B asic B essem er process. Considerations of its p ossibilities in England. V. H a r b o r d (Iron & Steel Inst., May, 1931. Advance copy. 17 pp.).—Considera
tion of the justification of the erection of a basic Bessemer plant would rule out the Cleveland and S. Wales districts, due to lack of local ore. Northamp
tonshire and Lincolnshire are more favoured and with an admixture of foreign high-P ore the total costs would compare well with those of Belgian or Luxemburg works. The plant would have to restrict its production to mild steel for re-rolling into miscellaneous semi
finished products, as the process is not controlled suffi
ciently accurately for high-class structural work. Some of the most im portant factors in favour of the Bessemer process are the lower labour costs, fuel costs, and depre
ciation, and the higher credit for slag ; the total saving is estimated at 7s. per ton. Typical analyses of North
ampton, Rutland, Lincoln, Luxemburg, and Lorraine ores, and comparative costs of basic Bessemer and basic open-hearth processes are given. C. A. Kin g.
B last-furnace data and their correlation. II.
E. C. E v a n s , L. R e e v e , and M. A. V e r n o n (Iron & Steel Inst., May, 1931. Advance copy. 6 8 pp.).—The mathe^
matical expression of Evans and Bailey (B., 1928, 405) has been confirmed, the figure for C used other than at the tuyeres being calc, from gas analyses. The curve showing the Fe-C relation is of hyperbolic form, which indicates th a t beyond a certain output further advant
age is counterbalanced by increased C requirements.
The mean time of stock descent for optimum fuel con
sumption and output is lower writh rich than with poor burdens, and the most im portant factor in efficiency is effective contact between ore and gas. This leads particularly to careful control in treatm ent of ore and quality of coke. Owing to the disparity in external heat losses in winter and summer, investigation into any advantage in insulation of the shaft is necessary.
C. A. Kin g. Blast-furnace slag and its utilisation. E. I.
Or lo v (Ukraine Chem. J., 1930, 5 , [Tech.], 139—153).—
An exposition of the methods of treatm ent of slag for conversion into industrial products. R. Truszkow's k i.
Fuel control in the iron and steel industry.
G. V. S lottm an (J. Inst. Fuel, 1931, 4, 275—280).—
The manufacture of 1 ton of steel from iron ore requires
the energy of 2 tons of coal. Economy is obtained by utilising the heat of blast-furnace gas, coke-oven gas, and flue gas, the fluctuations of load being carried by a gasholder, and auxiliary coal firing. Present tendencies in combustion control, gas cleaning, and regenerator furnace and burner design are discussed.
D. K. Mo o r e. Production econom y in iron and steel works. I.
O. Cr o m b er g (Iron & Steel Inst., May, 1931. Advance copy. 17 pp.).—The desirability of a systematic method of production-costing by timing the various work stages of manufacture, and of the co-operated working between
“ order ” and “ stock ” departments, with a view to a more continuous process output, is examined.
C. A. Kin g. Effect of carbon and silicon on the growth and scaling of grey cast iron. A. L. N o r b u r y and E.
M o r g a n (Iron & Steel Inst., May, 1931. Advance copy.
2 2 pp.).—Dilatometer measurements on grey cast irons containing 4—2 • 1% total C and 1 • 6—7 • 6% Si indicated th at as the Si increases up to 3—4% the growth increases.
W ith higher Si content decrease in growth resulted, due to the Si raising the crit. point and also increasing the resistance to oxidation. Accelerated growth tests in an atm. of moist C02 confirmed these results, and the increase in Si is so effective th a t growth and scaling may be reduced to negligible quantities even under severe service conditions. A mixture of C02 and S 02
was found to be particularly severe in its action. Growth is due to conversion of combined C into graphite, both external and internal oxidation, and the formation of cracks, which are caused probably by the lack of duc
tility in the metal or surface-oxidised layers. Irons containing 4—10% Si in conjunction with finely-divided graphite are being developed commercially.
