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October 16th, 1872. THE Institute assembled on Wednesday evening at the Western University, and was called to order by President Raymond. Mr. James Park, Jr., of Pittsburgh, made the address of welcome, which was responded to by President Raymond. The Council reported the following names, with approval, for election Ashburner, William, - San Francisco, Cal. Asmus, George, - New York. Baillie, Nathaniel, - Uniontown, Pa. Bowie, A. J., Jr. - San Francisco, Cal. Brown, A. J., - Treasure City, Nev. Butler, J. G., Jr., - Youngstown, Ohio. Chamberlin, J. G., - Leetonia, Ohio. Clark, R. Neilson, - Canyon City, Colorado. Cornell, A. B., - Youngstown, Ohio. De Crano, E. G., - San Francisco, Cal. Engelmann, H., - Salt Lake City, Utah. Faber du Faur, A., - New York. Janin, Louis, Jr., - San Francisco, Cal. Johnson, George J., - Salt Lake City, Utah.. Kent, Joseph C., - Phillipsburgh, N. J. Kent, William St. G., - Phillipsburgh, N. J. Liebenau, Charles von, - Silver City, Idaho. McClintock, A. H., - Wilkes-Barre, Pa. Miller, Thomas N., - Pittsburgh, Pa. Millholland, James A., - Mount Savage, Md. Peters, Ed. D., Jr., - Dudley, Colorado. Reese, Jacob, - Pittsburgh; Pa. Schirmer, J. F. L., - Denver, Colorado. Smith, W. S., - Fairplay, Colorado. Stoelting, Hermann, - Georgetown, Colorado. Sweet, W. A., - Syracuse, N. Y. Tripple, Alexander, - New York. Van Arsdale, W. H., - Swansea, Cal. Willard, Dwight D., - Bordentown, N. J. The following resolution was then offered and passed Resolved, That gentlemen present, not members, be invited to take part in the discussions of the Institute at the various sessions of the present meeting.

Jan 1, 1873

By S. Feuerstein

THE influence of environment on the mechanical properties of metals has been extensively studied and documented.' Most investigations have dealt with an interaction between a particular environment and a specific metal surface and the concomitant change in bulk mechanical behavior. Typical contributing media are oxide and metal film:;, electrolytes, and other surface-active agents. In the last category fall controlled gaseous environs (i.e., pressure or vacuum). Most vacuum exposure experiments prior to 1963 were conducted at pressures s>10-6 torr and elevated temperatures, or in such a manner as to prolong the exposure (e.g., by stress-rupture, creep, and fatigue). Little attention has been given to vacuum environment effects on the mechanical behavior of metals subjected to simple uniaxial deformation at room temperature. Test times and temperatures were assumed too ineffective as far as bulk changes were concerned. Further, the contribution of surface effects to the bulk mechanical behavior of metals was considered minimal. Under vacuums of the order of 1.0- 8torr and higher, molecular densities and, consequently, the rate of monolayer formation are such that exposures from seconds to days would be required for complete gas coverage. Thus, atomically clean surfaces created under ultra-high vacuum could conceivably maintain their cleanliness for time intervals orders of magnitude greater than at higher pressures. The influence of this unusual type of environmental surface phenomenon on the short-term bulk mechanical behavior of aluminum was first observed by Krame and Podlaseck in 1963.' kin equivalent effect was reported for magnesium by Williams and Nelson.3 It was concluded from these studies2,3 that vacuum and, consequently, the monolayer formation rate of the oxide, were responsible for the described changes in flow behavior. The presence of an oxide layer impedes dis- I) EXPERIMENTAL DATA: MOLYBDENUM The tensile behavior of molybdenum was investigated by the author4-6 at ambient temperature over a range of pressures from 760 to 10-10 torr. These studies revealed that the flow behavior of the bulk specimens (0.200 in. diam by 2 in. gage length) was independent of pressure on sintered (0.062 mm grain size) and arc-cast polycrystals (0.012 to 0.149 mm grain sizes) and single crystals. Since the specimens were relatively large in size, it was assumed that any flow behavior effect would be surface-limited because of the short-term deformation procedure. Strain-rate-change experiments performed to determine the activation volumes for individual specimens at 760 to 10- 10 torr further indicated that the surface flow contribution was either minimal or zero, contrary to the findings of Shen el a1.7 on aluminum. Although the flow behaviors did not change, specimen ductility did change. For the sintered material at a strain rate of 4.2 x 10-4, specimen ductility was -9 pct higher at l0- 10 torr than at atmospheric pressure (dry nitrogen). A more comprehensive investigations on this same material revealed a distinct pressure dependence, Fig. 1. Intermediate and atmospheric pressure tests were obtained by backfilling the system from l0- 10 torr with extra dry, prepurified nitrogen. Other environments (air and purified argon) were also utilized for the 760 torr experiments; the results were essentially the same as those for dry nitrogen atmospheres. Departure from the fracture strain values obtained at 760 torr takes place in the vicinity of l0-6 torr, as indicated by the scatter band; a noticeable ductility increase is apparent at l0-8 and 10-10 torr.

