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By W. A. Tiller, D. H. Lane

A simple zone melting technique for investigating the effect of ultrasonic irradiation upon ingot solidification is described. The effect of i) ultrasonic power level, ii) freezing velocity, iii) constant or variable frequency, iv) direction of irradiation, and v) transducer-cozlpling bar joint upon the grain size of type 316 stainless steel have been investigated. The results of this study support the postulate that the ultrasonic vibrations increase the nucleation probability in the layer of liquid adjacent to the freezing interface. In the first paper of this series,l the possible mechanisms whereby ingot structure may be altered by irradiating a solidifying melt with ultrasonic vibrations have been discussed. A new technique for efficiently introducing the ultrasonic energy into the solid-liquid interface region was presented and applied to ingot preparation by the consumable-electrode arc-melting technique. The experimental results support the postulate that the ultrasonic vibrations may refine the ingot structure by increasing the nucleation probability in the zone of liquid adjacent to the solid-liquid interface. The present paper describes the application of the same technique to a relatively simple laboratory-scale zone-melting apparatus. This apparatus is found to be well suited to the detailed study of ultrasonic technology in this area and allows one to determine, in particular, the minimum ultrasonic power level needed to produce a certain grain size in a particular material. The results of this study support the nucleation mechanism for grain refinement, but do not provide any deeper insight into the specific nucleation mechanism responsible for the effect. EXPERIMENT The apparatus used in these experiments is shown in Fig. 1 and illustrated schematically in Fig. 2. The material to be studied, type 316 stainless steel, was in the form of a 3/4-in. sq bar 30 in. long. This bar was placed in a square open-topped mold with open ends made from high-purity graphite coated with a flame-sprayed Al2O3, skin. Surrounding the crucible was a molybdenum susceptor with 3/8-in. diam holes spaced at 1-in. intervals along its length to serve as sight ports. A tapered transducer horn was brazed to one end of the specimen. The entire assemblage was enclosed in a quartz tube, the transducer itself projecting out one end and resting in a cooling tank. A vacuum seal between the coupling bar and the end plate enclosed one end. A similar plate and seal enclosed the other end. The system is gas tight and can be operated under vacuum or an inert atmosphere. For these experiments, flowing argon at 15 in. of Hg pressure was used. The heat source for melting the stainless steel specimen was a 2-in. long 3-kc induction coil placed around the quartz tube; this source heated the susceptor, inductively melting about a 3-in. zone of the sample by radiation. To move the molten zone at a specified rate, the induction coil was moved down the tube at this rate with the aid of a simple pulling device. Thus, the sample could be irradiated at varying ultrasonic frequencies and power levels and could be solidified at varying rates. The power input to the transducer was measured using a "John Fluke Model 120 VAW-Meter." 1 The power delivered to the interface region is probably only about 50 pct of that measured on the VAW-meter. In a typical run, when the ultrasonic power was turned on, the interface of the molten zone closest

Jan 1, 1961

By R. D. Nelson, D. H. Polonis

ThE eutectoid decomposition of 6 phase in the Cu-Sn system (32.53 wt pct Sn) has been studied by several investigators.1-6 On the basis of X-ray work, Iball and 0wen1 reported complete decomposition of 6 in powder specimens after 7 days at 300°C. Wang and Hansen followed the micro-structural changes during heat treatment of lump specimens and estimated 5 pct decomposition after 63 days at 300°C. Wang and Hansen suggested that the discrepancy between the decomposition rates of powder and lump specimens might be due to the excess surface free energy of powders. The present work involved 6 decomposition in copper-tin alloy powders containing 32.6 wt pct Sn. Alloy lump specimens exhibited entirely 6 phase after fairly slow cooling (air cooling) from above 350°C and were so brittle that they could be easily crushed to-200 mesh in a percussion mortar. X-ray diffraction study of the as-crushed powders (-200 mesh) revealed 100 pct 6 phase with very slight line broadening effects due to strain introduced by crushing. Only 6 phase was detected by X-ray diffraction in powders which were heat treated 4 hr at 450°C and air cooled to room tem-

Jan 1, 1960

By Edward H. Robie

OF the current Adirondack iron mine development, the Benson Mines operation of the Tones and Laughlin Ore Co. (Jones & Laughlin Steel Corp. wholly owned subsidiary) is the last to go into operation. Following an active construction program in 1943, the mine. concentrator and sintering plant were scheduled to enter production in the fall. This description therefore cannot include any operating data, and details of equipment and flowsheet have not as yet been released.