C. A. Kin g. Constitution of [iron] scale. L. B. P f e il (Iron &
Steel Inst., May, 1931. Advance copy. 19 pp ; cf. B., 1929, 437).—The microstructure and cooling curves of the range of composition of Fe oxide, as found in iron scale, has been studied. Pure oxides of desired composi
tion were prepared by mixing oxides of high and low Fe content followed by prolonged heating in vacuo to attain homogeneity. Most of the refractory oxides were definitely soluble in Fe203 and P t boats were used for melting the oxide. In the F e 0 -F e203 system the f.p.
decreased with increasing Fe content, but w-ith more than 77% Fe contamination of the couple rendered the results valueless. Double arrests on the curve occurred with 75-5, 74-84, and 74-5% Fe, only one arrest with 73-86% Fe, and double arrests appeared again below this value. The F e203 phase probably dissociates at high temp, with formation of magnetite. The equi
librium composition at 1000° of Fe203 was 70-3% Fe, of magnetite 72-35—72-5% Fe, and of the ferrous phase 76-9%. The last-named never corresponds to the compound FeO (77-75% Fe) without the presence of metallic Fe. The microstructure of scale produced by the oxidation of pure Fe at high temp, in air consists of all three phases. C. A. K in g .
Form ation of ferrite from austenite. (S ir ) H. C.
H . Ca r p e n t e r and J. M. Rob ert so n(Iron & Steel Inst., May, 1931. Advance copy. 35 pp.).—Experiments with
B r itis h C h e m ic a l A b s t r a c t s — B .
636 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.
three C steels cooled a t four different rates show th at the mode of formation of ferrite from austenite is con
trolled by the rate of cooling and the C content of the austenite. The two factors act in a similar way, by influencing the growth of ferrite through their effect on the diffusion of C in the austenite. These factors do not completely determine the final structure, however.
Three types of ferrite crystals are distinguished : (1) smooth crystals, sometimes rounded and sometimes sharp in outline, (2) irregular crystals, and (3) elongated crystals th a t form along the crystallographic planes in the austenite. A certain rate of cooling and concentra
tion of C in the austenite are necessary in order to pro
duce elongated crystals, but an increase in the rate of cooling or C content brings about a progressive change in the shape of the ferrite crystals. Ferrite always appears, in the first instance, a t the boundaries of the austenite grains, but the manner of its growth in these regions varies with the rate of cooling and the C content.
Large masses of residual austenite always transform into pearlite, but films may give rise to cementite. By decreasing the size of the particles of residual austenite an increase in the rate of cooling favours this formation, but by tending to promote the formation of more nuclei in a given Vol. it causes even the smallest particles to transform into pearlite. An increase in the rate of cooling has two opposing effects, therefore. These results are embodied in a theory of the structural change.
The factors, C content and rate of cooling, exercise their control through their effect on (1) the temp, at which the change begins, (2) the diffusion of C in the austenite, (3) the amount of C taken up by the ferrite, (4) the extent to which ferrite crystals coalesce. The work described includes many types of ferrite-pearlite structures and provides further information on the W idmanstatten and banded structures, the sub
boundaries in ferrite, and the cementite boundaries in
low-C steel. E. S. He d g e s.
Sub-crystalline structure of ferrite. G. 0. Ba n
n is t e r and W. D. Jon es (Iron & Steel Inst., May, 1931.
Advance copy. 15 pp.).—Three different types of sub- crystalline structure in ferrite have been observed in the microscopical examination of wrought Fe. Type I is associated with the presence of P in the metal and has been observed in wrought Fe and mild steel. I t is detected after deeply etching a polished surface with 5% H N 03 in EtOH. Etching reagents containing CuCl2 also develop the structure readily. No trace of the structure can be detected after annealing for 5 hr.
a t 820°. Type I I has been found in bars of wrought Fe, but is most readily distinguished in specimens after prolonged annealing in an atm. of H. This structure consists of a distinct veining of the ferrite crystals.
Type I I I has been found in wrought Fe specimens after prolonged etching with H N 03 and is a modification of type I I structure. I t is generally found in isolated crystals, although it sometimes affects a considerable area as fine markings. Annealing the specimens, followed by mild quenching, causes disappearance of this struc
ture. I t is suggested th a t types I I and I I I are mani
festations of microscopical or sub-microscopical inclu
sions in the metal. The effects of such inclusions are
discussed. E. S. He d g e s.