Jan 1, 1970

By J. J. Frawley, W. J. Childs

The dynamic nucleation of supercooled bismuth and Bi-Sn alloys has been studied over a frequency range of 15 to 20,000 cps. For low-frequency vibration, a minimum vibrational energy was required for enhancement of nucleation. Above this critical energy, the dynamic supercooling was less than static supercooling showing that vibration promoted nucleation. The amount of dynamic supercooling continued to decrease with increasing vibrational energy until a minimum or threshold value was reached. This minimum value of supercooling for nucleation remained constant joy all further increases in vibrational energy. For higher frequencies, similar results were observed. This behavior has been related to the necessity of cavitation for dynamic nucleation. When a liquid is cooled to a temperature below its equilibrium melting point, the solid phase is more thermodynamically stable. However, for solidification to occur, a two-step process, nucleation and subsequent growth of the solid phase, must occur. When a liquid is supercooled, that is cooled below the equilibrium melting point, the controlling process for solidification to begin is the rate of nucleation. Once nucleation has occurred, the solidification process is controlled by the rate of growth. Nucleation can be induced by two factors: either by a catalyst or by the use of mechanical shock. Numerous investigators1-4 have studied the effect of nucleation catalysis but much less systematic study has been made of nucleation by mechanical shock waves. The influence of vibrations on grain size in castings and ingots has been studied by many authors but no clear understanding of the mechanism or accurate prediction of the effect has been presented.5 It would be intuitively expected that the further the departure from equilibrium (i.e., the greater the supercooling), the easier it would be to induce nucleation. This has been quantitatively demonstrated both by walker6 and later by Stuhr,7 that the greater the degree of supercooling the easier it is to nucleate by a shock wave. Stuhr also attempted to obtain the mechanical energy required for nucleation of bismuth as a function of supercooling. He vibrated a crucible containing supercooled metal at low frequencies and various amplitudes and noted the corresponding dynamic supercooling obtained. The amount of supercooling was inversely proportional to the mechanical energy applied. Limitation of his experiment was the problem of the confinement of the liquid in the crucible without splashing and minimizing other unwanted modes of vibration. Tiller et al.8,9 did similar work on tin and Sn-Pb alloys using an electromagnetic stirring device. Their conclusions were that the magnitude of the magnetic field strength did not affect the amount of undercooling at which nucleation was initiated. While conclusive experimental results have been lacking to explain this effect of mechanical vibration on inducing nucleation, a number of theories have been proposed. Two of these theories are discussed below. 1) The Change in Melting:- Point Locally Due to the Change in Pressure (Clapeyron Equation). According to Vonnegut10 the most plausible explanation for the nucleation of a supercooled melt by cavitation is the effect of changing the melting point by a change in pressure. For materials where the volume decreases on solidification, an increase in pressure raises the melting point; for materials which expand on solidification, the melting point is raised for a decrease in pressure, i.e., rarefaction. Using the Clapeyron equation, the melting point of a metal can be calculated as a function of pressure. If it is assumed that the equation can also be used to calculate the temperature of nucleation of a supercooled melt as a function of pressure (i.e., the temperature of heterogeneous nucleation will increase with pressure at the same rate as the melting point), the amount of supercooling required for nucleation will be constant at all pressures as shown in Fig. 1. It is obvious that an isothermal change which results in an increase in melting point results in an equal increase in supercooling. This increase in supercooling may now be sufficient for nucleation. A pressure of 80,000 atm was calculated, using the Clapeyron equation, as the pressure required to increase the temperature of nucleation of nickel by 200°C. According to Lord Rayleigh,11 this very large pressure could be generated for a very brief period of time by the collapse of a cavity. This pressure wave is radiated in all directions from the collapsed cavity. If the temperature of the melt is slightly below its equilibrium melting temperature at atmospheric pressure, stable growth can follow; that is, once nucleation occurs, growth becomes the main driving force of the solidification process. This proposal has been extended to water which expands on freezing by assuming that nucleation occurs during rarefaction following the pressure pulse. This negative pressure pulse should follow immediately after the positive pressure pulse with its magnitude approaching the critical tensile strength of the liquid. The negative pressure developed during this period would raise the melting point of water and thus promote nucleation. Hunt and jackson12 have suggested this for water. Similarly, it could be postulated that bismuth which also expands on freezing could be nucleated during the negative pressure pulse. 2) Nucleation by a High-pressure Phase. An extension of the Clapeyron equation to systems where density decreased on freezing at atmosphere pressure has been proposed by Hickling.13 The phase diagram for water initially shows the well-known decrease in

