Monthly Journal of the Institute of Metals and Metallurgical Abstracts, Vol. 3, Part 6

The Monthly Journal o f the

INSTITUTE OF METALS

and

METALLURGICAL ABSTRACTS

CONTENT-

Institute News and Announcementsf-QL/TECHvip- •

737. A N o te on the Influence of Salt-Bath H e a t- T rea tm e n t on the Corrosion- Resistance of D u ralu m in Sheet. By A. J. Sidery and B. Evans

Notice to Authors of Papers

738. A F u rth e r Stu d y of the C on stitu tio n of th e C ad m iu m -Tin A lloys. By D. Han­

son and W . T. Pell-Walpole Author Index to Abstracts

M eta llu rg ica l A b stracts 293 255 257

259 266

267 291

JU N E 1936

C o p y rig h t Entered a t S tatio ners Hall

TRADE MARK

THIS COPPER-SILICON-MANGANESE ALLOY IS N O W AVAILABLE AS A BRITISH PRODUCT • • • •

“ E V E R D U R ” (i.cjmMd e‘a%Ltd.) offers these outstanding advantages

0 Strength equal to that of steel

• Remarkable corrosion resistance

• High fatigue lim it

• W e ld s readily by all usual methods

• Makes unusually sound castings

• Excellent machining qualities

• Easily w orked hot o r cold

• Com paratively inexpensive

The booklet “ Everd u r,” in addition to giving furth er details of these properties, also contains valuable information relating to applications and physical characteristics.

“ Everd u r” is available as sheet, strip, tube, rod, plates, w ire, in all sizes, and also in the form of casting ingots.

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

IM PERIAL CHEM ICAL INDUSTRIES LTD.

D E P T . M9, IM P E R IA L C H E M IC A L H O U S E , L O N D O N , S . W . I P lease send a copy o f the “ E v e rd u r " booklet

Name... ...

A d d re ss...

Pr i n t e d i n Gr e a t Br i t a i n b y Ri c h a r d Cl a y a n d So n s Lt d., Bu n g a y, Su f f o l k

¿ e

/ L

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o f 1

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From our wide ran g e we are able to supply refracto ry m a t­

erials o f high quality suitable fo r m ost industrial purposes.

In our various works, which a r e m o d e r n in d e s i g n a n d equipm ent, c a re is tak en in every s t a g e o f m a n u fa c tu re to ensure t h a t our products are m a i n t a i n e d a t a u n i f o r m l y

high stan d ard .

F or f u l l e r p a r ticu la rs, ask f o r o u r P a m p h let, No. 1.

m N Y B R I D C E

SCOTLAND

HEAT-TREATED CASTINGS

JJEAT-TREATMENT has come to stay. Where the necessary plant is available this process, by sub­

stantially adding to the strength of the metal, enables castings to be designed with thinner sections for any required strength and stiffness.

No. 5 alloy is probably the cheapest and simplest heat-treatable alloy available. It is widely used for cylinder heads and similar applica­

tions where stiffness at elevated temperatures is needed.

Prices, properties and information on correct heat-treatment on application to the Company, R ef : DEV.

The BRITISH ALUMINIUM Co.ltd.

HEAD OFFICE: ADELAIDE HOUSE. KING WILLIAM STREET, L0ND0N.E.C.4.

Telephone•• Mansion House 5561 £ 8 0 7 4 (Stines), telegrams: CRYOLITE, BILGATE. LONDON.

LON DON W AREHOUSE: BIRMINGHAM.4 : MANCHESTER. 3 ; LEEDS. 3 - BRISTOL, I NEW CASTLE-ON'TYNE. I : GLASGOW, C2=

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METAL MELTING

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AJAX-W YATT INDUCTION A JA X -N O R TH R U P INDUCTION EFCO HORIZONTAL ARC EFCO ROCKING RESISTOR CASTING EQUIPMENT

Enquiries to EL EC T R IC FU R N A C E C O M P A N Y LIM ITED

H E A T I N G

H EAT TREATMENT OF FERROUS AND NON-FERROUS METALS BRIGHT A N N EA LIN G

EN AM ELLIN G

FORCED AIR FURNACES

Enquiries to EL EC T R IC R ESIST A N C E FU RN A CE C O . LTD.

EFCO

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T E L E P H O N E S , A B B E Y 4171 (5 lin es) T E L E G R A M S , E L E C F R IF U R , P H O N E / L O N D O N L in d u m iv

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IN T U B E S , R O L L E D M E T A L S , E X T R U D E D BA R S, W IR E ,

Etc.

9 or all purposes where strength with lightness i s essen tia l.

JAMES BOOTH £ COMPANY

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Ve/ephoneEAST 1221 (Pte.8ch.Ex). 7e/egrams:’Booth, Birmingham' Codes:A.B.C.5tht6th. Ed. Lieber's 5 Letter. B en tleys Second Phrase.

W e s te rn U n io n

D U R A L U M I N

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

D a ALLO Y

ELEKTRON, etc.

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

ALLOYS

For the economical production of tubes with absolutely uniform wall thickness we supply

T U B E E X T R U S I O N P RES S E S

of vertical o r horizontal type, also the required pow er w a ter plants consisting of pressure pumps and accumulators, the latter of the electrically controlled, com­

pressed-air loaded ty p e w ith o u t anypistons o r floats, for which the H Y D R A U L IK Co.

owns patents in all countries of the w orld.

B ritish A g en ts: Aabacas Engineering Co., Ltd., 10Canning Place, Liverpool, I

THE GAS INDUSTRY

- A N INDEX TO TRADE RECOVERY

THE yearly statistics pu b lish ed b y the gas industry are a useful guide to the state o f trade in this country.

W h e n times are bad and factories are closed d o w n or n o t w orkin g fully, the sales o f gas to industry are low , rising as industrial prosperity returns.

