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By H. F. Walther

Basic electric-are furnace steel production mainly involves the use of two separate types of slags. The first, known as the "melt down" or oxidizing slag, which is in most cases removed from the furnace mechanically, and the heat finished under the second or deoxidizing slag, which is commonly known as the "finishing slag.'' The melt down slag is formed by the addition of lime or limestone to the charge, which combines with the oxides formed during the melting period and the product of any bottom erosion that may take place.

Jan 1, 1935

There are not many data about early coal production in Kentucky, but some legislative reports, early geological studies and occasional newspaper articles have left some figures. The earliest production with any authentic record is that of Lee County, the coal being boated down the Kentucky River to Frankfort. While never a large producer, this county has the longest record in the State. Production is recorded in several of the western coal counties in 1820, and in several others a few years later. The early production in Greenup County was for the iron furnaces operating there. Clay County had a large salt output in the early days and this required a large output, for those days, of coal; the amount of fuel is based on the quantity of salt. It will be noticed that several counties on the Ohio River produced considerable quantities of coal before the Civil War, much of it being consumed by the river steamers. Since the end of the war, these counties have never occupied the relatively important position they had prior to that time. All of the coal produced in the eastern mountain counties moved out of them by water before the war, and during that struggle nearly all mining was stopped. The growth of the railroads after the war greatly reduced the river traffic from these counties, and in some cases it was never renewed. The coal shipped from Lawrence County prior to 1861 all moved by water; after that date there was no production excepting for local use until 1879, and since that time, all shipments have been by rail. Some of the early railroad reports have been helpful in reporting shipments, but for the early years very few of them can be found, and after about 1879 the quantities reported cannot be identified as to origin. Pres. J. B. Hill, Louisville and Nashville Railroad, furnished all of the data available for his line. Sources of data are shown on Table 61; other figures are estimated. A list of early Kentucky mines is given in Table 13.

Jan 1, 1942

By R. M. Asimow

The magnetization curves for specimezs containing superparmagnetic particles are considered. It is shown that the curves may differ from a Langezlin function because of particle anisotropy, particle interactions , and the presence of a size distribution of particles. The various causes of particle anisotropy are considered, and magnetization curves for specimens with cubic and uniaxial anisotropy are presented. The magnetization curves depend on the In the particle-size below 100A it is quite difficult to obtain quantitative size and shape information on precipitate particles. All of the available techniques have their limitations; however, quantitative applications of superparmagnetism have not been developed as fully as possible due to a lack of analysis of the complete magnetization curve. With such an analysis it appears possible to obtain from a single magnetization curve of a specimen containing randomly oriented SPM (superparamagnetic) particles a quantitative volume distribution and a description of the particle shape.* sign of the anisotropy energy and in the case of a negative uniaxial anisotropy (prolate spheroids) the resulting curves may differ very considerbly from a Langevin function. A graphical technique is developed whereby it is possible to separate out the effects of the size distribution, the particle interaction, and the particle anisotropy. Thus it is possible to obtain quantitative values for both the particle shape and the size distribution. Langevin function2 I/Is = ctnh(HVIs/k T)-k T/HVIS [ 1 ] where I, is the saturation magnetization, V the particle volume, H the applied field, T the particle temperature, k the Boltzmann constant, and I the magnetization in the direction of the applied field. Such behavior is rarely if ever observed in actual systems. One explanation for this is that the SPM particles do possess a significant anisotropy and thus the magnetic energy associated with the particle depends on the direction of magnetization in a more complicated way than for the isotropic particle of Eq. [I]. In general the magnetic energy E of an isolated SPM particle embedded in a nonmagnetic matrix can be expressed as a sum of several contributions: E = Eh + Ed+Es+Ec [2] where Eh is the external field energy, Ed the energy resulting from the particle demagnetizing factor, E, the magnetostriction energy, and E, the crystalline anisotropy energy. In each term we consider only the part dependent on the orientation of the magnetization vector and the particle axes as the shape of the magnetization curve will be determined by these contributions. Following the same procedure used in deriving the Langevin function,

