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By L. L. Wyman

SINCE the observations of Heyn,1 relative to the embrittlement of copper after having been heated in hydrogen, this subject has received considerable attention from later investigators. The published works of Archbutt2 and of Bengough and Hill3 give the reasons for this embrittlement-the formation of steam by the reaction between cuprous oxide and hydrogen. From Ruder,4 Pilling,5 Moore and Beckinsdale,6 Bassett and Bradley,7 and from Smith8 can be obtained quantitative data concerning the action of hydrogen and other reducing gases on copper samples having various oxygen contents. This problem has been discussed from a practical standpoint by Fuller9 who calls attention to some of the instances of this embrittlement encountered in the manufacturing field. The examples he cites may be considered typical cases of copper embrittlement which were incident to the process of manufacture. In many cases, such difficulties are overcome by changes in the manufacturing process.

Jan 1, 1931

By Robert M. Dreyer

AGGREGATE With an annual domestic production of over 1.6 billion tons at a value of over $2 billion (see Table 15.1.1), the production of aggregate (crushed rock, sand, and gravel) is a basic industry of utmost economic importance. Because of the role of aggregate materials as essential ingredients of concrete, asphalt surfacing, and plaster, their delivered prices are major factors in determining the cost of construction. The annual domestic production comes from nearly 10,000 plants. About 15% of these plants account for over one-half the production. In a rapidly inflating economy, the average mine sales price of aggregate has remained relatively stable. The actual mine sales prices, however, vary greatly depending on quarrying costs in various parts of the country. Of much more importance in construction costs, however, is the delivered price of aggregate. This varies for each job, depending on the distance from the quarry and resulting transportation costs, as well as the initial cost at the mine. Because of a proliferation of regulations limiting new quarries in the vicinity of the encroaching urban sprawl, the average distance which aggregate must be transported has been increasing rapidly. Although it is impossible to derive an average delivered cost for aggregate, it should be noted that even an increase of only $1 per ton in average delivered cost over the last decade (probably a minimal assumption) would mean an annual cost $1.5 billion higher than ten years ago. In recent years, structural engineering considerations, as well as an increasing use of lightweight concrete blocks, have resulted in a rapidly increasing demand for lightweight concrete and plaster, the essential ingredient of which is lightweight aggregate. Principal lightweight aggregates are: pumice, slag, perlite (thermally expanded hydrous volcanic glass), vermiculite, and expanded shale, formed by the thermal expansion of shale and slate. The United States now has the capacity to expand, annually, over 13 million tons of shale and slate and to expand over 600,000 tons of perlite. In locating a site for aggregate production. the following factors must be considered: (1) tonnage available; (2) quality of aggregate (including local variations); (3) distance from major use areas; (4) transportation costs, including those resulting from present and possible future haulage restrictions; (5) zoning regulations; (6) operating costs, including the cost effects of compliance with local regulations governing blasting, air pollution, water pollution and drainage, noise levels, and operating periods. At one time, locating a suitable site for the production of crushed rock, sand, or gravel, in most areas, was regarded as an extremely simple task. In the past few years, however, finding a site for profitable production of aggregate has assumed ever-increasing com-

Jan 1, 1976

By J. B. Urnfileb

THE function of gas in the development and production of oil has far reaching consequences that should be emphasized. The technical aspects of the subject have recently had a great deal of attention but less thought has been given to fundamental concepts underlying oil and gas law and the many customs and practices that have grown up in the industry. I shall re- view briefly the advance in knowledge of the subject and attempt to relate these concepts to legislative, judicial and operating problems. Early writers on oil and gas in Pennsylvania noted their close association in oil pools and their contemporaneous decline in output; also, that as gas pressure decreases so does production, that new offset wells reduce the output of existing wells, and even that tubing a well lengthens its flowing life. Expanding gas was deduced as the principal expulsive force. These fundamental observations had been made at least as early as 1880.l They were treated, however, as academic considerations and did not greatly influence law or practice for many years except to instil into all operators an urgent desire to hasten offset drilling to obtain as much of the flush as possible.