Jan 1, 1943

Frank 11. Probert, Neudorf, Anhalt, Germany (communication to the Secretary): I have read with much pleasure Mr. Collier's valuable paper. But the system of timbering which he describes as used in the levels, stopes, etc., though it must be admitted to be very strong and safe, seems to me somewhat extravagant. The amount of timber required every month for such a system must be enormous; and only where suitable material could be cheaply obtained would such a plan be economically practicable. The first point which strikes me is the unusually great diameter of the timber employed. In the mines of Pfaffenberg and Meiseberg, which are under my supervision, the country-rock consists of argillaceous slates, traversed by innumerable small fissures or joints, dipping at all angles and striking to all points of the compass. Undoubtedly, this net-work has been caused by the upheaval of granite masses in the vicinity. Each fissure is accompanied by a more or less well-c1efinc.d gouge or fluccan, caused by the rubbing together of the slates at or after the original disturbance. In such

Jan 1, 1900

By AIME AIME

EVEN though most of the program of the joint meeting at Easton, Pa., on Oct. 30 to Nov. 1. was devoted to the interests of combustion engineers rather than to coal-mining engineers, nevertheless the A.I.M.E. Coal Division was well represented, with 83, or close to one third of those in attendance giving this as their affiliation. The fuels division of the American Society of Mechanical Engineers had 108 representatives, and an equal number reported no society affiliation. Added to the men's total registration was that of some twenty ladies so the total attendance was in the neighborhood of 325, exceeding that of the last two joint meetings, at Birmingham and Columbus, and equaling the 1938 crowd at Chicago.

Jan 1, 1941

By A. L. Mincher, W. F. Sheely

Mechanical properties of columbium have been studied over the temperature range of -196 to 1093oC. The decreased strengthening influence of cold-work at temperatures below ambient has been interpreted in terms of the Peierls-Nabarro effect. Maxima in the rate of strain hardening observed during tensile testing in the range 250-600°C. have been correlated with interstitial impurities to indicate the temperature ranges at which carbon, oxygen, and nitrogen, respectively, are responsible for strain aging. THE growing need for structural materials for use above the useful service temperatures of the iron-, nickel-, or cobalt-base alloys has caused the refractory metals to be considered as potential engineering materials. These metals, which include columbium, tantalum, molybdenum, and tungsten, are called refractory because the lowest melting point among them,that of columbium, is about 1000°C higher than the average melting temperatures of conventional high-temperature alloys. They are all body-centered cubic transition metals and, as such, their mechanical properties have basic characteristics which distinguish them from the face-centered cubic metals. For example, all show a much steeper rise in strength with decreasing temperature below room temperature than do the face-centered cubic metals, and their mechanical properties are strongly influenced by interstitially dissolved impurities. In order that these new metals may be used efficiently, it is necessary that their characteristics of behavior be fully known. In this paper, the mechanical properties of columbium will be examined over a wide range of temperatures. In particular, the influences of cold-work and individual species of interstitial impurity atoms on mechanical properties will be described, and basic mechanisms which may control the observed characteristics will be explored. EXPERIMENTAL The material used in this investigation was Union Carbide Metals Co. columbium roundels consolidated to four 4-in. diam ingots, three by consumable-electrode arc melting and one ingot by electron beam melting. Impurity contents of the ingots and methods of ingot conversion and treatment are summarized in Table I. The only metallic impurity occurring in any significant quantity was tantalum at about 0.1 pct. Iron, silicon, titanium, and zirconium were each less than 0.015 pct; boron was 1 ppm or less. This should have no appreciable influence on properties. The electron beam melted material, being the purest, will be used as the basis for comparison in the discussions to follow. Tensile tests were conducted from-196 to 1093oC, on both cold-worked and fully recrystallized arc-melted and electron-beam melted columbium using standard 1/4-in. diam, 1-in. long gage length test specimens. A strain-rate of 0.005 in. per in. per min was employed until the 0.2 pct yield strength was achieved and then the strain-rate was increased to 0.05 in. per in. per min for the balance of the test. Samples were protected in an inert atmosphere at tests above 300°C. The tensile properties obtained on the electron-beam melted columbium, E, in both the cold-swaged and recrystallized conditions are given in Fig. 1. The yield strength data of Dyson, et al.,' obtained on recrystallized electron beam melted columbium and the tensile strength data reported by Tottle2 on powder metallurgy columbium are included in Fig. 1. The material used by Tottle had been purified by vacuum sintering. There is excellent agreement between Dyson's data and those obtained in the present investigation. The tensile strengths obtained by Tottle were slightly greater than those obtained in this investigation on electron-beam melted columbium but varied with temperature in a similar manner. Tottle's data showed a maximum in tensile strength near 500°C, as did our data on electron-beam melted material, and also showed a small maximum at 300°C. The significance of these maxima will become evident later in the discussion. The tensile properties of cold-swaged and recrys-tallized arc melted columbium are plotted in Fig. 2. It was found that the properties of the recrystallized arc-melted columbium from all three heats showed very close agreement except at temperatures between about 500" and 800°C. A reason for this range of disagreement will be suggested in the discussion. The generally good agreement, however, attests to the ability of cold-working and subsequent recrystal-lization to erase the effects of the three different primary breakdown procedures and to produce nearly equivalent structures in the samples derived from the three different heats. wesse13 reported tensile data on columbium having interstitial impurity contents between those of the

