Search Documents

By R. L. Andelin, J. D. Knight, M. Kahn

Self-diffusion in single-crystal tungsten and diffusion of rhenium tracer in single-crystal tungsten have been measured over the temperature range 2660° to 3230°C by direct sectioning and radio-chemical analysis of W185 and Re183 and Re184 tracers. The initial radioactive layer was produced on the diffusion specimens by bombardment with 9.0-mev deuterons. Diffusion heating of the samples in high vacuum was accomplished by induction heating. Temperatures were measured by optical pyrometry, and the system was calibrated ALTHOUGH a considerable body of experimental information has been accumulated on self-diffusion in solids, the major part of the detailed work has by reference to the melting points of tantalum (2996°C), molybdenum (2620°C), niobium (2468°C), and rhodium (1966°C). The diffusion coefficients for the two systems, obtained by least-squares analyses of the data, are well-represented by the equations thus far dealt with relatively low-melting systems. Diffusion studies on the high-melting elements niobium,1 tantalum,2,3 and tungsten4'5 have been limited to polycrystalline material, for which data interpretation and theoretical analysis are sometimes difficult. Only recently, a study has been made with single-crystal molybdenum.6 The present work deals with the measurement of self-diffusion in single-crystal tungsten at temperatures approaching the melting point (3410°c).7 Since the method chosen for producing the radioactive tracer layer-bombardment with deuterons—produced detectable isotopes of rhenium as well as of tungsten, the diffusion of rhenium was measured also.

Jan 1, 1965

By J. E. Johnson

The subject of blast-furnace slag is one which has had much consideration, particularly from the scientific standpoint, and several years ago technical literature contained many learned discussions on the oxygen-ratio of the acids and the bases, all on the assumption that acids and bases must be present in a ratio depending on molecular weight and chemical valency. Much work has also been don.e, sometimes in conjunction with the former, on the total heat and the temperature of initial fusion or softening of various slags. A wider knowledge of the blast-furnace now enables us to say that for practical purposes this work has been of almost no value. It is now generally admitted that on,the physical side the important point of a given slag is neither its total heat of fusion nor its softening-point, but its free-running temperature, since this is the critical temperature of the furnace. This temperature bears no definite relation to the softening-temperature, as determined by Seger cones, for instance, because some slags melt relatively like ice, with a very short viscous-range, while others melt relatively like tar, with a very long viscous-range. In one the difference between the softening- and the free-running temperature may be very small, as little as 100° F., while in another this difference may easily be 200' or 300°. The importance of this difference is so great in practice as to destroy completely the value of exhaustive investigations, even such as those of 0. Boudouard, published a few years ago.'

Jan 1, 1913

By W. W. Weigel

In "Mine Drainage, Southeast Missouri Lead District," Trans. AIME, (1943) 153, 74-81, the general water conditions in the lead mines of Southeast Missouri were described. Some comments developed from the experience of time and some further

Jan 1, 1949

By Mario L. Villa

During 1938, oil activities in the Argentine Republic showed a favorable balance due to the increase in crude-oil production, the incorpora- tion of new producing areas and the discovery of deeper productive horizons. Drilling was as follows:

Jan 1, 1939

By Mario L. Villa

During 1938, oil activities in the Argentine Republic showed a favorable balance due to the increase in crude-oil production, the incorpora- tion of new producing areas and the discovery of deeper productive horizons. Drilling was as follows:

Jan 1, 1939

By J. Chipman, J. C. Fulton

BECAUSE of the great importance of the ternary system Fe-C-Si in ferrous metallurgy a considerable amount of attention has been devoted to the phase relations, particularly those occurring in the solid state.' The information on graphite solubility

Jan 1, 1955

By David J. Dunn, Richard G. Martin

Of many physical parameters critical to design of grinding processes, impact of grinding media is among the most difficult to measure or predict. Yet impact of falling grinding balls, pebbles, or rods accomplishes the fine grinding essential to metallurgical recovery of most important minerals. Unfortunately, the same impacts that break ore fragments deform or crack grinding mill liners. A project was undertaken at Climax Molybdenum Company to measure impact forces in operating ball mills so that they might be used to calculate stresses in liner materials and be correlated with service performance of mill liner alloys. Towards that end, a method of measuring impact forces on ball mill liners using an instrumented grinding ball has been developed. Preliminary tests show that impact forces and contact stresses imposed on bare mill liners are quite high but are greatly reduced by cushioning when coarse ore particles are crushed between balls and liners. Compressive and shear stresses induced in liners not protected by coarse ore are so severe that deformation or minute subsurface cracking are inevitable in all but the small production grinding mills, regardless of mill liner alloy strength or hardness.