Jan 1, 1932

By Samuel Hoyt

THE hardness of annealed copper has been given in the literature and is easily obtained by any of the standard methods of hardness testing. It is not our intention to correct published values or to add to them, but to describe tests of two bars of annealed electrolytic copper in which the methods of Meyer's analysis were employed. MEYER'S ANALYSIS OF BALL INDENTATION TEST The ball indentation test is probably the most valuable hardness test we now have but, as it is carried out in the Brinell or Rockwell test, the result may be seriously in error without the operator suspecting such to be the case. This condition results from the isolated and uncontrolled nature of the measurement. The accuracy depends on the accuracy of the equipment and the care and skill used in the operations; there is nothing in the impression diameter, which is all that is measured, to indicate the presence of error. Meyer's analysis supplies a control of the measurements that goes far toward eliminating unsuspected errors. The principles of this work maybe obtained from elsewhere.1 As this subject has not received the attention of this Institute, it may be well to summarize the more important points as follows.

Jan 2, 1926

By M. C. Flemings, A. A. Tzavaras

Analytical and experimental procedures are descrihed for quantitative determination of volume-fraction microporosity in metals by mimorarlio-graphg. The analysis assumes spherical pores but allows for the observed fact that pores or portions of pores smaller than a given thickness do not project an image on the film. Volume-fraction microporosity was measuured in cast low-alloy steel and shown to vary from 0.6 x 10-4 to 10 x 10 depending on mode of solidification and on whether the material was air- or vacuum-cast. The aim of work described herein was to develop a method of quantitative measurement of the volume fraction of microporosity in cast metals. Microporosity, present in nearly all castings and ingots, is always interdendritic in nature and may be large enough to be seen on a polished surface with the naked eye. More generally, it is smaller in size, and its detection more difficult. Three techniques might be considered for measurement of microporosity: 1) lineal analysis of a polished metallographic surface, 2) density measurement, or 3) quantitative microradiography. As will be shown later, volume fractions of porosity in directionally solidified castings may be the order of 10-4 to 10-3; such small amounts of porosity are difficult to identify and measure on a polished surface. Density measurement is also not a suitable technique (for alloys) when the volume fraction of porosity is low. This is because the density of the base metal is often not known within the necessary accuracy, due to microsegregation or partial phase transformations. In general, it is not possible to completely eliminate microsegregation without also altering the porosity. Because of the limitations of the foregoing techniques, quantitative microradiography was employed to determine amount of porosity. In recent work, microradiography has been found to be useful for qualitative measurement of porosity, including determination of size and shape of individual pores;&apos;)&apos; however, quantitative determination of amount of porosity has not been attempted. I) CALCULATION OF VOLUME-FRACTION POROSITY The following analysis employs procedures similar to those of Cahn and Nutting3 and Hilliard.4 Major simplifications are that pores are assumed to be spherical and to be present in sufficiently small quantities that no overlapping occurs. A basic difference from the previous treatments is that the limited "sensitivity" of microradiography is considered. Assume first 1) cavities are spherical and of uniform diameter, 2) cavities are randomly distributed, 3) volume-fraction porosity and specimen thickness to pore radius ratio are sufficiently small that overlapping of the projected images of cavities is negligible, 4) sensitivity is limited (i.e., holes or portions of holes of less than a given thickness do not project an image on the film). The sensitivity, is defined as: where 5 = minimum thickness of void from which an image will be projected on the film and t = specimen thickness. Now, from Fig. 1, it is possible to distinguish between two different types of holes. These are 1) holes whose centers lie within the region t/2 > X > 6/2, where X is distance from one surface of the specimen (positive into the specimen), and 2) holes whose centers lie within the region (6 — r) < X < 6/2, Holes whose centers lie outside X = (6 -r) project no image on the film. These two types of pores are considered separately below. Type 1 Pores. When 6 is greater than 0, the image of a spherical cavity of radius r appears on the film as a circle of radius a which is smaller than r. From geometry, Fig. 1: a2=r2-52/4 [2] where a = radius of image of pore on film and r = radius of pore. Since the pores are randomly distributed and spherical V =4/3pr2Nv [3] where V = volume fraction of voids and Nv = number of pores per unit volume and the number of images of Type 1 pores per unit area of film, N&apos;A, is