T h e marked increase then during the last year in the industrial sales o f gas is a reliable p oin ter to better times ahead. It n ot on ly shows w h ich industrial centres have b een quickest to shake o ff the depression o f the last few years, b u t affords evid en ce to o o f the m ov em en t o f trade from on e district to another.

In 1934, fo r instance, 56 per cent, o f the total gas sold in S h effield was b o u g h t fo r industrial purposes ; last year the percentage had risen to n o less than 62. R oth erh a m can show equally striking figures, w hile in­

creases in the am ou nt o f gas taken b y industries in alm ost every im port­

ant tow n in Lancashire reflect the healthier co n d itio n o f that C o u n ty ’ s trades.

A similar story is told b y recent statistics from the busy m an ufac­

tu r in g c e n tr e s in th e M id la n d s . C oven try , the h om e o f m otor-car m anufacture and a huge con su m er o f gas, show s a rise in the percentage o f gas sales to industry during the last tw o years o f from 30 to 3 5; in D erb y the corresp ond ing percentage in 1934 was 28, w h ich rose to 35 in the year that has just c lo s e d ; Stoke- u p on -T ren t and the Potteries, W e s t B rom w ich, Sm ethw ick, Leicester and W o lv e rh a m p to n also show that, w ith increasing prosperity, trades o f all kinds turn to the gas industry to supply them w ith a fuel suitable for m od ern m ethods o f m anufacture.

Industries in all these tow n s b ou g h t last year a fifth o f m ore o f the total gas sold.

T h e M o v e S ou th w ards A sharp rise in the industrial sales o f m any gas undertakings in or near L o n d o n show s that the trend o f industry southwards con tin ues. In the areas cov ered b y the W a tfo rd and

Increase o f gas sold fo r industrial p urposes b y on e large gas com p an y.

M aidstone gas undertakings the p ro ­ p o rtion o f sales fo r industrial pur­

poses last year was approxim ately d ou b le the 1934 figure, rising in the form er case from 9 to 17, and in the latter from 8 to 17 per cent. A t S lough the percentage has increased from 28 to 32, alm ost a third o f the total annual sales o f gas n o w going to industry; w hile in L o n d o n itself, the tw o largest gas undertakings disposed o f alm ost one-tenth o f their total annual sales last year to trades o f var­

ious kinds, and on e-fifth o f the yearly sales o f a third L o n d o n undertaking n o w go to industry.

Issued by the British Commercial Gas Association, 2 8 Grosvenor Gardens, London, S .W .l.

N E W !

A L U M I N A L A B O R A T O R Y

W A R E THE THERM AL SYNDICATE LTD.

Established over thirty years

Head Office and W o r k s :

W A L L S E N D - O N - T Y N E

London depot: Thermal House, 12-14 Old Pye St., Westminster, S.W.1

Alum ina W a r e (99-9% A l20 3) is suitable for w o rking tem peratures up to 1950° C. and is highly resist­

ant to fused metals, oxides, and salts. Tubes, crucibles, boats, and o th e r vessels w ill be found invaluable in metallurgical and ceramic w o rk at high tem peratures.

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THE IDEAL ZINC-BASE DIE-CASTING ALLOYS

The various grades of “ M azak ” are manufac­

tured accurately to patented formulae. A dvice w ill be gladly given as to the alloy best suited to any p articu lar problem .

“ M a z a k ” alloys are made only by N ational A llo ys Lim ited .

N A T I O N A L A L L O Y S L I M I T E D

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P H O N E : METropolitan 9252

SO LE SELLIN G A G E N T S: m o r r i s a s h b y l t d . , 1 7 L a u r e n c e p o u n t n e y L A N E , L O N D O N , E . C . 4

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Catalogues and Quotations from :

E. LEITZ (LONDON)

20 Mortimer Street, London, W.1

%

S IE M E N S

E L E C T R I C F U R N A C E S

with

F O R C E D A I R C I R C U L A T I O N

The powerful circulation of heated air over the charge ensures a high degree of tem­

perature uniformity and entirely prevents local overheating. The Siemens-Betz fan used in this furnace has an efficiency of over 70% and can circulate the air in either direction.

A d vt. of Messrs. Siemens-Schuckert (G re a t B rita in ) Ltd.,

Offices and W o r k s : G re a t W e s t Road, Brentford, Middlesex. Tel.: Ealing 1171.

Branch Offices and Agents: Glasgow, Newcastle-on-Tyne, Manchester, Sheffield, Birmingham.

THE INSTITUTE’S LIBRARY

"Donations o f any o f the under-mentioned would be welcomed to complete the Institute’s files :

Encyclopedia Britannica

(latest issue).

Searle, Alfred B. “Refractories” (latest edition).

“Brass W orld.”

Volumes 2- 6.

Metallurgical and Chemical Engineering (Chemical and Metal­

lurgical Engineering).

Volumes 1 2- 1 4 ; Volume 1 5 , Nos. 1 - 8, 10 - 1 2 ; Volume 16, Nos. 1 , 2, 4 ; Volume 1 7 , N o. 6 ; Volume 18, N o. 1 ; Volume 20, N o. 9 ; Volume 2 1 , N o. 1 1 .

Mineral Industry.

Issues since 1932 (incl.).

Foundry Trade Journal.

Volumes 1 - 25.

Journal o f the Electroplaters’ and Depositors’ Technical Society.

Volum e 1 .

Journal of the Iron and Steel Institute.

Volumes 1 - 1 5 .

Journal o f the Russian Physico-Chemical Society. (Chemical Part.)

1930, Volume 62, Part 4 .

Metallwirtschaft.

Volumes 1 - 5.

Mitteilungen aus dem Kaiser-Wilhelm-Institut fü r Eisenforschung zu Düsseldorf.

Volumes 1 - 10.

Proceedings o f the Institute of British Foundrymen.

19 1 6 - 1 7 . (Volum e 1 0 .)

Revue de Métallurgie.

Volume 1 .

Transactions of the American Electrochemical Society.

