to produce H -em brittlem ent. HCI is more costly b u t more efficient th a n H 2S 0 4, and is also less prone to cause em brittlem ent. H C 1+H F is the best pickle for removing scale combined with siliceous
m atter. J . W. C.
C o n tro l in th e [m e ta l] p ic k lin g ro o m . P. C.
St u f f t (Met. Clean, and Fin., 1938, 10, 326).—
Methods of determining the H 2SO,, HCI, Fe, total alkali, and soap contents of pickling solutions are
outlined. J . W. C.
H y d ro g e n -sic k n e ss of so m e m e ta ls . W. Ba u k-
l o h and W . St r o m b u r g (Z. Metallk., 1937, 29, 427—
433).—I f ordinary Cu is annealed in vac. to cause the Cu20 to migrate to the grain boundaries and is then annealed in H 2, severe intercryst. fracture occurs along the grain boundaries, showing th a t the presenco of Cu20 in Cu is the cause of “ H,-sickness.” E m brittlem ent of Cu by H 2 starts in 24 hr. a t 400°, in 5— 10 min. a t 500°, and in < 1 min. a t 650°. This phenomenon also occurs in F e and Ni but not in Al.
Electrolytic pickling of Cu does not affect its deep- drawing properties or its X -ray diagram ; similar treatm ent of Ni broadens the lines in the X -ray diagram bu t does not appreciably affect the Erichsen
no. A. R. P.
P h o to g r a p h ic p r i n t m e th o d in m e ta llo g ra p h y . H. Di e n b a u e r and R. Mi t s c h e (Berg.- u. Hiitten- rnann. Monatsh., 1938, 86, 33—35).—By adding NaCl to unfixed AgBr paper (Niessner p rint method) segregations and structural differences can be re
vealed in steels and m ottled cast Fe, and, above a certain min. particle size, F e phosphide inclusions can be detected in addition to Fe sulphide and oxide inclusions. The prints are preferably examined under
slight magnification. R. B. C.
S tr e s s in g , w e a r , a n d g r in d in g of ro lls fo r p ro d u c tio n of th ic k , m e d iu m , a n d th in [m e ta l]
sh e e ts . 0 . Em i c k e (Stahl u. Eisen, 1938, 58, 73—
82, 112— 117, 136— 145).—The m aterials of which rolls are m ade and the stresses to which they are subjected are considered. Non-alloy rolls are classified according to suitability for production of sheets of different thickness. Details of physical properties required, and composition and treatm ent of materials, are given. Graphs show the relation between C content, tensile strength of the core o f material, and Shore hardness of hard-chilled casting rolls. The effect of alloying elements, such as Cr, Mo, and Ni, on the wear-resistance and physical properties of chill-cast rolls is summarised. Free cementite in
creases wear-resistance. Much other d ata of a mechanical nature is given. C. M. A.
In flu e n ce of th e r a te of r o llin g o n th e re s is ta n c e to d e fo rm a tio n of so m e n o n -fe rro u s m e ta ls a n d on th e p o w e r c o n s u m p tio n . O. Em i c k e and K. H. Lu c a s (Z. Metallk., 1938, 30, 89—94).—The resistance of Cu, Pb, and some Al alloys to deform
ation in hot- or cold-working increases rapidly with speed of rolling up to 0-9— 1-2 m./sec., after which it remains practically const. Power consumption also increases w ith increase in rolling speed until it reaches m any times the mean compressive force.
A. R. P.
H a rd n e s s m e a s u r e m e n ts on w ire sp e c im e n s.
C. H. Jo h a n s s o n and G. We i b u l l (Z. Metallk., 1937 , 29, 418—420).—The wire is indented with a hardened steel cylinder and the area of the elliptical projection of the impression on a plane parallel to th e face of the cylinder is plotted against the load applied, several measurements being made on one specimen; the inclination of th e resulting straight line is a measure of the hardness of the whe. The use of the method in following the hardening of wires of Cu and some Cu alloys during drawing and the softening on annealing is shown graphically.