Jan 1, 1965

Jan 1, 1968

By G. J. Ballmer

Trucks Are Valuable Auxiliary Haulage Units in Rail Pits For: ( I ) Making railroad grades (2) Establishing benches (3) Making new dropcuts

Jan 10, 1951

By Manning W. Cox

Van Stone mine area is situated at the head of Onion Creek on the northwest flank of Gillette Mountain, Stevens County, Washington. The di strict was found during World War I, but the mine did not come into production until 1952. Production to the end of 1965 was 2,242,960 tons of ore that yielded 10,700 tons of lead concentrates and 120,000 tons of zinc concentrates. The area is part of the Selkirk Mountains Zinc-Lead Belt, or Kootenay Arc, extending from near Revelstoke, British Columbia, to Colville, Washington. A thick but incomplete section of Paleozoic marine formations occurs in the Kootenay Arc and is overlain by marine and continental Mesozoic formations. Both are invaded by Late Mesozoic-Tertiary batholiths. The belt is characterized by open complex folding and extensive high-angle and local thrust faulting. Principal ore deposits occur in the highly deformed carbonate rocks of Cambrian age-the Maitlen (Laib) and Metaline formations. The Van Stone mine occurs along a steeply S-shaped fold lying between the Kaniksu Batholith on the west and the Rogers Mountain Fault, a northeast-trending fault on the west flank of the Gillette Mountain Anticline, to the southeast. The fold is cut by northeasttrending faults containing notoriously irregular lamprophyric, diabasic, and pebble dikes. The host rocks, lower Paleozoic dolomites, are decolorized, silicified, and silicated in the mine area. Jasperoid and tremolite are the common alteration minerals. Other gangue minerals are barite, pyrite, brucite, calcite, and, near the batholith, pyrrhotite. Ore minerals are galena, jamesonite, and sphalerite. Ore minerals occur in bunches and pods intergrown with tremolite and jasperoid. Zinc is roughly eight times more abundant than lead. The highest ore outcrops at 3870 feet elevation, and an undeterminable portion has been removed by glacial scour. The lowest drill hole penetration has reached 3220 feet elevation. Oxidation ranges up to several hundred feet in depth and may be most closely related to pre-glacial groundwater circulation. The area of the mine was completely over-ridden by Pleistocene continental glaciers, and the present erosion surface is nearly continuously blanketed by up to 150 feet of glacial outwash.

Jan 1, 1968

By Walter Miller

Petroleum refining, like other industries in the United States in 1940, focused much attention on its duties and opportunities in the field of national defense. In crdiiter-distinction to the situation during the World War, the industry is well constituted as to existing equipment, processes, and capacity, together with planned additions, to handle any demands that may be made upon it by the defense program needs. Evident throughout was the growing sense of ability to manipulate oil molecules for the production of materials not hitherto considered as being available commercially from petroleum. The development and application of catalytically induced reactions on a broad front is one of the distinguishing characteristics of refining progress during the year. In the hands of the refiner, catalysis has developed into a most important means to secure higher antiknock motor fuels and 100-octane fighting grade aviation gasoline in greatly increased quantity. One illustration of the importance being assigned to catalytic refining is the construction by the Houdry group of an experimental laboratory at a cost of $7&apos;307&apos;30&apos;3, to be staffed with over 100 research men7 solely for the purpose of studying catalytic reactions. In the aviation gasoline picture a modification of specifications by the Government widened the field from which acceptable fuel can be secured, and the continued expansion of the alkylation process in itself promises to go far in filling the demands expected from 50,000 fighting planes. It is conservatively estimated that eyen now the industry can turn out 1,300,000 gal. of 100-octane aviation gasoline daily. The upper limits of octane numbers for regular grades of motor gasoline reached in 1939 were not exceeded, but the average octane number approached the upper level more closely. A survey made of the 1940-model cars showed no rise in average octane requirement of the engines. The trend throughout the year was for greater reliance on the A.S.T.M. method for octane determination. The "1939 Research Method" is less widely used, although still considerably in evidence; the older L-3 method seems to have lost considerable ground and to be on the way out. Re-forming Capacities Increased Interest continued to grow apace in re-forming low-octane naphthas into high-octane gasolines. Some additions, although not great, were announced in thermal re-forming capacity. Interest in catalytic re-forming was greatly stimulated by the technical success of the operation of the converted hydrogenation unit at the Bay-way, N. J., rehery of the Standard Oil Company of New Jersey, mentioned in last year&apos;s review, and also by the knowledge that recoverable proportions of toluene are present in the hydroformed (catalytically