Jan 1, 1962

By Fred E. Carter

AT first sight, the platinum group of metals seem of little import to we, the people," although actually the life of the common man is much influenced by them; this influence is usually indirect, hence his lack of knowledge and interest. He generally associates platinum with high-class jewelry and lets it go at that. Were 11e to go deeper, he would find that platinum metals play their part in his food supply, his clothing. his health, his transportation, his home. And the technical man is in general only slightly better informed, for he usually does not realize how necessary platinum metals are in the manufacture of the many construction materials and chemical products with which he is acquainted. Certainly, our daily lives would be profoundly affected if platinum were suddenly to become unavailable.

Jan 1, 1944

By John D. Weibmer

A strong step towards acknowledgement of mining as a skilled trade has been taken by the Tintic Division of Kennecott Copper Corp. In May 2 ceremonies, a pilot program was signed into force which, possibly for the first time in US history, recognizes mining as an apprentice trade and grants journeyman status to those who complete the prescribed training sequence. The apprenticeship standards, hammered out after months of consultation between management, labor, and government, are presently limited only to underground hard-rock mining and only within Kennecott's Tintic Division, but the architects of the program are confident that the concept will spread-first to other underground operations where miners desire documented evidence of their special skills, then to open-pit and soft-rock operations.

Jan 6, 1977

By Noel S. Christensen

COBALT is a silvery white metal with a slight bluish cast, strongly resembling nickel in its appearance and properties, notably its resistance to corrosion, although its alloys with other metals differ quite decidedly in their properties from those of nickel. The name cobalt was derived from the German "Kobold" meaning goblin and this came to be applied to the cobalt minerals which, although they resembled ores, did not readily yield metal when smelted by the primitive processes available in the Middle Ages. Cobalt minerals were used as pigments by potters and glass workers before the Christian era. Cobalt blue glass was found in the tombs of the Egyptians and in the ruins of Troy, and many colors used by the ancient Greeks and Romans contained cobalt. The ancients were entirely unaware that the colors they used were caused by cobalt and the metal itself was only isolated about the middle of the eighteenth century by Brandt although the preparation of cobalt compounds had been carried on in a small way ever since the opening of the silver-cobalt deposits at Schneeberg, Germany, in 1470. The metal is fairly hard, with a density when pure of 8.81 in the cast state and 8.92 after working. The commercial grade of cobalt has a density of about 8.75 in the cast state. The atomic weight is 58.97. The Brinell hardness of the pure metal is 124; that of the commercial grade varies from as low as 100 to as high as 138, depend¬ing upon the impurities present. Pure cobalt has a sharp melting point at 1478°C. The tensile strength of the pure metal in the cast condition is said to be higher than that of any other pure metal. Kalmus gives it as 34,400 lb. per sq. in. for cast unannealed metal; the effect of annealing at 850 to 900°C. is to raise the strength slightly. The yield point is close to the ultimate strength and the reduction in area and elongation are both low. Mechanical working raises the tensile strength of pure cobalt rapidly and in the form of wire it will be over 100,000 lb. per sq. in. The presence of small quantities of carbon in the commercial metal raises the tensile strength to as high as 61,000 lb. per sq. in., the reduction in area and elongation being raised at the same time to approximately 20 per cent.

