Com parative properties of w rought iron m ade b y hand-puddling and by the Aston process.
H. S. Ra w d o n and D. A. Kn i g h t (U.S. Bur. Stand. J.
R e s ., 1929, 3, 953—992).—In the Aston process pig iron from the cupola is desulphurised by the addition of
B r itis h C h e m ic a l A b s tr a c ts — B .
37G C l. X .— Me t a l s ; Me t a l l u r g y, i n c l u d i n g El e c t r o- Me t a l l u r g y.
sodium carbonate to the ladle and then blown in a Bessemer converter, the purified metal being poured into a bath of molten slag of correct composition and the resulting “ ball ” squeezed into bloom and rolled as usual. Pipe made of this material has been compared with th a t made from wrought iron produced by the old hand-puddling process, the chemical composition of the irons being almost identical. The carbon content of the Aston iron was much more uniformly distributed th an th a t of the hand-puddled iron and “ carbon streaks ” were absent. The former had a slightly lower tensile strength and greater ductility than the latter, but other
wise there was little to choose between the mechanical properties of the two irons. The resistance to corrosion, machinability, and welding properties were the same in both cases ; thus Aston iron is equal in every respect to hand-puddled iron and can safely be used for the manu
facture of pipe to meet all the standard specifications.
A . R . Po w e l l.
M alleable iron : sh ort-cycle anneal. I . R . Va l e n t i n e (Metals and Alloys, 1929, 1, 233—234).—
The influence of time and temperature on the absorption of FesC into solid solution was investigated. The temperature of maximum precipitation of temper carbon is 700—750°. A new method of annealing is described. Ch e m ic a l Ab s t r a c t s.
Peculiar crystal grow th in iron and copper and its cause. R. Ku h n e l[with E. Ne s e m a n n] (Z. Metallk., 1930, 22, 53—54).—Two cases of extraordinarily coarse crystal growth in mild steel and one case in firebox copper are described and the cause of trouble (incorrect heat and mechanical treatm ent) is briefly explained.
A . R . Po w e l l.
Effect of tensile overstrain on the m agneto
striction of steel. J. S. Ra n k in (J. Roy. Tech. Coll., Glasgow, 1930, 2, 173—187).—Changes in the magneto
striction of steel which had been overstrained to varying degree have been plotted from observations by an oscillating-valve ultramicrometric method. High-carbon steels showed less magnetostriction than soft low-carbon steels, but the effect of hardening a steel by tensile overstrain was to increase the magnetostriction con
siderably, though this change in extension does not depend simply on the am ount of tensile extension. Erom consideration of results in conjunction with the work of Webster (Proc. Roy. Soc., 1925, 109A) it is suggested th a t when a rod of iron is overstrained the axes of a large proportion of the constituent crystals veer into the direction’of the longitudinal axis of the rod, arid it is necessary only th a t a m ajority of the grains be so arranged to account for the increase in magnetostriction.
C. A. Ki n g.
Creep of steel under sim p le and compound str esses. R. W. Ba i l e y (Engineering, 1930, 129, 265—266, 327—329).—Limiting creep stresses as measured a t present are not likely, even if they do exist, to have practical importance in the development of high- temperature steam plant. The examination of a tube from a superheater working a t 340° and 195 lb./in.2 indicated the spheroidisation of cementite which resulted in a reduction of creep resistance. In 0-9% carbon steel the reduction in stress for a given rate of creep was
about 25%, a less value being expected in steels of lower carbon content. Similar structural alteration is likely to be accelerated a t higher working temperatures. In view of the probability th a t creep continues a t stresses far below those a t which a t present measurement is possible, a creep rate of 10“8 tensile strain per hour being regarded as of material importance, steels a t initial steam temperatures and working stresses must not be classed as permanent and elastic material. Annealing of tubes before use is advisable as annealed steel requires a tem perature a t least 50° above th a t of the normal metal for spheroidisation to occur in the same time. Similar results were obtained from creep tests a t 540° in air and steam, and oxidation of machined steel was not localised under medium arid low stresses. Torsional tests showed th a t creep by shearing stresses a t a plane was not influenced by the normal stress on th a t plane, and from tests on lead pipes under internal pressure creep may be expected in the direction of the diameter only unless there is superimposed axial stress. C. A. Ki n g.