X-R ay investigations on the crystal structure of hardened steel. E. O h m an (Iron & Steel Inst., May, 1931. Advance copy. 19 pp.).—X-Ray spectrographic examination of hardened steels has confirmed that tetragonal martensite (a') is a supersaturated solution of C in a-Fe. On effective quenching, the a'-phase has the same C content as the y-phase from which it was formed. The most probable distribution of the C atoms is a complex substitution of a group of two C atoms for one Fe atom. Decomposition of the a'-phase on tempering takes place continuously with a progres
sive decrease of the axial ratio. Causes of the hardness of quenched steel are discussed, and it is concluded th at all the known causes producing hardness may contribute
to this end. E. S. H e d g e s .
Accelerated cracking of m ild steel (boiler plate) under repeated bending. W. R o s e n h a i n and A. J . M u r p h y (Iron & Steel Inst., Mar., 1931. Advance copy.
20 pp.).—When bending occurs a t intervals of 24 hr.
with intervening rests, the metal being continuously submerged, visible cracking and fracture occur at earlier stages in tap water and brine than in air or a 50% solution of NaOH. The greatest reduction in endurance is produced by tap water. When there is no interval between successive deflexions the endurance is the same in all four media. C. A. K in g .
Surface décarburisation of steel at heat-treating tem peratures. W. E. J o m in y (Dept. Eng. Res. Univ.
Michigan, 1931, Bull. No. 18, 51 pp.).—Of all the constituent gases of a gas-furnace atm. moist H had by far the greatest decarburising action, which was apparent on heating steel for 24 hr. at 540°. Dry H had little effect in 1-hr. heating a t 870°, whilst pure N caused no décarburisation. Steel was decarburised by C02 at 730° and above, though there was less activity when mixed with 50% of steam, which by itself had only a slight effect at 788°, at which temp, air produced little décarburisation in 5 hr. Variations in pressure (i— H atm.) or in the rate of flow of the gases were negligible. The more strongly oxidising is the furnace atmosphere (as measured by the percentage of free O), the less the tendency to decarburise ; conversely, increasing the excess of gas increased this tendency, and consequently no relief from décarburisation is to be expected by using a high ratio of gas to air, although scaling is reduced by such means. Heating in a so- called neutral or slightly oxidising atm. is recommended ; e.g., with 4% of free 0 ordinary carbon steel may be heated at 840° for 1 hr., whereas 10 min. is the limit if 2% of CO is present. Tables of limiting times and compositions of furnace atm. are given. C. A. K in g .
X -R ay in v estig atio n of c e rta in nickel steels of low th e rm a l expansion. G. Phragmén (Iron & Steel Inst., May, 1931. Advance copy. 10 pp.).—An X-ray spectrographic examination of iron-nickel alloys con
taining about 36% Ni has shown th a t the low thermal expansion of these alloys is a property of the face- centred cubic phase. The low coeff. of thermal expan
sion is not due to a two-phase reaction, which com
pensates the normal dilatation of the two phases, and there does not appear to be any reason to assume the presence of a body-centred cubic phase in the
B r itis h C h e m ic a l A b s t r a c t s — B .
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. 037
low-expansion alloys. In alloys containing 20—40% Ni the size of the elementary cube increases with the Ni content, but with greater amounts of Ni it decreases with the Ni content. E. S. He d g e s.
A lloys for u se at high tem peratures. Complex iron-nickel-chrom ium alloys. III. Effect of com position and exposure to high tem peratures.
C. H. M. Je n k in s and H. J . Ta p s e l l(Iron & Steel Inst., May, 1931. Advance copy. 29pp.; cf. B., 1931, 24).—
The results of short and prolonged stress tests at 800°
have been studied in relation to composition with alloys containing Ni 30, Cr 30, W 4, and (Fe -f- Si + C) 36%. After heating between 600° and 1100°, alloys of this type undergo an increase in Brinell hardness and a change in microstructure. The most suitable alloys for stress resistance appear to be those which maintain, after the initial period, a fairly constant Brinell hardness after exposure to high temp. The greatest resistance to prolonged stress occurs in the alloy containing C 1-5% and Si 1%. In view of the high percentage of Ni and Cr, these alloys remain in the austenitic condition throughout the temp, range between their m.p. and room temp. The hardening action cannot be ascribed, therefore, to the suppression of the transformation in Fe. An alloy otherwise similar, but free from W, exhibits similar changes of microstructure, but undergoes no appreciable increase of hardness on heat-treatment. The strength of the W-free alloy under prolonged tensile tests is low. The phenomena described bear some resemblance to the age-hardening of A1 alloys. The hardness changes appear to occur simultaneously with the separation of a new constituent, but it is possible th a t hardness changes due to other phase separations may occur and not be accompanied by a visible structural change.