Volumes 1 -3 and Volume 1 1 .

Transactions of the American Foundrymen’s Association.

Volumes 1 - 1 5 , 18- 27 incl.

Transactions of the American Institute of Metals (American Brass Founders’ Association).

Volumes 3- 5.

Transactions of the American Society for Steel Treating.

Volume 1 3 . XÜ

£ F A B R IC A T E YOUR PRODUCTS IN

C le a n a n d a ccu ra te p r e s ­ sin gs a n d a ttra ctive p a n els c a n b e p r o d u c e d fro m a lu m in iu m a n d a lu m in iu m a lloys.

W h e r e lig h t w e ig h t, resist­

a n c e to c o r r o s io n a n d at­

tra ctiv e a p p e a r a n c e a re im p orta n t, a lu m in iu m is the id e a l m etal. It is easy to fa b r ic a te a n d m a in ta in a n d N o rth e rn A lu m in iu m C om ­ p a n y has a r a n g e o f a lloys w ith strengths fr o m 5 tons/

sq. in. to 2 9 tons/sq. in.

A L L O Y S A V A I L A B L E

NA. 2S . . NA. 3S NA. 4S . NA. 17ST

etc.

N O R T H E R N A L U M I N I U M CD L T D

BUSH HOUSE, ALDWYCH, LONDON, W.C.

T e le p h o n e : T E M P L E B A R 8844 (10 lin e s ).

And at BIRMINGHAM, MANCHESTER, BRISTOL and GLASGOW

M .I2 -

THE UNIVERSITY OF SHEFFIELD

FACULTY OF METALLURGY

P rofessor . . . J . H. A N D R EW , D.Sc.

T

H E D epartm ent o f M etallu rgy, situated in th e cen tre o f the steel industry, is specially equ ipp ed fo r in stru ction in the M etallu rg y o f Iron and Steel, N on -ferrou s M eta llu rg y and F ou n d ry Science. T h e cou rse exten ds o v e r th ree years fo r th e Pass D egree o f B.Met., and fo u r years fo r th e D egree w ith H on ou rs. T h e labora­

tories in clude a th o r o u g h ly equ ipp ed fo u n d r y fo r Iron and Steel and N on -ferrou s M e ta llu rg y ; and all facilities fo r heat-treatm en t are provided. T h e research la boratories are equ ipp ed f o r therm al, m icrograph ical, m agn etic and m ech an ical in vestigation o f metals, and fo r X -ra y analysis. T h e re is also a large-scale plant fo r the co ld -w ork in g o f m etals. T h e D epartm en t also includes a special la b ora tory fo r the testin g and in vestigation o f r e fra cto r y m aterials.

T h e h igh er degrees o f M .M et., D .M et., and Ph.D. are aw arded. A p p li­

cations fo r adm ission sh ou ld be m ade to the Professor.

W . M . G IB B O N S , R e g is tr a r .

" A E R A L "

ALUM INIUM CASTING ALLOY

The following are particulars for all existing B.S.I. and.

D.T.D. specifications which call for a definite elongation.

B.S.I. D.T.D. A E R A L

3L5 4L 11 L33 I33B 165 231 240 264 272 294

Ult. Tensile Strength, tons/sq. in. 9 7'5 I0'5 II 9 10 II 12 II

14

0-1 percent. Proof Stress . .3-5 3-5 3'5 75 5 3 6 4-5 8 11 Elongation per cent, on 2 in. . 2 I -5 5 2*5 3 5 l ‘5 2 2

3

WILLIAM MILLS LTD.

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SLOUGH

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• Bring your reference library up to date • • •

A copy of our new Catalogue with details of Britain’s finest Precision Balances and Weights gladly sent free on request to any industrial or educational laboratory. Please state whether interested in Chemical Balances, Assay Balances, or both.

Founded in London, 1849.

L. OERTLING Ltd., 65 HOLBORN VIADUCT, LONDON, E.C.1

XV ^{TAS/On. 12 3}

INDEX TO ADVERTISERS

JU N E , 1 9 3 6

PAGE PAGE

Anglo-American Oil Co., Ltd. — Incandescent Heat Co., Ltd. —

Avery, Ltd., W . & T. — International Tin Research Council — Bausch & Lom b Optical Co., Ltd. — Johnson, Matthey & Co., Ltd. . xviii Birmingham Electric Furnaces, Ltd. xvii Leitz, E. (London) . X

Bolton & Sons, Ltd., Thomas . — McGraw-Hill Publishing Co., Ltd. — Booth & Co. (1915), Ltd., James V McKechnie Bros., Ltd. xxi British Aluminium Co., Ltd., The iii Martin, W . E. & Co., Ltd. — British Commercial Gas Assoc., The vii Mills, W i n , L td . . xiv British Metal Corporation, Ltd., The xxi National Alloys, Ltd. ix British Oxygen Co., Ltd., The . — Northern Aluminium Co., L td. . xiii Carborundum Co., Ltd., The ^— Norton Grinding Wheel Co., Ltd. ^—

Consolidated Tin Smelters, Ltd. ^— Oertling, Ltd., L. X V

Demag A.G. . . . . ^— Pearson, Ltd., E. J. & J. . ^—

Electric Resistance Furnace Co., Ltd. iv Priestman, Ltd., T. J. X X

Fordath Engineering Co., Ltd. . — Ratcliff (Metals) Ltd., J. F. xvi

Foster Instrument Co. — Siemens-Schuckert (Gt. Britain) Ltd. xi

Foundry Services, Ltd. — Stein & Co., Ltd., John G. ii

General Electric Co., Ltd. — Sterling Metals, Ltd. viii

Griffin, Chas., & Co., Ltd. — Stewarts and Lloyds, Ltd. —

High-Duty Alloys, Ltd. . X V Thermal Syndicate, Ltd. . viii

Hilger, Ltd., Adam — University of Sheffield xiv

Hydraulik G.m .b.H . vi Wild-Barfield Electric Furnaces, Ltd —

I.C.I. Metals, Ltd. . xxii Zeiss (London), Ltd., Carl —

A D V A N T A G E S :

• A remarkable smoothness and brightness.