Jan 1, 1965

By Cornelius J. Dwyer

It is possible to hold a very optimistic view of the future of the U.S. coal industry, and there are those in the coal industry who generally choose to do so. For example, a major coal company stated recently in its annual report, "Coal's prospects appear brighter today than at any period in the past." In order to continue in this state of euphoria, it is only necessary to remind oneself of the following "facts":

Jan 7, 1967

By C. H. Hitchcock

Report C6 of the Second Geological Survey of Pennsylvania, by Charles E. Hall, describes the rocks of the Philadelphia belt, and sets forth conclusions widely different from those derived by others from the study of similar strata along the same stratigraphical line. Mr. Hall classifies these rocks into three groups: First, the Philadelphia schists and gneisses, well shown within the city limits and

Jan 1, 1884

By Edwin H. McKee

Eruption of rhyolitic ash-flow tuffs in the area of the McDermitt (Cordero) caldera began about 17.4 million yr (m.y.) ago and continued for about 1.5 m.y. During this period of silicic eruptions, a circular area about 30 km in diameter collapsed to form a caldera that subsequently filled with sedimentary and volcanic rocks. A total of more than 200 km30f silicic rocks was erupted from the volcano. The final phase of igneous activity, about 15.0 m.y. ago, included resurgent doming and intrusion in the south-central part of the caldera. Three to 4 m.y. later (-1 2 m.y. ago), hydrothermal solutions using the northern part of the caldera ring fractures as conduits deposited silica, cinnabar, pyrite, alunite, and other minerals in tuffaceous lake beds and volcanic rocks accumulated within the caldera. The ore-forming solutions may have been a residuum from the silicic magma, or connate water, or ground water heated by the still-hot resurgent magma in the central part of the caldera. The source of the mercury and other elements has not been identified.

Jan 1, 1977

By R. W. Nash, A. E. Schwaneke, V. R. Miller

The Bureau of Mines developed a detector for controlling sorting devices to separate the copper-bearing fragments from the barren portion of Michigan native copper and western prophyry copper ores. A successful sorter could be used to preconcentrate the ore and eliminate costly hoisting or hauling of waste. An induction balance unit was developed and used in sorting tests on crushed sized - 2.5 + 1. 3-cm (- 1 + 1/2- in.) ores from the Kingston (0.9% Cu) and Centennial (1.6% Cu) mines of Upper Michigan. Concentrates of 4.0% and 7.5% Cu, respectively, were obtained at recoveries of 85 and 80% of

