Calculation of carbon balance of m etallurgical furnaces. R. D. Pik e (Ind. Eng. Chem., 1928, 20, 1356—1361).—A systematic method of determining the carbon balance of a furnace is indicated. The general scheme is to calculate carefully the carbon passing up the stack, based on P it o t tube measure
ment, stack area, and gas analysis at the P itot tube station, and to equate this quantity to th a t introduced in the batch and fuel and also th a t in the gases which leak out of the furnace. Leakage is a considerable factor in fuel consumption, figures expressed as a percentage of the total flow being obtained as follows : secondary air outwardly from regenerators 23-4, outwardly from hearth 13-2, air inwardly to regenerators 21-9, inwardly through flue, valves, dampers, etc.
26-9. C. A. Ki n g.
Proposed new criteria of ductility [of m etals]
from a new law connecting the percentage elonga
tion w ith size of test piece. D. A. Ol iv e r (Inst.
Mech. Eng., 1929. Advance proof. 24 pp.).—Regarding the total elongation as made up of a general and a local extension, the total extension I and the original gauge length L are connected by the equation : I = a -j- bL, where a is a constant for the local extension. The value of a is approximately constant and independent of the cross-sectional area. The linear relation for each test piece confirms a law of the form kLa, and if plotted logarithmically a straight line is obtained which indicates that the constant k itself follows the law : k ~ a . A ?, where « and [3 are new constants. I t is proposed th at constants a and a should be adopted as criteria for ductility as they are constant for any grade of material and practically independent of the type and size of
test piece. C. A. Ki n g.
Corrosion and ru sting of alloyed and plain cast iron. P . K o t z s c h k e and E. P i v o v a r s k i (Arch. Eisen- hüttenw., 1928—9, 2, 333—340 ; Stahl u. Eisen, 1928,
48, 1716).—The distribution of graphite throughout grey cast iron, the amount of graphite present providing it is within the usual limits, and the physical charac
teristics of the graphite have no effect on the behaviour of the metal in corroding media. The resistance to corrosion by dilute hydrochloric acid increases with the silicon content to 1-5% Si, and the resistance to acetic acid increases with increasing silicon up to 3% ; on the other hand, silicon greatly reduces the resistance of cast iron to alkaline solutions, hence for general purposes this constituent should be kept as low as possible.
Nickel up to 6% increases the resistance to alkaline media, but has no effect in improving the acid-resisting properties of the metal. Cast iron with 0-5—1% Cr and 2 • 5% Ni resists corrosion by alkalis very well and by acids fairly well, but the addition of chromium introduces serious difficulties in working the metal.
The rate of oxidation of cast iron in a moist atmosphere is decreased by about 25% by the addition of 0 ■ 3—0 • 4%
Cu, but the resistance to acids is not improved by up to
0-9% Cu. A. R. Po w e l l.
Mechanical properties of steel w ire drawn at high tem peratures in relation to the degree of reduction, the tem perature of drawing, and the carbon content. A. Po m pand W . Kn a c k s t e d t (Mitt.
K .-W . Inst. Eisenforsch., 1928, 10, 117—174; Stahl u.
Eisen, 1928,48,1705—1712).—The inechamcal properti es of soft iron (0-03% C) wire and of three mild-steel wires (O'35, 0-70, 0-84% C) have been determined after drawing to varying degrees of reduction at temperatures between 20° and 300°. The soft iron wires had a struc
ture composed of medium-grained ferrite, whilst the structure of the steel wires was purely sorbitic. In all
Cases an increase in the drawing temperature up to 300° resulted in a considerable increase in the values obtained for the elastic limit, yield point, and breaking strain, but the iron wire rapidly became more brittle in torsion tests with rise in drawing temperature. Iligh- temperature drawing (200—300°) is to be recommended, however, for the steel wires owing to the great increase produced in the elastic limit with only a very slight decrease in the torsion strength. The paper contains a number of graphs showing the results obtained for all the four wires tested together with a full discussion.
A. R. Po w e l l.
Theory of steel hardening. E. Sc h e il (Arch.
Eisenhiittenw., 1928—9, 2 , 375—388; Stahl u. Eisen, 1928, 48, 1776—1777).—On quenching a steel with 0 • 93% C the transformation from austenite to martensite is more complete the greater is the rate of cooling; it may be rendered still more complete by cooling below 0°.
