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By G. R. Belton, Y. K. Rao

A galvanic cell, using liquid MgCl2 or MgC12-CaC12 mixtures as the electrolyte, has been used to determine activities in Mg-A1 liquid alloys between 700' and 880°C. The incovporation of a chlorine electrode in the cell also allowed measurements to be made of the standard free energy of formation of MgCl2(l). The results are shown to be in good agreement with thermo-chetrlical values from the literature, and this is taken as evidence that the small, known solubility of magnesium in iMgCl2 introduces no significant error in galcanic cell measurements. Within experimental error, the activity coefficients and relative partial molar enthalpies at 800°C are shown to be represented by the following "subregular" solution equations: logy~~ =-0.68(1 -xMgj3 log yAL =-1.02(1 - XMf + 0.68(1 - XMf H.M = -4400(1 - %)3 / cal Mg 7Ag' HZ =-6600(1 - xA1)' + 4400(1 - XMf cal SCHNEIDER and toll' have used a transpiration technique to measure the vapor pressures of magnesium over Mg-A1 alloys between 544" and 594°C. amsstad,' however, has since suggested that the extrapolation to zero flow rate, used by these authors in interpreting their apparent pressure vs flow rate data, gives unreliable results. Rogers, Tomlinson, and Richardson,3 in interpreting the results of solution equilibria between Mg-A1 alloys and liquid MgC12, also considered the measurements of Schneider and Stoll to be unreliable and preferred to derive activities for the alloys from the earlier boiling point determinations of ~eit~ebel~ and the partial molar heats recommended by Kubaschewski and ~atterall.~ These latter heats were based substantially on the early calorimetric work of Kawa-kami but, unfortunately, his work on other systems has sometimes been found to be inaccurate.7 Rogers et al., in the above-mentioned paper,3 tentatively concluded that the most likely species responsible for the limited solubility (0.3 mole pct at 800°C) of magnesium in MgC12 were Mg° (neutral) and Mg2++. Two more recent studies8,9 have supported Mg2++ as the soluble species. In the present study, activities in Mg-A1 alloys have been determined by means of a galvanic cell involving liquid MgCl2 or MgC12CaCl, mixtures as the electrolyte. Since the reactive nature of magnesium precluded simple Faraday yield experiments, a chlorine electrode was incorporated in the cell in order that the performance of the cell could be checked by measurements of the heat and free energy of formation of MgC12. This procedure was considered necessary since it has been suggested1' that the solubility of a metal in a molten salt might introduce electronic conductivity; also, previous determinations of the standard electrode potential for MgC12 differed by as much as 70 mv11-13 EXPERIMENTAL Materials. Analyses of the materials used in preparing the alloys and the electrolyte mixtures are presented in Table I. The alloys were prepared by induction melting weighed amounts of the metals in a graphite crucible held under an argon atmosphere. Pure anhydrous magnesium chloride was prepared by heating the mixture MgCl, . 6H20 +NH4C1(1:1) to 650°C, followed by melting under dry argon. The melting point of the dry MgC12 was found by differential thermal analysis to be 714.8oC, which compares well with the accepted value of 714C.14 This agreement was taken to be an indication of the high purity of the dried salt. Table I. Compositions of Materials, wt pn Impurity Mg Al MgCI2 CaCI, Ba - - 0.005 Ca - - 0.010 Cu 0.02 0.02 Fe - 0.10 0.001 0.010 Pb 0.01 - 0.001 0.005 Mn 0.15 0.001 Si - 0.10 Sr - - 0.005 MBSO* - 0.040 ARGON TUNGSTEN CHLORINE LEAD—411 11 II ALUMINA 'A I / ave GRAPHITE on irA~_ ( ^"l ROD MAGNESIUM S>ILICA~^ /, OR ALLOY-. I /A] ___________ -«^- _ ELECTROLYTE I y FRITTED DISCS Fig. l—Arrangement of chlorine and metal electrodes in electrolytic cell.