• Exact to width and free from burr.

• A smooth close grain of maximum tenacity.

• Perfectly flat and of exact temper.

Specify LUSTER Rolled Metal for the sake of economy and good quality.

J. F. RATCLIFF (METALS) LTD., NEW SUM M ER S TR EET, BIRMINGHAM

Telephone: Aston Cross 3576/7 Telegrams: “ Rodent, Birmingham.”

x v i

T h e photograph shows a B I R L E C b e lt co n veyor furnace installed a t T h e R enold & C o v e n try C hain Co. L td . fo r bright annealing cycle parts continuously.

This typ e o f B I R L E C brig h t annealing fu rnace is availa b le for a v e ry w ide range o f w o rk , including ferrous and non-ferrous blanks, pressings, sheets, strip , etc.

Y o u a re invited to let B I R L E C engineers investigate yo u r ind ivid ual pro b lem s and offer th e ir recom m endatio ns fo r fu rnace eq uip m ent w hich w ill give

T R U E B R I G H T A N N E A L I N G .

B I R M I N G H A M E L E C T R I C F U R N A C E S L T D .

E R D I N G T O N B I R M I N G H A M

xvii

T ^{h e r m o} -C ^{o u p le} W ^ires

Pure Platinum and 10 per cent, rhodio-platinum Pure Platinum and 13 per cent, rhodio-platinum

It is essential that all thermo-elements used with any one instrument show absolute con­

stancy in the E.M.F. yielded at any given temperature.

Only by means of a special refining process is it possible to ensure that the electrical properties of the metal are constant from batch to batch.

Thermo-elements produced by Johnson Matthey not only receive this special atten­

tion, but our tests from batch to batch are also checked with similar tests carried out and certified by the N.P.L.

Elements can be supplied separately or with fused ¡unction.

'

Pure Platinum Wires for Resistance Thermometry

The pure platinum wires supplied for this purpose are made from the same specially prepared metal as our thermo-elements, thus assuring the constancy of the temperature co­

efficient of resistance from wire to wire.

J O H N S O N , M A T T H E Y & C O ., L I M I T E D ,

HEAD OFFICE AN D REFINERIES

73/83, H A T T O N G A R D E N , LO N D O N , E.C.1

xviii

Editor ial Oppice : TH E Advertising

“ ï Ï Ï “ î ? S Monthly Journal o f the T.

INSTITUTE O F ^ 1®

Ed itor: CITT 4211 (2 lines).

G. S H A W SCOTT, E l I A I ^ Assistant E d itor:

M.So., P.O.I.S. r l L I / A I 3 S. 0 . G U IL L A N ,

V olu m e 3 J U N E , 1936 P a rt 6

CO N TEN TS

PAGE

Institute News and A n n o u n c e m e n t s ... 255 Personal N o t e s ... 257 7 3 7 . “ A Note on the Influence of Salt-Bath Heat-Treatm ent on the

Corrosion-Resistance of Duralum in Sheet.” By A . J. Sidery and B. E v a n s ... 259 N otice to Authors o f P a p e r s ... ... • . • 266 7 3 8 . “ A Further Study of the Constitution of the Cadm ium -Tin A lloy s.”

By D. Hanson and W . T. P e l l - W a l p o l e ... 267 Author Index to Metallurgical A b s t r a c t s ... 291

M E T A L L U R G IC A L A B S T R A C T S I. Properties o f Metals . . . . . II . Properties o f A lloys . . .

I I I . Structure (M etallography ; M acrography ; Crystal Struc

ture) . . . .

IV . Corrosion . . . . .

V . P rotection (other than Eleetrodeposition) V I. Eleetrodeposition . . . .

V I I . E lectrom etallurgy and Electrochem istry (other than Electro

deposition) . . . . .

V I I I . Refining . . . .

I X . Analysis . . . .

X . L aboratory Apparatus, Instrum ents, &c

X I . Physical and Mechanical Testing, Inspection, and R adiology X I I . Tem perature and Measurement Control

X I I I . Fou ndry Practice and Appliances X I V . Secondary Metals : Scrap, Residues, &c.

X V . Furnaces and Fuels .

X V I . Refractories and Furnace Materials X V I I . H eat-Treatm ent

X V I I I . W o r k i n g ...

X I X . Cleaning and Finishing

X X . Joining . . . . .

X X I . Industrial Uses and Applications X X I I . Miscellaneous . . . . X X I I I . B ibliography . . . . X X I V . B ook R eview s . . . .

193 198 202 203 206 208

210

210

211 213 213 214 216

217 219 219 222 227 227 234 The m on th ly issue of Metallurgical Abstracts m a y be cu t up for card indexes, as m em bers will receive early in 1937 the yea r’s abstracts in b oun d form .

b x ix

AND ARE P R O D U C E D IN

NOTCHED B A R S , INGOTS, ROLLING SLABS,

W I R E BA RS , STICKS AND

S H O T

ADMIRALTY • A.I.D. B E S A A N D ALL

STANDARD SPECIFICATIONS.

P a r h 'e u / a p a f / e n f i o n , '• > , i s d r a u / n t o o u r

S T A N D A R D I Z E D A L U M I N I U M A L L O V S

P O R

S A N D - C A S T I N G S , G R A V I T Y A N D P R E S S U R E D I E - C A S T I N G S A N D S P E C I A L H I G H - T E N S I L E A L L O Y S F O R A I R C R A F T A N D A D M I R A L T Y

W O R K .