Jan 1, 1941

By Walter Miller

Petroleum refining, like other industries in the United States in 1940, focused much attention on its duties and opportunities in the field of national defense. In crdiiter-distinction to the situation during the World War, the industry is well constituted as to existing equipment, processes, and capacity, together with planned additions, to handle any demands that may be made upon it by the defense program needs. Evident throughout was the growing sense of ability to manipulate oil molecules for the production of materials not hitherto considered as being available commercially from petroleum. The development and application of catalytically induced reactions on a broad front is one of the distinguishing characteristics of refining progress during the year. In the hands of the refiner, catalysis has developed into a most important means to secure higher antiknock motor fuels and 100-octane fighting grade aviation gasoline in greatly increased quantity. One illustration of the importance being assigned to catalytic refining is the construction by the Houdry group of an experimental laboratory at a cost of $7&apos;307&apos;30&apos;3, to be staffed with over 100 research men7 solely for the purpose of studying catalytic reactions. In the aviation gasoline picture a modification of specifications by the Government widened the field from which acceptable fuel can be secured, and the continued expansion of the alkylation process in itself promises to go far in filling the demands expected from 50,000 fighting planes. It is conservatively estimated that eyen now the industry can turn out 1,300,000 gal. of 100-octane aviation gasoline daily. The upper limits of octane numbers for regular grades of motor gasoline reached in 1939 were not exceeded, but the average octane number approached the upper level more closely. A survey made of the 1940-model cars showed no rise in average octane requirement of the engines. The trend throughout the year was for greater reliance on the A.S.T.M. method for octane determination. The "1939 Research Method" is less widely used, although still considerably in evidence; the older L-3 method seems to have lost considerable ground and to be on the way out. Re-forming Capacities Increased Interest continued to grow apace in re-forming low-octane naphthas into high-octane gasolines. Some additions, although not great, were announced in thermal re-forming capacity. Interest in catalytic re-forming was greatly stimulated by the technical success of the operation of the converted hydrogenation unit at the Bay-way, N. J., rehery of the Standard Oil Company of New Jersey, mentioned in last year&apos;s review, and also by the knowledge that recoverable proportions of toluene are present in the hydroformed (catalytically

Jan 1, 1941

By R. C. Gifkins

R. C. Gifkins (CSIRO)—In this paper evidence is put forward to support the idea of grain boundary shearing in aluminum at 4.2°K and the phenomenon is explained in terms of a low-temperature "equicohesive temperature". It is stated that these findings show that grain boundary shear cannot be ruled out in any situation by temperature arguments alone. We believe, from our own recent study of "apparent grain boundary sliding&apos;&apos; at temperatures below 0.45 Tm, that it can be ruled out on temperature arguments alone.45 Our experiments were made principally with magnesium and a Ms-A1 alloy ("Magnox A12"). Careful examination of offsets of marker lines or steps at grain boundaries produced by deformation at room temperature (-0.3 Tm) showed many of these to result from curvature over narrow zones along the grain boundaries. A significant residuum did, however, appear as a sharp offset or step. It was found that the mean value of this step rose to a small value during the first 0.5 to 1 pct strain and then remained at this level with further strain. Moreover, exactly the same values were obtained (at the same stress) at 75°C instead of 21°C. That is, in this range of temperature the "apparent sliding" was not temperature-sensitive. At 125°C and above there was sliding which increased with strain and which was temperature-dependent. When this temperature-dependent sliding was used to calculate the sliding to be expected at room temperature, this underestimated the "apparent sliding" by a factor of 104. The conclusion drawn is that the "apparent sliding" consists of shear localized in a zone of a width measured perhaps in microns, whereas it seems that true sliding occurs on the boundary surface.46 A model for such localized shear has been developed in general terms, following a similar model of Urie and Wain.47 Other strong evidence for low-temper- ature sliding has been based on the offsets of marker lines consisting of a substructure seen using the electron microscope to resolve these.48 We have repeated this work and found that the effects can be accounted for in terms of cracks in an oxide film which is produced when the substructure is etched up; these cracks form over zones of shear rather than at actual interfaces. However, in aluminum at room temperature (-0.3 Tm) there is no "apparent sliding" which is optically detectable. We suggest that, when the temperature is much lower (and possibly the rate of strain higher, too), as in the experiments of Chin et al., then aluminum behaves like magnesium at room temperature, and a narrow zone of shear develops to accommodate differences in strain across the grain boundary. Such a zone could well give rise to triple-point cracks. It is hoped to investigate these suggestions further. B. Y. Chin, W. F. Hosford, Jr., and W. A. Backofen (authors&apos; reply)—It is interesting to have Dr. Gif-kin&apos;s comments, although it is somewhat difficult to reply in detail without the reference containing the work that he describes. Apparently though, he does find a low-temperature temperature-independent sliding that would seem to be related to the observations reported here. Perhaps some of the difficulty has semantic origins, growing out of the distinction between (&apos;true sliding" and "apparent sliding".

