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By P. H. Lindon, J. C. Billington

Fe-O melts containing 0.045 pct 0 were deoxidized with Mn-Si-A1 alloys. Product compositions were reluted to the melt and alloy compositions and were found to be most sensitive to the aluminum content of the alloy. Low residual oxygen contents could be obtained when aluminum oxide was present in the Products because of the reduction of silica and manganese oxide activities. Flotation of the Products from a quiescent melt was followed both by analysis of the oxygen content and metallographic measurement of inclusion concentration. MnO-SiO2-A12O3 products were found to float most rapidly when their composition was such that their viscosity may be expected to be low. Changes in the particle size distribution indicates that particle coalescence occurred and differences in the degree of coalescence are thought to be responsible for the different flotation rates observed between products 0f differing composition. Measured flotation rates were slower than those Predicted from a model based on Stoke's Law, although alumina flotation might be reasonably accounted for by this model. Interfacial effects between oxide particles and the melt are believed to be responsible for the discrepancy. It has been recognized that deoxidation products constitute a large proportion of the nonmetallic inclusions present in killed steel. The amount of oxide inclusions which originate as deoxidation products depends largely upon three factors. These may be summarized, according to P16ckinger1 as: 1) Amount of primary products remaining in the steel prior to cooling. 2) Residual dissolved oxygen content of the steel after deoxidation. 3) Amount of secondary products, formed during cooling and solidification, which remain entrapped in the solid steel. In a well-deoxidized steel containing residual aluminum and/or silicon, the equilibrium dissolved oxygen content is usually very low and so the maximum amount of oxide which may be produced as secondary deoxidation products is small in comparison with the amount of primary products. It may be seen, therefore, that the amount of indigenous nonmetallic inclusions may be minimized if a low dissolved oxygen content is achieved by deoxidation and if the primary deoxidation products are efficiently removed. Oxides which originate by reaction of the metal stream with the atmosphere during teeming are not considered in the present study. It is known that two or more deoxidizers may result in a lower equilibrium oxygen content when used in conjunction with one another than when any of the individual deoxidizers are used alone. Equilibrium studies by Hilty and crafts2 and by Bell3 have shown that manganese increases the effectiveness of silicon as a deoxidizer, and Walsh and Ramachandran4 relate this to a reduction in the activity of silica in the products as the manganese :silicon ratio in the steel increases. It was also shown by Herty's work on deoxidation of steel by silico manganese alloys,5 that there existed an optimum ratio of manganese to silicon which gave a minimum inclusion content. This ratio was in the range 4:l to 7:l and the (FeO-MnO-SiO2) products formed by such deoxidation practice were found to lie in a composition range having very low liquidus temperatures (1170 to 1250°C approx). The optimum manganese:silicon ratio was then explained by postulating that these fluid products were able to coalesce and that the larger particles formed floated out of the steel very quickly as predicted by Stoke's Law. The present work examines the effectiveness of various Mn-Si-A1 alloys as deoxidizers and their effects on the composition and removal of primary deoxidation products from a quiescent melt. EXPERIMENTAL TECHNIQUE Approximately 250 g of prepared Fe-O alloy, containing 0.045 to 0.055 pct O, were melted in an alumina crucible and deoxidized at 1550°C by plunging a thin steel cartridge containing the deoxidizer below the melt surface. A high frequency induction furnace supplying current at 8.5 kHz was used to heat a graphite susceptor, the interior of which had been machined to give a wall thickness of 0.85 in. to form a receptacle for the alumina crucible. The iron melt was essentially quiescent as the induced current was concentrated at the external surface of the graphite susceptor by the skin effect. A nonoxidizing atmosphere was maintained over the melt by passing a continuous stream of argon through the lid of the susceptor. The melt temperature was measured before deoxidation, and again at the end of an experiment by means