T .J .P R I E S T M A N L ™

CUPRO F O U N D R Y , LEO P O LD STREET,

BIRMINGHAM,.*

I C O N T R A C T R s T O A D M I R A L T Y A N D P R I N C I P A L R A

'p h o v f: v/cro/?//\ 2 S 6 / - 2 - 3 ’g r a m s: s p e c/f/c, Bi r m i n g h a m. XX

I N S T I T U T E N E W S A N D A N N O U N C E M E N T S

Autumn Meeting in Paris.

Th eT w en ty-E igh th A utum n Meeting o f the In stitu te w ill b e held in Paris, from Septem ber 14 to 18, b y the kind invitation o f the Bureau International des A pplications de 1’A lum inium w ith the cordial co-operation o f the Chambre Syndicale des M etaux a Paris.

The headquarters o f the Institute, and the office o f the H onorary L ocal Secretary, w ill b e in a very attractive building, the M aison de la Chimie, 28 R u e St. D om inique, Paris, where all the m eetings, and a banquet, will be held.

A n influential R ecep tion C om ­ m ittee ( o f w hich the H onorary Secretary is M onsieur J. S. D ouche - m ent, a m em ber o f the Institute) has been form ed to carry o u t the necessary arrangements. A lready the program m e o f the m eeting is p ra c­

tically co m p le te ; it w ill be issued to all m em bers shortly after the appear­

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The m eeting w ill open on M onday, Septem ber 14, w ith the delivery o f the F ifteenth Annual A u tu m n L e c ­ ture b y Professor P. A . J. Chevenard (Corresponding M em ber to the Council for France) on “ The Scien­

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tem ber 19; another p a rty w ill p ro ­ ceed to Düsseldorf for the Autum n Meeting o f the Iron and Steel Institute.

I t is anticipated th at there will be a large attendance o f m em bers from all parts o f E urope. Those mem bers w ho exp ect to take part are asked to return as soon as possible the reply form s th at will shortly be in their hands, thus greatly facilita­

ting the com pletion o f arrangements b y the C om m ittee in Paris.

255

Institute News and Announcements

Committees of the Institute.

The Com m ittees app ointed b y the Council fo r the year 1936-1937 are as follow :

Fin ance and Oeneral P urposes Committee.

Charles, Lieut.-G eneral Sir R on ald.

Clarke, H . W .

D ix on , E ngineer V ice-A dm ira l Sir R o b e rt (Chair).

Greenly, L ieut.-C olonel J. H . M.

M orcom , E . L. (Vice-Chairm an).

M undey, A . H .

Preston, L ieut.-C olonel the H on.

R . M.

Seligman, D r. R . Turner, Professor T .

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Local Sections Committee.

A ndrew , P rofessor J. H . B row n sdon, D r. H . W . G ray, K enneth.

Greer, H . H . A.

Griffiths, W . T .

H anson, Professor D . (Chair).

H au gh ton , D r. J. L.

M undey, A . H .

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Im m ediate Past-President.

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sentative.

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Swansea L oca l Section.

M eetings Committee.

A ndrew , Professor J . H . Brazener, W . F.

B row nsdon, D r. H . W . (Chair).

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W eeks, H . B.

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Im m ediate Past-President.

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Chairman, P u b lica tion Com m ittee.

L oca l R ecep tion Com m ittee’s R e p r e ­ sentative.

L oca l Sections Com m ittee’ s R ep re­

sentative.

M em bership Committee.

Andrew , P rofessor J. H .

Charles, Lieut.-G eneral Sir R on ald.

Genders, D r. R . Gray, K enn eth (Chair).

M acnaughtan, D . J.

M orcom , E . L.

M undey, A . H . Seligman, D r. R . W eeks, H . B.

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Im m ediate Past-President.

L oca l Sections Com m ittee’ s R ep re­

sentative.

Publication Committee.

B row nsdon, D r. H . W . Desch, Dr. C. H . D orey, D r. S. F.

Genders, D r. R . G w yer, D r. A . G. C.

H anson, P rofessor D . H au gh ton , D r. J, L.

M urphy, A. J . Seligman, D r. R . Sm ith, Dr. S. W .

Sm ithells, Dr. C. J. (Chair).

Sutton, H .

Turner, P rofessor T.

Ex-Officio : T h e President.

Im m ediate Past-President.

Chairman, Finance and General P u r­

poses Com m ittee.

Membership.

A s o n ly m em bers are perm itted to take part in the social fun ction s and w orks’ visits con n ected w ith the Paris m eeting, an election is being arranged on J u ly 2 for the benefit o f those w ho desire to participate in the A u tu m n M eeting, b u t are n ot y e t m em bers o f the In stitu te. The Council exp ects th at as this election 256

Institute News and Announcements

occurs at the beginning o f a new financial year, there w ill b e m an y mem bership applications to be co n ­ sidered a t its m eeting. The Secre­

tary w ill b e gla d to forw ard p a r­

ticulars o f the In stitu te, and, if desired, a specim en c o p y o f the M onthly Journal, to any potential m em ber, on receipt o f nam e and address.

Local Sections.

A t the annual m eeting o f the L ocal Sections Com m ittee, held in L on don on M ay 6, the reports o f the sections for the past session were presented and program m es for the com ing session were subm itted. The c o m ­ pletion o f a useful yea r’s w ork was indicated b y the reports, and the program m es suggest th at a further period o f a ctiv ity is in prosp ect for the com in g session.

In order to m aintain the correct­

ness o f records o f m em bership o f the L ocal Sections, m em bers w ho rem ove from on e L oca l Section area to another are asked to n o tify their changes o f address to the Secretary, w ho w ill then inform the appropriate H onorary Secretary so th at m em bers will receive notices o f m eetings in their new locality.

The officers o f the several L ocal Sections fo r 1936-1937 are :

Birmingham Section.

Chairman : W . F . Brazener.

H on. Secretary : J. W . Jenkin, B .Sc., Ph .D .

H on. Treasurer : G. Bill-G ozzard.

London Section.

Chairman : H . J. Gough, M .B .E ., D .S c., P h .D ., F.R.S.