Jan 1, 1979

(The following list contains the names of those members of the Institute of whose connection with military service. we have only recently become acquainted; it also includes the names of a few who have recently been promoted or transferred. A complete list was published in the Year Book, issued as a supplement of the Bulletin for March, 1918.) ADAMS, HENRY, Major, Assistant to Department Engineer, North-eastern Dept. ALINE, P. A., Co. C, 316th Supply Trains. * Low-cost cottage construction in America; a study based on the housing collection in the Harvard Social Museum, by Winthrop A. Hamlin. Cambridge, Mass., Harvard University, 1917. (Publications of the Department of Social Ethics, No. 7.) 30 pp., 4 charts. Illus.

Jan 5, 1918

By Douglas A. Anderson

We have instrumented well-controlled free-face blasts with six- component borehole strain gages, in order to determine the complete strain tensor as a function of time due to explosive loading. The strain tensors have been diagonalized to determine the principal strain time-histories, and further processed to determine the octahedral shear strains as a function of time. Principal strain time-histories, when compared with a computer model, indicate the arrival of various direct and reflected phases. Strong shear strains coincide with the expected arrival time of shear waves. These shear waves are probably instrumental in the fragmentation of confined rock due to explosive loading, and should be incorporated in models of the fragmentation process.

Jan 1, 1984

DR. E. E. SOUTHARD,* Boston, Mass.-As Director of a Psychopathic Hospital, I am a sort of "voice in the wilderness" speaking to mining engineers. I suppose that I am here because Major Gilbreth had prevailed upon me to speak on a kindred topic before the mechanical engineers at the annual meeting of their Institute. You might wonder why a psychopathic hospital, a state institution for the first care of mental cases and especially for incipient, acute and curable cases, should have any part or lot in the industrial problem. We have obvious contacts in our institution with the retarded and exceptional children of the schools, with the defective and non-defective

Jan 4, 1918

By Cyril Smith

A STUDY of the precipitation-hardening of copper steels1 led the authors to investigate malleable iron containing copper, for the low-carbon ferritic matrix in malleable iron should lend itself admirably to precipitation-hardening. It was soon found that in addition to rendering malleable iron susceptible to improvement by precipitation-hardening treatments, copper has another potentially useful effect as an accelerator of graphitization. Brief mention of these effects was given in a general paper by Lorig and one of the present authors2; the present paper gives further details on the graphitization and precipitation-hardening effects only. After the completion of this work a paper by L. Lykkin3 appeared, confirming the authors' conclusions regarding graphitization.

Jan 1, 1935

By Benjamin F. Tillson

Although portable fire extinguishers are valuable for fires in an incipient stage, some medium that will dissipate a large amount of heat is needed to fight a fire in mine timbers, because of the size to which the fire will probably have grown before it is discovered. Scaling off, or otherwise smothering such a fire with gases that will not support combustion, is often ineffective for the residual heat will cause reignition when the area is opened and fresh air reaches the hot charred timber. The most effective ways of fighting mine fires, therefore, are to drown and cool the hot zone with water, and to "load out" the partly burned material. Either of these methods requires a direct attack of water ; upon the inflamed material; therefore, every mine containing a large ' quantity of timber or other combustible should be as completely equipped with a fire-hydrant system as it is with compressed-air mains. Mine managers may object to the expenditure, especially if they have not suffered from mine fires. The cost of such preventative measures, however, is only a small portion of the possible losses, and the water pipes can be used for other purposes, which will pay the carrying charges. They can supply water to the rock drills, which will encourage more wet drilling with hollow-drill steel, for the trouble and expense of packing water to individual tanks at the drills will be removed. The carbon-tetrachloride hand extinguishers seem to have no place in mining except for fires that start in electrical equipment. They give off noxious gas, which may prove poisonous in confined quarters; and as it is heavier than air it is of no value for smothering fires overhead or in side timbers and would be dissipated by a good ventilating draft. The old soda-acid extinguisher or the more modern "foam" types ' are preferable. The former probably does not rely for its efficacy on the carbon dioxide generated but on the smothering and cooling effect of the water and the trajectory of stream that may be obtained because of the gas pressure developed. The production of a foam having a tough film to smother a fire, even on overhead surfaces, with the added

