES FOUNDRY

COSTS

IB t v V .* » « m i r - « - » x ù

S q u e e z in g , v ib r a t in g a nd h e a tin g a re c a r r ie d o u t e le c t r ic a lly .

P r o d u c tio n o f d i f f i c u l t w o r k is ra p id and e ff ic ie n t — 100 m o u ld s can be p ro d u c e d

f o r o n e u n i t o f e le c t r ic it y .

D is t o r t io n o f m o u ld s is e lim in a t e d as r o llin g - o v e r

sq u e e z in g .

m a t ic a lly s tr ip p e d o n t o th e c o n v e y o r t h e e n e rg ie s o f th e o p e r a t o r a re

th e r e b y c o n s e rv e d f o r m o u ld p r o d u c tio n o n ly .

W r i t e f o r le a f le t M .1 15.

ROLLOVER'TYPE MAGNETIC MOULDING MACHINES

BRITISH INSULATED CABLES LTD.,

N.R.S.

“ NEWSTAD” RECIRCULATION SYSTEM

— N.R.S. STOVES—

fo r Efficiency, Q u a lity and Economy Types f o r any capacity and Foundry c o n d itio n

M ould and C o re Stoves, new and conversions

fo r coke, coal, gas o r o il

N.R.S. Heating Units and N. M O U L D DRIERS --- H o t A ir Units for Skin Drying ---

Sole Su p p liers :

MODERN FURNACES & STOVES LTD.

B O O T H S T R E E T , H A N D S W O R T H , B IR M IN G H A M 21 T e l . : S m e th w ic k 1334 ’ G ra m s : M o fu s to lim

N.R.S. C o n ve rsio n s o f T w o M o u ld D ry in g Stoves at Messrs. Clapham B ro th e rs Ltd.

in K e ig h le y , Y o rk s .

10 FOUNDRY TRADE JOURNAL M A Y I I . 1944

Putting

(•

into P ig Iron

C astings have now to satisfy specifications previously m et by steel. R esearch w ork car­

ried on fo r m any years by B R A D LE Y & F O S T E R and intensified b y w ar-tim e ex­

perience has led to the p ro d u ctio n o f b e tte r and still b e tte r ir o n — iron w ith

“ m u sc le ” in i t — iro n capable o f p ro d u cin g castings far in

advance o f earlier stan d ard s.

In th e p ro d u c tio n o f pig irons for h ig h d u ty castings for all p u rp o se s, B R A D LE Y

& F O S T E R have developed grades whose p o ten tialities for post-w ar reco n stru ctio n w ork will im p ress you. W e shall be glad to discuss the fu tu re o f h ig h d u ty castings in relation to y our own req u irem en ts.

B R A D L E Y & F O S T E R ^ltd

DARL AS T O N . S O U T H S TAFFS

M A K E R S O F

I

Flro.rn-iiqt in<r niP" iron.

M A Y I I , 1944 FOUNDRY TRADE JOURNAL M

i i

y y

u s e P L A S T I f l L

THE QUICK ACTION FILLET

R E G D . T R A D E M A R K

REQUIRES N O GLUE.

TAKES THE SHARPEST CURVES.

B R ITIS H P A T E N T N o . 508848. SAMPLES O N R E Q U E S T;

MADE BY

J. W. & C. J. PHILLIPS Ltd.

PO M ERO Y STREET, N E W CROSS, L O N D O N , S.E.I4

A l s o L E A T H E R F I L L E T , W O O D F I L L E T , P A T T E R N L E T T E R S , D O W E L S , E T C .

S t e m T u s t n m o v a l

y

T e le p h o n e s : T o tte n h a m 4522 ( tw e lv e lin e s ) T e le g ra m s : " K c ith b la c P h o n e L o n d o n .”

1 2 FOUNDRY TRADE JOURNAL M A Y I I , 1944

f o r t r i a l h e a t s a n d e x p e r i m e n t a l w o r k . . .

t he E F C O h ig h frequency furnace . . . ideal for m elting special ¿ h e a ts o f copper, alu ­ m inium , bronze, brass, iron, steel, nickel, silver, gold, platinum , iridium , palladium , rh od iu m , etc., etc.

Furnace Capacities : 4 ozs. to 40 lbs.

Spark Gap Converters : 3 to 35 K.V.A.

Electronic Equipment : 1 to 50 K.V.A.

Motor Generator Sets : 10 to 45 K.W .

Larger sets for production output.

These furnaces may be used fo r melting in vacuo or under inert atmosphere, fu l l technical information from ;

E L E C T R I C FURNACE

CO. LTD.

N E T H E R B Y , Q U E E N ’S R O A D , W E Y B R ID G E , SURREY

T e le p h o n e : W e y b r id g e 3891 T e le g ra m s : E le c tr ifu r W e y b r id g e

M A Y I I , 1944 FOUNDRY TRADE JOURNAL 13

r F o rg et

f y o u r R u st ^ p ro b lem s

by remembering

R a t l a s mm

USKILLyi

IRON & STEEL PRESERVATIVE PAINTS

—

the Paints o f Stam ina !

C o lo u r C a rd , p a rtic u la rs and p ric e s fr o m

Sole Mfrs.

ATLAS PRESERVATIVE COMPANY LTD

L U N D E R C L IF F W O R K S . E R IT H , K E N T J

V Telephone : E R ITH 2 2 5 5 -6

P

P O R T A B L E C O N V E Y O R

A T E R S O N H U G H E

E N G IN E E R IN G C O M P A N Y L IM IT E D W B e d fo r d H o u s e , B e d fo rd S t.,S tr a n d , W .C .2 T e r r p le B a r 7 2 7 4 /6 W y n d fo r d W o r k s , M a r y h ill, G la s g o /v , N . W . M a r y h ill 172/3

■ E M R M T T T T K n - l i ] ; l ! M

WITH WHICH 'IS INCORPORATED T H E IR O N A N D STEEL TRADES /O U R N AL

4 9 , W e llin g to n S tr e e t, L o n d o n , W .C .2 .

W A R T IM E A D D R E S S t o w h ic h a ll c o m m u n ic a tio n s sh o u ld be s e n t I—

3 , A m e r a h a m R o a d , H I G H W Y C O M B E , B u c k s . 'G ra m s i ’ ’ Zacatecas, H ig h W y c o m b e .”

•P h o n e i H IG H W Y C O M B E 1792 (3 lin e s ).