A. R. P.
C o n d itio n s fo r th e e x a c t m e a s u r e m e n t of h a r d n e s s im p re s s io n s . K. Sf o r k e r t (Z. Metallk., 1938, 30, 199—201).—Ball or diamond impressions should be measured under a magnification of 50 X , using dark field illumination. The new Zeiss micro
scope embodying these principles gives readings accurate to ± 3-5 |a. ; errors of up to 10% may occur w ith the ordinary bright-field illumination.
A. R. P.
In flu en ce of th e g r a in size a n d c r y s ta l o rie n t
a tio n o n th e m e c h a n ic a l p ro p e r tie s of so m e m e ta ls . H. Un c k e l (Z. Metallk., 1937, 29, 413—
417).—Tests on Cu, bronze, brass, Al, Pb, and Zn show th a t properties, such as hardness, tensile strength, yield point, and elongation, which depend on plastic deformation decrease appreciably with in creasing grain size, whereas the power required for shaping the metal, e.g., in drawing, increases. The mechanical properties of castings of cubic metals differ only slightly in the direction of the dendritic crystals from those in a direction transverse th e re to ; with Zn, however, deformation is easier transverse to the dendrites than in a direction parallel thereto.
A. R. P.
R e la tio n b e tw e e n th e b e n d in g -te n s ile s tr e n g th a n d th e fa tig u e l i m it in a lte r n a tin g -b e n d in g te s ts . E. Mo h r (Z. Metallk., 1938, 30, 71—73;
cf. B., 1938, 800).—The results obtained by Mohr’s modification of Buschm ann’s bending-tensile test (B., 1935, 230) on Duralumin, Electron, brass, Cu, electrolytic Zn, Ni, and steel agree closely with the fatigue lim it as determined by the Wohler test for stress cycles of 15—20x10® (non-ferrous metals) or 2—5x10® (ferrous metals). W ohler’s test, there
fore, appears to be a limiting case of the Buschmann test b u t the latter can be made in 2 hr. whereas the former takes several days. A. R. P.
T e s tin g of m a te r ia ls b y th e b e n d -te n s ile te s t.
E. Mo h r (Metallwirts., 1938, 17, 535—537).—The test as described previously (B., 1938, 800) has been applied to Cu, Mg, Al, Cr-Ni, steel, Electron, Duralumin, nickel-silver, and phosphor-bronze.
Typical stress-strain curves are given and the applicability of th e test is discussed. C. E. H.
P h y s ic a l in v e s tig a tio n of m e ta llu rg ic a l p r o b le m s . W. Ge r l a c h(Naturwiss., 1938, 26, 369—
376).—A review of th e applications of magnetic and electrical analysis to the study of structural changes giving rise to pptn.-hardening in binary alloys, when one of the constituents is ferromagnetic. A. J . M.
C l. X .—METALS; METALLURGY, INCLUDING ELECTROMETALLURGY. 1055
U se s of fe rro m a g n e tic m e a s u r e m e n ts in m e ta llo g ra p h y . W. Ge r l a c h (Z. M etallk., 1938, 30,77—81).—Curves showing the changes in coercivity and saturation magnetisation for N i-A u and Be-Ni alloys during the decomp. of supersaturated solid solutions on annealing are given to illustrate the val.
of magnetic methods in investigating th is phenomenon
in alloys. A. R. P.
Q u a n tita tiv e m e a s u r e m e n ts of te x tu r e b y th e m a g n e tic to rq u e m e th o d . L. P. Ta r a s o v (J. Appl.
Physics, 1938, 9, 192— 196).—The restrictions of the methods of Akulov and B ruchatov and of B itter are pointed out. A modification of the la tte r’s method is described which gives results in fair agreement with the pole figure of a cold-rolled F e-S i alloy.
H . J . E . T h e r m a l co n d u c tiv ity d e te r m in a tio n s [on m e ta ls ]. W. F. Ch u b b (Metal Ind. [Lond.], 1938, 52, 545—548, 579—580).—The guard-ring method has been modified to give an apparatus capable of yielding results accurate to 0-25%. Figures are given for specimens of C u of different 0 and Ni content. .
C. E. H.
I n d u s tr ia l s p e c tr o g ra p h ic a n a ly s is a t th e U n iv e rs ity of Li6ge. P. Sw i n g s and J . Ge n a r d
(Rev. Univ. Mines, 1938, 14, 339—342).—Problems encountered in th e detection of traces of metals in ores, glass, Fe, etc. aro discussed. R. B. C.