Jan 1, 1923

By Benjamin F. Tillson

Although portable fire extinguishers are valuable for fires in an incipient stage, some medium that will dissipate a large amount of heat is needed to fight a fire in mine timbers, because of the size to which the fire will probably have grown before it is discovered. Scaling off, or otherwise smothering such a fire with gases that will not support combustion, is often ineffective for the residual heat will cause reignition when the area is opened and fresh air reaches the hot charred timber. The most effective ways of fighting mine fires, therefore, are to drown and cool the hot zone with water, and to "load out" the partly burned material. Either of these methods requires a direct attack of water ; upon the inflamed material; therefore, every mine containing a large ' quantity of timber or other combustible should be as completely equipped with a fire-hydrant system as it is with compressed-air mains. Mine managers may object to the expenditure, especially if they have not suffered from mine fires. The cost of such preventative measures, however, is only a small portion of the possible losses, and the water pipes can be used for other purposes, which will pay the carrying charges. They can supply water to the rock drills, which will encourage more wet drilling with hollow-drill steel, for the trouble and expense of packing water to individual tanks at the drills will be removed. The carbon-tetrachloride hand extinguishers seem to have no place in mining except for fires that start in electrical equipment. They give off noxious gas, which may prove poisonous in confined quarters; and as it is heavier than air it is of no value for smothering fires overhead or in side timbers and would be dissipated by a good ventilating draft. The old soda-acid extinguisher or the more modern "foam" types ' are preferable. The former probably does not rely for its efficacy on the carbon dioxide generated but on the smothering and cooling effect of the water and the trajectory of stream that may be obtained because of the gas pressure developed. The production of a foam having a tough film to smother a fire, even on overhead surfaces, with the added

Jan 1, 1923

By William P. Blake

The copper-beariug rock formations of Cananea, Sonora, Mexico, present conclusive evidences of extensive and sharp plication. Some of these evidences are here briefly stated. 1. There is a succession of approximately parallel outcrops of an altered limestone, alternating with dikes and masses of porphyry. The great copper-ore deposits are in close association with these ridges of limestone, which trend northerly and southerly and stand nearly vertical. This parallel succession is so well-defined that the management of the mines has, for convenience, recognized and named five zones, known from the chief mines, in their succession from east to west, as the " Cobre-Grande," " Veta-Grande," " Esperanza," " Capote," and " Puertocitas " belts. The intervening and separating formations are coarsely crystalline feldspar porphyries, highly basic, of light color, which may be regarded as intrusive and, in part at least, as the cause of the metamorphosed condition of the limestone. 2. These cupriferous limestone-zones are similar in constitution, are similarly charged with copper-ore (in association with quartz as a gangue, or veinstone), and are marked by similar croppiugs of gossan. 3. Distinctly folded outcrops of the surrounding strata can be observed, especially on the eastern border of the copper-bearing district north of the Democrita ground, and not far from the Veta-Grande. 4. The limestone ridge adjoining the Veta-Grande ends a short distance north of the mine, and appears to be the extretne end of a synclinal trough. 5. The Capote limestone, the most western of the croppings of the central copper-bearing area, is contiguous to stratified sandstones and quartzites, uplifted at high angles, but showing an easterly dip. The Capote limestone is apparently conformable

Jan 1, 1905

By J. F. Enrietto

It is shown that one cannot approximate the broad internal friction Peaks observed in the Fe-Mn-N system as the sum of a number of subsidiary Peaks and still vetain the concept of a single relaxation time. Furthermore, the approximation of manganese affectirg only nearest neighbor interstitial sites is shown to be incompatible with the experimental results. The results of this experiment show that the influence of manganese in the ferrite lattice extends over 3 to 4 atomic distances. NUMEROUS experiments have shown that the presence of relatively small amounts of substitutional alloying elements can profoundly affect the profile of the damping spectrum in the vicinity of the Snoek peak in bee metals.1-7 Dijkstra and Sladekl observed this phenomenon in Fe-Mn-N alloys where it appeared as a broadening and shifting of the Snoek peak to higher temperatures. The authors interpreted this as being the result of a superposition of two damping maxima—the normal Snoek peak, located at its usual position and having a normal half-width, and an interaction peak having a normal half-width, but occurring at a somewhat higher temperature. They prclposed that the interaction peak was caused by nitrogen atoms jumping from Fe-Mn sites to Fe-Fe sites, the Fe-Mn interstitial sites having one manganese and one iron atom as nearest neighbors, and the Fe-Fe sites having two iron atoms as nearest neighbors. They further suggested that the Fe-Mn sites had a lower energy than the normal Fe-Fe sites because of the presence of the adjacent manganese atoms. From the relative heights of the two postulated damping peaks, the dif-