P U B L IS H E D W E E K L Y I 21a. p e r a n n u m (H o m e and O v e rs e a ) O F F IC IA L O R G A N O F i

C O U N C I L O F I R O N F O U N D R Y A S S O C I A T I O N S C h a irm a n I F lt iH e r b e r t W r ig h t , T h e B u tte r le y C o m p a n y R ip le y , n e a r^ D e rb y . S e c re ta ry i V . D e lp o r t, 2 , C a x to n S tr e e t, W e s t m in s t e i, P a rtic ip a tin g Associations I B r itis h B a th M a n u fa c tu re rs ' A s s o c ia tio n ; B r itis h Ir o n fo u n d e r s ’ A s s o c ia tio n ; B r itis h M a lle a b le T u b e F ittin g s A s s o c ia tio n ; C a st Iro n A x le b o x A s s o c ia tio n ; C a st Iro n C h a ir A s so cia ­ t i o n ; C a st Ir o n H e a tin g , B o ile r a nd R a d ia to r M a n u fa c tu re rs ' A s s o c ia tio n : C a st Ir o n S e g m e n t A s s o c ia tio n ; G re e n sa n d P ipe F o u n d e rs 'A s s o c ia tio n o f S c o tla n d ; Ir o n fo u n d e r s ’ N a tio n a l C o n fe d e ra tio n ; N a tio n a l A sso cia ­ t io n o f M a lle a b le Iro n fo u n d e rs ; N a tio n a l In g o t M o u ld A s s o c ia tio n ; N a tio n a l Ir o n fo u n d ln g E m p lo y e rs ’ F e d e r a tio n A s s o c ia tio n o f A u t o ­ m o b ile a n d A llie d H ig h D u t y I r o n f o u n d e r s ; B r itis h C ast Iro n Research A s s o c ia tio n ( a ffilia te d ) : B r itis h G r it A s s o c ia tio n ( a ffilia te d ) ; F lu s h in g C is te r n M a k e rs ’ A s s o c ia tio n (a ffilia te d ) ; I n s titu te o f B r itis h F o u n d ry m e n ( a ffilia te d ) . _____

I N S T I T U T E O F B R I T I S H F O U N D R Y M E N P R E S ID E N T , 19 4 3 —+4 : D . S h a rp e , F o u n d r y P la n t & M a c h in e ry . L t d . 113 W e s t R e g e n t S t r e e t , G la s g o w .

G e n e ra l S e c re ta ry I T . M a k e m s o n . A c tin g S e c r e ta ry , J. B o lto n . S a in t J o h n S tr e e t C h a m b e rs , D e an sg ate , M a n c h e s te r 3.

B R A N C H E S

B irm in g h a m , C o v e n tr y end W e s t M id la n d s i A . A . T im m in s , F .I.C . 3 3 . C a r t e r s L a n e , Q u i n t o n . B r is t o l a n d W e s t o f E n g la n d ; A . H a re s, 2 0 , G r e e n b a n k R o a d , H a n h a m , B r is to l. E. M id la n d s I S. A . H o r to n '* T h re e ,” M o s ty n A v e n u e . L lttle o v e r , D e rb y . Lancs l H . B u c k ­ le y , E lle s m e re , N o r f o lk A v e n u e , B u r n le y . L o n d o n : V . C . F a u lk n e r.

3, A m e ra h a m Road, H ig h W y c o m b e . M id d le s b ro u g h (p ro te rn .) ; J. K . S m ith s o n , N o rth -E a s te rn Iro n R e fin in g C o m p a n y , L im ite d , S tlllln g to n , S to c k to n -o n -T e e s . N e w c a s tle -u p o n -T y n e ; C . L ashly, S ir W . G . A r m ­ s tro n g , W h it w o r t h & C o . (Iro n fo u n d e r s ), L td ., C lo s e W o r k s , G ate she a d.

S c o ttis h i J. B e ll, 60, St. E no ch S qu a re, G la sg o w . S he ffield : T . R. W a l k e r , M .A ., E n g lis h S te e l C o r p o r a t io n , L t d . , S h e ffie ld . W a le s and M o n m o u th i A . S. W a ll, 14, P a la ce A v e n u e . L la n d a ff, C a r d iff. W e s t R id in g o f Y o r k s h ir e : D o u g la s J e p s o n , M .S c., 9 , A m b le s id e A v e n u e , B ra d fo rd . S o u th A fr ic a ; B. P. S k o k , M u tu a l B u ild in g . J o h a n n e sb u rg .

S E C T IO N S

B u r n le y i H . B u c k le y , E lle s m e re , N o r f o lk A v e n u e , B u rn le y , Lancs.

East A n g lia n i A . N . S u m n e r , 5 1 6 , N o r w i c h R o a d , Ip s w ic h . F a lk irk T . R. G o o d w in . “ V le w fle ld ,” F a lk irk R oad, B o n n y b rld g e . L in c o ln i E.

R. W a lt e r , P h .D ., T h e T e c h n ic a l C o lle g e , L in c o ln .

A S S O C I A T I O N O F B R O N Z E A N D B R A S S F O U N D E R S P r e s id e n t : H . B ls s e ll, J. S to n e & C o ., L td . , L o n d o n . S e c r e ta rie s : H e a th c o te & C o le m a n , 2 5 , B e n n e tts H il l, B irm in g h a m , 2

T H E I N S T I T U T E O F V I T R E O U S E N A M E L L E R S P re s id e n t I W . H . W h it t le , W . H . W h it t le , L im ite d , Eccles, nea r M a n c h e s te r. C h a irm a n l W . T o d d , P a r k in s o n S to v e C o .. L td . . S te ch - f o r d , B ir m in g h a m . H o n . Sec. i W . T h o m a s , A .I.C ., B a n k H o u s e , H ig h S tr e e t, R ic k m a n s w o r th , H e r ts .

F O U N D R Y T R A D E S ’ E Q U I P M E N T A N D S U P P L I E S A S S O C I A T I O N

P re s id e n t I G . E. F ra n ce, A u g u s t’ s, L im ite d , T h o r n T re e W o r k s , H a lifa x . H o n o r a r y S e c r e ta r y : K . W . B rid g e s . A s s is ta n t S e c re ta ry i Miss L . C o x , 5 2 , S u r b ito n H il l P a rk , S u r b ito n , S u rre y .

W E L S H E N G I N E E R S ’ A N D F O U N D E R S ’ A S S O C I A T I O N P re s id e n t I W . E. C le m e n t, C .B .E ., M o rfa F o u n d ry , N e w D o c k , L la n e lly . S e c re ta ry I J. D . D . D a vis, I , S t. James G a rd e n s , Swansea.