Jan 1, 1933

By S. Skowronski

PURPOSE OF INVESTIGATION Since cuprous chloride melts at 418° C., boils at 954° C. to 1033° C.,1 and is known to be volatile at a much lower temperature, the presence of chlorine in any form in or on copper to be melted has always been looked upon by copper refiners as a possible source of-serious copper loss. Although this fact has been known for some time, the copper literature contains little or no information regarding it and the field seems .never to have been properly investigated from a metallurgical standpoint. According to Greenawalt,2 cupric chloride, CuCl2, when ignited gives cuprous chloride; therefore cuprous chloride is always formed when copper enters into reaction with chlorine at a high temperature. Cuprous chloride melts somewhat below a dull red heat, and does not volatilize in closed vessels, even if strongly heated, but if heated in the air it goes off as a white vapor. Hofman3 gives the melting point of cuprous chloride

Jan 2, 1919

By A. B. Tanner

The effects of radon in drillholes on gamma-ray logs have been described by L. S. Hilpert and C. M. Bunker1 Since these effects may cause drastic error in the evaluation of uranium deposits, it is useful to know the conditions under which significant amounts of radon tend to accumulate in drillholes. In the studies described here, atmospheric conditions were found to dominate in the control of the behavior of radon in drillholes in the vicinity of a uranium orebody. The site of the investigation was in McKinley County, New Mexico, about 12 miles north of Grants. Drillholes of 4 1/4-in. diam, on 25-ft and 100-ft centers, penetrate ore in dry rock at a depth of about 100 ft. A geologic log of the drillhole of primary interest is shown in Fig. 1. Gamma-ray logs revealed three zones of ore-grade mineralization in the Todilto limestone. A 6-ft zone, the lowest of the three, assayed 0.20 pct U3O8 by chemical analysis. The limestone ores in this area contain disseminated uraninite and some yellow and orange secondary minerals. Only radon"", a member of the uranium'" series, was measured in this investigation. Radon is one of the chemically inert noble gases and is radioactive by alpha particle emission with a half life of about four days. In this discussion, amounts of radon are expressed in microcuries (1 microcurie equals 37,-000 disintegrations per sec) and concentrations of radon are expressed in microcuries per liter of drillhole air. Samples of air were obtained by lowering a sampling device (Fig. 2) into a drillhole and actuating the device at the desired depth. It was then raised to the surface and the sample was transferred to a storage tube. Within two days the sample was transferred to an ionization chamber, and the activ- ity of radon and its short-lived daughter products was measured at radioactive equilibrium with a vibrating-reed electrometer. The measurements were corrected back to the time of collection and involve errors estimated generally not to exceed + 5 pct to —15 pct. Radon Behavior in a Covered Hole: Fig. 3, a typical log of radon concentration vs depth in the covered drillhole, was made by using values of radon concentration at discrete depths. Continuous logs of alpha-particle radiation in the drillholes showed that such radon logs depict the continuous variation of radon concentration with depth quite accurately. Three features of radon logs were noted: 1) maximum

Jan 1, 1960

By Orville R. Lyons, A. C. Richardson

F. X. Ferney—We are pleased that this paper was presented at this meeting and thank Mr. Richardson and Mr. Lyons for their effort and work in preparing it. We agree with the authors that it was unfortunate that more comprehensive data were not available when the paper was prepared, this being particularly true since we had no knowledge that the paper was being written and could not make available data which were in our process files. Further, it is our opinion that because the data are not sufficiently comprehensive the results which are presented are erratic and will lead to false conclusions. As we see it, there are three Specific reasons why the data which are presented cannot be considered accurate. 1. The preparation plant was not at equilibrium while the samples were being taken. This is indicated by the fact that the percent of solids in the circulating water varied from 3.9 pct to 10.7 pct during the period when the plant was sampled. 2. We do not believe that the samples of Bird feed which were taken were representative and could indicatc the true feed to the filter. Evidence of this is shown in the data where the dewatered product leaving the centrifuge contains more coarse material than the feed to it, that is, material which is +6-mesh in size. 3. We question if the data concerning screen analysis in the fine sizes is accurate and would conclude (from the data) that these tests were made by a dry-screen method. We have found that wet screening is always necessary to obtain a true picture of the quantity of —200-mesh fines which is present. The test work described in the Lyons-Richardson paper was conducted some time ago and the tests were carried on during a period when the preparation plant had not ironed out all of their start-up problems. Since that time most of these problems have been corrected and now this is a smooth running, well-operated prep-