D eterm ination of carbon in h igh -m eltin g alloys, usin g the high-frequency induction furnace.
G. E. Sm i t h and G. L. Ho c k e n y o s (Ind. Eng. Chem.
[Anal.], 1930, 2, 36—38).—The determination of carbon in tungsten steels, stellites, and similar refractory alloys is greatly facilitated by carrying out the com
bustion with the aid of a high-frequency induction fur
nace in place of the usual resistance furnace. The sample (1 g.) surrounded by a weighed coil (6 g.) of soft iron of low (0-01%) carbon content is placed in a com
bustion thimble of alundum and clay. The whole is placed in a combustion tube of pyrex glass, set vertically in a water-cooled coil of flattened copper tubing. A 3-kw. mercury-arc converter is employed as the high- frequency induction equipment. The sample is burned in oxygen in the usual manner, combustion being started by the arc formed on the coil of soft iron when the power is applied. The method oilers the advan
tages th a t complete combustion even of refractory alloys is readily attained, and th a t the sample used may be in the form of chips or very coarse turnings. Full details are given of the complete apparatus employed.
II. F. Ha r w o o d.
Effect of depolarisation on speed of rusting.
F. To d t (Korrosion u. Metallschutz, 1929, 5, 169:—174 ; Chem. Zentr., 1929, ii, 2257).—Corrosion by oxygen depolarisation a t the cathode surface of local elements is m easurable; th a t found gravimetrically accords with th a t determined by measurement of the polarisa
tion current at a platinum surface in combination with iron. The corroding iron surface appears to consist of local elements composed of active and passive iron.
The practical significance of the experiments is dis
cussed. A. A. El d r i d g e.
Splayed m olten cadm ium coatings in gasoline storage tanks. L. Pe s s e l (Ind. Eng. Chem., 1930, 22, 119—121).—Corrosion tests were run for 60 days with pieces of steel plate coated with (a) zinc, and (6) cadmium immersed in petrol, to which was added distilled water, sea-water, sulphur, or an organic lead compound with distilled water. The liquids were agitated daily with air. The plates were then photo
B r itis h C h e m ic a l A b s tr a c ts — B ,
C r;. X . — -Me t a l s ; Me t a l l u r g y, i n c l u d i n g El e c t r o- Me t a l l u r g y. 3 7 7
graphed and the sludge was weighed. Uncoated plates showed heavy corrosion and pitting ; zinc-coated plates produced a considerable am ount of sludge from the zinc, though the steel was undam aged; cadmium- coated plates showed some corrosion with sea-water, but none with the other liquids. The lead compound apparently increases the corrosiveness of petrol. It is considered th a t cadmium spraying of storage tanks may be worth while in spite of the high price of the metal.
C. Ir w i n.
Influence of initial state on variations in hard
ness resulting from cold-w orking of certain m etals and alloys. Gu i c h a r d, Cl a u s m a n n, and Bil l o n
(Compt. rend., 1930, 190, 468—470; cf. B ., 1930, 331).—Using the method previously described, the relation between deformation (D) and hardness has been iuvestigated for the same metals unaunealed. Silver, copper, and copper-nickel alloys gave identical results.
Unannealed silver-copper alloys showed increased hardness throughout, the excess decreasing from about 60% for D = 0 to 20—35% for D = 90 ; the excess increases as the percentage of copper decreases.
C . A . SlLB ER RA D .