Jan 1, 1962

By C. J. Guntner, R. P. Reed

A commercial 18Cr-8Ni iron alloy (AISI 304L) was examined in tension at 300°, 76°, 20°, and 4°K. Continuous stress-strain recordings were made, X-ray analyses at periodic stress (strain) intervals were obtained, and the magnetic measurements were taken. From this data the percentage of martensitic products [bcc(a) and hcp (E)] was computed as a function of stress (strain). It was found thatup to 15 pct E phase forms at low temperntures. The amount of E formed increases to a maximum at about 5 pct strain, then decreases. This decrease indicates the additional transformation of E to a'. The total amount of E and a' was suppressed at constant stress (strain) at 4°K as compared to 76°K. It is proposed that the suppression of E and a' is associated with the decreased mobility of extended dislocations at very low temperatures. The yield strength decreased as the temperature was depressed below room temperature and then increased rapidly near 4°K. SOME ferrous alloys which are austenitic (fcc ?) at room temperature appear to be unique in that two martensitic products (hcp e and bcc a') may form on cooling to lower temperatures or on application of mechanical stress. The most common room-temperature austenitic ferrous alloys are 18Cr, 8Ni stainless steels. Most aspects of the spontaneous transformations have been previously described for these steels.' Several previous papers have described special aspects of the stress-induced transformations at low temperatures for the stainless steels, such as the existence of the hcp phase (c) after straining at 76oK,2-7 the morphology after straining using electron microscopy,7 and the decrease in E at higher strains at 76oK.4 However, for a complete representation, one must know the stress-strain characteristics and the dependence of both martensitic products on applied stress and temperature. It is the intention of this paper to provide that documentation. To accomplish this, continuous stress vs strain recordings were made at four temperatures: 300°, 76", 20°, and 4°K for annealed AISI 304L (a commercial 18Cr-8Ni alloy). At periodic stress intervals at each temperature the integrated X-ray line intensity of a selected peak for each phase (y, E, and a') was measured. In addition, photomicrographs of the strained surfaces were taken and magnetic measurements were made. The magnetic readings can be directly converted into percent a'.',e With these measurements the percentage of each phase may be plotted as a function of stress (or strain) and test temperature. It was found that up to 15 pct E phase forms upon stressing the AISI 304L alloy at low temperatures. The E percentage increases abruptly after the alloy yields, but then decreases gradually at higher stresses. The rapid increase in e at 76°K is associated with an "easy-glide" portion of the stress-strain curve. The total amount of a' + .G is suppressed below 76°K at a constant stress or strain. The yield strength decreases down to 76°K but increases rapidly below 20°K. EXPERIMENTAL PROCEDURE Tensile test specimens were cut parallel to the rolling direction from 0.1-in.-thick sheet. Continuous stress vs strain recordings were obtained at each test temperature (300°, 76o, 20°, and 4°K) using equipment and methods described elsewhere.' The specimens which were used in the X-ray analysis were stressed to successive increments of strain at each temperature, analyzed at room temperature, then restressed at the test temperature. This procedure was repeated until approximately ten X-ray analyses had been performed with approximately 1.0 pct strain increments. The specimens had a reduced section 1 in. long, 1.2 in. wide, and 0.1 in. thick. They were electro polished prior to testing and after each strain increment. Table I lists the chemical composition, grain size, and hardness for the alloy which was used. This is the same alloy for which extensive mechanical-property tests3 and morphological studies of the spontaneous transformations' have previously been made. For the low-temperature tests (76o and 4°K) below the Ms temperature the specimens were initially cooled to the test temperature, held for 1/2 hr, then warmed and X-rayed at room temperature. The results are listed in Table 11. From earlier work8 it was known that additional transformation on the second cycle would be considerably less (-0.1 pct