B e h a v io u r of e le c tric a l re s is ta n c e allo y s in v a rio u s g a s e s a t h ig h te m p e r a tu r e s . W . He s s e n- b r u c h, E. Ho r s t, and K. Sc h i c h t e l (Arch. Eisen- hiittenw ., 1937—8, 11, 225—229).—Spirals of N i- Cr, N i-C r-Fe, N i-C r-Fe-M o, and C r-A l-Fe alloys were heated a t 1050—1200° in 0 2, H 2, C 02, coal gas, water-gas, and air by passing a current through them and the effects produced on th e structure are shown in micrographs. Only H 2 is w ithout any effect on all the alloys; in carbonaceous gases, especially under reducing conditions, considerable carburisation occurs, the extent being dependent on the F e and Al contents of the alloy. N2 produces nitrides in C r- Ni and in C r-A l-Fe alloys; in the latter case nitrides of Cr and Al are pptd. to such an extent th a t the remainder of the alloy becomes so low in Al and Cr as considerably to im pair its life. All alloys contain
ing Ni are particularly susceptible to traces of S compounds in the gases, especially in the presence of moisture. Austenitic alloys are especially subject to intercryst. corrosion whilst ferritic alloys have a tendency to general scaling all over the surface.
A. R. P.
B e ry lliu m a n d b e r y lliu m allo y s. W . He s s e n- b r u c h (Metallwirts.', .1938, 17, 541—547).—P ro
perties and apphcations are reviewed, and vals. have been determ ined for the mechanical properties in different conditions of Cu-, Ni-, and Fe-base alloys
containing Be. C. E . H .
C o rro sio n of m a g n e s iu m a llo y s. IV . E fie c t of a n n e a lin g te m p e r a tu r e o n c o rro s io n . S.
Mo r i o k a (Sci. Rep. Tohoku, 1938, 26, 545-—559;
cf. B., 1937, 1066).—The effects of annealing a t temp, from 120° to 470° on the rate of corrosion and microstructure of Mg and its alloys are recorded.
The rate of corrosion of Mg and of Mg-Zn (< 2 % ),
Mg-Cd, Mg-Mn (< 2 % ), and Mg-Si alloys increases a t first with anneahng and then decreases as the anneal
ing tem p, rises. F or Al-containing alloys annealing affects the ra te of corrosion adversely above 290°;
below this tem p, it has no effect. This was particularly marked a t low Mg contents. As the Mg content rises th e anneahng temp, can be raised w ithout a concomitant increase in th e ra te of corrosion. For Mg-Zn, Mg-Sn, Mg-Cd, and Mg-Mn alloys the effect of annealing tem p, on corrosion rate is correlated with change in structure. No such correlation is detected in th e case of Mg, Mg-Si, and Mg-Al. D ata for Mg- Zn-Al and M g-Zn-Al-M n are also given.
C. M. A.
P r o te c tio n of m a g n e s iu m a n d its allo y s a g a in s t c o rro s io n . J . He r e n g u e l (Met. e t Corros., 1938, 13, 82— 83).—Dipping in chromate followed by varnishing is recommended. Chloride inclusions
should not be present. R. B. C.
N ew n o n -c o rro d ib le m a g n e s iu m lig h t allo y .
I . Ii t a k a, R. Sh i o t a, and T. Ya m a n o b e (Sci. Papers Inst. Phys. Chem. Res. Tokyo, 1938, 34, 508—
514).—The corrosive effect of 5% NaCl solutions on Mg and Mg-rich alloys (Mg-Al, M g-Al-Be, M g-Al-X, and M g-A l-B e-X , where X = Z n or Mn) has been determ ined a t room temp, over periods of 2 hr.—
2 months, by m easurement of tho H 2 evolved. Be reduces corrosion in Mg and its light alloys up to (small) optim um % varying with the non-Mg content . The easily workable ternary Mg alloy containing 2-5% Al and 1-1% Be is almost non-corrodible.