Jan 1, 1969

By W. E. Rudolph, R. E. Baylor

DUE to its location in the Atacama Desert, one of the most barren of the earth's surfaces, Chuquicamata's water supply presents unusual problems. Yearly rain-fall averages less than one tenth of an inch at the plant. However, there are summer showers above 12,000 ft in the Cordillera to the east, the resulting run-off flowing through old river valleys buried beneath more recent volcanic formations, to be impounded within sediment-filled basins. This water emerges at springs where the outlets of these basins are blocked by lava flows, and here are formed the small streams which feed the only important river of the region, the Rio Loa. Chuquicamata's water is obtained from these springs and rivulets. [ ] The map above indicates four pipe lines from which potable and industrial water are supplied. Potable water, amounting to 4500 metric tons per day, is conveyed in the Toconce pipe line from springs 59 miles due east of Chuquicamata. This water is used not only for drinking, but also for boilers and other needs requiring high quality. For industrial water at the oxide plant, there are two 12-in. pipe lines from the Rio San Pedro, carrying a total of 17,000 metric tons per day of slightly brackish water. This water is at present used mainly for leaching and for hygienic purposes. Water Source Found For the present and future needs of the sulphide plant, it was calculated that at least 32,000 metric tons per day of make-up water would be required. For this purpose, a pipe line of 44 miles length was constructed to bring in the entire flow of the Arroyo Salado, one of the eastern tributaries of the Loa. The salt content of this water is so high (over 5000 parts per million of solubles, mostly chlorides) that it is highly detrimental to farming, and the Chilean Government had been studying projects to separate these waters from others of the Loa system in order to improve agricultural conditions in the fertile valley of Calama. So it happened that the Government was willing to award rights to the Arroyo Salado waters under agreement whereby the Mining Company removes waters from the Rio Loa system above Calama for all time. The outlet of these waters, after serving their purpose at the new concentrator and leaving the plant in tailing, is the Salar de Talabre, an old salt lake which presents fully ten square miles of surface to serve as an evaporating pan, the outlets having now been blocked by dams. Here the dry climate of Chuquicamata is a favourable factor, evaporation averaging slightly above 1/4 in. per day. The Toconce and San Pedro pipe lines have been functioning from 26 to 34 years, and through the use of special cleaning tools which were developed at the plant, as well as deaeration of the more active Toconce water, these pipes are now maintained at capacities which do not diminish as years go on. Constructing the Dam The Arroyo Salado pipe line design and construction involved certain special and interesting features, and inasmuch as this line and its intake works are solely for the needs of the new sulphide plant, more detailed description is given. The waters are impounded at a gravity dam constructed of concrete to a height of 100 ft above the river bed, keyed into the precipitous Dacite walls of the narrow canyon (barely 6-ft wide at the bottom, only 25-ft width at 50 ft above). A small secondary dam was built 100 ft down stream from the main dam, providing a pool of 15-ft depth to protect the main structure from flood flows over the spill-way during the rainy season. A system of four 36-in. syphons was designed for discharging these flood waters from the lower depths of the lake, in order to avoid eventual sedimentation behind the dam. The lake has a length of 3300 ft, and its water level is controlled by an adjustable spillway permitting draw-down of eighty inches, amounting to 41,000 metric tons of available capacity. This regulation is necessary because of wide fluctuations in stream flow between day and night due to freezing of feeders. During the construction of the dam the entire river flow was handled within a 36-in. pipe line some 2000 ft in length. As the excavations proceeded

Jan 1, 1952

By Charles Macdonald

Wrought-iron eye-bars for bridges and roofs, designed upon what is known as the pin connection system, have been successfully manufactured in this country for some years. The most approved methods employed have been the hydraulic upsetting process, and by die-forging under a hammer. In upset eyes the fibre of the iron is necessarily much distorted ; and in bars of considerable size, this disturbance seriously impairs the strength of the connection. Mr. Collingwood, in discussing my paper on "Proportions of the Heads of Eye-bars," read before the American Society of Civil Engineers, Jan. 21st, 1874, submitted sketches of certain bars intended for the anchorage of the East River bridge, which had been exposed to the action of sulphuric acid a sufficient length of time to thoroughly cleanse the surfaces, and expose the condition of the fibre. These sketches are here reproduced for the purpose of illustrating the effect of this method of manufacture. In Figs. 1, 2, and 3, it will be observed that the fibres at A, and E, have been folded back upon: themselves and otherwise twisted and disturbed, in a manner not calculated to inspire confidence in the integrity of the connection. To compensate for this defect, a large excess of metal is thrown into the eye; but a method of manufacture which involves such a necessity, even although it be the one giving the best results thus far, all things being considered, is far from being perfect.

Jan 1, 1879

By A. C. Stevenson

THE hoisting equipment selected for use at the Hecla mine in 1907 was one of the first Ilgner type Ward-Leonard controlled hoists put into ser- vice. Development of the Hecla below the 2000-ft. level, which is the ultimate depth of the old equipment, and the additional service required by the "Star," necessitated additional hoisting capacity. It will be our endeavor to give j70u a brief summary of the engineering which determined the selection of the new equipment. The engineer in making his decision as to size, speed, etc., must .make a duty study approximating as closely &s possible the actual opePating conditions which will eventually result. Primarily, it is necessary to know what work must be done. The amount of material which must be hoisted under the maximum condition, as well as its distribution from the various levels of the mine was carefully studied by the mining engineering department, as the ore reserves, their relative-position and the probable method of working them had to be considered. The final figures reached, taking into consideration four different operating conditions, were, in tons per day, as follows:

Jan 1, 1930

By Henry R. Piehler

Continuous seven- and nine teen -filament close-packed silver-steel filamentary composites mere tested in tension. For purposes of comparison, the tensile behavior of the composite was predicted from the measured properties of the individual com-ponents. It was assumed that the axial strain is the same in both components and that the contribution of each component to the composite flow stress is proportional to its volume fraction. Good agreetnent was obtained between the observed and predicted tensile behavior. However, the composite elongation at fracture was about twice that observed when the individual steel wires were tested alone. Composites in which the filaments were widely spaced failed by the consecutive fracture of the filaments. In composites with closely spaced filaments, a composite instability preceded frachcre. These effects are explained in terms of a lateral restraint to the necking of the filaments which develops in the deforming composite. TWO-COMPONENT or composite materials are increasingly being developed and used as structural materials. Of all the composite geometries used, the filamentary configuration has proved to be the most successful. Polymer-bonded fiber-glas, the most common of the filamentary composites, has been investigated most extensively to date. One explanation of the behavior of fiberglas1 suggests that the load transfer between the glass fibers and the polymer matrix occurs primarily through friction. Bond separation between the fibers and the matrix is presumed to occur at very low stresses. Subsequently, only frictional bonding can provide for the transfer of load from the matrix to the fibers. The force normal to the fiber-matrix interface which gives rise to this friction is assumed to arise from the matrix shrinkage which occurs during solidification. The behavior of metallic filamentary-composite materials would be expected to differ from that of fiberglas in several significant aspects. Residual stresses resulting from differences in thermal contraction can be kept to a minimum by proper heat treatment. A strong wetted bond is formed between the two phases. In brazed joints,2 for example, the interphase bond is sufficiently strong that the weaker material will fail before separation occurs at the interface. Most metal filaments can undergo appreciable amounts of plastic deformation before failure. Failure by plastic instability or necking frequently occurs in metallic filaments, but not in glass fibers tested at room temperature. Differences between the behavior of fiberglas-polymer and metallic filamentary composites have indeed been observed in composites containing various types of metallic filaments in a silver matrix.3,4 At strains of the order of 10-2 pct, all the deformation was accommodated by the silver matrix. Hence, the strength of the composite depended only on the fiber concentration and not on the nature of the fiber. At higher strains, the strength of the composite increased when filaments with higher work-hardening rates were used. Surface slip line observations on a silver-mild steel composite that had been stretched 4 pct showed that an appreciable amount of deformation occurred in the filaments. Work on tungsten-copper filamentary composites5 has shown that the ultimate tensile strength for varying filament fractions followed a linear mixture rule. Assuming that the axial strains in both filaments and the matrix are equal, this linear mixture rule can be expressed as: The subscripts c, f, and m refer to the composite, filaments, and matrix, respectively. A and V are the area and volume fractions of each component. sc and of are the ultimate tensile strengths of the composite and the filaments. sm is the flow stress of matrix at a strain equal to the elongation at failure of the filaments. However, the tungsten filaments can undergo only a limited elongation before they fracture without an appreciable reduction in area. A composite containing more ductile filaments might indeed deviate from this linear mixture rule for the ultimate tensile strength, since filament failure by necking might be arrested by the matrix. SPECIMEN PREPARATION Specimens were prepared from 0.8 pct carbon steel piano wires of 0.015 in. initial diameter. The wires were given a thin nickel flash and a silver plate varying in thickness from 0.015 to 0.007 in., depending on the filament fraction desired. In order

Jan 1, 1965

By B. A. Wilcox, A. H. Clauer

The steady-state creep of TD Nickel NL + 2 001 pct TltOz) has been studied orer the telirperatve range 325&apos; to 1100O and the stress range 15,000 to 36,000 psi. At high temperatures (aboue 0.5 T& gran-boundary slzding is the )nost znportant )node of creep deformation, and the steady-state creep rate, is, can be related to stress and temperature by: where Q = 190 kcal pev mole and n has an unusually high value of 40. A creep mechanism based on cross slip of dislocations around The O2 particles can satisfactovily explain the low-temperature (T < 0.5 T,) cveep behavior, and the follo wing relation is applicable: Q, (a) is found to decrease from 57 to 46 kcal per mole as the stress is increased from 32,000 to 36,000 psi. THERE have been a variety of theories proposed to explain the influence of dispersed second-phase particles on the yield strength and flow stress of metals, and these have been reviewed recently by Kelly and icholson.&apos; However, only several attempts2"4 have been made to develop mechanistic treatments which characterize the creep behavior of dispersion-strengthened metals, and to date these have not been fully evaluated experimentally. weertman2 and Ansell and weertman3 proposed a quantitative creep theory for coarse-grairzed dispersion-strengthened metals, based on the concept that the rate-controlling process for steady-state creep was the climb of dislocations over second-phase particles, as suggested by choeck. The theory predicted that the steady-state creep rate, <,, was proportional to the applied stress, a, for low stresses and that is a4 o for high stresses. The activation energy for creep, Q,, was equivalent to that for self-diffusion, Qs.d., in the matrix. Some limited experimental evidence in support of this theory was obtained on a recrystallized Al-Alz03 S.A.P.-type alloy by Ansell and Lenel.6 Ansell and weertman3 also developed a semiquanti-tative theory for high-temperature creep of lineg-rained dispersion-strengthened metals in order to explain their results on an extruded S:A.P.-type alloy, which had a fine-grained fibrous structure. They suggested that the rate of dislocation generation from grain boundaries was the rate-controlling process, and fitted their results to the equation: where Q, was found to be 150 kcal per mole, i.e., QC- 4Q,.d. in aluminum. Similar high activation energies for creep7-&apos;&apos; and tensile deformation" of dispersion-strengthened alloys have been observed by other investigators for S.A.P.,&apos;" indium-glass bead omosites, and Ni + A1203 alls.&apos; There is no general agreement regarding the mechanisms involved in the creep of dispersion-strengthened metals, and this is due in part to the lack of detailed studies relating the structures of crept specimens to the mechanical behavior. The present investigation on thoriated nickel was undertaken with the aim of studying the structural changes which occur during creep of a dispersion-strengthened alloy and rationalizing the observed mechanical behavior in terms of the creep structures. EXPERIMENTAL METHODS The material used in this investigation was 1/2-in.-diam TD Nickel bar, which contained 2.3 vol pct Tho,. Obtained from E. I. duPont de Nemours & Co., Inc. The final fabrication treatment by DuPont consisted of -95 pct reduction by swaging followed by a 1-hr anneal at 1000°C. Transmission and replica electron microscopy revealed that the material had a fine-grained fibered structure with an average transverse grain size of -1 p and a longitudinal grain size of 10 to 15 p. Selected-area diffraction indicated that the fiber axis was parallel to (OOl), in agreement with the results of Inman eta1." All creep specimens were vacuum-annealed at 1300°C for 3 hr prior to testing. Transmission electron microscopy showed that the only structural change due to annealing was a slight decrease in dislocation density, confirming the reported high degree of structural stability.13 Furthermore, recrys-tallization or grain growth during creep was never observed. The structure typical of uncrept material (after the 1300 C, 3-hr anneal) is shown in Fig. 1. The grain boundaries are predominantly high angle and. although some areas show a tangled cell structure, the grain interiors are relatively dislocation-free. Individual dislocations are strongly pinned by the Tho2 particles; i.e., very rarely did dislocations move within a thin foil. The grey "halos" around some of the larger particles which protrude out of the foil surface arise from contamination in the electron microscoge. The Tho, particle size ranged from -100 to IOOOA, and the distribution is shown in Fig. 2. The technique used to obtain the data in Fig. 2 consisted of dissolving the nickel matrix in acid, collecting the Tho2 particles on cellulose acetate, and measuring about 1000 particle diameters in the electron microscope. Similar results were obtained by measuring about 600 particles in thin foils, an; the average particle size was found to be 2r, = 370A. Using the data in Fig. 2 (annealed structure), the mean planar center-to-center particle