B R I T I S H C A S T I R O N R E S E A R C H A S S O C I A T I O N A lv r c h u r c h , B irm in g h a m . 'P h o n e and ’G ra m s : R e d d ltc h 7 > 6 . S co ltls h L a b o r a t o r ie s F o u n d r y T e c h n lt a l.lo a t lt u r e .M e e k ’ i R o a d , F a lk lr k . (P h o n e I 332.1

D

¡4 FOUNDRY TRADE JO URNAL M A Y I I , 1944

The need for all p o ssib le co n ser v a tio n o f m an p ow er ; th e dem and for th e m a xim u m o u tp u t o f v ita l cast m etallic p rod u cts ; the in sisten ce u p o n th e lo w e st c o st o f p rod u c­

tio n ; and the n ecessity o f m ain tainin g, and even im proving, the q u ality o f th o se p ro d u cts.

A ll th ese c o n d itio n s co m b in e to p o in t to the on ly satisfactory s o lu tio n to all th ese p ro b lem s—

MECHANISATION

but it m u st be m ech a n isa tio n particularly con sidered , designed and adapted to the in d iv id u a l site c o n d itio n s ; to th e particular p rod u ct ; and w ith fu ll regard to

the factors, ec o n o m ic , geographical and h u m an , w h ich may have any bearing on th e p ro b lem .

In oth er w ord s c o n su lt :—

“ The Specialists in Foundry Mechanisation”

w h o se p rod u cts

“ Set the Standard b y which Foundry Plant is ju d g e d .”

’P h o n e s : 6 1 2 4 7 &. 8

H ALIFAX, ENG LAND

Sole L icen sees a n d m a n u fa c tu r e r s fo r B ritish E m p ire ( e x clu d in g C a n a d a ) o f the S im p so n S a n d M ixer

I ■ ■ -- ---

F o un dry T r a d e J o u r n a l, M u y 1 1 , 1944

V ol. 73 T h u rs d a y , May I I , 1944 N o . 1447

W IT H W H IC H i t IH C O R P O M T E D TH E IRON AND STEEL TRADES JOURNAL

esta b lish ed 1902

Foundry Dust H azard s

The p u b lic a tio n as T ech n ical R e p o rt N o . 1, by the In d u stria l W elfare D iv isio n o f the [A ustralian]

D epartm ent o f L a b o u r an d N a tio n a l Service, o f a booklet “ D u st H a z a rd s in A u stra lia n F o u n d rie s,”

m arks the beg in n in g o f a new era in th e co n d u c t of shops d ev o ted to the m a n u fa c tu re o f castings.

The A u th o rs, M r. A. A . R o ss a n d M r. N . H . Shaw , have p resen ted th e p n eu m o co n io sis p ro b le m in a new light. T h e y assu m e fro m th e lite ra tu re of the subject th a t p u lm o n a ry diseases can be associated w ith fo u n d ry p ractice; m o re w ith m echanical p ro d u c tio n th e h a z a rd is increased, because th e m a jo r d u st-p ro d u c in g o p e ra tio n s follow one a n o th er in a m o re ra p id sequence. U s in g 'th e Owen’s J e t D u st C o u n te r fro m sam ples collected with the G re e n b u rg -S m ith Im p in g er, th e A u th o rs have m ade a logical survey o f m o st fo u n d ry p r o ­ cesses, an d h av e estab lish ed w h ere the m ajo r hazards a re to be fo u n d . W ith such a statem en t available, th e in d u s try is n o w w ell p lace d fo r a proper atta c k o n th e p ro b le m w ith every chance of a successful o u tco m e.

The tech n iq u e u sed by th e A u th o rs has been to establish the stu d y o n th e n u m b e r o f p article-h o u rs per c.c. In seven fo u n d rie s using m ach in e m o u ld ­ ing, the figures w ere n o t high a t fro m 163 to 250 particle h o u rs p e r c.o., b u t th e figures c o u ld be much low er if o n ly the in d u stry can red u ce the d u st produced by the a p p lic a tio n o f p a rtin g po w d er, facing p o w d er, the b ru s h in g o f p a tte rn s, a n d clea n ­ ing them w ith a ir blast. I t is these th re e o p eratio n s which are th e p rin cip al fa c to rs in n o x io u s dust production, especially p a rtin g p o w d er, w hich in many cases carries a very high p ro p o rtio n o f silica flour. T h e so lu tio n s a p p e a r to be the use of pow ders free fro m silica an d a n a d a p ta tio n o f the vacuum clean er. T h e facin g pow ders, usually com pounded o f p lu m b a g o an d talc, d o n o t p ro d u ce silicosis, b u t th e in h alin g o f large q u an tities is n o t too h ealth y . T h e d u st a t th e k n o c k -o u t show s a som ew hat h ig h er d u st c o n cen tratio n , an d an exhaust v e n tila tio n offers the b est m eans o f co n tro l.

M uch d u st can b e g en erated d u rin g sand re c o n ­ ditio n in g , an d this can be reduced by pre-w etting and the strateg ic p o sitioning o f exhausts.

T h e A u th o rs included an ex am in atio n o f the in te rio r o f san d an d sh o t-b last helm ets, a n d as a result, th o u g h they fo u n d a low c o n cen tratio n , they d ra w a tte n tio n to th e need fo r the supply a ir to be ta k e n fro m a clean source o r th a t the a ir be filtered. T h e c o n d itio n s a ro u n d san d -b last room s a n d cabinets, w h ere d u st co n cen tratio n is d an g ero u sly high, d e m a n d a m e lio ra tio n by a rigid insistence on g ood housekeeping. R u m b lers, unless p ro p erly m o d ern ised , are soundly condem ned by the A u th o rs. T h is p ro b lem is resolved in the U n ite d K in g d o m by existing legislation. T h e use o f scratch b rushes produces, in m an y cases, a high d ust c o n c e n tra tio n , co n tain in g m u ch free silica, an d th e re is a reco m m en d atio n th a t this process sh o u ld be c o n d u cte d in an ex h au sted bo o th . T h e c o n cen tratio n s reco rd ed by the A u th o rs vary fro m 188 to 1,515, an d they ascribe th e m inim um figure as being d u e to th e rem o v al o f th e fines fro m the m o u ld in g in th e p a rtic u la r case yielding this result. T h e A u th o rs a re satisfied th a t fo u n d ry g rin d in g o p eratio n s are n o w in n o cu o u s, w ith the p ossible ex cep tio n o f som e p o rta b le a n d swing grin d ers w here the g u a rd only covers 180 deg., in ­ stead o f the 300 deg. o r so u su al w ith statio n ary g rin d in g w heels, b u t even th e n th e sw ing grinders p ro p el th e d u st aw ay fro m the o p e ra to r. P n eu m atic chisels used fo r fettling castings w hich are to o large for sh o t-b lastin g create ra th e r heavy d u st co n cen ­ tra tio n s, w hich co n tain high percentages o f free silica a n d w etting b efo re an d d u rin g cleaning is ad v o cated .