Jan 1, 1951

By Orville R. Lyons, A. C. Richardson

F. X. Ferney—We are pleased that this paper was presented at this meeting and thank Mr. Richardson and Mr. Lyons for their effort and work in preparing it. We agree with the authors that it was unfortunate that more comprehensive data were not available when the paper was prepared, this being particularly true since we had no knowledge that the paper was being written and could not make available data which were in our process files. Further, it is our opinion that because the data are not sufficiently comprehensive the results which are presented are erratic and will lead to false conclusions. As we see it, there are three Specific reasons why the data which are presented cannot be considered accurate. 1. The preparation plant was not at equilibrium while the samples were being taken. This is indicated by the fact that the percent of solids in the circulating water varied from 3.9 pct to 10.7 pct during the period when the plant was sampled. 2. We do not believe that the samples of Bird feed which were taken were representative and could indicatc the true feed to the filter. Evidence of this is shown in the data where the dewatered product leaving the centrifuge contains more coarse material than the feed to it, that is, material which is +6-mesh in size. 3. We question if the data concerning screen analysis in the fine sizes is accurate and would conclude (from the data) that these tests were made by a dry-screen method. We have found that wet screening is always necessary to obtain a true picture of the quantity of —200-mesh fines which is present. The test work described in the Lyons-Richardson paper was conducted some time ago and the tests were carried on during a period when the preparation plant had not ironed out all of their start-up problems. Since that time most of these problems have been corrected and now this is a smooth running, well-operated prep-

Jan 1, 1951

By T. L. Joseph

It is a distinct privilege to participate in this meeting convened to honor the memory of Henry Marion Howe, a distinguished scientist and metallurgist. Many have added to our rapidly growing fund of metallurgical knowledge but few have made the unique contribution of formulating basic concepts essential to an over-all comprehensive view of the subject of metallography. Of those previously selected to deliver this lecture, several have added a personal touch to their discourse because they were able to refer to their associations with Dr. Howe. It was not my good fortune to know him or to enjoy his inspiring influence. Like most of you, my contact has been with his published works, which are outstanding in that they provide lucid, detailed expositions of the nature and behavior of metals and alloys. His deep understanding and clarity of expression have greatly accelerated our progress in metallography and in the use of metals. The degree to which a man's thinking, experimentation and writing contribute toward an understanding of basic laws and phenomena determines whether his life's work is of transitory or permanent value. This occasion appropriately recognizes the fundamental importance of Dr. Howe's pioneer work in the field of metallurgy.. On two former occasions, gray iron was selected as a subject for discussion. The fact that the production of pig iron has not been discussed before does not reflect any lack of interest on the part of Dr. Howe or former lecturers in the process that underlies the production of steel. Although Dr. Howe's work in his later years centered around metallography, his earlier publications show a considerable interest in the production of iron and steel. He recognized that in the ascending spiral of metallurgical advancement we are not winding a single thread but are weaving a complex fabric. Specific evidence of his interest in the production of pig iron may be found in his book' on The Metallography of Cast Iron and Steel. In explaining why blast furnaces have been in constant use for about 600 years, he says: "The process is economical because it utilizes with extraordinary completeness the calorific power of the coke due to the thorough transfer of heat from the gaseous products of combustion to the charge." This emphasis on heat transfer, overlooked in many more extended and more recent discussions of the blast-furnace process, illustrates Professor Howe's ability to see the essentials. Other distinct advantages of the blast furnace, such as the removal of- much of the sulphur and practically all of the oxygen, were mentioned. It was also stated that although the blastfurnace process is complex in nature, its outward form is comparatively simple, thus permitting large-scale production at small labor costs. All who contemplate the production of metallic iron from its ores by any other process might well consider the

