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By J. E. Pollock

IN the oil-refining industry, steel comprises by far the greatest proportion of the materials used in construction work, but with an enormous number of alloy steels and nonferrous alloys available, and a greater knowledge of their properties and corrosion resistance; a substitu-tion first in the "hot spots" and then in locations of moderately severe corrosive conditions will be made as the greater expense can be justified. In new construction work, advantage is taken of the experience already gained and appropriate materials used, whether for high temperatures and pressures demanding additional strength or for corrosive conditions. The locations, however, where equipment in operation constantly requires replacement will soon become evident, as will the necessity for replacement in more resistant materials, if considerable down-time is to be avoided. In what direction and how far to go in the matter of alloys then becomes a question of the highest importance. Obviously, any replace-ment with more costly material must be. justified economically by the promise of longer life, thereby saving both material and installation costs besides the reduction of loss of production. Where the equipment is overcapacity and a regular schedule of cleaning periods is in force, the last item frequently must be ruled out and justification made on the basis of the first two only. Installation of material that will outlast the remainder of the equipment and have no recovery value must also be avoided; this is particularly important in temporary construction or in old equipment that will soon become obsolete.

Jan 1, 1935

By Charles C. Towle, Irving Rapaport

URANIUM mineralization along the north flank of the Zuni Uplift, in the vicinity of Haystack Butte, was discovered by Paddy Martinez, a Navajo Indian, in the spring of 1950. The find was reported to the Santa Fe Railway Co., which initiated a program of exploration upon its holdings in the district in December of 1950. The Anaconda Copper Mining Co. secured numerous leases in January and February, 1951, and began an intensive exploration and development program in March 1951. The district was extended into the Lucero Uplift in August of 1951 by the discovery of uranium mineralization in Todilto limestone by Joy Sinyella, a Supai Indian living on the Laguna Reservation. Initial reconnaissance was performed in the district by the Atomic Energy Commission in November 1950. A field office under the direction of the Denver Exploration Branch of the AEC was established at Prewitt, N. Mex. in January 1951 to study regional and detailed guides to ore, to evaluate the ore deposits, and to promote the development of the district by providing geologic services for the companies and individuals engaged in exploration. With the development of sufficient ore to warrant construction of a mill, the Grants area of New Mexico has come of age as a full fledged uranium mining district. The carnotite-type deposits of Grants, the first of major economic importance found in limestone, have extended the Colorado Plateau carnotite field into the more complex structure of the Basin and Range Province. General Geology The Grants uranium district is in northwestern New Mexico, along the southern flank of the San Juan Basin, between the cities of Gallup and Albuquerque. The region is at a mean altitude of about 6800 ft, vegetation is sparse, and outcrops are excellent. Mt. Taylor volcanic peak, at an elevation of 11,400 ft dominates the surrounding area. The overlying cliff-forming Dakota sandstone is the most resistant formation in the Grants District and characteristically erodes into dissected mesas as much as five miles wide. The principle uranium ore-bearing horizons are found in the underlying Morrison formation, and the Todilto limestone of the San Rafael group. The Morrison weathers into. a series of steep slopes and precipitous cliffs near the lower part of the Dakota-capped rims, while in contrast, the relatively resistant underlying. Todilto [ ] limestone forms broad benches extending out from the base of these Dakota rims as much as five miles wide. The Todilto benches are covered with overburden to an average depth of about 5 ft in the first thousand ft away from the Dakota rim, but increases to about 200 ft at the base of the rim. In many places however, a thick mantle of upper Cretaceous sediments and Tertiary volcanics "obscures the ore-bearing Jurassic, and precludes exploration. . The known uranium deposits of the Grants District are distributed throughout a zone 85 miles long and about 10 miles wide. Stratigraphy Rocks from pre-Cambrian through Tertiary are exposed in the uplifted areas, but uranium appears to be restricted chiefly to two zones in Jurassic sediments. The Jurassic sediments of the Colorado Plateau have been subdivided into three units, in ascending order: (1) Glen Canyon group, (2) San Rafael group, (3) Morrison formation. The Todilto limestone zone within the San Rafael group has produced the bulk of ore to date, but the promise of the Morrison zone is rapidly increasing. The Todilto formation extends about 300 miles east-west and about 100 miles in a north-south direction. It is composed of a lower, extensive, limestone member and a central, more restricted, thick, pure gypsum member. The Todilto is believed to be of lacustrine origin. The Morrison formation in this area is subdivided, rather arbitrarily, into three members: Recapture Creek, Westwater Canyon, and Brushy Basin. Ore