Kinetics of the eutectoidal decom position of y- bronzes. O. Da h l (Z. Metallic., 1930, 22, 48—52).—
Various bronzes having a composition within the (a+ y)- and (a + S)-ranges have been quenched from above the eutectoid transformation line at 520° and the mechanism of the changes which occur on annealing at 150—400°
has been studied by hardness-time and electrical resist
ance-time measurements. At 220—300° the resistance at first increases rapidly to a maximum, then decreases sharply to an ill-defined minimum, and finally increases slowly and regularly; a t 150° only the first increase is observed, and at 400° this increase does not occur at all. The first increase in resistance is attributed to the beginning of sub-microscopic precipitation of a, the subsequent decrease in resistance to the separation of a from the y-solid solution, and the final increase to the eutectoidal decomposition of the remaining y into (a -j- 8). Ageing at the lower temperatures results, therefore, in the formation of a supersaturated y-phase, which is unstable a t higher temperatures and which cannot be obtained by quenching alone. During the precipitation of a in the early stages age-hardening of the alloys occurs to a small extent. Similar phenomena have been observed in a [3-aluminium bronze with
11% Al. A. R. Po w e l l.
Technical an alysis of m anganese bronzes.
G . Se u f e r t (Chem.-Ztg., 1930, 54, 155—156).—The separations of manganese by hydrogen peroxide in ammoniacal solution and by persulphate in acid solution have been examined. In the electrolysis for copper the lead peroxide separated a t : the anode contains some manganese, from which it is freed by redissolving and again electrolysing. From the com
bined liquors manganese and iron are thrown down free from zinc, nickel, etc. by double precipitation with hydrogen peroxide in ammoniacal solution, and the manganese is separated by the persulphate method.
S . I . Le v y.
Effect of lead on the (a. + (3)-[3 equilibrium in a 60/40 b rass (Muntz m etal). L. R. v a n We r t
(Met. and Alloys, 1929, 1, 200—205).-—When the alloy (Pb 0-04—1*76, Fe 0-02—0-03%, Sn nil) was quenched in ice water after 0-5 hr. a t 750°, lead seemed to confer no added solvent powers on the (3-solution ; the solu
bility of a in 6 is decreased. After 0-5 hr. a t 800°
no undissolved a-brass was found in the alloy of lowest lead content, but considerable residual a-brass was found in the alloy of highest lead content. When the quenching temperature was 850°, the low-lead brass showed only ¡3-brass ; the higli-lead alloy still contained a-brass. The presence of lead increases the precipita
tion of the a-phasc from the supersaturated solution formed by quenching. Ch e m ic a l Ab s t r a c t s.
P ossib ilities of production of radium and vanadium from carnotite. H. A. Do e r n e r (Ind.
Eng. Chem., 1930. 22, 185—189).—The carnotite of Colorado and U tah was worked first for vanadium, afterwards for radium, bu t the practice is now discon
tinued. Production costs are discussed and it is concluded th a t the mechanical concentration of low-grade ore offers the best prospect of cheaper radium production, especially if an ore containing a t least 1% U30 8 can also be treated for vanadium. The carnotite forms un
desirable incrustations on sand grains, which must be removed by roasting. A metal trough with a double row of agitating paddles and fed with jets of compressed air is effective in separating carnotite dust from sand.
A concentrate so prepared may be treated with sul
phuric, hydrochloric, or nitric acid, but each method involves difficulties. The use of sulphuric acid might be possible if the large excess of acid were recovered by distillation. The alternative method of removing the gangue, principally silica, by alkali fusion is too expensive for a dust concentrate, and removal with hydrofluoric acid also appears doubtful. In the event of carnotite being again worked for vanadium it is urged th a t radium slimes should be stored for future
use. C. Ir w i n.
Preparation of pure electrolytic nickel. I.
E lim ination of copper from nickel-copper electro
ly tes. C. G . Fi n k and F. A. Ro h r m a n (Amer. Electro- chem. Soc., June, 1930. Advance copy. 14 pp).—The effects of various factors on the current efficiency of copper deposition from solutions of nickel and copper sulphates during electrolysis for 1 hr. have been studied.