T h e final process to be studied by th e A u th o rs is th e filling a n d em ptying o f m alleable annealing pans. H ere, w hilst the d ust p ro d u c tio n is high, the silica co n te n t is low (9 p er cent.) an d is relatively harm less. T h e R e p o rt very ten tativ ely suggests

(Continued overleaf, col. 2.)

Contents

F o u n d ry D u st H a za rd s, 21.—Iro n fo u n d ry F uel News—I I , 2 2 —C atalo g u es R eceived, 22.—S h rin k ag e a n d P o ro sity in L ig h t Iro n C astin g s, 2 3 — London B ra n ch A nnual M eeting, 30—C auses of Lost Tim e, 34.—A ll W elding M achines now S u b ject to L icen sin g , 34.—B ritis h N on-ferrous Sm elters' A ssociation. 34.—N ews in B rief, 36.—P erso n al, 36.—Com pany R esu lts, 38.—O b itu a ry , 38.—R aw M ate rial M ark ets, 40,

22 FOUNDRY TRADE JOURNAL H A Y I I , 1944

IR O N F O U N D R Y FUEL N E W S — II

T h e first phase in an y w orks fu el eco n o m y cam paign is, o f course, to save as m u ch fu e l as possible w ith existing plant. It m ay be fo u n d , how ever, th at very su b stan tial econom ies co u ld be effected by the in sta l­

lation o f som e new eq u ip m en t, an d to co v er such cases a c o m m o n s ta n d a rd fo r licensing the in stallatio n has been agreed u p o n by the G o v e rn m e n t d e p artm e n ts concerned. Briefly, it req u ire s th a t if the new p la n t does n o t affect the type o f fu el to be used th e schem e will b e a u th o rise d if the fu el saved in 2 \ y ears (from the d a te o f au th o risa tio n ) exceeds in v alu e th e cap ital cost o f the eq u ip m en t. T h e p e rio d o f 2 \ years m ay be in creased if the new p la n t enables the existing fuel to be rep la ced b y one w hich is in b e tte r supply.

A p p lica tio n s fo r licences f o r new fuel-sav in g p la n t sh o u ld be m ade to th e secretary o f y o u r R egional Fuel Efficiency C o m m ittee (M in istry o f F u e l an d Pow er), w ho w ill co n su lt the R eg io n al P an e l of the Iro n fo u n d - ing In d u stry F u e l C o m m ittee in th e cases o f a p p lic a ­ tions received fro m iro n fo u n d ers.

T h e Iro n fo u n d in g In d u stry F u e l C o m m itte e c onsider th a t the fo llo w in g types o f p la n t a re th o se w hich m ay w ith m o st ad v an tag e b e c o n s id e re d :— (a) F o rced d ra u g h t e q u ip m e n t f o r the co n v ersio n o f existing n a tu ra l d ra u g h t d rying stoves; (b) p o rta b le m o u ld driers to rep lace fire-baskets fo r d rying larg e m o u ld s;

(c) w eighing m achines f o r cu p o la charges; (d ) p ro p e r stoves to rep lace fire-baskets fo r sh o p h e atin g p u rp o ses;

(e) co m p lete new d rying stoves to rep lace existing stoves o f obsolete type; (/) c o n tin u o u s core-drying stoves to rep lace sm all b atch -ty p e stoves; (g) com plete new cu p o la s o r cup o lettes to replace m elting p lan t, the cap acity o f w hich is f a r in excess o f req u irem en ts.

W o u ld an y new p la n t such as the ab o v e e n ab le you to save a larg e a m o u n t o f fu e l? Y o u r R egional P anel will h e lp yo u to decide w h e th er the fuel w hich w ould be saved w ou ld ju stify the in stallatio n .

C A T A L O G U E S RECEIVED

Surface Hardening Com pound. M o n ard , L im ited, o f G re en L an e, B raughing, H erts, hav e ju st issued a fo u r-p ag e leaflet w hich o u tlin es the advantages of M o n ard su rface h a rd en in g co m p o u n d ; gives in stru c­

tions fo r its use, an d c arries a price list.

Wire Straightening and Shearing M achine. A m ach in e, w hich consists o f a b rillian tly conceived m eshed, h o rizo n tally -d isp o sed plate arra n g em en t, so as to fo rm a sq u are cavity on closing, is described an d illu stra te d in a fo u r-p ag e leaflet received fro m the C o lem an F o u n d ry E q u ip m e n t C o m p an y , L im ited, W in d so r W o rk s, S to tfo ld , Beds. W ires an d ro d s u p to

§ in. dia. in serted betw een the tw o sets o f m anganese steel plates o r dies a re on closing m ade qu ite straight.

By a sim ple a d ap tatio n , involving changing the dies, the m ach in e can be used fo r the fo rm a tio n o f gaggers.

A gain an a tta ch m en t is p ro v id ed fo r con v ertin g it into a sh earin g m achine. T h e a ir co n su m p tio n is 4 cu b . ft. p er m in. in th e sta n d a rd m ach in e carry in g a 12-in. len g th o f dies. T h e p a m p h le t is av ailab le to o u r read ers on request.

F O U N D R Y DUST H A Z A R D S (C o n tin u ed fr o m p re v io u s page.)

safe w o rk in g specifications, a final d ecisio n o f w hich m u st be ta k e n by th e fo u n d rie s th em selv es in o rd er th a t the in d u s try be m a d e as a ttra c tiv e as its c o m p etito rs. T h e sta n d a rd s su g g ested by the A u th o rs a re , as d e te rm in e d b y th e O w e n ’s J e t D u st C o u n te r; (a) W h en the d u st c o n ta in s less than 50 p e r cent, o f fre e silica, th e av erag e e x p o su re over a co m p lete cycle o f o p e ra tio n s sh o u ld n o t exceed 500 p a rtic le h o u rs p e r cu b ic c e n tim e tre ,' an d (b) w h ere th e p e rc e n ta g e is h ig h er th a n 50 p er cent., then 200 is suggested.

S om e o f th e g e n e ra lisa tio n s e n u n c ia te d by the A u th o rs a re o f d istin ct in terest. T h e y reassert th a t th e h a z a rd is h ig h e r in steel fo u n d rie s than o th e rs in o th e r types; th ey dislik e sa w -to o th roofs fo r fo u n d rie s, an d p re fe r the M o n ito r o r Inverted M o n ito r types; th ey re c o m m e n d th e use o f vacuum clea n ers f o r rem o v in g a c c u m u la tio n s o f d u st from ra fte rs a n d th e like. W h a t im presses u s a b o u t the R e p o rt is th a t th e p ro b le m is laco n ically stated , and w h en this is d o n e th e so lu tio n is w ell w ith in reach.