I t is therefore assumed th at tensile stresses accelerate the transformation whereas compressive stresses retard i t ; this would explain the further transformation th at takes place below 0°, as the difference between the coefficients of expansion of austenite and martensite would cause the development of tensile stresses in the residual austenite. Annealing tests on a martensitic steel showed a transformation to take place at 100°
and a second change at 300®, whereas the transformation point of austenite in the same steel was 250°. The transformation of austenite into pearlite can take place directly or through a series of intermediate ste p s;
B r itis h C h e m ic a l A b s t r a c t s — B .
9 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.
above 300° direct transformation ensues on annealing, whereas below 250° the second form of martensite is first produced. A third possibility is th a t separation of carbide from the supersaturated austenite is the first phenomenon to be observed. Which of these changes takes place depends on the number of nuclei present and the rate of crystallisation of the various decomposition products. A. R. Po w e l l.
Critical points of pure carbon steels. T. Sato
(Tech. Rep. Tohoku Imp. Univ., 1928, 8, 27—52).—
The transformation points of pure electrolytic iron and of pure carbon steels containing up to 1-55% C have been determined by measurements of thermal expansion and by magnetic analysis. The equilibrium diagram of the iron cemcntite system in the solid
state is given. C. W. Gibby.
Copper steel w ith a high carbon content. A. F.
Stogov and W. S . Me s s k in (Arch. Eisenhiittenw., 1928—9, 2, 321—331 ; Stahl u. Eisen, 1928, 48, 1743—1744).—The effect on the magnetic and mechanical properties of steel with 0-7—1-2% C of the addition of 1—5% of copper has been determined. In all cases the coercivity and the product of the coercivity and remanence arc increased more or less proportionally to the copper content, whereas the A rl point is lowered and the temperature interval between the Arl and Acl points is widened. The tensile strength, hardness, and yield point of a copper steel in the annealed condition increase .with, increasing copper content, but the elongation, reduction in area, and impact strength reach a maximum with about 3% Cu. In the case of hardened and tempered copper steels the tensile strength increases with the copper content when the structure is hypereutectoidal, and decreases therewith when the structure is hypoeutectoidal. In the quenched and tempered state copper steels have a high yield point and ultimate strength combined with good elongation and reduction in area. A. R. Po w e l l.
Recovery of apatite from the residual slim es [of phosphatic iron ores] b y flotation. W. Lu y k e n
and E. Bik r b r a u e r (Arch. Eisenhiittenw., 1928—9, 2, 355—359 ; Stahl u. Eisen, 1928, 48, 1775—1776).—
By flotation of the non-magnetic residue obtained in the magnetic separation of Swedish magnetite ores a yield of 75% of the phosphorus content was obtained in a concentrate assaying about 15% P, using about 1-8 kg./ton of sodium palmitate, provided th a t the tailings were dewat ered and the water was used repeatedly in the circuit to avoid losses due to precipitation of the flotation agent by the lime in the water or derived from soluble calcium salts in the ore residue.
A . R . Po w e l l.
Determ ination of oxygen in iron and steel.
0. Me y e r (Z. a n g e w . C h em ., 1928, 41, 1273—1276, 1295—1298).— A c o m p r e h e n s iv e r e v ie w o f r e c e n t w o r k o n t h is p r o b le m . A . R . Po w e l l.
Rapid determination of silicon in iron-silicon alloys b y density m easurem ents. W. De n e c k e
(Giesserei-Ztg., 1928, 25 , 304—306; Chem. Zentr., 1928, ii, 275).—Schlumberger’s method is applied to iron-silicon alloys containing smaller percentages of
silicon, benzene being used as volumeter liquid. Alloys containing less than 21% Si gave a remarkable distri
bution of results. A. A. El d r i d g e.
Age-hardening of beryllium -copper alloys fol
lowed by X -ray exam ination. 0. Da h l, E. Ho lm,
and G. Ma s in g (Z. M eta llic., 1928, 20, 431—433).—
The a-phase of beryllium-copper alloys is cubic face- centred whilst the ¡3-phase is body-centred ; the alloy containing 2 • 5% Be shows only the a-diffraction pattern in rontgenograms taken after quenching from 800°.
Subsequent annealing a t 350° produces traces of y in 10 min. and considerable separation of y in 6 hrs. At 150° no y is detectable after 243 lirs., but the lines of the a-structure become somewhat blurred after only 4 hrs.
a t 150° and more distinctly so a t 200° after a very much shorter period. These results indicate th a t highly dispersed y separates a t temperatures below" 300° in a few ho urs, whereas at higher temperatures the precipitated particles are much coarser. During the separation of the highly dispersed y, the electrical conductivity falls rapidly and the hardness and tensile strength increase greatly owing to the high internal stresses set up by the lattice distortion accompanying the decomposition of
the a-phase. A. R . Po w e l l.