Jan 1, 1970

By David A. Thomas, David N. French

The lrnrdness of WC crystals has been measured with the Knoop indenter at loads of 100 and 500 g on the (0001) and (1070) planes. The hardness as tneasitred on the basal plane is 2400 kg per sq mm and shows little anisotropy. The hardness on the prism plane, however, shows a marked orientation dependence, with a low value of 1000 kg -per sq mm when the long axis of the Knoop indenter is oriented parallel to the c axis and a high value of 2400 kg per sq mm when the indenter is perpendicular to the c axis. Slip lines (Ire observed surrounding the microhardness indentations and they show slip on (1010) planes, probably in [0001] and (1120) directions. This slip behavior can be explained by the crystal structure of TVC, which is simple hexagonal with a c/a ralio of 0.976. The hardness anisotropy call be explained by [0001]{1010} and (1130) {10l0] slii) and the resolved shear-stress analysis of Daniels and Dunn. HARDNESS anisotropy is a well-known phenomenon and has been reported for many metals, with both cubic and hexagonal structure.1-6 For hexagonal tungsten carbide, WC, a wide range of hardness values is reported in the literature. For example, Schwarzkopf and Kieffer7 give a hardness of 2400 kg per sq mm and report a value of 2500 kg per sq mm by Hinnüber. Foster and coworkerss give the average Knoop microhardness as 1307 kg per sq mm with a maximum value of 2105 kg per sq mm. Although these values and the structure of WC suggest the likelihood of hardness anisotropy, no such measurements have been made. We first detected a large apparent hardness anisotropy in WC crystals about 75 p large, in over-sintered cemented tungsten carbide. Prominent slip lines also occurred around many indentations. This report presents further observations and interpretations of hardness anisotropy and slip in WC crystals obtained from Kennametal, Inc. Both Knoop and diamond pyramid indenters were used on a Wilson microhardness tester with loads of 100 and 500 g. EXPERIMENTAL RESULTS The carbide crystals tended to be triangular plates parallel to the (0001) basal plane of the hexagonal structure. The side faces were parallel to the ( 1010) prism planes. Specimens were mounted approximately parallel to these two types of faces and metallographically polished. Laue back-reflection X-ray patterns were used to orient the specimens, which werethen ground to within ±1 deg of the (0001) and (1010) planes. The Knoop hardness values measured on the basal plane are plotted in Fig. 1. There is only a small anisotropy, with a hardness range of 2240 to 2510 kg per sq mm. The additional points at angles from 52.5 to 67.5 deg confirm the sharp minimum hardness at 60-deg intervals, consistent with the sixfold hexagonal symmetry. The average hardness of all values obtained on the basal plane is 2400 kg per sq mm. While the basal plane shows only slight anisotropy, the (1010) plane exhibits marked hardness anisotropy, from 1000 to 2400 kg per sq mm. Fig. 2 shows the hardness as a function of the angle between the long axis of the indenter and the hexagonal c axis, the [0001] direction. The minimum and maximum occur when the indenter is oriented parallel and perpendicular to the [0001] direction, respectively. The anisotropy of the prism plane is contrary to that reported for hexagonal zinc and hard- However, the basal-plane anisotropy is similar to these two metals.1'2 To check the accuracy and reproducibility of the measurements, a series of fifteen impressions was made at 100-g load in the same orientation in the same area of the specimen surface. The average for all was 2040 kg per sq mm, with a range of 1950 to 2130 kg per sq mm, giving an accuracy of about ± 5 pct. Thus the slight anisotropy on the basal plane is almost within experimental error. Fig. 3 shows slip lines around the Knoop indentations on the basal plane. The slip traces are in directions of the type (1130). The presence of slip steps on the basal plane indicates that the slip direction lies out of the (0001) plane. Because WC has a c/a ratio of 0.976,' the shortest slip vector is [0001], which suggests slip systems of the type [0001] (1010). Fig. 4 shows slip lines around the Knoop intentations on the (1010) plane. These slip lines are inconsistent with [0001] slip but can be

Jan 1, 1965

By S. F. Shaw

IT IS generally recognized that the natural gas absorbed in petroleum plays the leading r6le in moving the oil through the sands to the well and supplies the energy that delivers the oil to the surface when the wells are flowing. It is the purpose of this paper to note the amount of oil that could be lifted by this gas if 100 per cent. efficiency were obtained and the efficiencies actually obtained in the use of this gas. An article in MINING AND METALLURGY,' stated that in a Wyoming field, with a pressure of 300 lb. per sq. in., there would be absorbed 65 cu. ft. of gas per barrel, or 1.55 cu. ft. per gal. of oil. The writer does not know if data have been obtained, by experiment, for pressures beyond those indicated in this article, therefore, for the purpose of illustration, he has projected this curve to obtain figures for pressures greater than 300 lb., although probably experiment will show that the extended line is not quite correct.