I. Me A.
M e ta llu rg ic a l a lu m in iu m . A. Su g a r (Blast Furn. Steel P lant, 1938, 26, 406—410).—The use of Al for deoxidising and controlling the grain size in
steel is discussed. R. B. C.
B la c k e n in g of a lu m in iu m b y b o t ta p - w a te r . J . Fi s c h e r and W. Ge l l e r (Z. Metallk., 1938, 30, 192— 195).—The peculiar blackening frequently ob
served on Al utensils in which tap-H 20 is continuously boiled is shown to be an optical effect produced by light absorption by the metal surface which is sub-microscopically etched by th e H 20 . Blackening occurs only when the I I 20 is slightly alkaline and it cannot be prevented by annealing unless th e m etal is
99-85% pure; no blackening occurs with 99-99%
Al unless the H 20 is very alkaline or promoters, e.g., H 20 2, are present. Blackened Al resists corrosion better th an bright Al. A. R. P.
S o lu b ility of a lu m in iu m of d iffe re n t d e g re e s of p u r ity a n d of a lu m in iu m a llo y s in c a u s tic s o d a . W. J . Mu l l e r and E. Low (Aluminium, 1938, 22, 257—263).—W ith th e exception of Mg, metals accelerate the dissolution of Al in N-NaOH a t 20°.
The acceleration can be explained on the basis of Muller’s corrosion theory. C. R. H.
In flu e n ce of s m a ll a m o u n ts of s o d iu m c h r o m a te on th e r a te of d is s o lu tio n of a lu m in iu m a n d i t s allo y s in s u lp h u ric a c id . H . Li c h t e n b e r g
(Aluminium, 1938, 22, 264—265).—Na2C r04 increases the rate of dissolution of Al by oxidising nascent H and preventing bubble formation, but in presence of
1 0 5 6 BRITISH CHEMICAL AND PHYSIOLOGICAL ABSTRACTS.—B.
excess of N a2C r04 a protective layer is formed on the Al which prevents further a tta c k by H 2S 0 4.
0. R. H.
A n o d ic o x id a tio n of a lu m in iu m a n d i t s allo y s.
J . D. Cr a i g (J. Roy. Aero, Soc., 1938, 42, 603—
612).—A lecture. R. B. C.
D iffu sio n of n a s c e n t h y d ro g e n th r o u g h a lu m in iu m . H . Li c h t e n b e r g (Metallwirts., 1938, 17, 595—596).—From tests w ith a delicate apparatus it is concluded th a t nascent H does not diffuse through
Al. C. E. H.
D e te rm in a tio n of c o m b in e d n itro g e n in a lu m in iu m . A. L. D o y l e and W. H . H a d l e y (Analyst, 1938, 63, 426— 427).—The Al, in the form of freshly- prepared millings, is dissolved in redistilled aq. HCI, and the solution gradually added to 40% aq. K O H in Stanford’s apparatus (cf. B., 1935, 203). The N H 3 is distilled into dil. H 2S 0 4 and determined by nessleris- ation. The combined N of 99-5% Al was found to
be 0-0003%. E. C. S.
E x a m in a tio n of a n a lu m in iu m ca b le of 1919.
P. Be h r e n s and K. Sc h o n h e r r (Aluminium, 1938, 22, 269—270).—The changes in properties during service were very slight. C. R. H.
T h e o r e tic a l p rin c ip le s in v o lv ed in th e p u r i fic a tio n of s ilu m in . Ki r s t e n (Aluminium, 1938, 22, 266—268).—A review of theories on the structure of Al-Si alloys and on the removal of Si by th e addition
of N aF to the melt. C. R . H.
C o ld -ag ein g of c o p p e r-a lu m in iu m a llo y s. W.