Jan 1, 1965

By W. L. Worrell

R. C. Gifkins (CSIRO)—In this paper evidence is put forward to support the idea of grain boundary shearing in aluminum at 4.2°K and the phenomenon is explained in terms of a low-temperature "equicohesive temperature". It is stated that these findings show that grain boundary shear cannot be ruled out in any situation by temperature arguments alone. We believe, from our own recent study of "apparent grain boundary sliding&apos;&apos; at temperatures below 0.45 Tm, that it can be ruled out on temperature arguments alone.45 Our experiments were made principally with magnesium and a Ms-A1 alloy ("Magnox A12"). Careful examination of offsets of marker lines or steps at grain boundaries produced by deformation at room temperature (-0.3 Tm) showed many of these to result from curvature over narrow zones along the grain boundaries. A significant residuum did, however, appear as a sharp offset or step. It was found that the mean value of this step rose to a small value during the first 0.5 to 1 pct strain and then remained at this level with further strain. Moreover, exactly the same values were obtained (at the same stress) at 75°C instead of 21°C. That is, in this range of temperature the "apparent sliding" was not temperature-sensitive. At 125°C and above there was sliding which increased with strain and which was temperature-dependent. When this temperature-dependent sliding was used to calculate the sliding to be expected at room temperature, this underestimated the "apparent sliding" by a factor of 104. The conclusion drawn is that the "apparent sliding" consists of shear localized in a zone of a width measured perhaps in microns, whereas it seems that true sliding occurs on the boundary surface.46 A model for such localized shear has been developed in general terms, following a similar model of Urie and Wain.47 Other strong evidence for low-temper- ature sliding has been based on the offsets of marker lines consisting of a substructure seen using the electron microscope to resolve these.48 We have repeated this work and found that the effects can be accounted for in terms of cracks in an oxide film which is produced when the substructure is etched up; these cracks form over zones of shear rather than at actual interfaces. However, in aluminum at room temperature (-0.3 Tm) there is no "apparent sliding" which is optically detectable. We suggest that, when the temperature is much lower (and possibly the rate of strain higher, too), as in the experiments of Chin et al., then aluminum behaves like magnesium at room temperature, and a narrow zone of shear develops to accommodate differences in strain across the grain boundary. Such a zone could well give rise to triple-point cracks. It is hoped to investigate these suggestions further. B. Y. Chin, W. F. Hosford, Jr., and W. A. Backofen (authors&apos; reply)—It is interesting to have Dr. Gif-kin&apos;s comments, although it is somewhat difficult to reply in detail without the reference containing the work that he describes. Apparently though, he does find a low-temperature temperature-independent sliding that would seem to be related to the observations reported here. Perhaps some of the difficulty has semantic origins, growing out of the distinction between (&apos;true sliding" and "apparent sliding".

Jan 1, 1965

By C. L. Pillar

TWO shafts have been completed since the spring of 1948 when underground development started, and three are now under construction. The new program provides two main ore shafts, Nos. 3A and 3B, spaced 195 ft apart and located on the south- western end of the orebody. It is planned that eventually 35,000 tons of copper ore per day will be hoisted by these identical four-compartment shafts. The third shaft of this new group is 600 ft from the present No. 1 shaft and will provide caged sup- plies for the underground mining operations. This No. 4 shaft has the largest cross-section of any shaft in Arizona.