Jan 8, 1978

Map

Jan 1, 1943

By L. O. Storey

The McDermitt mine was found as a separate mercury ore-bearing occurrence approximately 305 m (1000 ft) northeasterly and in a different geologic setting from the old Cordero mine, which had been the district's major producer. The following briefly describes the discovery of the new deposit and the Placer Amex lnc. involvement. The Cordero mining property was under lease by Sierra Mineral Management from the owner Fred H. Lenway in February 1971, when the property was brought to the attention of Placer Amex Inc. (known at that time as American Exploration and Mining Co.) by Richard F. Hewlett of Sierra Mineral Management. The property was first examined by Amex geologists in the spring of 1971, who reported favorably on the project. During that year, Sierra Minerals Management had retained Dr. Larry Walters as a consultant. He proceeded to drill test mercury soils anomalies which he had found northeast of the old Cordero mine in an area overlain by recent alluvium and gravel. An area known as the D area was subsequently blocked out and ascribed a tonnage of about 18 1 kt (200,000 st) which occurs in the vicinity of the eastern edge of the currently defined McDermitt ore body. This mineralization was found in flat lying mercury-bearing lakebeds, unlike the steep structurally controlled ore which was mined in the old Cordero mine. It became apparent to Placer Amex that since the chances of much more extensive ore were good in such a geologic environment, additional exploration was warranted. A joint venture was formed in October 1972 by American Exploration and Mining Co. and Sierra Mineral Management to further explore the Cordero property. The project exploration was fully funded and managed by Amex. Sampling began by Placer Amex in the D area where an open trench had exposed the lakebed ore. Visible cinnabar could not account for the high-grade mercury assays taken from the trench, and an unknown mercury mineral was suspected. Subsequent work established the presence of a chlorine-bearing mercury sulfide which may have enriched the lakebeds as a secondary supergene mineral. Early identification of the mercury-bearing mineral corderoite (Hg3Cl2S,) aided in the geologic concepts for the ore occurrence and was helpful in exploring for the expansion of the D area. Corderoite was found occurring with cinnabar in the lakebeds, and in places it is a major contributor. Specimens of the unique ore were given to Dr. Eugene E. Foord and Dr. Pieter Berendsen at Stanford University, who subsequently identified the chemical and crystallographic makeup of the new mineral and described it for the first time as a naturally occurring substance. Metallurgical work on mercury recovery from the newly described mineral was carried out by the Placer Development Ltd. laboratories in Vancouver, and an acceptable recovery system was worked out together with a planned mill design. Step out drilling from the D area by Placer Amex Inc. encountered extensive flat lying lakebed ore. The McDermitt ore body, as subsequently defined by drilling, was found to contain 2.7 Mt (3 million st) of open pittable ore, containing approximately 5 kg/t (10 lb per st) Hg. The ore body gently dips to the north and is found lying mainly in claybeds just above an opalite breccia blanket which overlies the earlier volcanics. Some ore is also found in the opalite breccia. The mine and mill were constructed under an operating joint venture with Placer Amex Inc. and Sterling Mineral Ventures, and production began in June 1975 at the rate of 20,000 flasks per year. The mine is currently in progress.

Jan 1, 1985

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members) The following is a partial list of members and guests who called at Institute headquarters during the period May 10,1917, to June 10, 1917. F. J. Anderson, Cali, Colombia. W. F. Jahn, Kirkland Lake, Ont., Canada. George J. Bancroft, Denver, Colo. W. McA. Johnson, Hartford, Conn. W. F. B. Berger, Denver, Colo. J. E. Jopling, Marquette, Mich. F. J. Brulé, Toronto, Ont., Canada. William Kelley, Vulcan, Mich. J. Murray Clark, Toronto, Ont., Canada. H. M. LaFollette, La Follette, Tenn. Will L. Clark, Jerome, Ariz.. Dorsey A. Lyon, Washington, D. C. G. H. Clevenger, Palo Alto, Cal. James F. Magee, Lancaster, Pa. Paul S. Couldrey, Sound Beach, Conn. M. Ortin, Nijni-Novgorod, Russia. C. W. Crispell, Kingston, N. Y. - C. H. Palmer, Jr., Los Angeles, Cal. George A. Easley, La Paz, Bolivia. Edison S. Pettis, ?Mill Valley, Cal. Bancroft Gore, Butte, Mont. Mortimer A. Sears, Paintsville, Ky. John B. Guernsey, Roanoke, Va. W. J. Uren, Houghton, Mich. Rush M. Hess, St. Louis, Mo. C. E. Visel, New Haven, Conn. E. Hibbert, Nickelton, Ont., Canada. Percy E. Barbour, has resigned his position as managing editor of the Engineering & Mining Journal, to accept the appointment of Deputy Superintendent of the New York State Troopers, with headquarters at Albany, N. Y., with the rank of captain.. He has also been commissioned as captain in the 22nd Regiment, N: Y. N. G., having been formerly 1st Lieutenant.