Changes of length and of the m odulus of elasticity of beryllium -copper alloys during age-hardening.
O. Da h land C. Ha a s e (Z. Metallk., 1928,20,433—436).
—The length of a rod of a beryllium-copper alloy with 2-5% Be quenched from 800° increases linearly with the temperature up to 150°. W ith further rise of tempera
ture the hardness begins to increase a n d ’the rate o f . expansion to diminish until at 280° the rod begins to contract. At 300° another small expansion takes place, but a t 350° another contraction occurs if the rod is maintained at this temperature for 1 hr. On cooling again contraction ensues linearly. Annealing the quenched alloy a t 250° causes a contraction over a period of 8 hrs., the curve of which is similar to th a t showing the increase in hardness over the same period ; the elec
trical conductivity falls rapidly to a minimum in 1 J- hrs., then increases linearly with time of annealing. Ageing a t 400° causes a rapid increase in the torsion modulus and electrical conductivity during 1 | hrs., followed by a very slow increase for a further 16 hrs. ; a t 150°, liowTever, the conductivity decreases with time of ageing and the torsion modulus slowly rises. These results are considered to support the precipitation theory of age-liardening. A. R . Po w e l l.
Effect of inhibitors on the acid dissolution of copper and copper alloys. II. 0 . Fo r r e s t, J. K.
Ro b e r t s, and B. E. Ro e t iie l i (Ind. Eng. Chem., 1928, 20, 1369—1371).—Evolution of hydrogen from copper is quite slow in dilute acids a t 75°, but increases rapidly at concentrations of more than 23% HC1. The attack is slow a t atmospheric temperature even in concentrated solutions. Inhibitors are not very effective until a high acid concentration is reached, and the rate of corrosion is decreased probably when depolarisation due to mole
cular hydrogen becomes sufficiently great. The requisite q uartity of inhibitor is th a t which is sufficient to form a film of the inhibitor substance or of reaction products
B r itis h C h em ica l A b s tr a c ts— JB.
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. 09
oil the metal, thereby decreasing the area effective for depolarisation ; greater quantities are of little value.
C. A. Ki n g.
Absorbability of gases in casting copper and effect of adding cuprosilicon. 0. W. El i,i s (Amer.
Inst. Min. Met. Eng. Tech. Pub., 1928, No. 123, 26 pp.).
—W ater vapour has a high solubility in copper, and causes formation of oxide. Silicon reduces cuprous oxide, and then removes gaseous oxygen. Copper melted in a reducing atmosphere contained carbon dioxide, nitro
gen, and water, but practically no cuprous oxide.
Oxidised copper in contact with charcoal absorbed carbon as mon- and di-oxides up to 21-9% of gas. The ratio of occluded di- to mon-oxide increased with rise of temperature, but the occluded gas never contained more than 80-5% by wt. of dioxide. Hydrogen was present in only small quantities, except when oil was used for melting, when it was produced possibly by interaction of cuprous oxide and methane, although carbon dioxide, carbon monoxide, and water are the chief gases occluded. Ch e m ic a l Ab s t r a c t s.
Effect of cadm ium on m echanical properties of brass. W. Ba n n a u (Amer. Met: Market, 1 9 2 8 , 3 5 ,
12—14).—Up to 0-5% Cd the structure of 70% and 60% copper-zinc alloys is unaffected ; with 1—4*5%
Cd, free cadmium is present. Lessened resistance to shock and low elongation are observed. In 55% Cu brasses 3-6% Cd does not diminish the tensile strength, but 1-8% Cd affects the ductility and brittleness.
Ch e m ic a l Ab s t r a c t s.
Effect of heat treatm ent on som e m echanical properties of 86 :4 :6 :3 :1 cop p er-nick el-tin- zinc-Iead alloy. II. J. An d e r s o n (Amer. Met. Market, 1928, 35, 1—3, 14).—The alloy shows wide variations in hardness for a given trea tm e n t; it is evidently of the solid solution type. Ch e m ic a l Ab s t r a c t s.
Cadmium as corrosion preventive for light m etals. J. Do r n a c f (Korrosion u. Metallschutz, 1928, 4, 97—102 ; Chem. Zentr., 1928, ii, 109).—Cadmium is a satisfactory corrosion preventive for aluminium alloys.
Only small potentials are set up between aluminium and cadmium, the latter being the electrode attacked.
Cadmium protects aluminium from the action of solu
tions of mercury salt« ; it also exerts a protective action on magnesium alloys. A. A. El d r id g e.