Jan 1, 1947

By T. L. Joseph

It is a distinct privilege to participate in this meeting convened to honor the memory of Henry Marion Howe, a distinguished scientist and metallurgist. Many have added to our rapidly growing fund of metallurgical knowledge but few have made the unique contribution of formulating basic concepts essential to an over-all comprehensive view of the subject of metallography. Of those previously selected to deliver this lecture, several have added a personal touch to their discourse because they were able to refer to their associations with Dr. Howe. It was not my good fortune to know him or to enjoy his inspiring influence. Like most of you, my contact has been with his published works, which are outstanding in that they provide lucid, detailed expositions of the nature and behavior of metals and alloys. His deep understanding and clarity of expression have greatly accelerated our progress in metallography and in the use of metals. The degree to which a man's thinking, experimentation and writing contribute toward an understanding of basic laws and phenomena determines whether his life's work is of transitory or permanent value. This occasion appropriately recognizes the fundamental importance of Dr. Howe's pioneer work in the field of metallurgy.. On two former occasions, gray iron was selected as a subject for discussion. The fact that the production of pig iron has not been discussed before does not reflect any lack of interest on the part of Dr. Howe or former lecturers in the process that underlies the production of steel. Although Dr. Howe's work in his later years centered around metallography, his earlier publications show a considerable interest in the production of iron and steel. He recognized that in the ascending spiral of metallurgical advancement we are not winding a single thread but are weaving a complex fabric. Specific evidence of his interest in the production of pig iron may be found in his book' on The Metallography of Cast Iron and Steel. In explaining why blast furnaces have been in constant use for about 600 years, he says: "The process is economical because it utilizes with extraordinary completeness the calorific power of the coke due to the thorough transfer of heat from the gaseous products of combustion to the charge." This emphasis on heat transfer, overlooked in many more extended and more recent discussions of the blast-furnace process, illustrates Professor Howe's ability to see the essentials. Other distinct advantages of the blast furnace, such as the removal of- much of the sulphur and practically all of the oxygen, were mentioned. It was also stated that although the blastfurnace process is complex in nature, its outward form is comparatively simple, thus permitting large-scale production at small labor costs. All who contemplate the production of metallic iron from its ores by any other process might well consider the

Jan 1, 1947

By J. B. Clark

In 1933, R. paris1 published a phase diagram for the entire Mg-Ca-Zn system. He reported the existence of a ternary intermetallic phase, Mg5Zn5Ca2, which formed a quasi-binary with the magnesium solid solution. Since then, no extensive work has been reported on the system. Recently however, indications of the existence of a second ternary in-termetallic phase in equilibrium with the magnesium solid solution led to a reinvestigation of the solid phase equilibria involving the magnesium solid solution. The 335°C (635°F) isothermal section was chosen for study. Metallography and powder X-ray diffraction were selected as the best mutually corroborating methods for determining the solid phase constitution. Seventy-six alloys were prepared from singly sublimed (99.95 pct) magnesium, electrolytic (99.95 pct) zinc and USP calcium. The analyses of some of the alloys are shown in Fig. 1. The alloys were melted in a graphite crucible under a chloride flu and chill cast in a split graphite mold. Dif-fusion couples (see Fig. 2) were prepared by casting molten Mg-20 wt pct Zn alloy around a cylinder of Mg-30 wt pct Ca alloy. The alloy samples and the diffusion couples were sealed under argon in Pyrex vials and annealed in a furnace capable of controlling within 1/2°C of 335°C. At the conclusion of the anneal, the alloy samples were quenched in ice water and the diffusion couples were air cooled. Procedures standard for magnesium alloys were used for metallographic examination. Powder X-ray diffraction patterns were taken on a G. E. camera with a 14.32 cm dim using nickel-filtered copper radiation. The redetermined 335°C (635°) section of the Mg-Ca-Zn phase diagram is shown in Fig. 1. TWO ternary intermetallic phases, designated w and

Jan 1, 1962

By Basil B. Zavoico

ALTHOUGH the American petroleum industry was affected by the Second World War from its early beginning it was not until Dec. 7, 1941- that the industry was placed on full war footing. Even throughout most of 1942 the American overseas operations were limited and not until late in the year did expansion of military activities, more particularly the offensive in North Africa, affect the domestic supplies to such an extent that critical deficiencies developed locally in this country, particularly along the East Coast. The definite outlook for greatly expanded offensive operations by the United States on both Atlantic and Pacific fronts makes certain that during 1943 the domestic situation will. not be alleviated; rather it may become even more critical even though additional transportation facilities, now being built and planned. will be completed from the southwestern producing states to the East Coast.