Jan 1, 1967

By R. K. Iyengar, G. C. Duderstadt

An investigation was carried out to determine the effect of Ca-Si additions on the dissolved oxygen content of liquid steel. An apparent equilibrium was reached after holding the melt for some time when the total oxygen content of the melt was identical with the dissolved oxygen. Results of the investigation show that for deoxidation with silicon and manganese the apparent equilibrium is reached after 8 to 12 min and the oxygen content of the melt is in good agreement with values reported in the literature for similar steel compositions. Ca-Si additions decrease the dissolved oxygen content appreciably below that obtained with Si-Mn deoxidation. It is postulated that some calcium dissolved in liquid steel at the time of its vaporization combines with dissolved oxygen to form CaO which then fluxes the manganese silicate, thereby lowering the activity of the deoxidation products. Slow flotation of calcium silicate inclusions is attributed to their slower growth rate. An addition of aluminum (to yield <0.005 pct Alsol) prior to introduction of Ca-Si improves the kinetics of removal of resulting deoxidation products. WITH the introduction of continuous casting of billets and blooms, application of calcium-containing alloys for deoxidation purposes has gained new interest. More so than in conventional ingot casting, the degree of control of the dissolved and total oxygen contents in steel for continuous casting can determine the success or failure of the operation because these affect both surface (pinholes) and internal quality of the billets. Of the available deoxidizers, only silicon has so far found wide application. However, in the typical range of application (0.20/0.30 pct Si), it is too weak a deoxidizer to suppress pinhole frequency to the level desirable for all but the least demanding appli-cations (approximately 10/50 pinholes per sq ft, de-pending on degree of subsequent reduction). On the other hand, Vincent&apos; has shown that it requires ap-proximately 0.007/0.008 pct A1 soluble in the steel to suppress pinhole formation to <10 pinholes per sq ft. In view of the difficulty of consistently maintaining this aluminum level and the associated problem of tundish nozzle constriction2 when aluminum is added to the ladle, steelmakers have searched for other de-oxidation alloys to circumvent the problem. Calcium-containing alloys offer such a possibility. When employed as a partial substitute for silicon, CaSi (30 pct Ca/60 pct Si) additions are reported to yield adequate pinhole contro1.3 Its use simultaneously preserves the "fluidity" of the steel and ensures good castability.4 Oxygen contents as low as 0.007 to 0.014 pct have been obtained with CaSi additions varying between 3 to 8 lb per ton.5-7 Due to the high degree of vaporization of calcium at the temperature of molten steel and the different methods used to introduce it into the liquid, the reported results show considerable scatter and lack of consistency. According to several investiga- deoxidation tors, the flotation characteristics of CaSi products are not as favorable as those found for alumi-num but are similar to those established for silicates with low alumina content.678 Thus, cleanliness ratings were improved when CaSi was replaced by a com-bination of Si + A1 followed by CaMnSi additions.5,9 In view of the lack of a comprehensive description of the deoxidation potential of CaSi alloys, a study was undertaken of the effect of CaSi additions on oxygen content in comparison to Si + Mn and Si + Mn + Al. The alloy chosen for this study contained 63 pct Si, 32 pct Ca, <3 pct Al, and 2.5 pct Fe. EXPERIMENTAL PROCEDURE The experiments were divided in three groups as shown in Table I. In each group, the CaSi addition was increased successively while maintaining the melt composition constant. The experiments in the third group were designed to determine the effect of prede-oxidation with small amounts of aluminum. Ingot iron, containing 0.02 to 0.03 pct C and 0.03 to 0.05 pct Mn, was melted in a 100-lb magnesia crucible. Pig iron was added to the melt under air in an induction furnace to attain the desired carbon content of 0.05 to 0.15 pct and thereby control the initial oxygen content of the melt between 0.04 and 0.015 pct. After removal of the slag, the furnace was sealed and argon was introduced through an opening in the graphite cover, Fig. 1. When the desired temperature was reached, electrolytic manganese was added to the melt and pin samples were taken (7 mm silica tubing) to establish initial oxygen content. To obtain maximum efficiency, CaSi and metallic silicon were introduced in a sealed steel pipe into the bath. This procedure assured minimum loss of calcium through vaporization as the deoxidants were always released at the bottom of the melt. Samples were taken at regular intervals and quenched in water. Temperature of the bath was measured with a Pt/Pt-10 pct Rh thermocouple. Portions of the pin sample were used for oxygen analysis; five determinations per sample were made to obtain average oxygen content. Oxygen analyses were made by the inert carrier gas fusion method with frequent cross checks with the vacuum fusion method.