Jan 1, 1926

By A. J. Heckler, J. A. Peterson

A capsule technique was successfully employed to investigate the effect of nickel on the activity of nitrogen in Fe-Ni-N austenite in the temperature range 600" to 1200°C. This technique consisted of equilibrating nitrogen among various Fe-Ni alloys within a sealed silica capsule. Nitrogen transfer among the specimens occurred by N, gas at 900°, lOOO? and 1200?C. Nitrogen gas pressures within the capsules were estimated to be as high as 22 atm. The activity coefficient of nitrogen, fN , in Fe-Ni-N austenite is adequately described by the linear interaction equation: log . wt pct Ni where the standard state is chosen such that fN = I as wt pct Napproaches zero in binary Fe-N. This relationship was determined over the temperature range 873" to 1473°K and for nickel contents of 0 to 35 wt pct. ALTHOUGH chemical thermodynamics of liquid iron alloys have been extensively studied, experimental data for the solid state are needed. These thermody-namic data will provide a basis for understanding phase transformations, precipitation reactions, metal-gas equilibria, and so forth. The interaction of sub-stitutional alloying elements with the interstitial elements is of particular interest. In this investigation the thermodynamic behavior of Fe-Ni-N austenite has been studied. The solubility of nitrogen gas in iron austenite is known to obey Sieverts&apos; law up to about 65 atm.1-6 In addition, the solubility of nitrogen in Fe-Ni austenite has been investigated5"8 using the classical method of equilibrating Fe-Ni alloys with nitrogen gas at 1 atm. A capsule technique similar to that used to study the activity of carbon in alloyed austeniteg&apos;&apos;&apos; was employed in the present work to determine the effect of nickel on the activity of nitrogen in Fe-Ni austenite over the temperature range 600" to 1200°C. EXPERIMENTAL PROCEDURE A series of Fe-Ni alloys up to 35 wt pct Ni was vacuum melted and cast into 1 by 3 by 6 in. ingots. Chemical analyses at the top and bottom of each ingot demonstrated that the ingots were homogeneous with respect to nickel content. The nickel contents are given in Table I. Additional chemical analyses showed that wt pct Si < 0.05, s < 0.01, C < 0.01, Al < 0.006, 0 < 0.004, Mn < 0.002, and P < 0.002. A 2 in. section of each ingot was cold rolled to 0.015 in. The material was then decarburized to a carbon content of less than 0.004 wt pct. A portion of the material of each nickel content was nitrided to various levels in a H2-NH3 gas atmosphere to provide a source of nitrogen during subsequent equilibration. The experimental technique consisted of equilibrating the series of Fe-Ni-N alloys in a partially evacuated sealed silica capsule at the temperature of interest. Both Vycor and quartz capsules were used. In general, the final equilibrium nitrogen content for each Fe-Ni alloy was approached from both higher and lower nitrogen levels. The criterion for establishing that equilibrium was attained was that the final nitrogen content for each Fe-Ni alloy was the same irrespective of the initial level. A schematic drawing of the sample configuration in a capsule is shown in Fig. 1. The samples were arranged so that there was a minimum of physical contact. The samples were also dusted with a fine, high purity alumina powder to help prevent sticking. Several different types of furnaces were used in this study. In each case, a thermocouple was placed immediately adjacent to the capsule during equilibration and the temperature was controlled to within *4?C of that reported. At each equilibration temperature, the following times were found to be more than sufficient to attain equilibrium: 600°C-250 hr, 900°C-150 hr, 1000°C-150 hr, and 1200°C-50 hr. After equilibration the capsules were quenched in water and the nitrogen contents of the specimens determined by a Strohlein analyzer. Analyses of samples after equilibration at 1000" and 1200°C showed no silicon pickup from the silica capsules. RESULTS AND DISCUSSION Transfer Mechanism. The mechanism by which nitrogen was transferred among specimens in an initially hydrogen flushed and partially evacuated capsule equilibrated at 1000°C was investigated. After equilibration the gas in the capsule was collected over water and an estimate of the pressure at temperature

Jan 1, 1970

By Bradley Stoughton

AT THE meeting of the Board of Directors on May 20, the resignation of Bradley Stoughton as Secretary of the Institute was presented and regretfully accepted by the Board. The letter of resignation follows : Gentlemen: About two years ago, I indicated to the President and some members of the Board my belief that the office of Secretary of the Institute should not be a permanent one. It is my observation of events, not only in our own Institute, but also in several sister societies, that too long a tenure of office by the Secretary inevitably leads to a situation which is not good either for him or for the society. After submitting this in writing to the Directors on February 17, 1920, I was overpersuaded by members of the Board to defer resignation until a more convenient time for the

Jan 1, 1921

BECAUSE of the impetus given to placer mining since the price of gold was advanced to $35, several types of small dredges have made their appearance, especially in the Lincoln and Oroville areas of California. Some of these are known as "doodle bugs," and have been given considerable publicity, though many believe their performance has been overrated and that complete costs of construction and operation, if known would not put them in so favorable a light. Fig. 1 is a doodle bug owned by E. M. Clark and operated near Lincoln, Calif. It is understood that it was abandoned because of inability to handle deep ground. A similar machine that has been operated-profitably by Comstock Placers is shown in Fig. 2.