A high ratio of copper to nickel, high acidity, low current density, high temperature, and vigorous stirring lead to a high efficiency of copper deposition. From a well- stirred V-nickel sulphate solution containing 1 g./litre of copper at 55°, electrolysis at 1 amp./dm.2 for a time theoretically sufficient to deposit all the copper actually deposited over 90% of it. The principles underlying the separation and their application to the refining of com
mercial nickel are discussed. II. J. T. El l i n g h a m.
E lectrolytic cadm ium deposits as a ru st pre
ventative. B. Pl a n n e r and M. Sc h l o t t e r(Z. Metallk., 1930, 22, 41—47).—The grain size of cadmium deposits obtained from various acid and alkaline plating baths with and without addition of colloids has been investi
gated. Satisfactory deposits are obtained from cyanide baths containing 0-175 g.-mol./litre of cadmium cyanide and 0-57 g.-m'ol./litre of potassium cyanide, using 50—
B r itis h C h e m ic a l A b s tr a c ts — B .
3 7 8 C l. X .—Me t a l s ; Me t a l l u r g y, i n c l u d i n g El e c t r o- Me t a l l u r g y.
100 amp./m.2 a t 40—60° ; addition of 5 g./litre of caffeine reduces the grain size appreciably, but sodium silicate has no action whatever. The current yield is raised by rise of temperature but lowered bv increase of current density in alkaline baths. In acid baths the current yield increases with rise of temperature and with the current density, but the grain size of the deposit also increases; hence it is advisable to work with current densities of 100—150 amp./m.2 at 40°. The grain size also decreases with increasing mol. wt. of the acid used, being coarse with perchloric, medium with liydrofluo- silicic, and fine with phenolsulphonic acid. Bright, lustrous, bu t very brittle and poorly adherent deposits of cadmium are obtained a t 0—15° with high current densities (700—800 amp./m.2) from acid baths con
taining organic colloids. A cadmium deposit of only 22 g./m.2 is stated to protect iron from corrosion in the salt-spray test more efficiently than a zinc deposit of 400—500 g./m.2 A. R. Po w e l l.
C adm ium plate. R. Ho p f e l t (Korrosion u. MetaU- schutz, 1929, 5 , 176—180; Chem. Zentr., 1929, ii, 2259).—The use of cadmium plate for culinary utensils is considered. In presence of acids, e.g., acetic, con
siderable amounts of cadmium are dissolved. For most domestic utensils cadmium-plated iron is, however, specially suitable ; cadmium-tin plate is recommended.
A. A. El d r i d g e.
Photo-electrom etallurgy. R. W. Dr i e r (Ind.
Eng. Chem., 1930, 22, 153—157).—The possibility of separating minerals or other materials on the basis of colour or lustre was tried by conveying screened par
ticles on a moving belt under a highly illuminated area.
Reflected light from certain particles actuated a photo
electric cell, and the current produced was relayed to operate a picking-up device which separated the particles of high reflecting power. In this way 60% of the silver in a mixture of silver and copper was separated, the silver to copper ratio being improved from 1 in 100 to 1 in 10. Separation of a mixture of babbitt metal and brass was less successful as the indices of reflection were too close, but by treating the mixture with hydrogen sulphide a wider difference was obtained. Separation of other minerals was effected, but the principal diffi
culty lies in the mechanical design of the separating
device. C. A. Ki n g.
Change of volum e of ca st iron during solidifica
tion. K. Ho n d a, T. Ea s e, and Y. Ma t s u y a m a. (Sci.
Rep. Tohoku, 1930,18, 699—714).—See B., 1930, 14.
p H control. Ma g n u s.— S ee I. Burner design for furnaces. Se i i. a n d o t h e r s .— S e e II. C orrosion of copper. Be i j.—S e e IX. M easurem ent of cor
rosion. Go l l n o w.— S e e X I. Determ ination of cobalt. He i m.— S ee X III.