T h is b o o k le t is issued fre e o f c h a rg e to A u stralian citizens, b u t n o d o u b t fo r im p o rta n t foundry o rg a n isa tio n s a n d in d iv id u a l firm s in this country, a few copies w ill be av ailab le. T h e ad d ress of th e D e p a rtm e n t is 129, S w an sto n S treet, M elbourne.

A u stralia.

M elting Plant. A leaflet received fro m the M ono­

m eter M an u fac tu rin g C o m p an y , L im ited , G re en Lane.

B raughing, H erts, illu strate s o n one side an open- h e arth ro cking a n d tilting fu rn a c e designed to operate on eith er gas or oil. A w ide range fro m 600 to 1.750 deg. o f o p e ratin g te m p e ra tu re is c laim ed , th u s m aking the p la n t a p p licab le fo r use as a rece iv er an d super­

h e ater f o r cu p o la m etal, o r as a co n tin u o u s melting fu rn ac e fo r a lu m in iu m a n d o th e r n o n -ferro u s alloys.

T h e reverse side p ictu res a h o t m eta l receiv er of the fo re h e a rth tilting ladle type. T h e cap acity range is from 1 to 3 tons.

Research on the heat-treatment o f grey cast iron d escribed by M . B a d e r in the “ A rc h iv fu r angew.

W issen. u. T e c h n ik ,” indicates th a t if the c a rb o n co n ­ te n t o f cast iro n is v aried betw een 3 an d 3.3 p e r cent, a n d the Si betw een 1.5 an d 2.5 p e r cent., a b o u t 0.7 to 0.9 per cent. C w ill be p resen t as F e c a rb id e , th e re­

m ain d e r being p re cip ita te d a s g ra p h ite in th e m atrix.

T h is m atrix will be p e arlitic to so rb itic in stru ctu re a n d possess the c h aracteristics of steel, e n ab lin g it to be h e at-tre a te d in a m a n n e r sim ilar to steel. In tern a l stresses in the cast iro n m ay be relieved by an n ealin g at a m ax im u m te m p e ra tu re o f 500 deg. C ., b u t if the a n n ea lin g p erio d is m ad e lon g er, the te m p e ra tu re m ay be re d u ce d to 250 to 300 deg. V a rio u s types of h e at- tre a tm e n t, w hich a re o u tlin ed in the P ap e r, m ay be em ployed.

M A Y I I , 1944 FOUNDRY TRADE JOURNAL 23

SHRINKAGE AND POROSITY IN LIGHT IRON CASTINGS*

Bearing o f varia ble factors o f casting o f metals on the occurrence o f shrinkage and porosity

By C. A. PAYNE

It is generally a p p rec ia te d th at the casting of any metal w hatsoever is a tte n d ed by a w hole h o st of variable facto rs, the m ajo rity of w hich c a n n o t be elim inated. T h e o b ject o f m etallu rg ical co n tro l is to hold each o f th e v ariab les w ith in such a n arro w range that the effects o f each are m inim ised, w ith a resulting closer ap p ro ac h to u n ifo rm ity an d consistency o f p ro ­ duction. N eedless to say, th e u ltim ate objective can be achieved only by th e closest a tte n tio n to detail of each stage o f the process.

Some of the p rin cip al fa cto rs affecting the p ro d u c ­ tion of castings, an d th eir in ter-rela tio n sh ip s, are set out in the “ fam ily tree ” o f the fo u n d ry process (Fig. 1). A few m in u te s’ study of the diagram will make its m eaning self-evident. It is th e object o f this Paper to draw a tte n tio n to som e o f the item s indicated in Fig. 1, p a rticu la rly in th eir b e arin g on the occurrence of shrinkage an d p orosity.

The definition o f shrinkage, fo r the p u rp o se o f this Paper, is the decrease in volum e o f cast iro n w hilst cooling dow n in the liquid state an d w hilst u n d e r­

going solidification. P o ro sity is m ore difficult to define concisely. It is to be co nsidered as the o ccu r­

rence of voids o r d iscontinuities w ith in the stru ctu re of the m etal (ranging fro m those large enough to be visible on frac tu re to m icroscopic defects), w hich by their presence lead to fa ilu re u n d er p ressu re tests.

Both these defects hav e th eir origin in th a t period of time w hich elapses b etw een the filling o f the m ould with m olten m etal an d the su b seq u en t co m p lete solidi­

fication of th a t m etal.

T he m ost co n v en ien t asp ect fro m w hich to view the variables th at com e u n d e r the head in g o f “ m etal ” is that of the eq u ilib riu m diagram . As the P a p e r deals with a very com plex alloy, nam ely c ast iron, the simplified p ictu re p resen ted by the iro n -ca rb o n o r a section o f the tern a ry iro n -carbon-silicon diagram (Fig. 2) can be o nly a sta rtin g p o in t an d n o t the complete story.

W ithout co nsidering this d iag ra m in detail, the following p oints are stressed. F irst, the liq u id zone in which the volum e o ccupied by a given w eight of the alloy will decrease w ith decreasing tem p eratu re, i.e., on cooling dow n w ithin this range, we get the purely liquid shrinkage. N e x t com e th e areas b o u n d ed by the “ liq u id u s ” line on th e u p p e r side, an d by the

“ solidus ” lines on the low er sides. In these areas, except a t the p o in t 3.7 p e r cent, carb o n , solidification takes place over a ran g e o f tem p era tu re, and the w ider the range th e g re ater the tendency fo r segregation to

* A P a p e r re a d b efore th e L incoln S ectio n o f th e E a s t M id lan d s B ran ch o f th e I n s titu te o f B ritish F o u n d ry m en , M r, J , H . B inglev p residing.

occur. In this zone occurs the solidification shrinkage, an d the final fo rm atio n o f such defects as internal p orosity, ex tern al shrinkage, cavities, blow holes arise.

T h e th ird zone is the shaded a rea in w hich g rap h itisa­

tio n occurs. It is to be no ted th a t ab o v e eutectic com p o sitio n this zone extends in to the liq u id zone (sep aratio n o f kish g raphite), b u t a t the low er range o f c arb o n it does n o t sta rt m uch above the “ solidus.”

In view o f the p resen t lim ited know ledge o f the actual detailed m ode of solidification of cast iron, this zone m u st be considered as a convenience o f p resentation ra th e r th an a q u a n titativ e statem en t of fact. Lastly, an d o f im p o rtan ce, in assessing th e effects o f graphitisa-

THE CASTIN6

DESIGN MOULOING MATERIAL

Fi g. 1.— Fa c t o r s Af f e c t i n g t h e Pr o d u c t i o n o f a Ca s t i n g.

tion, is the p o in t w hich show s the m axim um per­

centage o f c arb o n soluble in y iro n a t th e com pletion o f solidification. F u rth e r referen ce w ill be m ade to these po in ts la te r in th e P aper.