Jan 1, 1938

By R. Dawson Hall

WHAT are the opportunities for the services of engineers in the coal mines? The best answer perhaps can be made by detailing the present lines of development in the bituminous coal mining regions. They are just at the beginning of a period that can be conservatively termed revolutionary. A few glimpses of new possibilities in economic mining that will reduce the cost of bituminous coal at the mines by at least one half have convinced almost everyone that a change must shortly come about. The cost of housing has become such a burden, especially in mountainous regions, that development which demands the hiring of more men and constructing more houses would not be profitable. The introduction of mechanical aids to mining, transportation and dumping suggests a way of obtaining a large tonnage with the same or a smaller number of men with no further house construction. At the same time the restriction of immigration has made it increasingly difficult to obtain men inured to hard labor. Modern civilization is not productive of muscular energy and at the same time it provides men who are not indisposed to the use of the mental effort required to direct the physical forces now available for the replacement of such energy.

Jan 1, 1924

By Frank T. Sisco

The discovery of phosphorous is usually credited to the German alchemist Brand, in 1669, and the element was rediscovered the next year by Boyle in England. IT was more than 100 years later, however, before its presence was detected in high-carbon iron produced in early blast furnaces. In 1781 the German chemist Meyer published the results of his investigation on the ?white earth? that he had found in cast iron made from bog ores. This white earth was metallic in appearance, it was extremely brittle, it was readily fusible, and it was not attracted by magnet. Meyer noted that cast iron containing this white earth was more fusible than other cast iron, and he was sure that he had discovered a new metal ? for which he proposed the name Wassereisen, or the Latin term Hydrosiderum. Two years later the distinguished Swedish Chemist Bergmann made the same discovery, finding a ?white calx? in cast iron, which he also mistakenly considered to be a new metal, and for which he proposed the Siderum.

Jan 1, 1944

By William C. Harrigan, William D. Nix

Dynamic measurements of Young&apos;s modulus have been made for poly crystalline Ni-W alloys from room temperature to 800°C. The alloys studied range in composition from pure nickel to Ni-10 at. pct W. The results indicate that Young&apos;s modulus decreases linearly with temperature above the Curie temperature. The rate of change of Young&apos;s Modulus with temperature mas found to range from 104 psi per "C for pure nickel to 0.82 x 104 psi per °C for Mi-10 pct W. At all temperatures the elastic modulus decreases with increcrsing tungsten content up to 1 at. pct W, and increases as the tungsten content is increased above that level. Young&apos;s modulus decreases slightly as the carbon content is increased from 0.002 to 0.09 wt pct C THE knowledge of the elastic modulus of metals and alloys is important for a number of reasons. The first and most obvious reason comes from the need to predict elastic deflections under given loading conditions. A second and somewhat more subtle reason comes from the fact that the elastic properties of an alloy must be known before a proper account of the mechanisms of plastic deformation can be made. This is especially true for high-temperature creep of crystalline solids. Sherby and his coworkers have shown that the high-temperature steady-state creep rates of crystalline solids are inversely related to the elastic modulus1,2 and that the temperature dependence of the elastic modulus must be taken into account if reliable determinations of the activation energy for creep are to be made. In addition, measurements of the elastic constants of solid solutions are needed to allow one to assess the modulus interaction contribution to solid-solution Strengthening.3-5 Pelloux and Grant6 have demonstrated that substantial solid-solution strengthening at room temperature and elevated temperatures occurs when refractory metal solute atoms are added to nickel. While the high-temperature elastic properties of pure nickel have been measured by a number of authors,7-10 the elastic properties of nickel-based refractory metal alloys have not been determined. The purpose of this paper is to report on measurements of Young&apos;s modulus of polycrystalline Ni-W alloys at elevated temperatures. It is expected that these measurements will be valuable to studies of the mechanical properties of nickel-based refractory metal solid solutions. I) EXPERIMENTAL Young&apos;s moduli of polycrystalline samples were determined by a dynamic method in order to reduce high- temperature anelastic and plastic relaxations. The samples were forced in transverse free-free vibration; that is, both ends of the sample were unrestrained and the vibration was transverse to the long axis. The fundamental resonant frequency was determined by the Forster method.11 The analysis of this type of vibration which was formulated by Rayleigh,12 Timo-chenko,13 and pickett,14 and reviewed by Fine," leads where fn is the resonant frequency of the nth mode, r is the radius of the circular cross section. L is the specimen length, ßn is 1.5056 for free-free vibration in the fundamental mode of vibration, 6 is the mass density, and E is Young&apos;s modulus in the axial direction. This equation can be transformed into: E = 9.17605 x 10-6(L/D)E/Lf2 [2] where E is Young&apos;s modulus in psi, L is the length in inches, d is the diameter in inches, W is the weight in grams, and f is the resonance frequency in cps. Eq. [2] was further modified in order to take account of the thermal expansion of the samples. The resulting correct term is: where the thermal expansion coefficients for nickel and tungsten, respectively. Xw is the atom fraction of tungsten in the sample and T is the temperature in "C. The treatment of the thermal expansion coefficient as a linear function of composition seems sufficiently accurate since an error of 25 pct in the expansion coefficient will result in only a 0.3 pct error in the modulus at 1000°C. A) Apparatus. The equipment for this investigation has been described by Lytton et al.16 Several modifications of the equipment have been made. The most significant change involved replacing the detector crystal transducer with a magnetic transducer. A phonographic magnetic transducer was employed as a sensing device since the contact pressure necessary to produce a stable signal is much less than that for a crystal transducer. This magnetic transducer is also not affected by conditions of high temperature and vacuum which are present in these experiments. The vacuum was 10-5 torr at room temperature and about 5 x 10-4 torr at 900°C. This was sufficient to prevent surface contamination of the samples during the tests. The samples were heated in an elliptical furnace with a quartz lamp at one focal line and the sample at the other, as described by Lytton et a1.16 The temperature of the sample was measured by monitoring the