Jan 1, 1964

By Joseph Jensen, F. W. Hertel

Many fields have been zoned by nature with shales and intermediate waters between oil zones. Limitations thus imposed have been the basis on which a field was developed. In contrast thereto, in the Ventura Avenue field, nature proved more generous. Always expecting to find such similar limitations, operators drilled deeper and deeper into the oil zone without finding any distinctive shale bodies other than the Gosnell shale and only one intermediate water, which became the point below which the final water shut-off of each well was made. Thus, on top of the structure, about 3300 it. of oil-bearing zone has been penetrated below this intermediate water—a distance of 4000 ft. below the Gosnell shale. At first it seemed that the greater penetration in the zone, the better the well. The error of this assumption became evident as time passed. Other pressing attendant problems requiring consideration also developed. In the spring of 1929, the Associated Oil Co., still having a large undrilled area, adopted a method for developing this land by dividing the oil formation into zones, so as to drill two classes of wells and to prepare for others, if conditions in the future justified or required such action. Wells now completed are considered as permanent completions in the zone or class for which they are drilled, and are not looked on as a ready means for deepening or accepted as a temptation for deepening to get some flush production quickly. Provision has also been made to avoid future water problems. The most striking demonstration resulting from such work is the fact that the top of the structure is far from being the point at which the largest oil recovery is made. Wells on the flank of the structure invariably produce with lower gas-oil ratios and secure much larger oil production. Zoning of Oil Sands The Gosnell shale separates the upper light 50 gravity oil from the lower 30 gravity oil below. As the light oil zone is of practically no importance at present, it is not being exploited. The development pro-

Jan 1, 1931

By John V. W. Reynders

Our entry into the World War suddenly brought home to us in a startling way the vital importance of manganese. Since the war, much has been written and said upon the subject of manganese and a great deal of time and money have been spent in attempts to find an adequate substitute for this metal in the manufacture of steel; none has been found. It is true that ways are known by which it is possible to make small amounts of good steel without manganese, but taking into consideration the diminishing quality of iron ores and fuels as well as the increasing exaction of specifications for finished products, it may safely be assumed that, high-grade manganese ore will be more and more a necessity in the production of steel as time goes on. Taking world resources as a whole it may be well to point out that the problem of obtaining needed supplies of manganese from a strictly commercial viewpoint is now less serious than it was before the war. Formerly it was feared that world resources of high-grade manganese ore might be exhausted in a relatively short time, but, largely as a result of the stress laid upon the importance of manganese during the war, the world's available supply of high-grade manganese ore has been greatly augmented by new discoveries and fuller development of previously known deposits. Sources of Production Russia alone, of countries producing the major part of the world's stee1, has within its geographical boundaries sufficient manganese to supply its needs. The domestic production of England is inadequate and English requirements for high-grade manganese are supplied principally from India. France also draws largely upon India, as it depends upon foreign sources of supply except with respect to a small tonnage of silico-manga-nese and silico-spiegel produced in the Hautes-Pyrénées. Germany and the United States likewise depend upon foreign sources of high-grade ore, though each possesses comparatively large reserves of ferruginous manganese ore and manganiferous iron ore. At present the world demand for high-grade manganese ore is met with ease by the production of Russia, India, Gold Coast and Brazil.

Jan 1, 1927

By Bruce A. Kennedy

The place of the young engineer in the mining industry has been the subject of a large number of keynote addresses, magazine articles, and papers in the past year. One of the best of these was the keynote address given by Mr. J. C. Kinnear, Jr. at the Fifth Annual Intermountain Minerals Conference in Vail. Colorado. Mr. Kinnear presented as part of his address the statistics of a Canadian survey Instigated to find out why young engineers and geologists are leaving the mining industry. The results of the survey showed four main reasons for leaving: 1) insufficient money 2) slow promotion 3) lack of association with senior engineers, as well as insufficient opportunity to keep abreast of technological development 4) geographic isolation

Jan 1, 1970

By Andrew W. Jenike

An efficient storage plant contains a known available volume of bulk solid, and feeds it at the required time, the prescribed rate and without degradation of the product. A storage bin may also perform other functions, such as blending different grades, degasifying aerated powders and isolating different gaseous media. A contact bed of particles flowing by gravity in counter-current with a gas or liquid may be used as a continuous reactor. In order to design an efficient storage plant or contact-bed reactor, it is necessary to be aware of the problems which can arise in flow and storage. The typical problems are no flow, erratic flow, flushing, insufficient flow, lack of designed capacity, segregation, degradation of the product and level control.

Jan 5, 1968