See a ls o A., M a r .. 284, X-R ay an alysis of sy stem n ickel-b ism uth ( H a g g a n d F u n k e ) . S y ste m ’ lead - germ anium ( B r i g g s a n d B e n e d i c t ) . S ystem s ilv e r - copper-zinc ( U e n o ) . 285, T ernary sy stem C u-Sn-Sb
( T a s a k i ) . 299, E lectrolysis of alum ina ( Wa s i l e w s k i
a n d M a n t e l ) . 304, E lectrodeposition of chrom ium
( M u l l e r a n d E s s i n ) . 305, E lectrolytic preparation of m etals from fused borates ( A n d r i e u x ) . 309,
Pyrophoric iron ( Fi n z e l). 311, Reagent for sulphide m inerals (Wi l k e- Do r f u r t).
Pa t e n t s.
H ot-bli/st cupolas, (a) C. D. Ba r r a r id W . D. Mo o r e, (b) W . D.' Mo o r e, A s s r s . t o Am e r. Ca s t Ir o n Pi p e Co.
(U.S.P. 1,740,886 a n d 1,740,900, 24.12.29. A p p l., [a]
24.3.28, [b] 15.11.27. R e n e w e d [a] 9.11.29).—(a) T he h o t g a s e s f r o m j u s t a b o v e t h e m e l t in g z o n e a r e ’w ith d r a w n f r o m t h e f u r n a c e t h r o u g h a n a n n u l a r s p a c e f o r m e d by a s u s p e n d e d t u b u l a r a p r o n s p a c e d f r o m t h e w a ll an d h a v i n g p i p e s o r f lu e s l e a d i n g f r o m i t t o a p o i n t in the c u p o la a b o v e t h e c h a r g i n g d o o r . I n t h i s w a y d e p o s itio n o f s u l p h u r f r o m t h e g a s e s o n t o t h e d e s c e n d i n g c h arg e is a v o id e d , (b ) T h e c y l i n d r i c a l b o d y o f t h e f u r n a c e is b u i l t u p o f a n u m b e r o f v e r t i c a l , h o llo w s e c ti o n s w ith a t r a n s v e r s e l y c u r v e d s h a p e a r r a n g e d w i t h t h e i r edges a b u t t i n g , a n d e a c h b e in g i n d e p e n d e n t l y c o n n e c te d to a b u s t l e p i p e a n d t o a t u y e r e t o c o n d u c t a i r t h r o u g h th e s e c ti o n f r o m a b l o w e r t o t h e f u r n a c e . T h is c o n s tr u c tio n a d m i t s o f r e a d y r e p l a c e m e n t o f w o r n p a r t s w ith o u t d i s m a n t l i n g t h e w h o le f u r n a c e . A . R . P o w e l l .
Reverberatory furnace. W. F . Sk l e n a r, and Br it. Re v e r b e r a t o r y Fu r n a c e s, Lt d. ( B .P . 324,339,22.10.28).
—In a reverberatory furnace with a hollow' bed and a combustion chamber above, the tapping hole is above the normal level of the metal. From the other end of the bed a vertical shaft is provided with a charging door, above which pipes may be inserted to preheat the air required for combustion, or the shaft may be utilised for heating ladles of metal after tapping. C. A. Kin g.
Operation of an open-hearth furnace. W. T h i n k s
(U.S.P. 1,741,002, 24.12.29. Appl., 22.6.23).—Air ports are arranged symmetrically on either side of a central gas port, the normal air supply meeting the gas at the mouth of the gas port. From each air port a narrow duct leads air into the gas port- and a jet of compressed air is used to increase the velocity in these duct«. At the outgoing end of the furnace the je t of compressed air is maintained to prevent flue gases passing through the secondary air ducts. C. A. Kin g.
Open-hearth furnace structure and its opera
tion s. R. B. Ke r n o h a n, J. S. Lo c h h e a d, and W. Think s
(U.S.P. 1,741,025, 24.12.29. Appl., 1.10.21).—In an open-hearth furnace having a centrally disposed gas port and an air port above, small air ducts branch from the rising air-main into the gas duct. Jets of c o m p r e s s e d
air in these, subsidiary ducts increase the velocity of the
air current. C. A. Kin g.