Jan 1, 1970

By R. E. Ogilvie, J. I. Goldstein

The a and y solubility limits in the Fe-Ni phase diagram have been redetermined at temperatures above 500°C. Both a diffusion-couple and a quench and anneal technique were used. The solubility limits were measured with an electron-probe micro-analyzer. The nickel concentration at the phase boundary is increased below 700°C and the a solid-solubility range is much larger than had been previously measured. The solubility limits are also extrapolated to 300°C. It is suggested that the solubility of nickel in a FeNi reaches a maximum in the temperature interval 400o to 500°C. THE equilibrium diagram has been of great use in the field of meteoritics, where the phase relations between kamacite (a) and taenite (?) in metallic meteorites can be described by means of the Fe-Ni diagram. The study of metallic meteorites by electron-probe microanalysis has cast some doubt on the accuracy of the presently available Fe-Ni diagrams.1, 2 Recent thermodynamic studies of the Fe-Ni system also suggest that the diagram may be in error.3 For these reasons the high-temperature (800o to 500°C) part of the diagram was redetermined. INTRODUCTION The currently accepted Fe-Ni diagram is that of Owen and Liu.4 Above 910°C, there is a region of complete solid solubility, ? (fee). Below 910°C, the a (bee) phase is stable in pure iron. The effect of increasing amounts of nickel is to stabilize the y phase. The phases that form when Fe-Ni alloys are heated or cooled bear little relation to the equilibrium diagram. If an alloy is cooled from the y state and held at a temperature within the a + y field, no evidence has been found for the occurrence of the y - a transformation.5 If the alloy is cooled to low enough temperatures the y phase breaks down into a supersaturated bee phase called a2. In fact, in alloys over 27 pet Ni the y phase is retained at room temperature.6 The a, phase has the same composition as the original y. The temperature at which a2 forms, the M, temperature, has been determined experimentally.&apos; A state of equilibrium can be approached by cooling below M, to form a2 and then reheating the alloy into the two-phase region of the diagram. The y phase will then begin to precipitate out of the a2 phase and grow. The growth of the phase, however, is quite slow. Using the interdiffusion coefficients -Da of Goldstein et al.,8 it is estimated that it takes about 1 year to grow a 10-µ-wide region of ? at 700°C in a 5 pet Ni alloy. Owen and Liu4 used the technique just described to form the equilibrium phases. The phases present were determined by means of X-ray analysis. The accuracy of their diagram depends on the number of alloys available near the phase boundary at a given temperature. In this study two different techniques were used to determine the a/a + ? and ?/a + ? solubility limits. The inherent accuracy of both techniques was greatly improved over that used by previous investigators because the phase-boundary compositions were measured with an electron-probe microanalyzer. PROCEDURE The two methods used to determine the Fe-Ni diagram are the diffusion couple (D.C.) and the quench-and-anneal (Q.+A.) techniques. In the first method, diffusion couples whose diffusion path goes through a two-phase region of the phase diagram were used. A description of the technique used for making the diffusion couples has been described in a previous paper.&apos; After the diffusion treatment a discontinuity in the resultant concentration vs distance profile was measured. The nickel concentrations in the a and ? phases at the interface of the discontinuity are the solubility limits of the a and ? phases in the phase diagram at the diffusion temperature. If the interface com-

Jan 1, 1965

By Arthur F. Taggart

PROGRESS in a technical art is of several kinds. It springs .from many diverse sources. It comprises invention, mechanical improvement, operating advance, analytical study, education. Invention is, by definition, a relatively great, essentially individual step, taken quickly. Operating advance is the slow, cumulated march of practice; in contrast, it moves at the pace of the tortoise, but over, the years its effects rival and, in some cases, surpass those of invention. Mechanical improvement- is a usual concomitant of the reduction of invention. to operating practice; thereafter it is a primary tool of operating advance. Analytical study is the process of mental digestion of the fruits of invention and practice. Its purpose is to render these into a form assimilable by the art as a whole, and by the perennial crop of would be practitioners. Education, disseminating the results of such study, consolidates and maintains the positions gained. Thus, slowly at first, but continuously accelerating, the tide of progress grows- to flood. Such growth, in mathematical parlance, is expressible in the general form y = mxn, where x is time, n is some positive number greater than one, m is another positive number, and y is the state of the action at instant x. When n is 2, the readers will recognize the graph of the equation as one branch of the familiar square parabola, whose property it is to become parallel to the y-axis; i.e., to move at an infinite rate, in that never-never

Jan 1, 1947

By Thomas H. Sheehan

The purpose of this paper is to present an application of computer technology to assist the mineral company financial executive in assessing exchange risks. The paper is divided into five parts: Background, Translation Approaches, Theory, Empirical Validation, and Conclusion. BACKGROUND Exchange risk results from a change in the rate of exchange between a host and a home country&apos;s currencies. Legitimate reasons exist for changes in the currency exchange rates among countries in a world with over a hundred different currencies. These reasons include: different economic growth rates, social factors, cultural heritages, and political motivations. The problem of exchange rate changes are perennial and exist whether the world operates on exchange rates or floating exchange rate practices. The cause of the problem is trade and international payment imbalances. If one accepts the premise that exchange rates fluctuate over time, then the mineral company financial executive faces a continual process of reassessment of the impact of exchange rate changes on the financial worth of his company. (1) The mineral company financial executive prepares balance sheets and income statements that are audited by certified public account- ants annually for shareholders, bankers, and tax authorities. The financial executive translates assets and equities denominated in foreign currencies into domestic dollars, e.g., Japanese firms convert to Yen, French firms convert to Francs, and so on. When figures from foreign subsidiary operations are consolidated into the balance sheets of the parent corporation, estimates of the company&apos;s finan-