Jan 1, 1943

By Thomas T., Read

IT will be recalled that the first professor of metallurgy in the United States, appointed in 1855, never really gave any instruction in metallurgy and gradually turned into a professor of mineralogy. Metallurgy was included with. mining in the early curricula, two students who took the B.S. in mining engineering from the Polytechnic College of Pennsylvania in 1862 wrote their graduation theses on the metallurgy of copper and zinc, respectively. Even after Columbia School of Mines established, in 1868, a separate curriculum leading to the Ph.B. degree in metallurgy, very few students elected it,* preferring to take the mining degree, since they received in its curriculum nearly all the metallurgical instruction they would have in the metallurgical curriculum. For many years a large proportion of the men who attained prominence in metallurgical enterprises had taken mining rather than metallurgical degrees. METALLURGY Clifton Sorby's study of thin sections of rocks under the micro¬scope, beginning in 1850, and its subsequent development by Zirkel and others, had made microscopic petrography a recog¬nized department of geological research as early as 1873. . It was inevitable that the idea of studying polished metal surfaces-¬under the microscope by reflected instead of transmitted light would occur to investigators. Sorby himself did it in 1864, and Adolph Martens and Floris Osmond may -be especially named among the many European workers who, by the late eighties, had so developed the, necessary techniques that they were able to photograph polished metal surfaces at magnifications as high

Jan 1, 1941

By John A. Baker

S EVERAL FACTORS have brought about a vastly greater interest in the gold-mining industry in the last two or three years. Outstanding is the fact that there is an open market at a fixed price for all that can be produced. a condition that holds for no other commodity. Costs of production have decreased greatly, owing to lower prices of supplies and equipment and lower wages. Improved metallurgical processes and equipment are also available. To big new gold district is being opened up but virgin ground is being prospected with some success in many of the more remote parts of the world and right here in the United States many old properties are being reopened 111 the light of present condition<, tailing dumps are being re- worked, and profitable leases taken on abandoned property. Many of the men who are becoming interested in gold are mining engineers whose experience has all been with base metals heretofore: some are engineers with no mining experience; some are not engineers at all but men who cannot find profitable employment in their usual field of activity and are attracted by the age-old lore of the yellow metal. Some are business men with a little money and an idea that under present conditions gold mining offers a safer investment for it than most other kinds of business. It is to those more or less inexperienced new- comers in the gold-mining industry that this article i4 ad dressed. Those who are connected with the large gold mines or who have had rears of experience with the small ones will find in the following pages little or nothing of interest but it is hoped that the newer generation of small mine operators, on whom the healthy growth of the industry depends so much, may find here some helpful hints.

Jan 1, 1932

By John Jermain Porter

The chief purpose of this paper is to indicate the laws governing the fuel-economy of the cupola, to examine the feasibility of some of the proposals for increasing its fuel-economy, and to show that the conditions limiting fuel-economy here are altogether different from those prevailing in the blast-furnace. The two methods available for studying the thermal efficiency of the cupola and determining the factors limiting fuel-economy are: 1, by the determination of the total heat-balance; and 2, by the application of the theory of critical temperatures. The case selected as an example represents a cupola operating under fairly efficient conditions. The data are as follows : Cupola, GO in. in diameter, 15 ft. high to the charging-door, with a 9-in. lining. Bed-charge, 2,000 lb. of coke and 4,000 lb. of iron. Subsequent charges, 400 lb. of coke and 4,000 Ib. of iron. Total number of charges, 20. There was 800 lb. of coke recovered from the drop, hence the total coke burned is 8,800 lb., or 0.11 lb. of coke per Ib. of iron. Coke contains 90 per cent. of fixed carbon and 2 per cent. of moisture. 300 1b. of kindling-wood is used in lighting. 80 lb. of limestone (95 per cent. of CaCO,) is used per charge, or 0.02 lb. per Ib. of iron. Melting-loss, 4 per cent.; distributed thus : Fe, 3.5; Si, 0.25; Mn, 0.25 per cent. Average analysis of top-gases : CO2, 15.1; CO, 10.0 per cent. Average temperature of top-gases, 1,600" F. Temperature of air and stock charged, 60" F. Dew-point of air, 50 F. The items entering into the total heat-balance and their calculation are as follows: 1. Heat of combustion of fuel.—Total heat evolved = 14,580 x lb. of carbon burned + 7,200 X Ib. of wood burned. Hence B.t.u. per lb. of iron charged =

Jan 1, 1913