Jan 7, 1954

During the year Jan. 1 to Dec. 31, 1916, 962 applications for member-ship in the Institute were received, as compared to 558 during the corresponding period in 1915. The lines along which the Committee has, worked during the year, group themselves under seven principal heads. Large Companies.-Early in the year a letter was addressed to each member of the Institute who is the executive head of an organization, pointing out to him the advantages that would accrue to that organization through having as many of its subordinate members as were qualified participating in the activities of the Institute. This was followed by a second letter to those who made no reply to the first. The response to these letters was very gratifying, 12 new members having been secured at a single plant, and smaller numbers at others. This was effectively supplemented by our President, who wrote the executive heads of some of the largest mining and smelting companies, pointing out to them the advantage to be derived from sending some of the junior members of their staff to attend the Arizona Meeting. One organization sent 24 of its younger men, many of whom were not members of the Institute, but who, subsequently sent in applications for membership. It is to be hoped that the precedent thus set&apos; will be acted &apos;on in -fuller measure in succeeding years.

Jan 2, 1917

NEW MEMBERS The following list comprises the names of those persons who became members during the period Nov. 10, 1916 to Dec.10, 1916. BARNSDALL, THEODORE N., Treas. & Mgr., Highland Gas Co., 24 West Corydon. St., Bradford, Pa. BEASLEY, FRED E., Asst. Supt., Copper Refinery, Consolidated Mining & Smelting Co., Trail, B. C., Canada., BREWSTER, THOMAS T., Vice Pres., Gen. Mgr., Mt. Olive & Staunton Coal CO., 1012 Federal Reserve Bldg.,-St. Louis, Mo. BRINDLE ARTHUR ST. C.... Mining Recorder&apos;s Office, Trout Lake, B. C., Canada. BULLOCK, Harry E., Pres Kentucky-Jewel Coal Co., Lothair, Ky. BUTLER, PERCY BENNETT, Mine Operator :..P. 0. Box 335, Joplin, Mo. BUTLER, ROBERT S Supt., Three Johns Mining CO., ,Joplin,.Mo. CABOT, Godfrey, L., Carbon Black Maker, Gas Engr., 940 Old South Building Boston Mass.

Jan 1, 1917

By R. W. Heckel, R. L. DeGregorio

The DeHoff method of determining the size distribution of ellipsoid-shaped, second-phase particles has been applied to the spheroidization of cementite in a eutectoid steel. The surface area of Precipitates determined from the various size fractions in the distribution was correlated with surface-area measurements based on the number of intersected interfaces on a random lest line. The precipitate particles were found to be oblate ellipsoids with an axial ratio of about 0.90. The size distributions were found to be log-normal. A method is proposed whereby the shrinkage of small particles and growth of large ones can be determined from the experimental data. The experimental data are compared to previously proposed mathematical models describing diffusion-controlled kinetics and various types of interface-controlled kinetics. The experimental growth and shrinkage rates are considerably slower than those predicted by diffusion-controlled kinetics. The best fit is obtained for a model describing interface-controlled kinetics limited by the rate of formation of cementite at the growing interfaces where the interfacial reaction rate is proportional to the solute thermodynamic activity gradient across the surface. THE subject of spheroidization of second-phase particles has been considered previously by other investigators. Livingston1 has studied the precipitation of the cobalt-rich phase from copper alloys containing 0.7 to 3.2 wt pet Co. His results indicate that the average particle size increases as the cube root of the heat treatment time in accord with diffusion-controlled kinetics.&apos;-&apos; Komatsu and rant&apos; in their studies of the growth of SiO2 in a dispersion-strengthened copper-silica alloy found that the initial growth of SiO2 proceeded by diffusion-controlled growth and later stages were limited by interface-controlled growth. The values of the activation energy obtained for the interface- controlled process led them to the conclusion that the process was limited by the dissociation of SiO2 at the shrinking interface. The transition from diffusion-controlled growth to interface-controlled growth was characterized by a particle size which varied with the heat-treatment temperature. It is also interesting to note that the particle-size distribution as found by Komatsu and Grant exhibits log-normal behavior when replotted on log-probability coordinates. Dromsky, Lenel, and Ansell9 have observed the growth of Al2O3 particles having a mean free path of about 1.5 to 13 µ. Their photomicrographs indicate that the Al2O3 particle sizes were larger than those observed by Komatsu and Grant. Dromsky, Lenel, and Ansell concluded that the Al2O3 coarsened by an interface-controlled growth mechanism limited by the solution of A12O3 at the shrinking interfaces. Bannyh, Modin, and Modin10 have studied the spheroidization of a eutectoid steel (0.83 wt pet C). Their spheroidization (tempering) treatments were carried out in the range from 210o to 700°C for times between 1.5 sec and 20 hr. Measurements of mean particle size as a function of time indicated a cube root of time dependence of size at 700°C, in agreement with previous analyses of diffusion-controlled kinetics.2°7 At lower temperatures, the time dependence was less than the one-third power. It is important to note that, although mathematical models of growth* considering particle-size distribution have been available, measurements of only mean particle size have been carried out. DeHoff11 has presented a quantitative metallography technique which is applicable to the determination of the size distribution of ellipsoids of constant shape. This method is applicable to both oblate and prolate ellipsoids of all ratios of minor to major axis and is based upon an extension of Saltykov&apos;s analysis12 of the distribution of spheres of varying size. DeHoff&apos;s analysis is based upon measurements of the minor axis of the particles on a random plane of polish in a unit area. This method provides a measure of the number of ellipsoids in various size ranges per unit area. As pointed out by DeHoff, such measurements may be used to obtain surface area and total precipitate volume data. Thus, the accuracy of the distribution analysis may be checked by comparison of the surface and volume