Contraction o f Cast Iron

F ro m th e n ext illu stratio n (Fig. 3) an idea is given o f the a m o u n t o f c o n tra ctio n during the solidification process. T h e iro n -ca rb o n diagram , as ap p licab le to w hite iro n s, is m atched against th e percentage c o n trac ­ tion, an d it is interesting to n o te th e sim ilarity in shape o f the tw o curves, p a rticu la rly the m inim um a t the eutectic p ercentage o f carb o n . T h is m eans in fact

24 FOUNDRY TRADE JOURNAL M A Y 1944

Shrinkage and Porosity

th a t fo r the least po ssib le sh rin k a g e a e u tectic co m ­ p osition is indicated. In the b o tto m p o rtio n o f the d iag ram th ere is o n a sim ilar scale th e shrinkage, changing in to a n ex p an sio n , as influenced by the sep a ra tio n o f g rap h ite. T h is curve is a very m uch idealised rep re se n tatio n , b u t cle arly indicates the influence o f increasin g g ra p h ite. T h e trip le row o f figures atta ch in g to this p a rt o f th e d iag ra m brin g s o u t the re la tio n s h ip o f c a rb o n an d g ra p h ite in the p resence o f 2 per cent, silicon, u n d e r the stip u la ted conditions

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g r a m ( Gr e i n e r, Ma r s h a n d St o u g h t o n,

Mo d i f i e d).

th a t the coo lin g ra te resu lts in eq u ilib riu m , an d th a t all the c a rb o n in excess of th a t so lu b le in the austenite (1.5 p er cent. C fro m Fig. 2) is as grap h ite. T h e p ercen tag e o f g rap h ite given is th a t existing a t this p a rtic u la r tem p e ra tu re, an d will be fu rth e r increased by se p a ra tio n o f c a rb o n fro m the sa tu rate d au stenite as cooling proceeds below th e solidus. D ep en d en t u p o n th e cooling ra te below th is p o in t, th e u ltim ate g rap h ite c o n te n t w ill be som e 0.6 to 1 p er cent, h igher. T h is is tak en b y w eight. T ak in g the p ro p o rtio n b y volum e, it is quick ly realised w hy this d e p osition o f g rap h ite causes such a m ark e d change in th e p ro p erties o f cast iro n . T h e expression “ C + 0.3 Si ” gives the effective c a rb o n c o n te n t fo r given analyses, w here C is the

a ctu al to ta l c arb o n an d Si is the silicon co n te n t. If th is c o rre c tio n be m ad e to the c a rb o n p e r cen t, figures given it will be fo u n d th a t th ey a re scaled off to m atc h the c arb o n c o n te n t in th e u p p e r p a rt o f the diag ram . W hen th in k in g in term s o f the iro n -carb o n d iag ram alo n e, it is alw ays n ecessary to m ak e such a c o rre c tio n fo r th e silicon c o n te n t o f th e p a rtic u la r cast iron u n d e r discussion.

C o n sid erin g these tw o d iag ram s fro m the practical aspect, th e c o n clu sio n is re a c h e d th a t, as regards solidification sh rin k ag e a n d m in im u m o p p o rtu n ity for segregation, th e m o st su itab le c o m p o s ito n to w ork to w ou ld be th at of the eu tectic. In p ra ctic e it is an u n c ertain business to re ly o n the expansion d u e to g ra p h ite in co m p o sitio n s above the eutectic, fo r this g ra p h ite m ay com m ence to p re cip ita te (as kish ) w hilst the iron is m o lten , a n d its effects o n th e a c tu a l solidi­

fica tio n z o n e a re thus c o n sid era b ly reduced.

F u rth e rm o re , th e so lidification o f such iron in v ary in g sections re su lts in v ery variable g ra p h ite stru ctu res, a n d is to b e considered too u n re lia b le fro m a p o in t o f soundness.

W h ere th e d esired test resu lts are the m ain fa c to rs, th a t is, w hen castings are re q u ire d in a h ig h -d u ty iro n , the extent to w hich th e c o m p o s itio n c a n fa ll below the e u tectic is co n tro lled by circum stances affecting coo lin g ra te s fo r graphitisation an d m ac h in ab ility , the need fo r feeding or use o f denseners to o v erco m e th e differential solidification d u e to th e w id er ra n g e between liq u id u s a n d solidus. I n the m ain , the bulk of light iro n c astings ra n g e fro m 2.0 to 2.5 p e r cent, silicon a n d 3.2 to 3.5 p er cent, carb o n , the stro n g e r g rades o f iro n being on the low er lim its fo r b o th c arb o n and silicon.

A n o th e r th in g to be ta k e n in to account w ith iro n s in th e lo w e r effective carbon ranges is th e in cre ase in tem p eratu res at w hich so lidification com m ences. O n e hears o ften th a t these iro n s a re difficult to pour because o f th e ir “ sh o rte r freezin g range.”

A single glance a t the d iag ra m in Fig. 2 will show th e rev erse to b e the case. A

“ sh o rte r p o u rin g ran g e ” is the better term , in d icatin g th e ra n g e b etw een tapping te m p e ra tu re a n d the m in im u m tem perature giving freed o m fro m m is-ru n n in g . It is this range th a t is decreasing, n o t the solid ificatio n range.

T h e q u e stio n of p o u rin g tem p e ra tu re s is one o f very g re at in terest, a n d the b ib lio g ra p h y o f the subject issued by the B .C .I.R .A . gives m u ch fo o d fo r thought in this direction. U n fo rtu n a te ly m u ch co n fu sio n is caused by the loose e m p lo y m en t o f the term hot a n d co ld as a p p lied to p o u rin g te m p e ra tu res It is not sufficient even to give a ctu al tem p e ra tu re values for these m ust be am plified by referen ce to such facto rs as section thickness, w eig h t o f casting, gating relative to sectional changes, the p ro v isio n , if any m ade for feeding an d the chem ical co m p o sitio n an d tV D e o f irons being used. T a k in g in to a cc o u n t the casting

M A Y I I , 1944 FOUNDRY TRADE JOURNAL 25 design a n d the m eth o d of m o u ld in g , w ith a given

co m p o sitio n o f iro n , the h o tte r th e p o u rin g te m p e ra ­ ture, the g re ater p ro v isio n sh o u ld be m ade fo r feeding.