Jan 7, 1917

By D. L. Ritter, N. J. Grant, B. C. Giessen

The crystal structures of eight of the nine intermediate phases in the Nb-Rh system were investigated by X-ray techniques. The following structures occur: a,Nb3Rh (Cr3O type);o(ofe - cr type) (H.T. phase, structure unknown); Q2 (AuCU type); a, (orthorhombic, analogous to a,, (Ta-Rh)); a (AuCd type); a,, (monoclinic, related to samarium type); a-8 (VCo3 type); a, NbRh, (AuCu, type). Structural relationships between the six close-packed intermediate phases are discussed and a comparison with the Nb-Ir, Ta-Rh, and Ta-Ir systems is made. In the Nb-Rh phase diagram,' nine intermediate phases were encountered. In order to understand the phase sequence in the diagram and to be able to plot atomic volumes, several unknown crystal structures had to be worked out. These and the evi-

Jan 1, 1964

By M. Cepak, K. Donovan, W. G. Pariseau

This paper examines the difficulties of applying the finite element (FE) method of analysis to quantitative design of cable bolt systems. Cable bolt systems are in general use for ground control in VCR (Vertical Crater Retreat) topes throughout the world. However, despite their widespread use and importance, design of cable bolt systems is highly subjective. Two difficulties with the FE approach are examined: (i) the use of standard elements with a high aspect ratio (slender elements) to represent bolts, and (ii) the influence of cable bolts on hanging wall stability of a VCR study stope. Analysis results indicate that the use of slender elements for bolts is practical in large scale finite element analyses of VCR stopes. There are significant advantages in this approach to the engineering design of cable bolt systems in underground mining.

Jan 1, 1984

To ensure the receipt of the Bulletin, all changes of address must be received before the 20th of the preceding month when the mailing lists must be closed.

Jan 2, 1919

By J. H. Jackson, P. D. Frost, C. H. Lorig, A. C. Loonam

THIS paper describes (1) the effect of sodium on the tensile ductility of magnesium-lithium base alloys, and (2) the precautions necessary to avoid sodium contamination. Effect of Sodium on Properties The harmful effect of sodium in magnesium-lithium base alloys has been recognized by other investigators.1,2 However, quantitative data on its effect have not hitherto been published. The effect of sodium on the ductility of an 87 pct Mg-9 pct Li-4 pct Zn alloy is shown in fig. 1. The sodium was introduced by adding sodium chloride to the flux, which consisted of 50 pct LiC1-50 pct KC1. Moderately high ductility was obtained at an indicated sodium content of about 0.05 pct. Actually, the value probably was less than 0.05 pct, be-cause analyses of the lithium, which were more accurate than those of the alloy, indicated that the highest ductility was obtained when its sodium content was 0.02 pct or less. In fact, in alloys having somewhat greater strength than this particular composition, the sodium content of the lithium must be under 0.01 pct to avoid embrittlement. The effect of sodium on the ductility of several alloys having fairly low strength levels is shown in fig. 2. These alloys were melted with a flux containing 75 pct LiC1-25 pct LiF, to which various quantities of sodium chloride had been added. Sodium had no significant effect in pure magnesium but markedly decreased the ductility of the magnesium-lithium-zinc alloy, even though the alloy contained only 3 pct Li. As the lithium content of the binary alloys was increased, the ductility of the sodium-free alloys also increased. However, the effect of sodium on ductility became progressively more pronounced. Sodium raised the minimum hot-rolling temperatures, particularly those of the high-strength alloys, but its effect, in this respect, was less critical than its effect on tensile ductility. For optimum cold roll-ability, a low-sodium content was required. No deleterious effect of sodium on the stability of properties at slightly elevated temperatures was found. Control of Sodium in the Alloys Optimum ductility is obtained in the magnesium-lithium base alloys when sodium-free materials are used. Commercial lithium was formerly the chief source of contamination. Now purified lithium is usually available. When lithium of ordinary purity is used, the effects of sodium can be minimized by using a flux consisting of 75 pct LiC1-25 pct LiF. Bubbling nitrogen through the melt also helps remove sodium. The damaging influence of sodium on the ductility of the magnesium-lithium base alloys was observed very early in the alloy development program. The discovery came about as a result of chemical analyses made on the lithium used in the alloys. Ductile alloys had been made from lithium containing about 0.2 pct Na, whereas the lithium used in the brittle alloys contained about 0.9 pct Na. The first magnesium-lithium alloys were melted under commercial fluxes ordinarily used in melting magnesium alloys. These fluxes were unsuited for scavenging the contaminating sodium, and the resulting alloys were not ductile. Next, a flux containing 50 pct KC1-50 pct LiCl was tried. This was somewhat more effective but still was not satisfactory. After a number of different experimental fluxes had been investigated, one containing 75 pct LiC1-25 pct LiF was adopted. This flux made it possible to obtain good ductility in the alloys. The