Jan 1, 1970

By AIME AIME

BLANDFORD. C. BURGESS, the new Chairman of the Industrial Minerals Division, took the advice of Horace Greeley in reverse-he turned his hack on San Francisco and the Golden Gate, and after a few side excursions toward Alaska and Arizona, hit the trail eastward, not for the lonesome pine, but for Spruce Pine, N. C. Born Aug. 10, 1893, in San Francisco. Burgess found his first job, shortly after finishing high school at 19, as axeman for a surveying party of engineers working for the Southern Pacific Co. in Oregon. Later he moved on up with them into Alaska. He liked the engineering profession, and decided to equip himself further so he entered the University of California in the fall of 1913. and for the next two years devoted himself to acquiring an education in civil engineering.

Jan 1, 1945

By John V. Beall

Since the U. S. Metals Refining Co. works was established, around the turn of the century, near the town which is now called Carteret, N. J., it has grown to be a major producer of refined copper and the main source of that special brand known as "oxygen-free high-conductivity copper." Owing to the complex metallurgical problems arising from handling a variety of raw materials such as copper concentrate from Matahambre, Cuba, copper and brass scrap from the New York area, and domestic blister copper, the organization is geared from top management down through its 2000 employes to maintain a high degree of flexibility in plant operation. The Company is a subsidiary of The American Metal Co. Charges for the smelter furnaces, one reverberatory furnace and one blast furnace, are made up in. bedding bins so that they may be tailored to the production of a constant grade of blister copper. The reverberatory furnace smelts the .sulphide charge, which may be a blend of ten different materials but principally the Cuban concentrate, and the matte from the process is poured into a converter. This reverberatory is 80 by 20 ft, silica lined with a slag bottom, fired by pulverized coal, and continuously side-charged from the top by bottom-dump cars which keep the side walls covered. It produces a 40 to 50 per cent copper matte. The fuel-charge ratio is 4.35 tons of solid charge per ton of coal. The furnace has a capacity of 10,000 tons of charge per month and produces from 5000 to 6000 tons of slag per month which must be disposed of. About 5000 tons of converter slag is produced monthly and returned molten to the reverberatory furnace. The converter gases go through a spray chamber to a Cottrell precipitator and thence to the flue system. Smoke from the

Jan 1, 1948

By Bieniawski, Z. T.

The importance of understanding the phenomena associated with rock fracture has long been fully appreciated in rock mechanics. This is clearly apparent from the special attention paid to rock fracture in the comprehensive papers published within the past four years. These papers present a picture of how the knowledge of brittle fracture of rock was gradually enriched and also show that what was often taken for granted three or four years ago is no longer considered as valid today.

Jan 1, 1972

By J. A. Ede

The property of the Spring Valley Coal Company, situated in Bureau county, Ill., comprises something more than 30,000 acres of coal-lands, on which have been opened four mines, designated as Nos. 1, 2, 3 and 4. Figs. 1, 2, 3 and 4 are plans of the first three; and Fig. 7 is a view of the surface-plant at No. 4, the workings of which it is not necessary to illustrate, as this mine has been practically merged in No. 2. No. 4 shaft is only 500 feet from No. 2, and both are ventilated by the same fan, and are in the same circle of air-supply. In speaking of No. 2, we now include No. 4. The system pursued in all the mines is " long-wall advancing," and the shafts are all vertical. The seam worked is locally and commercially known, in the Illinois series, as No. 3; but its position in the geological series is that of No. 2. It averages in thickness about 42 inches, arid has no partings, but mines in rectangular lumps, which stand a large amount of handling before breaking. An analysis made from Colliery No. 1 gave the following : Per cent. Moisture,.......... 1.45 Volatile combustible matter,.47.27 Fixed carbon,.........41.97 Sulphur,.........2.46 Ash,....... .. .. .. 6.85 Plate 6 shows a photographic view of this seam. The staff seen in the view is 37 inches long. The table on page 188, recorded in my office, which I presume to be correct, may be of interest. The bottom is fire-clay, varying in thickness from 6 to 24 inches. It affords what is considered good mining-ground. The roof immediately above the coal is a dark shale, lying in small bands, from 4 to 9 inches in thickness. Between the

Jan 1, 1900

By F. A., King

THE problem of the proper size and capacity of the open-hearth furnace has been a predominant issue ever since its inception some sixty years ago. The original furnaces, built in 1868 at Landore, England, were only to 3 to 4 tons capacity, and from' this there has been a steadily increasing and almost uniform rate of expansion until furnaces producing 300 tons are in successful operation today. At the end of the first half of this 60-year period, or about the year 1900, 50-ton furnaces we're common. Up to this time the problems of expansion had been largely those relating to suficient capital and the engineering development of larger units. But as 75, 100-ton and larger furnaces were proposed apprehension grew and other questions assumed leading consideration.