F irst, th ere is a decrease in volum e in the liq u id state, this being increasingly im p o rta n t w ith increasing size of casting. It m u st n o t be o v erlooked, how ever, th a t with m any o f the sm aller-sized a u to m o b ile castings, particu larly in m u ltip le p a tte rn m oulds, th e volum e of m etal in the m o u ld is sufficient to reflect this volume change. T h en , due to increased tem p eratu re of the m o u ld , solidification in the h eav ier sections tends to tak e place m ore slow ly, giving tim e for segregation an d fo r “ self feeding ” o f th e earlier freezing sections. W ith hig h -d u ty iro n s— the inoculated types p a rticu la rly — h ig h er p o u rin g tem p eratu res are usual to get th e b est resu lts in p h ysical p ro p erties, as well as ensuring in m an y cases, m ac h in eab ility and freedom fro m m is-ru n n in g in the lig h ter sections.

Less Shrinkage

W ith the h ig h er silicon, h igher c a rb o n irons, there is less sh rin k ag e to cope w ith a n d a som ew hat low er

Fi g. 3 .— Ef f e c t o f Ca r b o n a n d o f Gr a p h i t e o n So l i d i f i c a t i o n Sh r i n k a g e.

liquidas tem p e ra tu re. W ith such iro n s the principle of flash gates into th in sections w ith the heavier sections if “possible in the drag, an d generally very little provision fo r feeding, is com m o n ly em ployed. W ith ru n n er system s o f th is k in d it is im p o rta n t th a t their sensitivity to v ariatio n s o f p o u rin g tem p e ratu re and m etal com p o sitio n s sh o u ld n o t be overlo o k ed , n o r sh o u ld slow ru n n in g , p er se, be considered as synonym ous w ith progressive solidification. In this system the lo catio n o f the gates is the p rim ary c o n ­ sid eratio n . the size o f gates being determ ined by the section o f the casting m e ta l com position, an d desirable p o u rin g tem p e ra tu re.

T w o o th er p oints to b e m en tio n ed befo re leaving

the su b ject of m etal, are the effects o f the type of grap h ite fo rm atio n , an d o f th a t recen tly m uch- publicised elem ent, p h osphorus. W ith reg ard to the g rap h ite fo rm atio n , the classical investigations o f N o rb u ry an d M o rg an into the occurrence an d m ethods o f p ro d u ctio n o f super-cooled g raphite stru ctu res have estab lish ed th eir p ecu liar p ro p e rty o f alm o st com plete freed o m fro m p o ro sity in considerably w ider ranges o f c o m p o sitio n th a n is perm issible w ith an iro n giving a n o rm al flake grap h ite stru ctu re. T his w ould seem to be due in great m easure to the difference in th e time o f p recip ita tio n o f graphite. In the case o f norm al flake g rap h ite structures, it is highly p ro b a b le th at the fo rm atio n o f grap h ite is spread over a considerable p o rtio n o f the solidification period, so th a t the ex p an ­ sion due to g rap h ite a t an y given p o in t o f tim e m ay n o t be v ery effective in c o u n terb alan cin g the shrinkage

cAfteo* - -

Fi g. 4 .— T . C . a n d Si Re q u i r e d t o Ob t a i n So u n d n e s s w i t h Va r y i n g P Co n t e n t s (B.C.I.R.A .).

o f the iro n , p articu larly in the case o f v ariab le section thicknesses, w here solidification takes place at different tim es in different p a rts o f the casting. W ith the fine g rap h ite stru ctu re, how ever, this sep a ratio n occurs at a low er tem p e ra tu re th an n o rm al, solidification o f the u n d erco o led iro n being extrem ely ra p id an d g rap h itisa­

tio n v irtu ally instan tan eo u s. A s a result o f this sudden g rap h itisatio n , an intense pressure is set u p ifi the in te rio r o f the m eta l due to the increasing volum e req u ired to accom m odate the graphite.

T h is u n d erco o lin g can be achieved in m o re ways th a n o ne; the B.C .LR .A . titan iu m a n d C O . trea tm e n t being ap p lied a fte r tap p in g in the ladle: or by m e use o f m o u ld s o f h ig h th e rm a l conductivity fo r casting

2 6 FOUNDRY TRADE JO URNAL M A Y I I , 1 9 4 4

Shrinkage and Porosity

irons of su itab le com p o sitio n . T h is latter m eth o d has the m erit o f being a p p licab le to cu p o la m elted cast iron, a p o in t u p o n w hich th ere is som e d o u b t w ith regard to the T i a n d C O . trea tm e n t. T h is difference in g rap h ite fo rm a tio n p roduces a p ro n o u n c e d differ­

ence in frac tu re, th a t o f the su p er-co o led iro n being lustreless, d ark grey to black in a p p ea ran c e, as against the b rig h te r “ crystalline ” fra c tu re o f the n o rm al g rap h ite iron.

Influence o f Phosphorus

P h o sp h o ru s is an elem ent w hich h a s a m a rk e d effect up o n th e solidification o f iro n -ca rb o n alloys. In b rie f it low ers th e in itial freezing p o in t som e 30 to 40 deg.

C. fo r 1 per cent, of p h o sp h o ru s, an d th e final solidification tem p e ra tu re o f an y free p h o sp h id e co n ­ stitu en t th a t fo rm s is in the reg io n o f 960 deg. C.

As does silicon, p h o sp h o ru s low ers the c arb o n c o n te n t

Fi g. 5 .— Ty p i c a l Ex a m p l e s o f De s i g n Li a b l e t o Pr o d u c e De f e c t s.

of the eutectic by a p p ro x im ate ly 0 .1 per cent, fo r each 0.3 per cent, p h o sp h o ru s. (N ote: tak in g 4.3 per cent, c a rb o n as eutectic p o in t fo r iro n -ca rb o n alloys, w ith 2 per cent, silicon this is red u ced to 3.7 p er cent., an d w ith 2 per cent, silicon and 1 per cent, phosphorus there is a fu rth e r re d u ctio n to 3.4 p e r cent.). T h e influence o f p h o sp h o ru s on the solidification te m p e ra ­ ture is the basis fo r the im proved fluidity o f p h o s­

phoric irons. But, ow ing to the w ider in terv al betw een the beginning a n d th e end o f solidification, th ere is the increased o p p o rtu n ity fo r th e segregation o f the low er m elting p o in t co n stitu e n ts to the last areas to solidify, an d fo r the “ self-feeding ” in w hich the th in n er, m o re quick ly fro zen , sections of the casting w ith d raw liquid m etal fro m the heavier, m o re slowly cooled, sections. A m ong the v arious pu b licatio n s upon the effect o f p h o sp h o ru s, the B .C .I.R .A . give

th eir o p in io n o n the m odifications to be m ad e to c a rb o n a n d silicon w ith vary in g p h o sp h o ru s co ntents in o rd e r to achieve soundness a n d to m ain tain satis­

fa cto ry phy sical p ro p erties. T h is in fo rm a tio n is given in g rap h ic fo rm in Fig. 4. T h e c o n clu sio n to be draw n fro m this g rap h is th a t to ach iev e the sam e resu lts w hen m od ify in g the p h o sp h o ru s c o n te n t, co m ­ p en satio n m u st be m ad e in th e a m o u n t o f e ith e r or b o th c a rb o n a n d silicon.