Jan 1, 1969

By R. W. Raymond

FOUR portraits have recently been hung in the rooms of the Institute, in recognition of four illustrious men with whom we, as mining engineers and metallurgists, may claim fellowship. LUTHER. Martin Luther is often spoken of as a miner&apos;s son; but it is less generally known that John Luther, his father, was, in a small way, a metallurgist as well as a miner, and that Martin Luther himself, in his youth, worked in a forge or bloomary established by his father at Mansfeld, Saxony. Since this is the only manual occupation on his part of which we have any record, it is fair to assume that the great scholar and reformer derived from his work in this department the practical familiarity with the conditions of human labor so abundantly evinced in the homely illustrations which accompany even his serious arguments, and in the witty apothegms of his famous "table-talk." At the same time, I must confess that 1 have not been able to find in any of the works of Luther distinct allusions to mining or metallurgy. KÖRNER. Theodor Körner, a student at the Mining Academy of Freiberg, Saxony, threw himself into the German War of Freedom in the first decade of the 19th Century. He was a poet of no mean rank ; and his " Song of the Sword " is one of the great lyrics of literature. This poem was written but a few days before he died in battle. In many respects, Körner may be compared with our American hero Theodore Winthrop, who similarly met a glorious fate, and left behind him prophetic indications of genius, of which his premature death prevented the complete fulfillment. I am informed by a member of the Institute that Körner&apos;s admirable collection of minerals is still preserved at Dresden.

Nov 1, 1908

By Blamey Stevens

(San Francisco Meeting, October, 1911.) My previous paper is entitled, The Laws of Igneous Emanation Pressure. The present paper lays no claim to the exactitude and completeness of a law, since it is of a provisional nature and may be disregarded when experiments have established a basis for more exact reasoning. The general physical states in which aqueous emanations may occur are first considered. The possible physical conditions under which the mineral elements may occur in emanations are then discussed, and a classification of deposits, dependent on emanation, is proposed. A system of scientific experimental investigation is outlined, and it is shown that the physical and chemical properties of emanation may be exactly determined thereby. The investigation is urged as feasible and simple, and not necessarily requiring large and costly apparatus. It is the only step necessary to make possible the formulation of a complete set of laws of igneous emanation. Process of Emanation. In a rising column, magma ranges in temperature from 900° to 1,200°C. Exhalation must begin at some fairly great depth. What this depth may be we can only surmise, since no experimental evidence is available. Exhalation, however, continues as the magma flows upward, until at another level the occluded gases have all escaped. This depth is probably upward of 5,000 ft. (See Fig. 1.) All exhalations must come from between these two levels. As the whole emanation is the sum of the exhalations and residues, the residues must come from below the uppermost level. They will be most abundant when coming, from those parts of the intrusion which have solidified below the lower level.