Jan 1, 1928

By David B. Reger

New discoveries of gas in the southern counties featured the petroleum industry in West Virginia during 194;. Drilling for oil increased slightly over 1944 and a small increase of initial production resulted. Out of 28 wildcats drilled, there were 16 gas discoveries and 12 dry holes. No commercial oil was found in the 28 wells.

Jan 1, 1946

By James A. Barr

Phosphate rock is a natural rock containing one or more phosphate minerals usually calcium phosphate, of sufficient purity and quantity to permit its use, either directly or after beneficiation in the manufacture of commercial products.1 The principal minerals in phosphate rock have the apatite structure which may be represented by the type formula: Ca10(X2) (PO4)6 where X represents the hydroxyl group (OH), chlorine or fluorine, either singly or collectively. The calcium may be partly replaced by sodium, magnesium, and other positive ions such as manganese, strontium, lead, uranium, cerium, yttrium and other rare earths. The PO4 radical may be partly replaced by small quantities of UO4, AsO4, SiO4, CO3, SO4, or Vo4. A typical commercial rock is usually a calcium phosphate containing 3 to 4 pct fluorine, the major impurities being limonite or other iron oxides, clay, aluminum phosphates and silica as quartz sand. A little vanadium is present in most of the domestic rock deposits (except the Tennessee Brown Rock), according to Jacob, Hill, Marshall and Reynolds! A little uranium occurs in the Florida leached zone, as will be brought out later. The chemical analyses are reported as P205, or tricalcium phosphate Ca3(PO4)2, the latter often designated by the trade name BPL (bone phosphate of lime). Commercial analyses usually report iron and alumina as oxides, lime as CaO and silica or insoluble. Colony3 examined many samples of apatite, staffelite, dahlite and American phosphorites and concluded that all have identical X-ray diffraction patterns. The phosphates in the phosphate rock have very minute crystalline structures. The mineral apatite Ca3(F.Cl) (PO4) 3 is the principal primary source of the element phosphorus, and occurs widely distributed in igneous rocks but rarely in a minable mass. Only about 12 pct of the world production of phosphate rock comes from primary apatites; the remainder is derived from secondary phosphorites. These phosphorites have been formed by the alteration of sediments by solutions containing phosphoric acid. Such solutions have come from the weathering or leaching of igneous rock containing apatite, bone deposits of prehistoric animals, marine life or guano deposits. These phosphorites are mostly alterations of phosphatic limestones. The sedimentary phosphate deposits are of marine origin and may have been enriched by subsequent solution of the more soluble calcium carbonate by waters containing carbon dioxide, by physical concentration by wave action, and by redeposition of the dissolved phosphate ions. Uses of Phosphate Phosphorus is the spark of life and is the structure builder and one of the main elements of plant food (fertilizer). Without phosphorus, life cannot exist. A "complete" plant food[t] in addition to phosphorus compounds contains potash, which acts as a catalyst to convert nutrients to useful forms, nitrogen to supply the growth element and many minor elements. The cycle of supply of phosphorus is from the apatite to solution and soil, absorption of plant life, decay and return to the soil or by animal life feeding on the plants. With insufficient supply of phosphorus in vegetation, life is not prolific. If crops are removed from

Jan 1, 1960

By H. E. Kramm

During the summer of 1910, I had the opportunity to study in detail the geological conditions of what is known in northern California as " Harrison gulch," in Shasta county. Though the district, as a whole, that is, the western part of Shasta and the eastern part of Trinity county, has contributed during the last 15 years a considerable share of the gold-production credited to Shasta county, very little is known of its geology, perhaps because the country is covered with a dense growth of brush which makes exploration and prospecting extremely difficult. Topographically the district presents a succession of ridges trending approximately N-S., and alternating with deep, narrow canyons. The drainage is partly into the Sacramento, partly into the Trinity river. Climatic conditions in summer time are almost ideal. It is true, the thermometer may climb to 115°, but the air is dry