Jan 1, 1951

By Thomas T. Read

It is natural, in reviewing the progress that has been made in mineral industry education during the three quarters of a century that has elapsed since the American Institute of Mining Engineers was organized in 1871, to seek to establish some significant correlation. Earnest endeavor along such lines, however, produces nothing more in the way of fundamental relationship than a technical economic interest in mineral production and utilization in the United States, which had been steadily increasing since 1800. This is a sound correlation, since it is unquestionable that organized and systematic mineral industry education had its origin in Germany, more than 150 years before 1871, in an economic interest in producing minerals for use with the maximum of recovery at a minimum of cost. Mineral industry became the originator* and creator of systematic technical education because of the political and economic fact that in all European (and most other) countries, prior to 1800, precious metals belonged to the ruling power, no matter upon whose land they were discovered. The practical way of working under this system was to grant to a discoverer the right to work the deposit on payment

Jan 1, 1947

By Paul Gordon

The distribution coefficient, k, of interest in zone refining is generally defined as the ratio of the solid to the liquid solubilities of one element in another at the normal melting point of the solvent. In practice, distribution coefficients are frequently calculated from solubilities at temperatures well below the melting point of the solvent, e.g., at a eutectic temperature. This is done because of the general lack of accurate data on the liquidus and solidus curves in most phase diagrams. The practice is equivalent to assuming that the liquidus and solidus curves are straight lines in the temperature range between the melting point of the solvent and the temperature at which data for the solubilities are known. It is recognized that the k values so derived may be in serious error; we have found evidence in recent zone-refining operations that a case in point is silicon in aluminum. The phase diagram found in the literature for silicon in aluminum indicates a eutectic on the aluminum-rich side at 12.5 at. pct Si and at 577°C,1 and a solid solubility of silicon in aluminum at this temperature of 1.59 pct.2 It also shows the liquidus and solidus as nearly straight lines from 577°C to the melting point of aluminum (660°C)1,2 The k value obtained from this data is 0.13. This is almost exactly the same as the k value (about 0.14)' obtained in a similar way for copper in aluminum. Yet we have found by mass-spectrograph analyses* of three bars of zone-refined aluminum that copper is efficiently removed from aluminum by zone refining but silicon is not. Two of the three bars of aluminum were zone-refined in our laboratories, the other in the laboratories of AIAG Metals, Inc. The former two bars, designated bars PG2 and PG3, were 30 in. long by 1 in. in diameter during refining; each was processed in a high-purity graphite boat* and kept under refining stage of the process consisted of thirty unidirectional zone traverses at rates of about 1 to 2 in. per hr, with a zone length of 1 to 2 in. At approximately the middle of the refining period a 6-in. piece of the impurity-laden finishing end of the bar* was cut off and replaced with new start- ing material. Following refining, the purest 20-in. section of the bar (obtained by discarding approximately 2 in. of the starting end and 8 in. of the finishing end of the bar) was leveled and then analyzed. The AIAG bar was 16 in. long and about 1.2 in. in diameter; it was purified by eight passes of a 2-in. zone at a rate of 1.6 in. per hr, the bar being contained in a sintered alumina boat lined with loose alumina powder of the highest purity. Data for the silicon and copper contents of the three refined bars are given in Table I. Derived data for the efficiencies of the zone-refining operations are listed in Table 11. It is clear from these two tables that the copper is removed much more efficiently—by a factor of 10 to 50 times—from aluminum during zone refining than is silicon. For example, in bar PG3 the thirty zone passes reduced the copper content from 10 to 0.02 ppm, i.e., by 500 times, whereas the same treatment lowered the silicon content by only a factor of about 16. It seem virtually certain, therefore, that the distribution co efficient, k, for silicon in aluminum is well above that for copper and is very likely not much below unity. This also implies that the solidus line on the aluminum-rich side of the A1-Si phase diagram is very probably appreciably curved near the aluminum melting point since the phase-diagram data indicate such curvature is unlikely in the liquidus.