It is to be u n d e rsto o d a n d a p p re c ia te d th a t very m an y go o d castings fro m a ll sorts a n d sizes o f pattern s, h ave been p ro d u c ed in a v ery w ide ra n g e o f p h o s­

p h o ru s c o n ten t. T h e re is, h o w ev er, a class o f w ork w hich is m o re difficult to m ak e p e rfe c tly so u n d in the higher p h o sp h o ru s iro n s. T h e c h ie f ch ara cte ristics of this class a re sudden ch an g es o f section thickness, usually (w ith lig h t castings) in the fo rm o f c o m p a ra ­ tively large bosses ad jo in in g th in w alls, freq u en tly

inaccessible fo r the a p p lic atio n o f feeders. O ften, too, th e design o f the casting re su lts in h o t spots, w here p rojecting tongues o f sa n d a re h e ated u p by th e m etal to such a n ex te n t th a t th ey , in tu rn , delay the cooling o f the casting in the n e ig h b o u rh o o d o f the sand p ro ­ jections. A fu rth e r fa cto r is the d em an d th a t m any castings w ith these fe atu res o f design sh all w ithstand high, fluid, o r a ir p ressu re a fte r m ach in in g . Some typical sections are show n in Fig. 5.

Influence o f D esign

T he design of a casting is a m atte r o f the g reatest im p o rtan ce to the fo u n d ry m a n as w ell as to the user W ith o u t d o u b t, the m o st satisfacto ry design is th a t achieved by the intelligent co -o p era tio n o f these two parties. T o this e n d the fo u n d ry sh o u ld kn o w clearlv the inten tio n of. an d the lim itatio n s im posed by o th e r

M A Y h, 1944 FOUNDRY TRADE JOURNAL 27 circum stances of m an u fa ctu re upon, the designer. In

tu rn the designer sh o u ld be aw are o f the scope and the lim itatio n o f the fo u n d ry science an d a rt, b u t fo u n d ry m en can h a rd ly hope fo r this unless they are fully aw are o f the latest know ledge an d d evelop­

ments in th eir ow n field. As a re su lt o f fo u n d ry m en ’s endeavours, m an y test-pieces have been evolved fo r the fu rth er investigation o f sh rin k ag e an d p o rosity. F o u r representative test-pieces are illu stra te d in Fig. 6. O f these, the tw o larg er a p p ro a c h the su b ject m o re from the angle o f volu m e changes in u nfed b ulk of m etal, with fairly sym m etrical coo lin g ; an d the o th er, sm aller, test-pieces are m o re directly re la te d to th e effects of abrupt, sectio n al changes, w ith corresp o n d in g ly different solidification ra te s in the differing sections.

The a u th o r’s ideas on the m a tter w ere based on the ruling p ro b lem as it a p p ea red to h im ; a c o m p a ra ­ tively heavy boss, usu ally unfed, b u t req u irin g to be sound, ad jo in in g a change o f thickness. T h e th in n er section o f this test-piece is a useful guide to any chilling tendency. F u rth e r, as this casting is o f sm all

Fi g. 7 .— Su r f a c e De f e c t s Re l a t e d t o Ru n n i n g Co n d i t i o n s.

size, it is a c o m p arativ ely sim ple jo b to section it and to polish the c u t surface.

M o u l d i n g

In q u a n tity p ro d u c tio n o f light castings, generally, the type o f iro n to be used is determ in ed by the design, service req u irem en ts, an d the supplying in a com petitive m ark e t, an d u sually the choice is restricted to a sm all n u m b er o f stan d ard ised mixes. M etal, or sim ilar, p e rm a n en t lay o u ts o f p a tte rn p la n t a re de­

m anded; an d the p ro b lem s a re to decide up o n the m ost satisfacto ry m eth o d of running, an d of feeding, if an d w here necessary, to give soundness; to m a in ­ tain close dim ensional to lerances; to en su re freedom fro m m is-running in the thin n est sections (p a rticu la rly w ith the low er c arb o n , low er silicon type o f high-duty iro n )' lo catio n an d su p p o rtin g of cores; to give b ut a very sh o rt list. M ou ld in g m ate ria l is generally green sand, an d v ariatio n s in this m aterial have a p ro fo u n d

effect upon the results, adding to the fo u n d ry m an 's problem s.

It is a t this stage th a t the in fo rm atio n to be gained fro m such test-pieces as indicated is of inestim able value. T h e m eth o d of o btaining the in fo rm a tio n can be varied, but, b ro ad ly speaking, two a p p ro ach es are av ailable. F ro m daily sam ples over a long period, by a c o rre latio n of the reco rd s of all the observed c o n ­ ditions hold in g fo r each sam ple, a critical analysis of the d a ta w ill indicate the influence o f the m ajo r variables. A lternatively, by a series of tests in which, as closely as possible, all facto rs are h eld constant, b ut the one w hose effect is to be determ ined, a m ore detailed know ledge o f the influence of these m ajo r variables can be obtained. T h e two m ethods are really co m p lem en tary , fo r the one m ethod can be em ployed to verify, or m odify, the opinions derived fro m th e study o f the results obtain ed with the o th er m eth o d . In an y case, the final arb iter is alw ays the soundness o r otherw ise o f the general casting p ro ­ duction.

Fi g. 8 .— Sh o w i n g In f l u e n c e o f Ph o s p h o r u s o n Se v e r i t y o f De f e c t s.

Isothermal Studies

In o rd e r to u n d erstan d the resu lts o b tain ed w ith the a u th o r’s test-piece m ore clearly, it w as necessary to get som e idea o f the v ariatio n s in solidification rates in the differing sections. T his w as done b y sketching isotherm als fo r b o th casting and the m o u ld surface, at various stages o f the cooling. C o n firm ato ry evidence was so u g h t by knocking o u t test-pieces a t short intervals a fte r casting, an d th en break in g th em up.

A ny resid u al liquid m etal gave obvious indications during the b reakage, and fro m ex am ination o f the fractu res when cold, the final picture was constructed.

T ak in g the case w hen the boss w as u p p e rm o st, the casting being flash-gated at the thin end, solidification com m ences w ith a th in cru st w here the m etal contacts the sand surface on the b ottom , on the sides o f the steps an d over the top o f the thicker step, the cru st thickening ap p recia b ly as the boss fills up. T he sam e applies in the boss, the cru st form ing w ithin a very