Jan 1, 1977

By Wayne Anderson

Regarding the technical paper by Thomas E. Finch and Edward L. Fidler, "Recovery of Stray (Thin) Seams in Western Coal Mining." I would like to comment on this subject. In western Canada, most strip mines encounter thin seam coal or rider seams. Although the paper addresses the problems and costs associated with the recovery of this coal, it does not take into account what the savings are. Without looking at the savings, the "Total Objective" is of course not clear. I feel that in a stripping operation the mine can spend per ton (of the thin seam) up to their dragline stripping costs per ton to recover a rider seam or thin seam. The reasoning behind this is simply that this is the price the mine will have to pay to expose an equivalent amount of coal without the recovery of these thin seams. If the mine can recover a rider seam or thin seam for less than the dragline operating costs per ton, a savings will be realized. By recovering a thin seam or rider seam, the life of an ore body is extended by that amount of coal not thrown away. In addition, the cost of land acquisition, associated permits, capital, and reclamation will be reduced as more coal is delivered for a given area. When the above points are considered, the recovery of these thin seams can be very profitable and indeed worth recovering.

Jan 1, 1983

By Eric L. Christiansen

A dynamic simulation model for the iron blast furnace has been developed which predicts flow rates, compositions, and temperatures of the top gas, slag, and hot metal exit streams as a function of time from specification of the time-dependent tuyere inputs and raw material charges. As a matter of convenience, a previously developed steady- state model is employed to fix furnace-dependent parameters. It also provides initial conditions for the internal states of the furnace for subsequent dynamic solution of the simultaneous differential equations which describe the local rates of chemical reaction, heat transfer, and mass transfer in the stack, bosh, combustion zone, and hearth of the furnace. The dynamic model was tested by a demonstration of its ability to relax to steady-state representations of the time-averaged data from two separate industrial blast furnaces and of its ability to follow eight days of time-dependent operating data for one of them. Simulated responses to step changes in tuyere input and burden variables have been shown to be of the correct magnitude and duration. Although complex functions of many variables, a proper description of these responses is needed for the development of optimization and control strategies . The model correctly predicts the non-minimum-phase type dynamic response observed in real furnaces in which the output variables proceed through local minima or maxima, often including inverse responses (i.e., opposite signs from their final steady-state values ) .

Jan 1, 1984

Another excellent Swedish underground crushing plant is that at Crusher Station 51 of LKAB in Kiruna, Sweden. Bottom-dump rail cars pass over a dump scroll to discharge magnetite ore into a 288 cu yd (220 m3) pocket equipped with a Hewitt Robins E-13 vibrating grizzly feeder. The grizzly section is 59 in. (1500 mm) long and has bar spacings 3 in. (76 mm) wide. Any oversize boulders which will not pass the chute opening to the feeder are blasted. The primary breaker is a Morgardshammar overhead eccentric 55 in. by 71 in. (1400 by 1800 mm) jaw crusher powered by a 200 hp (149 kw) motor. An open side setting of 10. 8 to 11. 8 in (275 to 300 mm) accounts for the high capacity of this crushing unit (2760 stph or 2500 mtph). This figure compares favorably with the capacity of many gyratory crushers but is typical of the Swedish jaw crushing installations, which are often followed by three more stages of crushing or by autogenous grinding. Crushed ore from the jaw crusher is combined with the grizzly under- size in the crushed ore pocket and is fed by a second vibrating grizzly feeder to the secondary cone crusher. Both crushers are serviced by 50/5 ton overhead bridge cranes. During maintenance operations air -operated gates shut off the flow of ore from the dump and primary crushed ore pockets.

Jan 1, 1978

Meeting of Dec. 19, 1913.-The President reported the appointment of the Committee on Junior Members and Affiliated Student Societies, and the Committee on Coal and Coke, which .appointments were approved. The President was authorized to appoint the members of a Committee on Safety and Sanitation. The President appointed the Finance Committee of the Institute as a Committee to audit the accounts of the Treasurer (By-Law V). On the recommendation of the Executive Committee, Charles F. Rand was appointed a representative of this Institute on the Board of Trustees of the United Engineering Society for a term of three years (By-Law XIV of the Institute, By-Law XI of the U.E.S.). The Executive Committee reported that it had passed the following resolutions: That the next summer meeting of the Institute be held at Salt. Lake City during Aug. 10 to 14, 1914, inclusive; That an exchange of .the Bulletin and Transactions be made with the Canadian Bureau of Mines; That a sum of $50 be contributed for the year 1914 to the Commission publishing the Annual Tables of Physical and Chemical Constants; That the Secretary be given power to reduce at his discretion the number of exchanges between the Bulletin and other publications which are not retained as a permanent part of the Library; That the contract for binding Volume XLV of the Transactions be awarded to the Butler, Ward Co., in accordance with their bid of Nov. 21, 1913;

Jan 1, 1914

By Robert R. Turner, Arthur R. MacPherson

This chapter reviews the steps which should be taken from the time it is decided to consider autogenous grinding in the development of a new ore deposit or the expansion of an existing plant up until the purchase of the new autogenous mills. In this case the term autogenous includes semi -autogenous, secondary pebble mills, and lump milling as well as fully autogenous grinding systems. Also, both wet and dry grinding alternatives have been included. Before the test program it must be decided how many bulk samples are required to properly assess the autogenous grinding possibilities of the deposit. Also, a decision must be made on where and how the samples are to be ground i.e. pilot mill at site or in established location, wet and or dry grinding, etc. In the test program itself, certain fundamental data must be obtained. The testing should include enough work to determine whether fully autogenous or semi-autogenous grinding should be used and what type produces best power efficiency. Also, all the other pertinent data should be collected such as power; tonnages; feed, charge, and product sizing; circulating loads, etc. If a secondary mill is required to produce a final grind the decision on whether a pebble or ball mill should be used may require additional test work. Finally, the concentration of the mineral may play an important part in selection of the circuit and should become a part of the final testing once the grinding has been established.