Jan 1, 1965

By R. Simon, D. J. Graue

This paper presents correlations for predicting the solu-lility, swelling and viscosity behavior of CO2-crude oil sys8i.m~. The correlations were developed from experimental data obtained by the authors. These data are also presented. The data were determined by measuring the properties of mixtures of CO, and nine different oils. Experiinental conditions covered a range of 100 to 250°F and pressures up to 2,300 psia. Properties predicted by the correlations have average deviations, expressed as per cent of experimental value, of 2 per cent for solubility, 0.5 per cent for swelling and 12 per cent for viscosity. INTRODUCTION Interest in CO2 injection as an oil recovery process has led to the development of performance prediction methods which can be applied to specific reservoirs.1 iS To use these performance prediction methods, it is necessary to know the solubility, swelling and viscosity properties of CO2-crude oil mixtures at reservoir conditions. Some information on these properties has appeared in the literature; however, this information did not cover the range of different oils and conditions needed to prepare generalized correlations for reservoir engineering purposes. Consequently, an experimental program was undertaken to collect the data needed. The data obtained and the correlations developed from the data are described in the following sections of this paper. SOLUBILITY OF CO2 IN CRUDE OILS CO2 solubility data in the literature come from six principal sources. The solubility prediction method of Welker and Dunlop3 is limited to 80F. The information in Ref. 4 is of two types: the first includes binary and ternary mixtures of CO, and light hydrocarbons (C1 to C6), and the second gives data for CO1 and heavy hydrocarbons for a temperature range of 40 to 90F. Ref. 5 contains a KCO2 chart for systems whose convergence pressure is 4,000 psia. The KCO2's are based mainly on CO2-natural gas mixtures. Poettmann's work covered CO2 solubility in one condensate and one crude oil6,7 Ja-coby and Rzasa measured CO? solubilities as a function of pressure and temperature for two natural gas-absorber oil mixtures and two natural gas-crude oil mixtures.'8 CO, concentration in these four systems was fixed at 5 mol per cent. The work reported in this paper extends CO, solubility data to a variety of different crude oil types in a temperature range from 110 to 250F and pressures up to 2,300 psia. The experimental procedure used by the authors to obtain the solubility data consisted of combining known amounts of pure CO, and crude oil in a visual cell at a fixed temperature and measuring the bubble point of the mixture. Measurements were made for a total of 40 different CO2-oil mixtures and the results are shown in Table 2. The mixtures included nine different oils (seven crude oils and two refined oils) whose properties are listed in Table 1. All nine oils had vapor pressures less than 1 atm at the experimental temperatures. Consequently, analysis of the bubble-point vapor showed a CO, concentration over 99 mol per cent. At no time during these experiments was a second, more dense, liquid phase observed. The solubility correlation which was developed from the data in Table 2 is presented in Figs. 1, 2 and 3. In these figures, solubility is expressed as xco2 the mol fraction of CO, in the CO2-oil mixture. Fig. 1 shows solubility as a function of CO2 fugacity6 and temperature. Fig. 2 shows the same solubility data expressed as a function of saturation pressure and temperature. The solubility shown in Figs. 1 and 2 is for an oil whose UOP characterization factor is 11.7. UOP characterization factors of crude oils can be determined from Ref. 10 if the viscosity and APT gravity of the oil are known. Fig. 3 gives the solubility correction factor for oils whose UOP characterization factors differ from 11.7. The solubility correlation in Figs. 1, 2 and 3 predicted