Apr 1, 1912

By D. J. McAdam, G. W. Geil, R. W. Mebs

As shown in previous papers by the authorsg-17t the resistance of a metal to fracture, like its resistance to plastic deformation, is a function of all three principal stresses. A technical cohesion limit is the technically determined resistance to fracture under a specific stress system. The technical cohesive strength thus comprises an infinite number of technical cohesion limits corresponding to the infinite number Of possible com-binations of the principal stresses. The technical cohesive strength, therefore, may be represented by a surface in a diagram with the three principal stresses as coordinates. As shown in previous papers,&apos;-&apos;&apos; the technical cohesive strength increases with plastic deformation, with decrease in temperature, and with increase in the strain rate. The technical cohesion limit, therefore, is affected by the same factors that affect the flow stress,$ namely, the stress system, plastic deformation, temperature, and the strain rate. More- over, the influence of each of these factors on the technical cohesion limit has been shown to be qualitatively similar to the three of the same factor on the flow stress.9-18 Advance of knowledge about the conditions determining fracture of metals has been retarded by the reluctance of some investigators to abandon preconceived ideas about how metals &apos;&apos;should,, behave. The incorrect idea is still prevalent that the conditions determining resistance to fracture are very different from those determining the flow stress. Attempts are still being made to express resistance to fracture in terms of a single parameter, such as a limiting value of the greatest principal stress, the maximum shearing stress, or the volume stress (one-third the algebraic sum of the three principal stresses). In these attempts, a sharp distinction is sometimes made between a ductile or ,plasticdeformation, fracture,, and a "brittle frat-ture.H In making this distinction, however, the meaning attached to the term "brittle fracture" sometimes is not made clear. The term could mean fracture after very little plastic deformation or it could be used to designate the type of fracture. An ordinary fracture of a ductile metal at room temperature starts as a cleavage, generally transverse to the direction of the greatest principal stress, but eventually changes to a shearing fracture&apos; In some conditions, however, the metal fractures entirely by cleavage, with no evidence of plastic deformation during the fracture; the surface of such a fracture may have a

Jan 1, 1948

By R. W. Mebs, G. W. Geil, D. J. McAdam

As shown in previous papers by the authorsg-17t the resistance of a metal to fracture, like its resistance to plastic deformation, is a function of all three principal stresses. A technical cohesion limit is the technically determined resistance to fracture under a specific stress system. The technical cohesive strength thus comprises an infinite number of technical cohesion limits corresponding to the infinite number Of possible com-binations of the principal stresses. The technical cohesive strength, therefore, may be represented by a surface in a diagram with the three principal stresses as coordinates. As shown in previous papers,&apos;-&apos;&apos; the technical cohesive strength increases with plastic deformation, with decrease in temperature, and with increase in the strain rate. The technical cohesion limit, therefore, is affected by the same factors that affect the flow stress,$ namely, the stress system, plastic deformation, temperature, and the strain rate. More- over, the influence of each of these factors on the technical cohesion limit has been shown to be qualitatively similar to the three of the same factor on the flow stress.9-18 Advance of knowledge about the conditions determining fracture of metals has been retarded by the reluctance of some investigators to abandon preconceived ideas about how metals &apos;&apos;should,, behave. The incorrect idea is still prevalent that the conditions determining resistance to fracture are very different from those determining the flow stress. Attempts are still being made to express resistance to fracture in terms of a single parameter, such as a limiting value of the greatest principal stress, the maximum shearing stress, or the volume stress (one-third the algebraic sum of the three principal stresses). In these attempts, a sharp distinction is sometimes made between a ductile or ,plasticdeformation, fracture,, and a "brittle frat-ture.H In making this distinction, however, the meaning attached to the term "brittle fracture" sometimes is not made clear. The term could mean fracture after very little plastic deformation or it could be used to designate the type of fracture. An ordinary fracture of a ductile metal at room temperature starts as a cleavage, generally transverse to the direction of the greatest principal stress, but eventually changes to a shearing fracture&apos; In some conditions, however, the metal fractures entirely by cleavage, with no evidence of plastic deformation during the fracture; the surface of such a fracture may have a

Jan 1, 1948

By Albert Hoskinson

PROGRESS on the earth depends to a large extent upon the rapid inter-change of ideas and commodities between the various nations of the world. The smooth flow of commerce, by which these ideas and com-modities move, is accelerated by accurate and complete maps of the various land and water areas of the earth, The production of accurate maps depends upon a complete knowledge of the figure and dimensions of the object to be charted, therefore a knowledge of the shape of the earth is a prime necessity for accurate charting purposes. Gravity observa-tions were first undertaken to aid in determining the shape of the earth so that the geodetic surveys of its land and water areas might be more accurately connected to form an undistorted map. A large part of the earth&apos;s surface is water and it is therefore necessary to get gravity values at sea as well as on land before a complete and accurate figure of the earth can be determined. Dr. F. A. Vening Meinesz, of Holland, was the first scientist to perfect a pendulum instrument that would accurately measure gravity at sea. He had previously developed a multiple pendulum apparatus for measur-ing gravity upon swampy and unstable land areas in Holland and it was therefore quite natural that he should adapt the instrument to give accurate results upon a still more unstable support, the surface of the sea. His instrument as perfected gives satisfactory results when mounted in gimbals on any vessel where the roll and pitch are not more than about 5° and where the vibrations from rotating machinery and wave action are not large enough to cause the pendulums to shift on the knife-edges. This degree of stability can be obtained on surface craft only in protected waters or on very calm days. Therefore, Dr. Meinesz mounted his instrument in a. submarine so that he could submerge below the disturbed surface waters and get the desired stability in nearly any kind of weather by simply diving to greater depths. Most of the gravity-at-sea work has been done with a Meinesz instrument and a very large number of the observations have been made by Dr. Meinesz himself. He has occupied nearly 1000 sea stations and probably has traveled as many miles by