Jan 1, 1965

By Walter R. Hibbard

THE term lineage was first introduced by Buerger1 to denote dendritic branches, grown from a crystal nucleus during solidification from the liquid, with imperfections in alignment of the order of 10-1 [ ] to 10-4 cm. These imperfections are associated with distortions of the dendrites caused by the subsequent solidification of the inter-dendritic filling and are illustrated in Fig 11. Buerger etched zinc single crystals made by the Bridgman2 method to develop this dendritic pattern and show lineage microscopically. Since maximum crystal growth in face-centered cubic metals occurs along the [100] directions,2 lineage would appear in copper as small deviations of dendritic branches from these directions. Elam4 and others5-8 reported etching effects resulting from coring along the cube face traces of various copper alloy crystals. These traces were used by Samans8 to orient single crystals. Williamson9 noted a "lined structure (in alpha brass single crystals) consisting of an ordered arrangement of etch pits" which were probably traces of {100} planes but somewhat uncertain because they were never straight (i.e., apparently lineage). Greninger10 described the distortion and multiplicity of Laue spots in back reflection X ray photograms of copper single crystals showing lineage. The present investigation includes metallographic, X ray and property studies of lineage in large grain and single crystal specimens of copper. PREPARATION OF SPECIMENS Specimens 10 in. long and ½ in. diam of oxygen-free copper (O.F.H.C.) (99.985 pct) were melted vertically in graphite crucibles under an atmosphere of commercial nitrogen purified through a gas train including sulfuric acid, potassium chloride, magnesium chlorate, hot copper chips and phosphorus pentoxide. After a temperature of 1200°C had been maintained for ½ hr, the furnace was turned off and the specimens cooled at a rate of about 150°C an hour. This method of direct solidification was used by Greninger10 to produce single crystals with marked lineage and in this investigation produced a fair yield of single crystal specimens in