Jan 1, 1952

Meeting of Mar. 27, 1914.-President Thayer announced the appointment of H. S. Munroe as a member and E. Gybbon Spilsbury as Chairman of the Library Committee of the Institute. The President announced the appointment of the Committee on Papers and Publications, the Technical Committees, the Committee on Increase of Membership, and the Committee on Junior Members and Affiliated Student Societies. The President announced the appointment of Dr. George F. Kunz as a member of the Reception Committee of the International Engineering Congress, 1915. It was voted that the Institute accept the invitation of the Mining and Scientific Press to occupy space at the Panama-Pacific Exposition next to them and avail itself of the service of their representative to receive and register members of the Institute who visit this space during the exposition.

Jan 5, 1914

By Albert Sauveur

As director of the Division of Metallurgy of the Technical Section of the Air Service, American Expeditionary Forces, from August, 1917, to January, 1919, I devoted much time to the study of the steels best suited to the construction of aircraft. It became apparent at a very early stage of my investigation that the practice of builders varied greatly in regard to the number of different steels to be used, to the kinds of steels, and to their treatment. Some manufacturers employed as many as fifteen steels while the builder of one of the newest motors, favorably passed upon in the United States, assured me that two or, at the most, three kinds of steel were all he needed to produce satisfactory results. In the matter of treatment, the manufacturers were also greatly at variance. Some treated their steel with considerable refinement while others paid but scant attention to this feature. Some manufacturers case-hardened many parts, while others used the case-hardening process sparingly, if at all. Nickel-chromium steels were used at some works for case-hardening while at other plants this treatment was applied exclusively to carbon steels. Air-hardening nickel-chromium steel was used extensively by some and not at all by others. Considerable variance existed likewise in regard to the steels used for admission and exhaust valves. The conclusion was obvious, that no two manufacturers of airplane motors held like opinions as to the steels to be used or as to the treatment they should receive. Was it to be inferred from this that the many committees and associations that had been created, in part at least, for the standardization of aircraft steels had failed to make proper recommendations or that the manufacturers had ignored their recommendations ? Confining our inquiry to the committees and associations that had dealt with this question in England, France, and the United States, it was found that in Great Britain the British Engineering Standards Committee, now the British Engineering Standards Association, had devoted much time to the problem of satisfactory standards for aircraft steels. In April, 1918, this Association presented a set of specifications described as "British Standard Specifications for Aircraft Steels for Government Purchases in the United States of America." They included twenty-one different steels and, as the title indicates, were drawn for the

Jan 1, 1920

By Herbert Clark Hoover, Lou Henry Hoover

We give the following brief notes on early works containing some reference to mineralogy, mining, or metallurgy, to indicate the literature available to Agricola and for historical notes bearing upon the subject. References to these works in the footnotes may be most easily consulted through the personal index. GREEK AUTHORS.-Only a very limited Greek literature upon subjects allied to mining or natural science survives. The whole of the material of technical interest could be , reproduced on less than twenty of these pages. Those of most importance are : Aristotle (384-322 B.c.), Theophrastus (371-288 B.c.), Diodorus Siculus (1st Century B.c.), Strabo (64 B.c.-25 A.D.), and Dioscorides (1st Century A.D.). Aristotle, apart from occasional mineralogical or metallurgical references in De Mirabilibus, is mostly of interest as the author of the Peripatetic theory of the elements and the relation of these to the origin of stones and metals. Agricola was, to a considerable measure, a follower of this school, and their views colour much of his writings. We, however, discuss elsewhere1 at what point he departed from them. Especially in De Ortu ct Causis does he quote largely from Aristotle's Meteorologica. Physica, and De Coelo on these subjects. There is a spurious work on stones attributed to Aristotle of some interest to mineralogists. It was probably the work of some Arab early in the Middle Ages.[ ]