Hartnagel (Z. Metallk., 1938, 30, 81—86).—When a quenched Cu-Al alloy is allowed to age a t 25° the resistance (II) increases oc the log of th e time (t) to a flat max. and then decreases; in the first stage the val. of Alt j At is const., b u t in the second stage it increases. Before the B -log t curve becomes linear there is a more or less prolonged “ running-in ” period during which there is only a very slow increase in R ; this period is the shorter the smaller are tho internal stresses. The inclination of the rectilinear portion of the graph cc degree of supersaturation of the solid solution. All these changes are reversible by heating the alloy to 150° and the cycle can be repeated indefinitely provided th a t i t is n o t heated appreciably above 150°. The mechanism of ageing is therefore suggested to be : a t 25° an interm ediate phase is formed according to a logarithmic time law, the first step in this process being the collection of the Cu atom s into positions which slightly distort the lattice and thus produce an increase in R, and the second step th e formation of small regions having a smaller resistance of their own so th a t R begins to decrease; this interm ediate phase is formed with very little liberation of heat so th a t when the alloy is heated to 150° i t reverts to th e solid solution form, b u t when heated to 300° the heat of formation of CuA12 is liberated and this compound separates
irreversibly. A. R. P.
D e te c tio n of s m a ll a m o u n ts of c o ld a g e -h a rd e n in g o r in te r n a l s tr e s s [in c o p p e r-a lu m in iu m allo y s] b y th e 1 ‘ re -fo rm a tio n ’' m e th o d . H . A u e r and K. S ie m e n s (Z. Metallk., 1938, 30, 86—87; cf.
preceding abstract).—The measurement of a change
in electrical resistance or other property when a Cu-Al alloy is heated a t 150° for 2 min. to re-form the quenched solid solution is used as the basis of a method fo r detecting whether th e alloy has been allowed to cold-age or contains internal stresses. As little as 1% of cold-ageing m ay be detected. A. R. P.
A g e -h a rd e n in g of b in a r y c o p p e r-a lu m in iu m a llo y s. G. Wa s s e r m a n n (Z. Metallk., 1938, 30, 62—67).—The mechanism of ageing in a 4—8% C u- Al alloy m ade from extrem ely pure m etals was investigated by X -ray and micrographic methods.
The “ interm ediate s ta g e ” always appears a t all tem p. <300° and is so stable th a t only prolonged annealing a t 300° will cause it to disappear entirely;
a t 150° this stage persists unchanged after 1 m onth.
Complete conversion into CuAl2 a t >300° is accom
panied by a m arked improvement in ductility which is extremely low in the interm ediate stage.
A. R, P.
In flu e n ce of th e c o p p e r a n d m a g n e s iu m co n t e n ts of c o p p e r-m a g n e s iu m -a lu m in iu m allo y s o n th e a g e in g p ro c e s s . M. Ha n s e n and K . L .
Dr e y e r (Z. Metallk., 193S, 30, 55— 58).—The alloys investigated contained Cu 1— 4 and Mg 0-5—3-3% ; within these limits increase in Cu increases the strength after quenching, accelerates cold-ageing, and increases the final hardness obtained, whilst increase in Mg raises the hardness after quenching, retards cold-ageing (when Mg is >1-5% and Cu < 3 % ), and a t first increases and then decreases the final hardness obtained. F or commercial purposes alloys with Cu 3, Mg 1-5% or Cu 2, Mg 1-5—2% are recommended since their mechanical properties are equal to those of the Cu 4, Mg 0-5% alloy (Duralumin) and they have the advantage of being workable after quenching due to the effect of the high Mg content in restraining
cold-ageing. A. R. P.
T e s tin g of th e a tm o s p h e ric c o r ro s io n - r e s is t
an c e of a lu m in iu m allo y s. G. Sc h i k o r r (Metall
wirts., 1938, 17, 593—595).—Salt-spray tests were applied to Al-Si, Al-Mn-Mg, aiid Al-Mg alloys, and to an alloy (A) which had suffered severe corrosion in a harbour atm . The attack on A was on the other alloys. Tests in an urban atm . and with an artificial “ d e w ” containing HCI and H 2S 0 4 showed the resistance of A to be intermediate. I t is con
cluded th a t th e salt-spray test is unsuitable for evaluating th e resistance of Al alloys to inland atm .