Jan 1, 1913

By D. D. Pollock

Many constitution diagrams do not indicate the limits oJ solid solubility of the silver-rich solid solutions below 200°C. Thermoelectric measurements were employed to determine this limit in the nieighborhood of room temperature. The appearance of a second phase causes a discontinuity to occur in the tkevtrroelectric power as a function of cornposition at constant temperature and pressure. This discontinuity was employed to determine the limits of the silver-rich terzinal solid solutions of the Ag-A l, Ag-As, Ag- Bi, Ag--Ge, Ag-In, Ag-Pb, Ag-Sb, and Ag-Sn systenls at 30°C. CONSIDERABLE work has been done on the constitution of binary alloys of silver. The available data have been compiled by Hansen1 and Elliott.2 However, many of the binary diagrams do not show the limits of solid solubility of the silver-rich solutions below about 200° C. This work was undertaken in an attempt to extend these limits to the neighborhood of room temperature . PREPARATION OF ALLOYS All of the alloys were made with silver containing less than 0.014 pct (by weight) of impurities. The materials were weighed out into 225-g heats and melted in a high-frequency induction furnace. The indium, tin, and antimony alloys were melted in A1203 crucibles, under a boric anhydride cover, and were poured into split graphite finger molds. The aluminum, germanium, arsenic, lead, and bismuth alloys were melted in machined graphite crucibles; they were also covered with boric anhydride and poured into split graphite finger molds. The $-in.-diam ingots were heated to 750°C and were forged and hot-rolled down to 0.1 by 0.1 in. The wires were pickled in a 25 pct HNO3-75 pct H2O solution to remove any oxygen-rich surfaces. The wires were then annealed at 550°C for 2 hr in a dissociated ammonia atmosphere. They were then furnace-cooled for 20 hr to room temperature in this atmosphere. The wires were cold-drawn to 0.0808 in. diam. The finished wires were again annealed at 550°C in the same manner as in the first anneal. Thermoelectric Power. The thermoelectric power of a single specimen of each alloy was determined against pure silver which contained a maximum impurity content of 0.014 pct by weight. The wire specimens were straightened and then cleaned with ethyl alcohol. They were then reannealed in the same way as the finished wires to assure that any residual stress would be at a minimum level. Previous work has shown that the presence of small amounts of stress has the effect of decreasing the thermoelectric power. The alloy specimen was soldered to the pure silver wire to form the measuring junction. A standard set of copper leads was then soldered to the reference junctions of the thermocouple. These junctions were maintained in separate dewar flasks which contained finely shaved melting ice during the test. The thermal electromotive forces of the thermocouples were measured at four temperatures between 15° and 45°C. A known source of electromotive force was balanced against the output of the thermocouple until a null balance was reached. The data were then expressed in terms of the thermoelectric power at 30°C. The results were then converted to absolute thermoelectric power, s303.3 These data have an average error of less than ±0.2 pct. RESULTS AND DISCUSSION All of the experimental data are given in Table 11. Since the electromotive forces of the binary alloys of silver were determined against the pure silver from which they were made, the resultant thermoelectric powers are only a function of the intentionally added binary elements at the constant test temperatures. This provides a direct measure of the effects of the alloying elements. The absolute thermoelectric power of an alloy of silver is given4 by:

Jan 1, 1968

By D. M. James, J. C. Martin

The results are presented of a study of the application of analytical methods to the solution of two-phase flow into single wells. Approximate analytical expressions for the pressure distribution in two-phase flow are found ;;; a number of conditions. The results obtained from the analytical solutions me found to be in good agreement with results obtained by finite difference techniques using a high speed digital computer. Mathematical solutions for four sets of boundary conditions are presented. All of these solutions are composed of a short-term transient plus a steady or quasi-steady state. The rates of decay of the short-lived transients are analyzed. It is found that the durations of the short-term transients may be characterized by a parameter defined as the time constant which can be determined from simple relations. It is shown also that if the outer radius is much greater than the radius of the well. the short term transients decay at rates which are proportional to the square of the exterior radius, and the rates of decay are only slightly dependent upon the radius ratio. Numerical solutions based on finite difference techniques are presented for a number of conditions. The numerical solutions are in good agreement with the predictions based on the theoretical analysis for small and moderate drawdowns. Examples involving large drawdowns indicate that the nonlinearities in the equations of flow do not appreciably alter the longevity of the short-term transients. In all cases the time required for the short-tern transients to disappear is predicted satisfactorily. INTRODUCTION The mechanism by which oil and gas flow into a single well is of vital interest to the petroleum industry. The fundamental equations of two-phase flow which describe this mechanism are nonlinear partial differential equations. Numerical solutions of these equations describing pressure transients have been obtained with the aid of electronic computers. Although solutions obtained in this manner take into account a large number of effects, the reduction of this information to useful generalities is difficult. One method of obtaining generalities is the use of linearized approximations of the nonlinear equations. Since it is possible to obtain explicit solutions of the linearized equation, general properties of the role of pressure in the flow mechanism may be ascertained. Results obtained from this approach are limited to some extent by the linearizing assumptions. The severity of these limitations may be evaluated by comparing solutions of the linear equation with numerical solutions of the more exact nonlinear equations of two-phase flow. In the past considerable amount of work has been devoted to studying pressure build-up using the single-phase flow theory. Unfortunate1y, most prep sure build-up tests involve multiphase flow. A small amount of work has been done studying pressure build-up where the flow is two-phase. The encouraging results of these studies suggest that useful results may be found from additional studies of not only pressure build-up, but also the rapid transients associated with placing a well on production. This paper presents the basic theory of the pressure transients associated with placing a well on production and with closing it in. The paper is concerned chiefly with two-phase compressible flow; however, the results also apply to single-phase flow. The results are based on analytical solutions of the flow equations, and they are verified by numerical solutions using finite difference techniques. Much of the previous work on compressible flow into wells has been confined to single-phase flow. Some work has been done on compressible two-phase steady state flow, and solutions of the equations of flow have been found by finite difference techniques using high-speed computers. Muskat1 presents some rather general solutions to the equations of single-phase compressible flow into wells. Much work has been done on pressure build-up in wells (see, for example, Refs. 2-6). Almost all of the work on pressure build-up concerns single-phase flow with the exception of Ref. 5 and part of Ref. 2. Some work has been done on pressure fall-off in injection wells.718 Muskat9 presents the solution of the equations for radial steady state two-phase compressible flow. Handyl0 extends Muskat's solution to obtain

By O. R. Bergmann

Two approaches were taken to obtain direct experimental evidence jar the existence oj a jet in the explosion-cladding pvocess: 1) direct observation of the claddirg jwocess by rtzeans ojf kig-h-speed photography using a fvartziiy catnera and 2) use of a plated-surface experiment in contribution with clzetrzical analysis. The framing-camera records showed clearly the presence of a jet it1 the form of what appears to be a line spray. The jet velocity is considerably highev than the detonation velocity arid in vacuum it is almost twice as high as the detonatiou velocily. The results jrorrz the plated-surface experiment also corzfivtned the preseizce of- a jet. The artzoutlt o,f etzergy dissipated in the jetting process was foundd lo be consislent with the basic theovetical model o/ the cladding mechanism.. MaNY reports on metal working with explosives have appeared in the literature during the last few yearsThis paper describes experiments concern- ing the mechanism of the explosive metal-cladding process. It has become increasingly important as a unique method for bonding metals and a typical cladding arrangement is shown in Fig. 1. A theoretical analysis of the mechanism of explosive bonding and a description of the nature and types of bond zones obtained was given by Cowan and oltzman." A further discussion of the basic principles of the process, a detailed description of the different bond-zone types, and extensive information on the properties and the applications of explosively bonded metals was recently published by Holtzman and cowan. " The process is now in commercial use by E. I. du Pont de Nemours & Co. The concept of the existence of a jet during metal bonding with explosives forms a central part in the theoretical analysis of the cladding mechanism described by Cowan and Holtzman When a layer of explosive is detonated on a metal plate that is separated from a second metal plate by a small distance the metal plate in contact with the detonating explosive is accelerated by the detonation pressure. An angle is established between the undeflected and deflected portions of the plate. Subsequently the deflected portion of the first plate collides with the second metal plate.