Jan 1, 1950

By Kent W. Pilz

Wet dust suppression can be achieved by 1) confinement of the dust within the dust producing area with a curtain of moisture, 2) wetting of the dust by direct contact between the particles and droplets of moisture or 3) the formation of agglomerates too heavy to remain airborne, or too heavy to become airborne, by combining small dust particles with each other and with the droplets of liquid. From the standpoint of economy, availability and safety, water is the ideal fluid; however, it is not as effective for dust suppression as when small percentages of specially formulated dust control compounds are blended with it. Performance of dust control com pounds is related to surface active agents and surface activity. In all liquids there is an attractive force between molecules which varies inversely as the sixth power of the distance between molecules. Thus, in the liquid phase where molecules are crowded together, the intermolecular forces are powerful; whereas in the liquid-vapor phase where the molecules are relatively far apart, these forces diminish rapidly. In the body of a fluid there is an uneven distribution of forces resulting in an inward pull called surface tension. The force which keeps two surfaces apart or causes them to coalesce is termed interfacial tension. Fluids of high surface tension exhibit poor wetting, spreading and penetrating qualities. Water has the unusually high surface tension of 72.75 dynes per cm at 20°C.

Jan 7, 1972

By Harry H. Power

WHILE the attention of all engineering branches is focused today on changes and improvements in the several curricula, we are concerned here with the many questions arising in industry and college concerning the preparation for the petroleum engineering profession. The succession of problems confronting the petroleum engineer demands a degree of versatility not ordinarily encountered in other professions. As a consequence, the student cannot acquire mastery of all the several engineering branches represented in field practice, and as an alternative, he has learned to appreciate the value of thorough training in the basic or fundamental sciences as a preliminary foundation for professional work. While our attention is directed primarily to the training of engineers in educational institutions, it is necessary that the ultimate education of the professional engineer be kept in mind. It is apparent that his success as an engineer is limited not only by his educational and job experience, but by his native endowments: mentality, personality and health. The engineer's lack of job experiences often proves as much a handicap as the lack of adequate college training. If the final product proves to be satisfactory, both industry and technical institutions are to be congratulated. However, if the product is found wanting, the one most responsible should be apprehended. FITNESS FOR PROFESSION For the most part, students of engineering colleges have had their interests in applied science awakened at a relatively early age. Many of them entered college as a convenient means of acquiring a technical education, but undoubtedly would have had better prospects in a shorter program offered by institutions of noncollege grade. The activating motive of practical interest is also strong in students suitable for college training, but in many cases an intellectual interest must be awakened in order that it may survive graduation. Numerous engineers believe that this progressive process of selection and determination of career aims is one of the essential services rendered by the engineering colleges. Industrialists, who are more interested in quality than quantity of petroleum engineering graduates, have pointed out the good that should result if more emphasis were given to the work of eliminating the misfits. They also point out the protective measures that have been taken by other professions for the betterment of professional standards. Mention has been made of the beneficial results to be obtained by collective determination of the market for the products of engineering schools, particularly in that the students unsuited to the profession would have an opportunity to prepare themselves for employment more suited to their personalities and other qualifications. In the event that such a system of coordinated personnel direction is developed by the

Jan 1, 1941

The following is an incomplete list of members and guests who called at Institute headquarters during the period Oct. 10, 1918 to Nov. 10, 1918. J. Carson Adkerson, Virginia. George H. Parsons, Hayden, Ariz. Andrew B. Armstrong, Connecticut. W. E. Pomeroy, New York. Courtenay DeKalb, San Francisco. Ezra C. Rider, Bisbee, Ariz. Clifford G. Dennis, San Francisco. H. W. Seaman, Chicago, Ill. Rudolph Emmel, Boston, Mass. William Allen Smith, Northampton. Emil Gathmann, Baltimore Md. R. K. Stockwell, Salt Lake City, Utah. Ernest S. Geary, Denver, Colo. W. G. Swart, Duluth, Minn. W. E. Hopper, Washington, D. C. Kirby Thomas, New York. W. Spencer Hutchinson, Boston, Mass. - Warren D. Thompson, Harvard Club. E. W. Kohl, Jr., Philadelphia, Pa. H. Vincent Wallace, Los Angeles, Cal. E. C. Nighman, Butte, Mont. Paul T. Benson, formerly with the Tacoma smelter, has resigned his position there to accept one with the Great Metals Mining and Milling Co. at Nespelem, Wash. Prof. Edward E. Bugbee, of the Mining Department of the Massachusetts Institute of Technology, has been granted a leave of absence to accept the position of Assistant Director of Education for the S.A.T.C. of five southern states with headquarters at Raleigh, N. C.