M echanism of rolling, ham m ering, and drawing zinc and cadm ium . 6. Ma s i n g (Z. M e ta llk ., 1928, 20, 425—427).— T h e c o e fficie n t o f lin e a r e x p a n s io n o f zin c a n d c a d m iu m r o d s a n d w ires is in c r e a se d v e r y c o n sid e r a b ly in a lo n g itu d in a l d ir e c tio n b y r o llin g , sw a g in g , or d r a w in g . T h is is a sc r ib ed t o t h e fo r m a tio n o f tw in n e d c r y s ta ls w h ic h c o m m e n c e s t o t a k e p la c e s im u lta n e o u s ly w it h t h e c o m m e n c e m e n t o f c o ld w o r k a n d c o n tin u e s t h r o u g h o u t t h e w o r k in g . A. R. Po w e l l.
T en sile properties of crystals of alum inium alloys w hich undergo age-hardening. G. Sa c h s
(Z. Metallk., 1928, 20 , 428—430).—Single crystals of 5% copper-aluminium alloy were prepared by annealing drawn wires a t 525° for 6 lirs., then a t 300° for 1 hr., stretching them l -5%, and annealing for 6 days at 450—515°. After quenching in cold water and ageing a t 100° for 30 min., tensile strengths of 33—45 kg./mm.2
were obtained without reducing the normal ductility.
X-Ray examination by the Lane method gave similar patterns for the annealed and age-hardened wires, and both broke along a plane a t an angle of 45° to the wire axis when pulled in a tensile machine. The age-hardened wires recrystallised at a lower temperature than annealed wires, and the new crystals produced were larger, other
wise no difference between the two could be detected.
A . R. Po w e l l.
Gold alloy “ 750/2.” Behaviour after cold-draw
ing and heating. W . He ik e and F. We st e k h o l t (Z.
anorg. Chem., 1928, 176 , 200—204).—The mechanical properties of the alloy of composition 75% Au, 4% Ag, 21% Cu have been studied with special reference to the time and temperature of heating and rate of cooling.
Ii. F. Gi l l b e.
Tantalum as a constructional m aterial for chemical apparatus. F. He in r ic h and F. Petzold
(Chem. Fabr., 1928, 689—691).—The inertness of tantalum towards corrosive solutions, with the exception of those containing hydrofluoric acid or the caustic alkalis, renders the metal particularly valuable for the construction of chemical apparatus, especially such as is required to withstand the action of aqva regia or hydrochloric acid. The metal is not attacked by mercury or any salt solution, but bromine dissolves it slowly and fused salts readily destroy it. Tantalum vessels should not be heated above 300° in any gas as rapid embrittlement ensues especially in gas mixtures containing hydrogen or nitrogen. A. R. Po w e l l.
Monel m etal as tower packing. G . We i s s e n- b er g erand L. Pi a t t i (Chem. Fabr., 1928, 703—704).—
Monel metal and aluminium gauzes were treated for 1 hr. a t 100° with 5% solutions of sulphuric, hydrochloric, acetic, and nitric acids. The loss of the monel metal gauzes did not exceed 0-11% with the first three;
with nitric acid it was 2-13%. Aluminium was as resistant to nitric and acetic acids as monel metal, but was attacked by sulphuric acid and particularly by
hydrochloric acid. C. Ir w i n.
Nickel anodes and the acidity of the solution. R.
G. Su m a n (Metal Ind., 1928, 26, 350).—For nickel plating, a solution of 6-1 is most efficient. The solution used contained 255 g. of single nickel salts and 19-8 g. of ammonium chloride in 3-8 litres of water.
The reaction varied with the composition of the anodes.
Ch e m ic a l Ab s t r a c t s.
Factors affecting the relative potentials of tin and iron. E. F. Koh m a n and N. H . Sa n b o r n (Ind.
Eng. Chem., 1928, 20, 1373—1377).—The electro
chemical relation between tin and iron is influenced considerably by the presence of organic acids such as are present in canned fruit. At concentrations equivalent to 0-75% of malic acid, tin is distinctly cathodic in acetic, malonic, and succinic acids, only slightly cathodic in malid acid, and distinctly anodic to iron in citric acid.
Addition of apple pomace to acetic, malonic, and succinic acids reverses the condition and the tin becomes anodic, a further protection to iron being also induced by the presence of tin in solution, which raises the cathodic polarisation on iron. In hydrochloric and sulphuric acids of concentrations ranging from 0-05 to
B r i t is h C h e m ic a l A b s t r a c t s — B .