H on . Secretary : S. V . W illiam s, B.Sc.

H on. Treasurer : A . J. M urphy, M.Sc.

North-East Coast Section.

Chairman : H . D un ford Sm ith, M.Sc.

H on. S e cre ta ry : C. E . Pearson, M.Met.

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Scottish Section.

Sheffield Section.

Chairman : Professor J. H . Andrew , D.Sc.

H on . S e cre ta ry : H . P . G adsby, Assoc.M et.

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Swansea Section.

Chairman : R oosevelt Griffiths, M.Sc.

H on. Secretary and Treasurer :

PERSONAL N OT E S

Mr. F . A . Ch a m pio n, B .Sc., A .R .C .S ., has recen tly taken u p an appointm ent in the Corrosion D epa rt­

m en t o f the R esearch L aboratories o f The British A lum inium Com pany, Lim ited, W arrington.

M b. F . Di c k i n s o n, B .S c., has left the Research Departm ent, W o o l­

wich, for an appointm ent w ith The M ond Nickel Com pany, Lim ited, in their Research and D evelopm ent Departm ent, Tham es H ouse, Mill- bank, L on don , S .W .l.

M b. J . E . Je n k i n s has left M erthyr T ydfil as he has recen tly been appointed to the Spelter L a b ora tory of the N ational Sm elting C om pany, L td ., A von m ou th W orks, A v on - m outh, B ristol.

D r . A . G. Ra m s a y, B .S c., has been appointed D epu ty Production M an­

ager o f I.C .I. Metals, L td ., K yn och W orks, W itton , Birm ingham.

De. - In g. Pa u l Ro s b a t j d, until recently director o f the technical science section o f Metallwirtschaft, join ed Verlag Julius Springer on M ay 1. H is new address is Linkstr.

22—24, Berlin W .9 ; telephone B 1 K urfürst 8111.

Mr. A. J. G. Sm o u t has been a p ­ poin ted G roup Chairman o f the Metal Section of Im perial Chemical In d u s­

tries, L td.

M e. T . D . W e i/b y is on a visit to E n gland from Calcutta, In dia, and correspondence m a y be addressed to him c /o Messrs. L loy d s Bank Lim ited, G.3, 6 P all Mall, L on d on , S .W .l, u ntil Septem ber 13, 1936.

Birth.

C h airm an : J . W . D onaldson, D .S c. Ha a s. To Dr. M ax and Frau H o n . Secretary : H arold Bull. H aas, on M ay 3, 1936, a son, H ans

H on . Treasurer : M. Brow nlie. Max.

257

Institute News and Announcements

Loose Copies oi Papers.

Mem bers are rem inded that, for the convenience o f m em bers a tten d ­ ing the In stitu te’s general m eetings, the Council has authorized the su p ply o f special loose prints o f the papers.

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Annual Subscriptions, 1936-1937.

M embers and stu den t m em bers are rem inded th at their annual su b scrip­

tions o f £3 3s. and £1 Is., respec­

tively, becom e payable, accord ing t o the R u les, “ in advance on J uly 1.”

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fore, to send their rem ittances to the Secretary, the In stitu te will be saved the expense o f forw arding “ re ­ m inders,” w hich co s t a substantial sum each year and in volve m uch clerical la b ou r th at m igh t be m ore u sefully em ployed. D elay in the p a ym en t o f subscriptions is n ot on ly unnecessarily costly to the Institute, b u t it also prevents m em bers from receiving their M onthly Journals prom p tly. The In stitu te’s p u b lica ­ tions are n ot sent to m em bers whose subscriptions are in arrear.

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258

PAPER No. 737. T h is p a p er is c o p y rig h t. I t m a y b e rep rin ted , w h o lly o r in p a rt, in the P ress (w ith d u e a ck n ow led g m en t) a fte r th e A n n u a l A u tu m n M eetin g o f th e In stitu te to b e h eld in P a ris fro m S ep tem b er 14 t o 18, 1936. T h e In stitu te as a b o d y is n o t re­

sp on sib le fo r th e statem en ts o r op in ion s expressed in this p a p er, o n w h ich written dis­

cussion m a y b e sen t t o th e S ecretary n o t later th a n O cto b e r 1, 1936.

A NOTE ON THE INFLUENCE OF SALT-BATH HEAT-TREATMENT ON THE CORROSION- RESISTANCE OF DURALUMIN SHEET.*

B y A. J. S ID E R Y ,f Assoc.M et. (Sheff.), Me m b e r, and B. EVANS,i B.Sc.

Sy n o p s is.

Some experiments were carried out to provide information as to whether the use of a nitrate salt-bath as the medium in the final heat- treatment of Duralumin has any deleterious effect on the corrosion- resistance of the material as compared with that of material which has been heat-treated in an electric furnace. Further, the influence of salt residues on the surface of the sheet during prolonged storage was investigated.

It was found that the use of nitrate salt-baths in the heat-treatment operation has no deleterious effect on the corrosion-resistance of Dural­

umin, but that salt residues are liable to foster local surface, pitting of the material during storage.

In view of the extensive use of salt-baths in the commercial heat- treatment of Duralumin, it was considered desirable to investigate the influence of this method of heat-treatment on the corrosion-resistance of the material as compared with that of heat-treatment in air at the same temperature. Two series of tests were made.

For the first series a supply of Duralumin that had not been in con­

tact with salt at any stage of its manufacture was procured. Samples were heat-treated at 490° C. in pure sodium nitrate, in salt mixtures, and in salts supplied and as used by four aircraft contractors, viz.

Messrs. James Booth & Co. (1915) Ltd., Fairey Aviation Co., Ltd., Hawker Aircraft, Ltd., and Supermarine Aviation Works (Vickers), Ltd. The heat-treatment was followed by quenching in cold water, or in some cases, in cold dilute solutions of the salts employed in heat- treatment. These variously heat-treated samples were then subjected to immersion tests and to intermittent sea-water spray tests for ap­

propriate periods. The corrosion-resistance was investigated by visual and microscopical observations and also by mechanical tests.