Jan 12, 1918

By F. S. Crawford

IRON and copper are mined in the Lake Superior district. The iron mines of the district have the best safety record for that industry in the country as a whole, while the copper mines of the district rank second in two of the four years recorded (Table 1). In Utah copper comes mainly from open-pit mines, which enables that state to lead easily in safety. All of the Michigan production comes from deep under-ground workings. About 60 per cent of the iron miners in St. Louis County, Minnesota, are employed at open-pit mines; this favorably affects the combined open-pit and underground accident-frequency rate, as this county pro-vides most of the Minnesota-mined iron ore. In Michigan, however, there are few open-pit mines, the bulk of the production coming from underground mines, while all of the Wisconsin production, just across the state line from Michigan, is from underground mines. In spite of the fact that fewer mines in Michigan use the safer open-pit method, the iron-mining industry of that state maintained a consistently low record from 1931 to 1934; however, it was many points behind its nearest com petitor, Minnesota, with its much greater production from open-pit mines.

Jan 1, 1939

By Hugh M. Roberts

The important place in the economic life of the country that is occupied by the United States Geological Survey and the various state surveys is appreciatcd by most members of our Institute. To the public at large, the functions of these surveys are no doubt largely unknown, and taken for granted. Possibly a realization of the value of the work of these government branches is brought home most fully to that group of our members whose duties as examining engineers and mining geologists take them to mines and prospects in many different parts. The examining engineer or geologist is usually seeking for a judgment on the value of an enterprise from the standpoint of the useful minerals that may or may not be present; he must also attempt some prediction as to future market prices. On his opinion rests the determination of the expenditure of money, which rendered into other language means the expenditure of human effort. An opinion on an exploring venture or the reasoning out of the probable extensions of an orebody requires among many other things a background of knowledge covering the geologic horizons not only of an immediate area but of the surrounding area, a knowledge of the structural geology and of the causes that have operated to form the ores as they are. The great storehouses of this knowledge are the statistics, reports and maps issued by the various geological surveys. They supply the groundwork for additional observations. To these, reference is always made when going into a new district. The technique of work in the field and laboratory, and to some extent the hypotheses that underlie our methods of approach, have been formed by men such as Van Hise, Leith, Kemp, Spurr, Emmons and Lindgren, who developed their powers in the service of the geological surveys. In addition to whatever originality of thought, or power to observe facts and analyze them, may be our portion, we require, in the application of the arts and sciences, a knowledge of what has already been done. We stand on the shoulders of those who have gone before, and the extent of our vision often depends upon the thoroughness with which we form earlier work into one whole and make use of it.

Jan 1, 1935

By Hugh M. Roberts

The important place in the economic life of the country that is occupied by the United States Geological Survey and the various state surveys is appreciatcd by most members of our Institute. To the public at large, the functions of these surveys are no doubt largely unknown, and taken for granted. Possibly a realization of the value of the work of these government branches is brought home most fully to that group of our members whose duties as examining engineers and mining geologists take them to mines and prospects in many different parts. The examining engineer or geologist is usually seeking for a judgment on the value of an enterprise from the standpoint of the useful minerals that may or may not be present; he must also attempt some prediction as to future market prices. On his opinion rests the determination of the expenditure of money, which rendered into other language means the expenditure of human effort. An opinion on an exploring venture or the reasoning out of the probable extensions of an orebody requires among many other things a background of knowledge covering the geologic horizons not only of an immediate area but of the surrounding area, a knowledge of the structural geology and of the causes that have operated to form the ores as they are. The great storehouses of this knowledge are the statistics, reports and maps issued by the various geological surveys. They supply the groundwork for additional observations. To these, reference is always made when going into a new district. The technique of work in the field and laboratory, and to some extent the hypotheses that underlie our methods of approach, have been formed by men such as Van Hise, Leith, Kemp, Spurr, Emmons and Lindgren, who developed their powers in the service of the geological surveys. In addition to whatever originality of thought, or power to observe facts and analyze them, may be our portion, we require, in the application of the arts and sciences, a knowledge of what has already been done. We stand on the shoulders of those who have gone before, and the extent of our vision often depends upon the thoroughness with which we form earlier work into one whole and make use of it.