Jan 1, 1978

A High-speed Dilatometer and the Transformational Behavior of Six Steels in Cooling. By Arthur L. Christenson, Edward C. Nelson and Clarence E. Jackson. (With discussion).................................606 Dilatometric Studies of the Graphitization of Cast Iron. By N. A. Ziegler. With discussion) 627 An Interferometer Type of Dilatometer and Some Typical Results. By- L. &apos;4. WIlley and W. L. Fink. (With discussion).........................642 The meeting was held in the Pine Room of the Statler Hotel, Cleveland, Ohio, on Tuesday afternoon, October 17, 1944. The chairmen were F. M. Walters, Jr. and Howard Scott. Introduction F. M. Walters, Jr.—The principal advantages of the dilatometric method perhaps are two, as compared with the method of thermal analysis. One is that the dilatometric method can be applied with a large variety of rates of heating and cooling, whereas thermal analysis—that is, the study of the transformational characteristics by means of heat evolution—is limited to the rates of heating and cooling that reveal the evolution of heat. The dilatometer can be used for the study Of reactions at zero rates of heating and cooling; that is, isothermal reactions. As you will hear this afternoon, the rates have been pushed up as far as 500°C. a second. The other advantage is that the dilatometric method shows that a two-phase region is a two-phase region, whereas the thermal analysis merely reveals the temperature at which the rates of heat evolution are greatest.

Jan 1, 1945

By Alan D. Randolph

INTRODUCTION The production of fines is an unwanted side-effect in most crystallization processes. The definition of “fines" is relative to the size of the desired product and varies from <30 mesh for coarse KC1 fertilizers to subsieve organic material produced by salting-out pro- cesses. Sometimes a well-developed fines distribution is necessary in the production of large crystals, e.g. the fines removal stream from a potash crystallizer. The production of fines is usually not desired in a crystallization separation step. However, product purity can either improve or degenerate with a decrease in crystal size depending on the relative importance of product washing vs mother liquor occlusions in determining over-all purity. Typically, both washing efficiency and mother liquor occlusions decrease with decreasing particle size. Fine crystal distributions have historically been difficult to measure and categorize; however this situation is changing rapidly with the use of electronic particle counters of the electrical zone- sensing or light scattering type. In fact, fine-crystal measurement is perhaps the key to better understanding and control of coarse- crystal crystallization processes. The fine-crystal distribution carries much useful information from which nucleation and growth rates can be inferred. The purpose of this paper is to briefly discuss a few crystallization processes in which production and/or measurement of fines is important and to categorize the process conditions which yield a fine- crystal product.

Jan 1, 1980

By H. M. Morse

This report on oil and gas development in Mississippi covers the period from Jan. I, 1944, to Dec. 31, 1944: Salt Domes During the year six salt domes were drilled for sulphur, but no commercial sulphur deposits were found. One salt dome, the Bruinsburg, in Claiborne County, has produced gas- at 935 to 940 ft&apos; in Moody&apos;s Branch marl. The Stringer salt dome in Smith County and the Ruth salt dome in Lincoln County both had a slight showing of heavy oil. Other salt domes have been dry. In addition to the Bruinsburg dome, the Allen salt dome, in Copiah County, and the Richton salt dome, in Perry County, were discovered in 1944; also the Sumrall dome, in Covington County. New Oil Fields Baxtemille Oil Field.—The Baxterville oil field was discoveredby the Gulf Refining Co, in sec. 7, T. I N., R. 16 W., Lamar County. At the end of the year this field had one oil well, with two active operations. Production for 1944 was 1047 bbl. of oil. GwinvilLe Field.—Gwinville field was discovered by S. W. Richardson, in sec. 24, T. 9 N., R. 19 W., Jefferson Davis County. This discovery well was a gas-distillate well, the oil being crystal clear. At the end of 1944 there were two gas wells and one oil well in the field. The oil well is approximately 2 1/2-miles from the gas- distillate wells. Gas production was 55,801 M cu. ft. and the distillate production was 2644 barrels. Heidelberg Oil Field.— The Gulf Refining Co. discovered the Heidelberg field in sec. 30, T. I N., R. 13 E., Jasper County, in January 1944. This field has by far exceeded the other 1943 and 1944 discoveries, having approximately 56 oil wells, 7 dry holes, and 10 active wells at the end of the year. Production to Jan. I, 1945 was 1,441,192 bbl. of oil. Mallalieu Oil Field.—The california Company discovered the Mallalieu oil field in set. 10, T. 7 N., R. 8 E,, Licoln. County. At the end of the year there was one well in the field with three active operations. Production was 32,303 bbl. of oil. Old Oil Fields Brookhaven Oil Field, in Lincoln County, has one oil well, which produced 2590 bbl. of oil during 1944. CarY Oil Field, Sharkey County1 has only one producing well, which produced 11,818 bbl- of oil during the Year- In Cranfield Oil Field, dams County, II oil wells and two gas-distillate wells were drilled in 1944 and there were five active wells on Dee. 31, 1944- The total production for the Year was 5251422 bbl-of oil. The gravity of the oil is 40" to 54.9&apos;- In Eucutta Oil Field1 Wayne County1 34 oil wells were completed during 1944. There were five dry holes and six active wells at the end of the year.. The field produced 454,332 bbl. of all d the average gravity is 25" Flora Oil Field, Madison County, pro-

Jan 1, 1945