In the second series of tests an attempt was made to examine the

* Manuscript received April 18, 1936.

f Scientific Officer, Royal Aircraft Establishment, South Farnborough.

J Technical Assistant, R oyal Aircraft Establishment, South Farnborough.

Note to Abstractors and Other Readers.— This paper will be published, in permanent form, in the Journal of the Institute of Metals, Vol. L IX , 1936.

Reference should accordingly be as follow s: J. Inst. Metals, 1936, 59 (Advance copy).

259

737

corroding effect of adhering salt from the heat-treatment bath during subsequent storage of the material.

De s c r i p t i o n o f Ex p e r i m e n t s. S e r i e s I.

The materials used in the experiments consisted of 20- and 15- S.W.G. Duralumin sheets, the analyses of which are given in Table I.

Sidery and Evans : Effect of Salt-Bath Heat-

T a b l e I.

20-S.W .Q . 15-S.W .G . Copper, per cent..

Silicon, „ . Manganese, ,, . Iron, ,, . Magnesium, ,, . Aluminium, ,, .

4-46 0-28 0-62 0’47 0-55 remainder

4-47 0-24 0-63 0-56 0-44 remainder

Samples measuring 10 X 2-5 cm. were cut in the direction of rolling and subjected to heat-treatment for 15 minutes at 490° C. as follows :

(a) Heated in pure sodium nitrate and quenched in cold water.

(b) Heated in pure sodium nitrate and quenched in a 1 per cent.

aqueous solution of the salt.

(c) Heated in eutectic mixture of sodium and potassium nitrates and quenched in cold water.

(d) Heated in eutectic mixture of sodium and potassium nitrates and quenched in a 1 per cent, aqueous solution of the salt mixture.

(e) Heated in salt supplied and as used by aircraft contractor “ A ” and quenched in cold water.

( /) Heated in salt supplied and as used by aircraft contractor

“ B ” and quenched in cold water.

(g) Heated in salt supplied and as used by aircraft contractor “ C ” and quenched in cold water.

(h) Heated in salt supplied and as used by aircraft contractor “ D ” and quenched in cold water.

(j) Heated in an electric furnace and quenched in cold water.

After being allowed to age for 7 days the specimens were subjected to the following corrosion tests :

(i) Water-line immersion test for 28 days in normal sodium chloride solution acidified with 1 per cent, by weight of hydrogen chloride, equivalent to 294 c.c. of hydrochloric

260

acid of sp. gr. 145, or 274 c.c. of hydrochloric acid of sp. gr.

146, per litre.*

(ii) Water-line immersion test in sea-water for 28 days.

(iii) Sea-water spray test for 6 months.

In the sea-water spray test the samples were exposed to the open air, but protected from rain, and were sprayed with sea-water from the English Channel three times during each working day at intervals of approximately 3 hrs. The sea-water was directed at the specimens in the form of a fine mist by means of compressed air.

Sufficient samples were heat-treated to provide duplicates in all conditions.

“ Water-Line ” Immersion Tests.

Superficial observations: All the samples immersed in the acidified sodium chloride reagent behaved similarly, slight effervescence being observed soon after immersion. This activity increased to a maximum intensity after 2 days and then slowly subsided. A loose dark-brown coating accumulated on the immersed surfaces and surface pitting occurred. The samples immersed in sea-water were apparently all corroded to the same extent. The degree of attack, however, was not comparable with that obtaining in the acid sodium chloride solution.

A white gelatinous deposit appeared at the water-line in increasing quantities as the test proceeded and small centres of surface attack became perceptible.

Microscopical observations: Sections across the water-line were prepared from the various samples and examined microscopically. It was found that most of the corrosion took the form of surface pitting.

The sections from the specimens immersed in the acidified sodium chloride solution were irregularly and deeply pitted, but .no inter­

crystalline channels had developed except in two cases, where minute traces of this form of penetration were observed. One case was on a section taken from a sample that had been heat-treated in an electric furnace and quenched in cold water, while the other case was on a section taken from a sample that had been heat-treated in a sodium nitrate salt-bath and quenched in water, any adhering salt being completely removed by washing. It is considered that the extent of these inter- crystalline channels would not justify any importance being attached to their occurrence. Examination of the sections from the various samples immersed in sea-water did not reveal any appreciable variation in the degree of attack. Some irregular surface pitting was observed,

* This reagent has proved of service in producing intercrystalline corrosion consistently in samples of Duralumin susceptible to this type of corrosion. Sidery, Lewis, and Sutton, J. Inst. Metals, 1932, 48, 168.

261

Treatment on Corrosion-Resistance of Duralumin

Sidery and Evans : Effect o f Salt-Bath Heat-

■9 i n ' l l r rt p _ 0) c3

«¿3- Æte-

15 S.W.G. 11-6 15-5 17-2 264 14-0 9-7

Heat Salt: Mnfr. Quenc Cold \ 20 S.W.G.

10 CD - f 9

© CO 00 Ó r-H 1—1 1—1 (N

8-6e-ii

Heatedin Saltfrom Mnfr. “ C,” Quenchedin Cold Water. 15 S.W.G. 11-5 15-5 17-2 26-0 14-0 9-9

20 S.W.G. 100 171 18-9 27-3 e-oie-ii

ed in Erom “ B,” hed in Vater. 15 S.W.G. 10-2 15-4 17-2 265 15-0 10-2

Heati Salt1 Mnfr. Quenc Cold \ 20 S.W.G. 9-9 170 18-6 26-8 12-0 10-7

Heatedin Saltfrom Mnfr. “A,” Quenchedin Cold Water. 15 S.W.G. 9-2 15-5 17-2 26-6 16-0 10-3

20 S.W.G. 11-8 16-4 18-3 25-5 9-0 10-2

Heatedin K/NaN03 Bath, Quenchedin 1%Soln. of SaltMix. 15 S.W.G. 11-9 15-9 17-4 26-0 14-0 10-3

a

Ë 20 S.W.G. 10-6 16-3 18-2 26-9 14-0 10-3

. 2 t!