Jan 1, 1966

By Oliver B. Hopkins

The Peruvian production increased over 3 million barrels from 1933 to 1934—from approximately 13¼ million barrels to over 16¼ million barrels—bringing the cumulative production of the country up to 171 million barrels. Most of this production, as well as most of the increase in 1934, came from La Brea-Parinas Estate, the property of the International Petroleum Co., Limited. In 1932 Peru stood eleventh among the oil-producing countries of the world, but in 1933 her production exceeded that of Trinidad, Argentine and Colombia, which placed her in eighth position. In 1934 Peru's production was exceeded by that of Colombia by about one million barrels, and by that of the Argentine by about 1½ million barrels, thus placing her in tenth position. After several years of relative inactivity in drilling and exploration there was a noticeable increase during 1934 in both of these lines of activity. Oil Fields La Brea-Parinas Estate.—Production on the La Brea-Parinas Estate. reached a significant total of 85,080 bbl. as early as 1891. It increased to over one million barrels in 1912, and to over 10 million barrels in 1929, and in 1934 it reached an all-time high of over 14 million barrels. The total production from 1890 to 1934 was 133,784,609 barrels. Practically all the drilling on the property has been done with cable tools, but during 1934 three strings of rotary tools were introduced. One was a heavy outfit for drilling a deep test and the other two were lighter outfits for deepening wells in the newer section of the field, where the gas pressure was too high to permit safe drilling with standard tools. During 1934 a total of 28,127 ft. was drilled, 66 wells were deepened, and 6 new wells were completed. At the end of the year 2844 wells had been drilled on the Estate, of which 1814 were still productive. The remaining 1030 wells represent abandoned producers or dry holes. The total area that has been productive up to the present time is estimated at 13,369 acres. An interesting article on the various phases of operations of the International Petroleum Co. was written by Arthur Iddings and published in The Oil and Gas Journal (Dec. 27, 1934).

Jan 1, 1935

By William P. Blake

The metallic element Nickel, discovered by Cronstedt the mineralogist, in the year 1751, as a peculiar metal in kupfer-nickel, remained for a long time comparatively unknown in its true charac-

Jan 1, 1883

By Alexander Squire

One of the principal factors that have contributed to the hesitancy of design engineers to use metal-powder parts is the difficulty experienced in the determination of the mechanical properties of compacted components. Because standard test methods cannot usually be applied in the inspection of such parts, and because adequate special test methods have not been developed, it has been considered desirable to investigate the methods that are applicable. These may then be included in specifications for metal-powder materials and components in order that the design engineer may be assured that the subject parts possess the desired mechanical properties for satisfactory performance. It is known that direct relationships exist between usually nonmeasurable properties as tensile strength and elongation and shear strength and the angle through which compacts may be plastically deformed before fracturing. These correlations are valuable in the inspection of specific parts, but it is necessary to set up standards before they may be satisfactorily employed. Apart from the use of correlations, the number and character of the inspection methods that are applicable to almost all powder parts is limited to three—chemical analysis, density, and hardness. The last of these may or may not be a pertinent characteristic, since the indentation hardness of many powdeied-metal materials is so low as to have little significance. It is, however, occasionally desirable to use hardness measurements as an indication of the uniformity of the structure of pieces of a given type. Chemical analysis reveals very little about the physical properties of metal-powder compacts, since the unpressed powder is usually of a composition almost identical with that of the finished pieces. Density determinations are simple to perform and have the advantage of being nondestructive in character. If the dimensions of a machine part are known (and usually they are), the average density may be determined by weighing a given number of pieces and dividing by the calculated volume of the parts. More accurate measurements may be made by the water-displacement method. It is recognized that mechanical properties of metal-powder materials are related to their density, but usually these relations are determined for only one type of powder, processed under a given set of conditions. Comparisons of the pioperties of compacts formed from different types of powders are made on the basis of compacting pressures instead of density, and for this reason the results obtained by using powders of different types appear widely variant.

Jan 1, 1947