Jan 1, 1935

By Glenn S. Wyman

CHUQUICAMATA, located in northern Chile in the Province of Antofagasta, is on the western slope of the Andes at an elevation of 9500 ft. Because of its position on the eastern edge of the Atacama Desert, the climate is extremely arid with practically no precipitation, either rain or snow. All primary blasting in the open-pit mine at Chuquicamata is done by the churn drill, blasthole method. Since 1915, when the first tonnages of importance were removed from the open pit, there have been many changes in the blasting practice, but no clear-cut rules of method and procedure have been devised for application to the mine as a whole. One general fact stands out: both the ore and waste rock at Chuquicamata are difficult to break satisfactorily for the most efficient operation of power shovels. Numerous experiments have been made in an effort to improve the breakage and thereby increase the shovel efficiency. Holes of different diameter have been drilled, the length of toe and spacing of holes have been varied, and several types of explosives have been used. Early blasting was done by the tunnel method. The banks were high, generally 30 m, requiring the use of large charges of black powder, detonated by electric blasting caps. Large tonnages were broken at comparatively low cost, but the method left such a large proportion of oversize material for secondary blasting that satisfactory shovel operation was practically impossible. Railroad-type steam and electric shovels then in service proved unequal to the task of efficiently handling the large proportion of oversize material produced. The clean-up of high banks proved to be dangerous and expensive as large quantities of explosive were consumed in dressing these banks, and from time to time the shovels were damaged by rock slides. As early as 1923 the high benches were divided, and a standard height of 12 m was selected for the development of new benches. The recently acquired Bucyrus-Erie 550-B shovel, with its greater radius of operation compared to the Bucyrus-Erie 320-B formerly used for bench development, allowed the bench height to be increased to 16 m. Churn drill, blasthole shooting proved to be successful, and tunnel blasts were limited to certain locations where development existed or natural ground conditions made the method more attractive than the use of churn drill holes. Liquid oxygen explosive and black powder were used along with dynamite of various grades in blast-hole loading up to early 1937. Liquid oxygen and black powder were discontinued because they were more difficult to handle due to their sensitivity to fire or sparks in the extremely dry climate. At present ammonium nitrate dynamite is favored because of its superior handling qualities and its adaptability to the dry condition found in 90 pct of the mine. In wet holes, which are found only in the lowest bench of the pit and account for the remaining 10 pct of the ground to be broken, Nitramon in 8x24-in. cans, or ammonium nitrate dynamite packed in 8x24-in. paper cartridges, is being used. This latter explosive, which is protected by a special antiwetting agent that makes the cartridges resistant to water for about 24 hr, currently is considered the best available for the work and is preferred over Nitramon. Early churn drill hole shots detonated by electric blasting caps, one in each hole, gave trouble because of misfires caused by the improper balance of resistance in the electrical circuits. Primarily, it was of vital importance to effect an absolute balance of resistance in these circuits, the undertaking and completion of which invariably caused delays in the shooting schedule. Misfires resulting from the improper balance of electrical circuits, or from any other cause, were extremely hazardous, since holes had to be unloaded or fired by the insertion of another detonator. The advent of cordeau, later followed by primacord, corrected this particular difficulty and therefore reduced the possibility of missed holes. After much experimentation, the blasting practice evolved into single row, multihole shots, with the holes spaced 4.5 to 5 m center to center in a row 7.5 to 8 m back from the toe. Sucti shots were fired from either end by electric blasting caps attached to the main trunk lines of cordeau or primacord. The detonating speed of cordeau or primacord gave the practical effect of firing all holes instantaneously. Double row and multirow blasts, fired instantaneously with cordeau or primacord, proved to be unsatisfactory in the type of rock found at Chuquica-