1 0 0 Cl. X I.—El e c t k o t e c h n i c s.
20%, tin becomes increasingly more anodic to iron with increasing concentration of acid even when the metals are not in electrical contact, and corrosion of tin is very greatly increased with metallic contact, due to galvanic action. The potential conditions are influenced chiefly by the hydrogen-ion concentration and negligibly by the conductivity of the solution. The results agree with those of commercial practice in which the more acid fruits produce little perforation of the container, although less acid fruits, e.g., black cherries, in the juice of which tin is only mildly anodic to iron, cannot be canned successfully because of the hazards of corrosion.
C. A. Ki n g.
Influence of bism uth on the m echanical proper
ties of lead. 0. Ba u e r (Giesserei-Ztg., 1928, 25, 297—
299 ; Chem. Zen tr., 1928, ii, 286).
Nickel catalyst. Ba g.—See II. Lead pigm ents for iron protection. Ei b n e r and La u f e n b e u g.—See XIII.
Pa t e n t s.
Apparatus for the concentration of graphite and other ores b y flotation. J. F. M. R . d e Ro h il l a r d ( B .P . 275,673, 9.8.27. Fr., 9.8.26).—The sides of the flotation cell are provided with a number of small apertures covered with fine wire gauze, on to which streams of water are directed from jets of smaller cross-section than th a t of the apertures so as to cause bubbles of air to be drawn into the cell by the injector action of the water. A. R . Po w e l l.
Manufacture of [steel] containers for com pressed gases. H. E. St u r c k e (U.S.P. 1,692,521, 20.11.28. Appl., 8.5.24).—Fully annealed mild steel billets are formed into the required shape of container, these are annealed again, subjected to internal pressure corresponding with the ultimate test pressure, and then heat-treated to remove the mechanical stresses set up by this treatm ent. A. R. Po w e l l.
Separate production of iron, nickel, cobalt, or other m etals which form carbonyls, from m ix tures containing several such m etals. J . Y.
Jo h n so n. F ro m I. G. Fa r b e n i n d. A.-G. (B.P. 301,099, 25.6.27).—The product from which the metals are to be extracted is treated in a suitable way to obtain the free metals in a finely-divided form, the metals are converted into carbonyls, and the mixture of carbonyls is fractionally distilled in an atmosphere of carbon monoxide. E.g., chloanthite is heated at 550° in air and steam to expel sulphur and arsenic, and the oxides are reduced a t 450° in hydrogen. The product is treated a t 140° with carbon monoxide under a pressure of 180 atm ., the evolved gases are condensed a t — 20°, and the product is fractionally distilled, giving first nickel then iron carbonyl. The residual cobalt com
pound is purified by heating it a t 150° under 200 atm.
in carbon monoxide, and subsequently subliming the obalt tetracarbonyl. [Stat. ref.J A. R. Po w e l l.
Protection of articles m ade of brass and like alloys against discoloration. Ge n. El e c t r ic Co.,
Lt d., Assees. o f Pa t e n t-Tr e u h a n d Ge s. p. e l e k t r. Gl ü h l a m p e n m.b.H . ( B .P . 289,441, 25.4.28. G er.,
27.4.27).—Articles are heated, preferably at 500—
600°, in a current of reducing gases, e.g., a mixture
containing 80% of nitrogen and 20% of hydrogen, after being cleaned by pickling. J . S. G. Th o m a s.
Reduction of zinciferous m aterials. L. Me l l e r s h- Ja c k so n. From Ne w Je r s e y Zin c Co. ( B .P . 300,519, 8.8.27).—Agglomerates made by carbonising briquettes of fine oxidised zinc ore and a coking coal bonded with sodium carbonate as an accelerator of reduction arc passed through a long, narrow, horizontal, reducing furnace on a moving hearth containing a bed of fine ore on which is a layer of coarser ore. The charge is previously preheated in a recuperator or the coked briquettes may be discharged directly from the coking furnace to the hearth of the reducing furnace. The waste gases from the recuperator are utilised for heating the preheater or in the coking furnace. A. R. Po w e l l.
Manufacture of alum inium alloys. A. Ge y e r
(B.P. 284,722, 3.2.28. F r„ 4.2.27).—Cuprosilicon, cupromanganese, and/or iron are added to a bath of molten aluminium at 800—1100° under a layer of coal or other carbonaceous material, a small quantity of
(B.P. 284,722, 3.2.28. F r„ 4.2.27).—Cuprosilicon, cupromanganese, and/or iron are added to a bath of molten aluminium at 800—1100° under a layer of coal or other carbonaceous material, a small quantity of