Jan 1, 1967

By D. D. Pollock

The resistivity, temperature coefficient of resistance, and absolute thermoelectric properties of some binary terminal solid solutions of silver were determined. Equations are given which permit the calculation of these properties. CONSIDERABLE work has been done on the constitution and electrical conductivity of binary alloys of silver.1-l2 Some of these alloy studies are apparently complicated by doubtful chemical analyses. In some cases the limits of solid solubility are questionable. Those references which present electrical properties of binary silver alloys usually give just one particular set of characteristics such as conductivity (or resistivity). As a means of checking and extending this earlier work, an investigation was undertaken to describe and calculate the resistivity, temperature coefficient of resistance, and thermoelectric power of binary terminal solid solutions of silver. PREPARATION OF ALLOYS All of the alloys were made with silver containing less than 0.014 pet (by weight) of impurities. These materials were carefully weighed out into 225-g heats and melted in a high-frequency induction furnace. The indium, tin, and antimony systems were melted in Al2O3 crucibles, under a boric anhydride cover, and poured into split graphite finger molds. The aluminum, germanium, arsenic, lead, and bismuth alloys were melted in machined graphite crucibles, and they were also covered with boric anhydride and poured into split graphite finger molds. The alloys containing magnesium and manganese

Jan 1, 1964

Jan 12, 1951

By R. McDonald, B. C. Maine

CERRO'S power system consists of three main hydroelectric plants and one steam-electric plant. These are located on the eastern slope of the main Andes range at altitudes between 12,000 and 13,000 ft. The hydroelectric group utilizes the watershed which extends for about 150 kilometers south from Cerro de Pasco, divided into two catchment areas which lie adjacent. The northern area serve,, the medium-head plant of Mal¬paso. while the southern area provides for the high-head plants at Pachachaca and Oroya. The rainfall, as registered at the rain gauging stations of the three hydroelectric plants, averages 33 in. per year; all these stations are subject to the same hydrological conditions, and the bulk of precipitation occurs between October and March. Rainfall during the dry season, April till September, has no appreciable effect on the total annual runoff. Table 1 shows the storage capacities of the main reservoirs of the hydroelectric group. The four plants are tied together electrically by a 50-kv. transmission network, the system being 3-phase 3-wire at 60 cycles with a solidly grounded

Jan 1, 1945

By C. A. Heiland, W. H. Courtier

The investigations described were made on a portion of Clear Creek basin near Golden, Colo. (-4 portion of the area under survey is shown in Fig. 1. The photograph was taken in the vicinity of station No. 2 of Line 11.) Three principal purposes were in the minds of the investigators: 1. To repeat with modern, more sensitive and more reliable instruments magnetometric placer investigations previously made. 2. To disprove the recently advanced theory that deposits of the glacial period have no pronounced magnetic effects. 3. To develop in detail the theory of the magnetic effects produced by placer deposits. Six years ago, the first magnetic observations were published, which proved that it is possible to locate gold-bearing channels with relatively crude instruments.' Two years ago, K. C. Laylander published results obtained with similar instruments.2 The measurements of the latter were discussed by the senior author of this paper.3 At that time, however, the material available for such a discussion was somewhat scarce and not made with the most modern magnetic instruments, although very brilliant results were obtained. Therefore, the senior author felt that magnetic investigations should be made on very clear geologic conditions with the most modern instruments. Comparison of Magnetometers The junior author undertook this work in the spring of 1928. The magnetic field balances, for vertical and horizontal intensities, designed by Schmidt were used (Figs. 2 and 3). The scale value of these instruments was approximately 257 and 157, respectively. The middle

Jan 1, 1929

By I. N. Zavarine

The observations presented in this paper were recorded during a study of the spheroidizing process. Spheroidization of cementite in steel is either brought about to develop a set of desirable mechanical properties or is an incidental result of mechanical and heat-treating manipulations. Physical properties of steel are materially influenced by the state of the cementite. Conversion of cementite from the lamellar to the spheroidal state is usually accompanied by a decrease of hardness and of strength and by an increase in ductility. The spheroidized structure is usually considered as an ultimate step in the process of the softening of steel. The unorthodox hardening of a 3.5 per cent Ni steel (SAE No. 2330) after a heat-treatment that previously proved entirely suitable for a complete spheroidization of cementite in carbon steels led to the observations that constitute the subject of the present paper. Experimental Procedure The steels used for the experiments described were bought on the market. All were in the form of 3/4-in. round bars. Their chemical compositions are given in Table 1. The spheroidization of cementite in steels can be obtained in several ways. The method used in the present work is, perhaps, the least known. It consists of cyclic heating and cooling of steel, the temperature being