Jan 1, 1953

By Glenn S. Wyman

CHUQUICAMATA, located in northern Chile in the Province of Antofagasta, is on the western slope of the Andes at an elevation of 9500 ft. Because of its position on the eastern edge of the Atacama Desert, the climate is extremely arid with practically no precipitation, either rain or snow. All primary blasting in the open-pit mine at Chuquicamata is done by the churn drill, blasthole method. Since 1915, when the first tonnages of importance were removed from the open pit, there have been many changes in the blasting practice, but no clear-cut rules of method and procedure have been devised for application to the mine as a whole. One general fact stands out: both the ore and waste rock at Chuquicamata are difficult to break satisfactorily for the most efficient operation of power shovels. Numerous experiments have been made in an effort to improve the breakage and thereby increase the shovel efficiency. Holes of different diameter have been drilled, the length of toe and spacing of holes have been varied, and several types of explosives have been used. Early blasting was done by the tunnel method. The banks were high, generally 30 m, requiring the use of large charges of black powder, detonated by electric blasting caps. Large tonnages were broken at comparatively low cost, but the method left such a large proportion of oversize material for secondary blasting that satisfactory shovel operation was practically impossible. Railroad-type steam and electric shovels then in service proved unequal to the task of efficiently handling the large proportion of oversize material produced. The clean-up of high banks proved to be dangerous and expensive as large quantities of explosive were consumed in dressing these banks, and from time to time the shovels were damaged by rock slides. As early as 1923 the high benches were divided, and a standard height of 12 m was selected for the development of new benches. The recently acquired Bucyrus-Erie 550-B shovel, with its greater radius of operation compared to the Bucyrus-Erie 320-B formerly used for bench development, allowed the bench height to be increased to 16 m. Churn drill, blasthole shooting proved to be successful, and tunnel blasts were limited to certain locations where development existed or natural ground conditions made the method more attractive than the use of churn drill holes. Liquid oxygen explosive and black powder were used along with dynamite of various grades in blast-hole loading up to early 1937. Liquid oxygen and black powder were discontinued because they were more difficult to handle due to their sensitivity to fire or sparks in the extremely dry climate. At present ammonium nitrate dynamite is favored because of its superior handling qualities and its adaptability to the dry condition found in 90 pct of the mine. In wet holes, which are found only in the lowest bench of the pit and account for the remaining 10 pct of the ground to be broken, Nitramon in 8x24-in. cans, or ammonium nitrate dynamite packed in 8x24-in. paper cartridges, is being used. This latter explosive, which is protected by a special antiwetting agent that makes the cartridges resistant to water for about 24 hr, currently is considered the best available for the work and is preferred over Nitramon. Early churn drill hole shots detonated by electric blasting caps, one in each hole, gave trouble because of misfires caused by the improper balance of resistance in the electrical circuits. Primarily, it was of vital importance to effect an absolute balance of resistance in these circuits, the undertaking and completion of which invariably caused delays in the shooting schedule. Misfires resulting from the improper balance of electrical circuits, or from any other cause, were extremely hazardous, since holes had to be unloaded or fired by the insertion of another detonator. The advent of cordeau, later followed by primacord, corrected this particular difficulty and therefore reduced the possibility of missed holes. After much experimentation, the blasting practice evolved into single row, multihole shots, with the holes spaced 4.5 to 5 m center to center in a row 7.5 to 8 m back from the toe. Sucti shots were fired from either end by electric blasting caps attached to the main trunk lines of cordeau or primacord. The detonating speed of cordeau or primacord gave the practical effect of firing all holes instantaneously. Double row and multirow blasts, fired instantaneously with cordeau or primacord, proved to be unsatisfactory in the type of rock found at Chuquica-