Jan 1, 1938

By A. R. Jr. Amos

LOG washers have been used for many years in the washing of clay iron ores, phosphate rock and manganese ores, but not until the past 15 years have they been employed to any extent in the preparation of aggregate materials and fluxing stone. For a machine of such importance where tenacious clay or soft rock must be eliminated, there are few data generally available. The purpose of this paper is to set forth the results obtained from several operations, together with a few suggestions for planning a specific installation. Where the material to be washed out consists of loose surface soil, silt, or small amounts of quickly soluble clay, there is little competition with other forms of washers, because greater power and maintenance are required for the operation of log washers, but where the foreign matter is a stiff clay, such as occurs with high-calcium limestones and in marginal gravel deposits, the ability of other kinds of washers to eliminate com-pletely the hard clay balls is at least uncertain. Then the log washer comes into its own field, for with the breaking and churning action of the logs it will clean out the toughest clay. Even with material from the hydraulic dredge, if it contains tough clay, the log washer is desirable unless the gravel is subjected to a costly soaking and rehandling process. Recently there has been a considerable development in other types of machines to accomplish these results but it is not within the scope of this paper to make comparisons between competitive types, but to present the best obtainable data on log washers only. From the primitive design that gave it its name, a long log hewn from a tree, with paddles forged to shape from strap iron and attached by lag screws, the log washer has gradually been developed to the present all-steel type. As now manufactured, the log washer consists essentially of two built-up logs on which are mounted a series of paddles, carried by shafts fitted at the ends of the logs on bearings fastened outside the enclosing steel box, or trough, which is set at an angle of about 5° to 10° and into which the material is fed. Stuffing boxes at the places where the shafts pass through the box at the lower end are equipped with water-

Jan 1, 1936

By Thos Gibson

THE object of taxation is the raising of a revenue. Unless a tax accomplishes this, it is a failure. The right to take for public purposes a part of the moneys obtained from the carrying on of private enterprises is an attribute possessed only by a lawful government, and may indeed he called the supreme attribute of government. In free, democratic communities this power must of necessity rest upon the consent of the governed. Power implies obligation, hence it is obviously the duty of a government, in framing a system of taxation, to provide one which, while effective in producing a revenue, is also just and impartial. It will be conceded that mines and mining property ought to bear a fair share of the public expenditure. The question is, upon what basis taxation should proceed. Two separate taxing principles are usually contended for: Taxation should be proportionate to the benefits received by the person or property taxed; taxation should be based on ability to pay. A third is sometimes added, taxation should have reference to the extent and value of the natural resources enjoyed. As applied to mining taxation, it is pointed out by those who support the first mentioned basis that, mines being usually situated in rocky and hence sparsely peopled regions, mining companies are frequently obliged to construct roads, railways, telegraph and telephone lines, schools, water and sewerage systems, and many other amenities and conveniences of civilization, the cost of which in regions better suited for agriculture and consequently more thickly populated, has either been defrayed locally, or can be spread over a sufficiently large taxable group of people to materially lighten the financial burden on the mine. The mining com¬pany, it is argued, having made these outlays, should receive credit for, them and be relieved of taxation to a corresponding extent. There may be some force in this contention, but the situation is capable of relief without attempting to place taxation upon so unworkable a basis as the value of benefits received. Who is to be the judge of these benefits, and how are they to be valued? The very existence of a mining company and its ability to carry on business in peace and security, depend on the prevalence of law and order, which is a result of good government. The state provides protection against violence, and courts of law for

Jan 4, 1919

By Joseph E. Pogue

THERE are two methods employed in the development of oil pools. The older and dominant method is one in which the primary object is the protection of the underground deposit from drainage through competing wells, and considerations of efficiency of extraction and cost of production are subordinated thereto. The newer and less prevalent method is one in which maximum efficiency and minimum cost are the first objectives and developments to these ends may proceed undisturbed by the exigencies of competitive drainage. The second method has developed mainly in pools under single ownership and the term "unit operation" has come to be applied to this procedure. A single ownership, however, is not essential to the method, for unity of operation may be achieved by agreement under split ownership, or even by a concert of enlightened purpose. There are examples of unit operation where neither the ownership nor the management is a unit, but merely where unity of procedure has been attained, as is the case of the Yates pool. .Throughout this paper unit operation is used in its broad sense without implying sole ownership or single management, although unit operation is more conveniently attained where these conditions are present.