C. E. H.
R e c r y s ta llis a tio n te m p e r a tu r e of a lu m in iu m - m a g n e s iu m a llo y s. W . Bu n g a r d t and E. Os s w a l d (Z. Metallk., 1938, 30, 202—205).—The min.
recrystallisation temp, of hard-rolled Mg-Al alloys, determined by X-rays, is raised b y addition of Mg from 246° (pure Al) to a max. of 280° w ith 2% Mg and th en decreases linearly to 240° w ith 4-5% Mg (limit of solubility); further addition of Mg causes a rapid, almost linear increase in th e recrystallisation tem p, owing to the effect of th e (3-phase. H eating of a hard-rolled supersaturated solid solution alloy a t > th e min. recrystallisation temp, b u t a t <; the solubility line produces pptn. of [i along the grain boundaries of th e new crystals; heating a t 410°
produces incipient pptn. of (3 and raises the
recrystallis-Cl. X .—METALS; METALLURGY, INCLUDING ELECTROM ETALLURGY. 1057
•ation tem p., b u t if the alloy is heat-treated to produce a stable duplex structure prior to rolling the re
crystallisation tem p, is unchanged. A. R . P.
R a p id d e te r m in a tio n of m a g n e s iu m in a lu m in iu m a llo y s of th e a lu m in iu m - s ilic o n -m a g n e s iu m ty p e . A. Br e nn e k and S. He n g l (Metallwirts., 1938, 17, 596).—The weighed sample is boiled with NaOH, tho residue filtered off and heated with HCl + H 20 2, and the solution thus obtained diluted with H 20 and filtered. The filtrate is boiled, citric acid + (NH4)2H P 0 4 being added, and made ammoniacal.
A fter cooling with stirring, more aq. NH3 is added and the ppt. of Mg2P 20 7 filtered off, washed with aq. NH3, ignited, and weighed. C. E . II.
Q u a n tita tiv e s p e c tr o g ra p h ic a n a ly s is of a llo y s.
In flu e n ce of a t h i r d m e ta l o n th e A l/M g in te n s ity r a tio in lig h t m e ta l a n a ly s is . G. Ba l z (Z.
Metallk., 1938, 30, 206—211).—The presence of
> 1 0 % Zn in Mg-Al alloys containing < 1 % Al leads to high results for Mg when Zn-free alloys are used for comparison of tho line intensities; the standard alloy should therefore contain about as much Zn as the specimen under test, or alternatively graphite electrodes soaked in a solution of the alloy should be used for exciting the spectrum. Good results m ay also be obtained by using th e alloy as one electrode and a Zn rod as the other. A. R. P.
A lu m in o th e rm y . J . Ga l i b o u r g (Chaleur et Ind., 1938, 19, 381—384).—I t s applications are
reviewed. ' R. B. C.
E le c tro d e p o s itio n of s ilv e r f r o m so lu tio n s of s ilv e r n it r a t e i n p re s e n c e of a d d itio n a g e n ts . R. Ta f t and L . H. Ho r s l e y (Trans. Electrochem.
Soc;, 1938, 74, P reprint 6, 77—90).—The effect of ad
dition of 140 org. compounds and 30 inorg. salts has been investigated under standard conditions, viz., 30°; c.d. 0-5 amp. per sq. dm.; [AgN03] 0-25m.
In general, colloids of mol. wt. > 25 0 produce abnormal or striated deposits, and certain higher aliphatic and cyclic acids and inorg. salts give fine cryst.
deposits. H C 02H, AcOH, and E tC 0 2H do not give fine-grained deposits; (CMe.‘N-OH)2 and
CHPh!CH,C02H give a striking coarse cryst. structure.
The d ata are illustrated by 30 photomicrographs, and the compounds are suitably classified. C. R. H .
In flu en ce of th e s u rfa c e c o n d itio n of th e b a s is m e ta l o n th e p ro te c tiv e a c tio n of e le c tro p la te d c o a tin g s a g a in s t c o rro s io n . M. Sc h l o t t e r and H. Sc h m e l l e n m e i e r (Z. Metallk., 1938, 30, 178—
181).—The effect on the porosity of various thick
nesses of Sn and N i plate on Cu of the smoothness of the Cu has been determined, using a special apparatus for measuring the brightness of metallic surfaces. The results show th a t porosity is the dess the smoother and brighter is the surface to which the plate is apphed; hence for adequate protection thicker coatings m ust be apphed to rough surfaces th an to smooth, and specifications should there
fore mention no t only the thickness of plate bu t the degree of polish to be given to the basis
fore mention no t only the thickness of plate bu t the degree of polish to be given to the basis