Jan 1, 1939

By I. N. Zavarine

The observations presented in this paper were recorded during a study of the spheroidizing process. Spheroidization of cementite in steel is either brought about to develop a set of desirable mechanical properties or is an incidental result of mechanical and heat-treating manipulations. Physical properties of steel are materially influenced by the state of the cementite. Conversion of cementite from the lamellar to the spheroidal state is usually accompanied by a decrease of hardness and of strength and by an increase in ductility. The spheroidized structure is usually considered as an ultimate step in the process of the softening of steel. The unorthodox hardening of a 3.5 per cent Ni steel (SAE No. 2330) after a heat-treatment that previously proved entirely suitable for a complete spheroidization of cementite in carbon steels led to the observations that constitute the subject of the present paper. Experimental Procedure The steels used for the experiments described were bought on the market. All were in the form of 3/4-in. round bars. Their chemical compositions are given in Table 1. The spheroidization of cementite in steels can be obtained in several ways. The method used in the present work is, perhaps, the least known. It consists of cyclic heating and cooling of steel, the temperature being

Jan 1, 1939

By E. W. Parker

THE anthracite region, from which there is produced annually about 80,000,000 tons, or approximately 15 per cent. of the total coal supply of the United States, has a combined area of a little less than 500 sq. mi. The total area occupied by the bituminous fields (including the sub-bituminous and lignite fields) is in the neighborhood of 400,000 sq. mi., so that 15 per cent. of the total output comes from this small area of only a little more than 0.1 per cent. of the coal-producing territory. of the United States. The productive anthracite area is divided into a series of basins or troughs, roughly parallel, extending. in a northeast-southwest direction through the. Counties

Jan 1, 1921

By John Johnston

WHEN I was honored by being invited to give the Howe Memorial Lecture, I decided to read Howe's book, "The Metallography of Steel and Cast Iron," published in 1916-that is, about 25 years ago-in search of a text. I found the book written in fine, clear, attractive, yet precise style, as I expected, knowing that his father ¬Dr. Samuel Gridley Howe, his mother-Julia Ward Howe, and all of his four brothers and sisters had lived in a New England literary atmosphere and had written books. This leads me to suggest that many authors of metallurgical papers and books could well study Howe's writings with a view to the improvement of their own. I failed to find a specific text, but did find a subject, for in reading his book I was struck by the few instances in which time is considered explicitly as a factor in the phenomena examined, and by the fact that many of the hottest arguments would have been settled had time been taken properly into account. Indeed, Howe hardly mentions time except in a rather incidental way, as in a few references to lag; for instance: The lowering of temperature at which the transformation occurs by rapid cooling . . . is a phenomenon of undercooling or lag. It is in part explained by the fact that the transformation itself is a time-consuming reaction which, setting in during a rapid fall of temperature. is naturally protracted till the temperature has sunk far below that at which it is due. He does discuss, quite fully, the iron-carbon equilibrium diagram, as known at that time, introducing it by stating: As he is a reasonable man who is not deterred from using a hand truck for moving his trunk by the consideration that he has thus to move a trunk plus a truck, so am I reasonable in putting into your hands this useful, indeed indispensable, tool for mastering the ABC of iron metallurgy. Somewhat later, in introducing a discussion of the phase rule, which "it would be hardly proper to pass . . . by without an attempt to outline its meaning," for "a clear exposition of its applicability or jurisdiction is needed to restrain the half-initiated from misusing it and the uninitiated from being misled by these misuses," he writes-and I quote his statement because we cannot properly discuss the influence of time on a process until we know the state of equilibrium which would ultimately be reached by the system under consideration It is a most remarkable and valuable generalization, its conceptions help greatly toward getting a broad outlook on metallography, but its misconception has brought out a flood of obscuring writings. It tells us about the constitution towards which alloys tend, that which they reach when equilibrium is complete, when all tendencies have corrected themselves and have been complied with completely. Its application, in absence of true equilibrium, is like determining density with a telescope or even with a tuning fork; it is like the mad tea party at which the butter put into the works "f the watch was the best butter. If the reader learns no more than to beware of attempts to decipher the conditions of inequilibrium by a law which touches only the conditions of exact

Jan 1, 1942