Open-hearth furnace. R. B. Ke r n o h a n and J. S.
Lo c h h e a d (U.S.P. 1,741,024, 24.12.29. Appl., 29.10.20).
—Regenerated air a t a pressure of about 1-5 in. water- gauge is introduced into an open-hearth furnace through a port centrally situated, near the end of which port producer gas is also adm itted to effect better mixing and a more concentrated flame to be directed on to the bed of the furnace. Slag pockets are provided in con
junction with the port. C. A. Ki n g.
Open-hearth furnace. S . Tr e v e r t o n, A s s r. to Ce n t r a l Al l o y St e e l Co r p. (U.S.P. 1,741,666, 31.12.29.
A p p l., 8.9.27).—T h e w a lls o f t h e f u r n a c e a r e s te p p e d
B r itis h C h e m ic a l A b s tr a c ts —B .
C l. X I.— El e c t k o t e c h n i c s. 3 7 9
so th a t the lining may be renewed with loose material a t its natural angle of repose. The buckstaves are cranked to avoid large masses of idle brickwork filling.
B. M. Ve n a b l e s. M u ltip le-h earth r o a stin g fu rn ace. A . E . Wh i t e.
From Nic h o l s Co p p e r Co. (B.P. 324,471, 5.12.28).—In addition to hollow rabble arms the vertical, central shaft of a shelf roasting furnace is provided with sockets into which heat-absorbing arms may be fitted as re
quired to cool certain hearths. Air which has circulated through the rabble or the cooling arms m ay be con
ducted down an annular space in the shaft to heat similar arms over the cooler hearths lower down the
furnace. C. A. Ki n o.
R o a stin g and a g g lo m e r a tio n o f fin e ore or ro a stin g r e sid u e s. S o c . p o u r l’En r i c h i s s e m e n t e t lAg g l o m e r a t io n d e s Mi n e r a i s (B.P. 307,708, 11.3.29.
Ger., 10.3.28).—A furnace for roasting fine ores consists of a horizontal, endless, chain-grate conveyor totally enclosed so th a t uniform suction may be applied under the length of grate on which the material is roasted.
The grate is stationary during the actual roasting period, and is moved only during the charging and discharging operations. Ore may be roasted direct on the grate or on a bed of protective material, and is ignited by means of burners arranged above the grate. C. A. Ki n g.
C ontinuous p r o ce ss and furnace for th e th erm a l trea tm en t of m e ta ls e tc . In f r a, Assees. of V. So r r e l
and L. A. La f o n t (B.P. 306,446, 2.10.28. Fr., 20.2.28).
—An electrically heated, inclined, tube-furnace is pro
vided a t one point in its length with either natural or electro-magnets for the purpose of retaining magnetic materials within the furnace so long as they remain magnetic. When demagnetised by a sufficient duration of heating the material falls through the furnace by gravity either into an auxiliary chamber for further heat-treatm ent or into any suitable cooling medium.
C . A . Ki n g. A n n ealin g and h e a t-trea tin g fu rn a ces. A. T.
Ka t h n e r (B .P. 320,841 and 320,865, 16.4.28).—The furnace comprises a heating chamber and a cooling chamber in horizontal alinement, the cross-sectional area of the latter being less than th a t of the heating chamber and its length one third greater than th a t of the heating chamber. The tops of both chambers are composed of a number of arched sections which can be individually raised or removed for adm itting cooling air or for cleaning the conveyor mechanism which passes along the floor of both chambers (cf. U .S .P . 1,669,902 ;
B., 1928, 527). A. R . Powell.
T rea tm e n t o f s te e l c a s tin g s or oth er m e ta ls.
G. He r r m a n n and L. Ze r z o g (B.P. 325,307, 26.11.28).—
After annealing, a casting is cooled uniformly and rapidly by cither blowing or sucking air through the hollow' travelling hearth on which the casting rests, thereby causing a distribution of cool air around the metal.
The hearth may be built up of blocks having both
The hearth may be built up of blocks having both