Jan 1, 1930

By George W. Riter

OUR mineral-land laws need revising so as to provide definite title at the outset to the mineral deposits within any definite piece of land. The laws as they now stand, especially those applicable to lodes, breed uncertainty as to rights of possession prior to patent; and to my mind this is the worst feature of all, worse even than the apex bugbear. It is now almost impossible for anybody to tell-with certainty what mineral rights exist within any area that is not covered by patent, or whether any valid rights exist at all. Our system is unique in permitting individuals to appropriate and exploit mineral lands of the public domain without notice of any kind to the Federal government, and to relinquish them without any ceremony at all. The result is a clouded record that cannot be cleared up until each claimant is put to some sort of final proof. In order to accomplish this, new Federal legislation will be required. The requirements for a mineral survey and the proceedings for patent have always been cumbersome and expensive; and perhaps out of regard for the poor claim owner, who can ill afford the outlay for that sort of thing, the law does not require him to go. through it unless he chooses to do so. Consequently, every active mining district has become encumbered with tangled groups of doubtful or conflicting locations, whose rights and boundaries, when any valuable ore is found, must usually be determined by lawsuits that are as expensive and as distressing as the stakes are high. So deeply has litigation entered into our mining system that a claim whose rights have never been disputed would probably be set down offhand, by $miner of the old school, as of no value. Think of the litigation over rights of possession on the Com-stock lode—12 leading companies involved &apos;in an aggregate of 245 suits within a period of less than eight years! Ambiguous local records; the chance of erroneously placed or obliterated monuments; doubt as to the sufficient performance of the statutory annual labor; uncertainty as to prior conflicting or overlapping locations; anxiety as to the changing attitude of the Department of the Interior and the Forest Service—such considerations as these make an unpatented mining claim an unclean thing in the eyes of possible investors. Is it any wonder that they keep themselvesand their money at a safe distance,

Jan 1, 1915

By A. R. Jr. Amos

LOG washers have been used for many years in the washing of clay iron ores, phosphate rock and manganese ores, but not until the past 15 years have they been employed to any extent in the preparation of aggregate materials and fluxing stone. For a machine of such importance where tenacious clay or soft rock must be eliminated, there are few data generally available. The purpose of this paper is to set forth the results obtained from several operations, together with a few suggestions for planning a specific installation. Where the material to be washed out consists of loose surface soil, silt, or small amounts of quickly soluble clay, there is little competition with other forms of washers, because greater power and maintenance are required for the operation of log washers, but where the foreign matter is a stiff clay, such as occurs with high-calcium limestones and in marginal gravel deposits, the ability of other kinds of washers to eliminate com-pletely the hard clay balls is at least uncertain. Then the log washer comes into its own field, for with the breaking and churning action of the logs it will clean out the toughest clay. Even with material from the hydraulic dredge, if it contains tough clay, the log washer is desirable unless the gravel is subjected to a costly soaking and rehandling process. Recently there has been a considerable development in other types of machines to accomplish these results but it is not within the scope of this paper to make comparisons between competitive types, but to present the best obtainable data on log washers only. From the primitive design that gave it its name, a long log hewn from a tree, with paddles forged to shape from strap iron and attached by lag screws, the log washer has gradually been developed to the present all-steel type. As now manufactured, the log washer consists essentially of two built-up logs on which are mounted a series of paddles, carried by shafts fitted at the ends of the logs on bearings fastened outside the enclosing steel box, or trough, which is set at an angle of about 5° to 10° and into which the material is fed. Stuffing boxes at the places where the shafts pass through the box at the lower end are equipped with water-

Jan 1, 1936

By AIME AIME

AWRDED jointly by the four AW Founder Engineering Societies the John Fritz Medal is generally regarded as the most signal honor that American engineers can confer on a fellow engineer. The roll of 34 recipients contains the names of Lord Kelvin, George Westinghouse, Alexander Graham Bell, Thomas. A. Edison, George W. Goethals, Guglielmo Marconi, and Michael I. Pupin; and among members of the A.I.M.E. now living, Sir Robert A. Hadfield, Herbert Hoover, and Daniel C. Jackling. On the evening of March 1 7 the name of Paul Dyer Merica was formally added to this list of illustrious engineers when the medal was presented to him at a dinner at the Metropolitan Club in New York. The citation read. For important contributions to the development of alloys for industrial uses. Arrangements for the dinner were made by the following committee representing the four Founder Societies: R. C. Allen, George S. Davison, A. A. Potter, and J. B. Whitehead.

Jan 1, 1938