—1 O -S 15 S.W.G. 11-7 16-3 17-9 26-9 16-0 9-6

MM ö "o

0 * 0 20 S.W.G. 9-2 16-2 17-8 26-2 e-n SOT Æ.g 's

— c8 »ö •

'ö M £ & 15 S.W.G. 9-6 15-3 17-3 26-5 0-91 soi r? ü r/) c3

c5 O a m

W a 20 S.W.G. 8-9 16-5 181 25-5 10-0 10-6

3d in ¡ Bath, hed in Vater. 15 S.W.G. 10-3 16-1 17-9 26-6 14-5 10-1

l § ¡ 2 ₂⁰

S.W.G. 11-0 16-0 18-1 26-8 14-0 10-1

tí ¿

. 3 . 0 cfr^ ^ rrj ’5 2 ® ¹

5 S.W.G. 9-4 15-5 17-4 26-4 17-0 10-5

3 - 3

a o ²⁰ _S^.W

.G. 10-2 16-5 18-4 26-3 130 10-6

•ÖP

Heatedin Electric Furnace, Quenchedin Cold Water. 15 S.W.G. 8-7 15-1 17-0 27-0 19-0 10-9

Oo

s ²

0 S.W.G. 10-9 15-9 18-2 28-0 19-0 10-2

Treatment. Limitofproportion­ ality, tons/in.2. 0-1%Proof Stress, tons/in.2. 0-5%ProofStress, tons/in.2 UltimateStress, tons/in.2.

tí rî O -~—.5 i-H to

G .

S c g.-i _ X bß „ tí G«

3 ° w H 2

262

Treatment on Conosion-Resistance of Duralumin

but no trace of intercrystalline corrosion was detected in any of the samples.

Sea- W ater Spray Tests.

It was considered that the determination of the tensile strength after six months’ exposure to the sea-water spray test would afford a con­

venient means of measuring the relative corrodibility of the variously treated samples.

The dimensions of the individual samples were determined prior to the test and the stress values after exposure calculated accordingly.

The mean results of duplicate tests, together with the values for the uncorroded material, are given in Table II.

The tensile values obtained do not indicate that heat-treatment in nitrate salt-baths is deleterious, nor does there seem to be any dis­

advantage, from the point of view of corrosion-resistance, in the use of such media in comparison with heating in an electric furnace. In fact, there was no marked margin of variation in the values as a whole.

S e r i e s II.

Ordinary commercial British Duralumin in three thicknesses, 16,18, and 24 S.W.G., was obtained for this part of the work. The results of chemical analysis of samples of each gauge of material are given in Table III.

T a b l e III.

1G-S.W.G. 18-S.W .G. 24-S.W.G.

Copper, per cent. 3-82 4-11 4-17

Silicon, ,, 0-55 0-36 0-23

Manganese, per cent. 0-51 0-58 0-60

Magnesium, ,, 0-79 0-59 0 - 6 6

Iron, per cent. 0-38 0-57 0-45

Aluminium (by difference), per ce n t.. 93-95 93-79 93-89

Strips measuring 2 ft. long by 2 in. wide were cut from the respective sheets. Five lengths of each thickness were taken and assembled to form three coils having an outside diameter of 5 in. Each coil con­

sisted of about eight turns or laminations and the clearance between successive laminations varied to a maximum of 0-006 in. In addition to these coils, strips measuring 1 ft. long by 2 in. wide were prepared from each of the three sheets.

The coils and strips were then heat-treated in a commercial salt mixture having a melting point of about 180° C. The mixture con­

sisted essentially of sodium and potassium nitrates and solidified from 263

Sidery and E vans: Effect o f Salt-Bath Heat-

the liquid state to form a hard, dense mass which did not dissolve very rapidly in still cold water. A qualitative analysis indicated the presence of considerable amounts of nitrites, while chlorides were also present in small quantity.

The heat-treatment temperature employed was again 490° C. The coils were held in the bath for 30 minutes and the strip samples for 20 minutes before they were quenched in cold water. The water was allowed to drain away from the samples, which were then dried off normally without any other treatment. The amount of salt entrapped at the interfaces of the laminations in the coils was, of course, much greater than that which remained on those samples heated and quenched as single strips.

The treated coils and strips were then stored in an unheated building for a total period of twelve months. Superficial observations were made at intervals, while at the end of the test period a thorough superficial and microscopical examination was made.

Results o f Tests.

Superficial observations : Examination of the coiled material showed that considerable quantities of salt still remained on the sheet surfaces corresponding with the interfaces of successive laminations. Where the salt had been entrapped there was a large amount of greenish-grey deposit, which was fairly adherent, on the surface of the sheet. When this deposit was removed pronounced pitting as well as more general surface etching was in evidence. In the case of the single strip speci­

mens, isolated spots of white deposit were fairly general over the surfaces. Very small surface corrosion pits were observed on all the strip samples and there was no appreciable difference in the appearance of the sheets in the three gauges.

Microscopical observations : Sections were prepared from the lower edges of the inner, middle, and outer lengths of strips in the coils.

There was a tendency for the entrapped salt to be more plentiful in the regions chosen than on the other portions of these strips.

Numerous corrosion pits were observed on all the sections examined.

The actual depth of these pits, however, was surprisingly small and none more than 0-005 in. deep were detected.

There was no trace of intercrystalline corrosion on any of the sections examined. The complete absence of this type of corrosion from the sections taken from the middle strip in the different coils was also surprising, inasmuch as it would be expected that these would have had a higher susceptibility towards intercrystalline penetration, by virtue of the lower rate of cooling on quenching from the salt-bath during

264