The extent and velocity of the changes differ widely in the various alloys examined. On account of the gradual changes which produce hardening, these materials retain their high initial strength for long periods at 800°. The somewhat narrow range of composition in which the most favourable properties occur appears to be associated with the separation of a special com
pound or phase. The tendency of a material to harden at the service temp, is probably accelerated by deforma
tion, such as is likely to occur in an alloy subjected to high stress in service. E. S. He d g e s.
Resistance of copper-nickel steels to sea action.
J. N. Fr ie n d and W . We s t (Iron & Steel Inst., May, 1931. Advance copy. 5 pp.).—Test-bars were sub
jected to the action of sea-water as in previous work (B., 1927, 844) for 2 years. The addition of Cu up to 3-7% increased the resistance of steel to corrosion.
The most resistant alloy contained I -16% Cu and 3-75% Ni. In general, forged alloys suffered slightly greater corrosion than corresponding annealed bars, but there was no general correlation with fineness of
grain. C. A. Kin g.
Resistance of m etals and alloys to the action of salt solutions. II. Solid sa lts. III. Aqueous solutions. E. M a a s s and W . W i e d e p .h o lt (Korrosion u. Metallschutz, 1930, 6, 241—250, 265—277 ; Chem.
Zentr., 1931, i, 1161—1162).—II. The action on Ni,
Cu, Fe, and their alloys, and on A1 alloys depends on the moisture-attracting power and the nature of the anion. MgCl2 had the greatest, and MgS04 the least, ac tio n ; carnallite, “ Iiartsalz,” KC1, and NaCl were also used. Ni-Cr steels were most resistant; a- and (3-brass gave white corrosion products.
III. In sylvine, carnallite, Na2S04, and MgS04
solutions, Fe suffers the greatest, and Ni-Cr steels the least, corrosion. Sylvine causes the greatest corrosion.
The degree of corrosion is, in general, less than with the solid salts. Materials containing Cu acquire a protective layer when treated with MgS04. Access of O increases the corrosion. A. A. Eld rid g f,.
Effect of sodium chloride solutions on the course of corrosion. E . K. 0 . S c h m id t (Korrosion u. Metall
schutz, 1930, 6, 250—255; Chem. Zentr., 1931, i, 1161).—The effects of repeatedly dipping lautal rods in NaCl solutions (1—20%) on the physical properties are described. A. A. E l d r i d g e .
Unusual corrosion problem s. F. B. P o r t e r (J.
Amer. Water Works’ Assoc., 1931, 23, 534—537).—
Failure of boiler tubes and oil-well piping has been attributed to internally generated electric currents produced when steel is in contact with an electrolyte and when there are differences in temp, and composition.
p s values of 9-0 or over are recommended as a means of preventing corrosion in pipe lines and in boiler steam drums below the water line. I t is advisable to mix some boiler water with a feed of turbine condensate and distilled water make-up to reduce corrosion in the
economisers. C. J e p s o n .
Chloride volatilisation process [for ores]. R. II.
B r a d f o r d and C. M. M a c f a r l a n e (Univ. Utah Dep.
Min. Met. Res. Tech. Paper, 1928, 3, 21 pp.).—CaC03
was increasingly deleterious to chloride volatilisation as the amount in the gangue increased above 2 0% ; HoO vapour was beneficial with ores having a high calcareous gangue. HC1, which was a more active chloridiser than NaCl or CaCl2, was prepared by spray
ing a solution of CaCl2 or NaCl into the roasting furnace, S i02 being necessary with NaCl. For a Cu ore an atm.
containing 4—1 1% O is desirable.
C h e m i c a l A b s t r a c t s . Developm ent of processes for treatm ent of crude ore, accum ulated dum ps of tailing and slim e at Broken H ill, N .S.W . M e m b e rs o f t h e B r o k e n H i l l B r a n c h o f t h e A u s t r a l . I n s t . M in . M e t. (Proc. Austral. Inst. Min. Met., 1930, 379—444).—
A n historical account is given of the development of flotation processes on the Zn-Pb ores of the Broken Hill district. ' A . R. P o w e l l .