Jan 1, 1947

By Charles Morgan

An increased demand for brown iron ore in the Birmingham district during the past 18 months has caused renewed activity both in prospecting and mining these ores. In recent years the production in Alabama has ranged from 41,559 tons in 1932 to 639,351 tons in 1928. During the last 9 years about 83 per cent of the total brown ore produced in the United States has come from Alabama (Tables 1 and 2). Prospecting Two methods of prospecting are used in this district: (1) test pits, (2) churn-drilling. Usually there is certain quite definite information on an area to be prospected; some of the indications are float ore such as small gravel or small and large boulders known as "dornicks" scattered over the surface, and ore exposed by erosion in gulleys and ravines, which have cut or eroded through the overburden. Often these natural erosions furnish an indication of the thickness of the ore and to some extent of the area of the ore body. Deposits of brown ore are very irregular both in thickness and extent. Deposits are often lens-shaped or long narrow leads, some of which may be parallel and separated from one another by sand, clay or gravel. The bottom—the footwall—is also very irregular. This footwall is usually lime clay—disintegrated limestone, locally called "white horse," which usually is found at a depth of 6 in. to 20 ft. overlying the limestone. At some places sand and gravel is found under the ore instead of clay. No ore is found under the lime clay, although often the ore has sunk or slumped and is found in the upper portion of this clay, as at some of the Sloss workings at Russellville. The origin of these ores has been discussed by Major E. C. Eckel and Dr. E. F. Burchard in U. S. Geological Survey Bulletin 400, and recently the latter has done further work on ores in the Russellville district, of which reports undoubtedly will be published.

Jan 1, 1940

By Charles Morgan

An increased demand for brown iron ore in the Birmingham district during the past 18 months has caused renewed activity both in prospecting and mining these ores. In recent years the production in Alabama has ranged from 41,559 tons in 1932 to 639,351 tons in 1928. During the last 9 years about 83 per cent of the total brown ore produced in the United States has come from Alabama (Tables 1 and 2). Prospecting Two methods of prospecting are used in this district: (1) test pits, (2) churn-drilling. Usually there is certain quite definite information on an area to be prospected; some of the indications are float ore such as small gravel or small and large boulders known as "dornicks" scattered over the surface, and ore exposed by erosion in gulleys and ravines, which have cut or eroded through the overburden. Often these natural erosions furnish an indication of the thickness of the ore and to some extent of the area of the ore body. Deposits of brown ore are very irregular both in thickness and extent. Deposits are often lens-shaped or long narrow leads, some of which may be parallel and separated from one another by sand, clay or gravel. The bottom—the footwall—is also very irregular. This footwall is usually lime clay—disintegrated limestone, locally called "white horse," which usually is found at a depth of 6 in. to 20 ft. overlying the limestone. At some places sand and gravel is found under the ore instead of clay. No ore is found under the lime clay, although often the ore has sunk or slumped and is found in the upper portion of this clay, as at some of the Sloss workings at Russellville. The origin of these ores has been discussed by Major E. C. Eckel and Dr. E. F. Burchard in U. S. Geological Survey Bulletin 400, and recently the latter has done further work on ores in the Russellville district, of which reports undoubtedly will be published.

Jan 1, 1940

By Charles Morgan

AN increased demand for brown iron ore in the Birmingham district during the past 18 months has caused renewed activity both in prospecting and mining these ores. In recent years the production in Alabama has ranged from 41,559 tons in 1932 to 639,351 tons in 1928. During the last 9 years about 83 per cent of the total brown ore produced in the United States has come from Alabama (Tables 1 and 2). PROSPECTING Two methods of prospecting are used in this district: (1) test pits, (2) churn-drilling. Usually there is certain quite definite information on an area to be prospected; some of the indications are float ore suck as small gravel or small and large boulders known as "dornicks” scattered over the surface, and ore exposed by erosion in gulleys and ravines, which have cut or eroded through the overburden. Often these natural erosions furnish an indication of the thickness of the ore and to some extent of the area of the ore body. Deposits of brown ore are very irregular both in thickness and extent. Deposits are often lens-shaped or long narrow leads, some of which may be parallel and separated from one another by sand, clay or gravel. The bottom-the footwall-is also very irregular. This footwall is usually lime clay-disintegrated limestone, locally called "white horse," which usually is found at a depth of 6 in. to 20 ft. overlying the limestone. At some places sand and gravel is found under the ore instead of clay. No ore is found under the lime clay, although often the ore has sunk or slumped and is found in the upper portion of this clay, as at some of the Sloss workings at Russellville. The origin of these ores has been discussed by Major E. C. Eckel and Dr. E. F. Burchard in U. S. Geological Survey Bulletin 400, and recently the latter has done further work on ores in the Russellville district, of which reports undoubtedly will be published.

Jan 1, 1937