Com position and exam ination of som e blendes.
G. Fr e e (Chem.-Ztg., 1931, 5 5 , 353—354).—Notes on the various impurities which occur in blende concen
trates in different parts of the world and their effect on the determination of Zn and Pb in the blende.
A . R. P o w e l l .
E lectrolytic determ ination of copper in steel.
L. A n d e r s o n (Chemist Analyst, 1931,20, No. 2, 7—8).—
The metal (5 g.) is dissolved in 3A7-H2S 04 (100 c.c.);
the residue is treated with hot dil. H N 03 and the filtrate is electrolysed. Ch e m ic a l Ab s t r a c t s.
B r itis h C h e m ic a l A b s t r a c t s —B .
638 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.
Electrogalvanising of w ires and strips at high current densities. D. V. S te p a n o v , B . D. K a b a n o v , and N . T. K u d r i a v t z e v (Tzvet. Met., 1930,1151—1158).
—Circulation of the bath permits the use of higher c.d.
than usual (200—400 am p./dm.2). At 50 am p./dm.2
H 20 (30 litres), H 2S 0 4 (1 kg.), and H 3B 0 3 (10 g.) must be added to a 1 0 0 0-litre bath per hr. ; the best temp, is 45°. At higher c.d. the temp, should be higher. Cooling is effected by air-stirring. Tables show the change of voltage with temp, and with the distance between the electrodes, and optimal conditions for c.d. of 50,100, and 200 amp./dm.2 are specified. C h e m ic a l A b s t r a c t s .
Gas producing in steel w orks.—See II. Na3P 0 4.
—See VII. Refractories for furnaces.—See VIII.
Pa t e n t s.
Cupola furnace operation. V. S. D u r b i n (U.S.P.
1,778,524, 14.10.30. Appl., 11.2.29).—The furnace is provided with two sets of tuyeres, one some distance above the other. The melting is started with the lower set open and the upper set closed, and after tapping the metal produced the furnace is run with the upper set open and the lower set closed. A. R. P o w e l l .
Operation of b last furnaces. J . C. H o p k in s and A. Oso l in (U.S.P. 1,780,485, 4.11.30. Appl., 13.5.29).—
The furnace is tapped with the blast on and plugging is effected by forcing a stream of moist clay from a “ mud gun ” against the stream of molten Fe.
A. R. Po w e l l. Annealing furnace. G. B. S h i p l e y and H. A l i n d e r , Assrs. to I n t e r n a t . N i c k e l Co., I n c . (U .S .P . 1,782,481, 25.11.30. Appl., 4.1.29).—A continuous furnace adapted for annealing tubes, rods, etc. is claimed. C. A . Kin g.
[M etal-]heating furnaces. R . E . E l l i s . F ro m R u s t F u r n a c e Co. (B .P . 346,381, 6 .1 2 .2 9 ).— A fu r n a c e fo r r e - h e a tin g b a rs , b ille ts , e tc . is d e sc rib e d .
B . M . Ve n a b l e s. Recovering [volatile] m etals [from slag]. U. A.
G a r r e d , Assr. to A n a c o n d a C o p p e r M in in g Co. (U.S.P.
1,782,418, 25.11.30. Appl., 8.4.27).—Pulverised coal, oil, or gas is introduced with air under high pressure into molten slag. The fuel should be in sufficient excess to reduce the metallic oxide to the volatile metal, which is later re-oxidised by the admission of air at low pressure. Cold materials or slag may be added to blast
furnace slag before this treatment. C. A. K in g . Heat-treatm ent of m agnétisable m etals [steel].
H. C. Kn e r r (U.S.P. 1,779,604, 28.10.30. Appl., 21.4.21. Renewed 11.3.30).—The steel is suspended within a magnetic field by means of a counterbalance wt. somewhat less than the wt. of the steel and heated until it loses its magnetic properties, whereupon it
H. C. Kn e r r (U.S.P. 1,779,604, 28.10.30. Appl., 21.4.21. Renewed 11.3.30).—The steel is suspended within a magnetic field by means of a counterbalance wt. somewhat less than the wt. of the steel and heated until it loses its magnetic properties, whereupon it