Jan 1, 1953

By O. N. Carlson, W. M. Paulson

A phase diagram is proposed for the Y-C system based on the vesults of thermal analyses, microscopic obsevvations, and X-ray diffraction studies. Three intermediate phases occur in the system: a congru-ently melting fcc phase with a wide range of homogeneity about the composition Y2C, an intermediate solid-solution region between 55 and 58 at. pct C, and a bct dicarbide melting congruently at 2415°C. All three compounds undergo a phase transformation at elezlated temperatures. A continuous serzes of solzd solutions exists between the fcc phase and the high-temperature form of YC2 with a maximum in the solidus at 2000°C and 30 at. pct C and a minimum at 1805°C and 54 at. pct C. THIS investigation of the Y-C system was undertaken as part of a nuclear materials development program. Yttrium-base alloys are of interest as possible containers for liquid metals, and carbides are currently receiving increased attention as high-temperature materials for advanced reactors and other applications. Previous work on this system was limited in scope, and the results were somewhat inconclusive and at times contradictory. Spedding et al.&apos; reported the existence of a triyttrium carbide having an fcc structure with a wide range of homogeneity and Dean et a1.2 reported the existence of a rhombohedra1 phase having the stoichiometry of Y2C. Bachella et a1.3 observed that the latter was the result of ordering of carbon atoms in the fcc solid solution. The ordering range was placed at 800" to 1000°C. Vickery et a1.4 reported a high-melting compound which they identified as yttrium dicarbide, and Spedding and coworkers1 determined the structure of this phase as bct with lattice parameters a = 3.66 and c = 6.17A. Samsonov et al.5 reported the melting point of YC2 as 2300" * 50°C. Recently Bowman et a1.6 found a transformation in the dicarbide from the tetragonal to an fcc form at 1320 20°C. Samsonov and coworkers7 reported a monocarbide of yttrium melting at 1950" * 20°C and also a sesqui-carbide melting at 1800" * 50°C. The existence of the latter has also been indicated by others,1&apos;8 but neither compound has been definitely established. The Y-C phase diagram shown in Fig. 1 was proposed by Chubb and Keller8 in 1964 based on the data available at that time. The tentative nature of this diagram together with the uncertain status of the compounds indicated that additional work on this system was needed. EXPERIMENTAL PROCEDURE Yttrium metal of 99.9 pct purity was prepared for use in this study by the reduction of YCl, with calcium to form a sponge product.9 The major impurities in this material were as follows: 100 ppm C, 150 pprn H, 20 ppm N, 300 to 1000 ppm O, <20 ppm Ca, <100 ppm Cr, <80 ppm Cu, 150 ppm Fe, <30 pprn Mg, <400 ppm Ta, and <100 ppm Ti. Alloys were prepared by arc melting yttrium sponge together with pieces of high-purity graphite rod in a purified argon atmosphere. Homogeneity was insured by repeated melting, inverting the ingot between melts.

Jan 1, 1969

By Robert A. Colten, Frederick C. Hull, Robert F. Mehl

It is known that pearlite forms from austenite by a process of nucleation and growth, and that the rate of formation of pearlite may be described by a rate of nucleation and a rate of growth.l,2 The manner in which these two quantities operate to produce the observed isothermal reaction curve has been analyzed in a paper published in I939.3 Two types of process were described: (I) that in which nucleation occurs at the grain boundaries of the parent phase, with the nodules growing toward the centers of the grains, initially as hemispheres and then after impingement as roughly radial-columnar structures; and (2) that in which nucleation occurs generally, with the nodules growing to full spheres until impingement with other growing nodules restricts growth. Both cases are met in the formation of pearlite from austenite (Fig. I);2,4 the former, occurring near the knee of the S-curve, has been named "grain-boundary transformation," and the latter, occurring at temperatures near Ael, has been named "group-nodule transformation." In developing our knowledge of the factors that determine the rate of formation of pearlite from austenite, it is important1,2 to obtain data on the rate of nucleation and the rate of growth of pearlite. Such data, when obtained near the knee of the S-curve, will furnish information of use in understanding the factors that affect hardenabil-ity; when obtained at higher temperatures, such data will be useful in understanding the behavior of steels that during heat-treatment react to pearlite.2 It is the purpose of this paper to present data on the rate of nucleation and the rate of growth of pearlite in dependence upon composition, grain size, temperature, and the degree of homogeneity of the parent austenite. The studies are restricted chiefly to plain carbon commercial steels." Previous Data on Rate of nucleation and rate of Growth Data on the rate of nucleation and the rate of growth of pearlite have been published by Scheil and Lange-Weise,5 by Mirkin and Blanter,6,7 by Meh1,l and by Dorn, De Garmo and Flanigan.2, It is difficult to interpret the data, for in most cases too little information is given on austenitizing temperatures and times, the state of homogeneity of the austenite (presence or absence of carbide, etc.), austenite grain size, and mode of formation of pearlite at the temperatures given. Except for the approximations of Mehl and the work of Dorn, austenite grain size was disregarded, though it is well known

Jan 1, 1942

By Robert A. Colten, Frederick C. Hull, Robert F. Mehl

It is known that pearlite forms from austenite by a process of nucleation and growth, and that the rate of formation of pearlite may be described by a rate of nucleation and a rate of growth.l,2 The manner in which these two quantities operate to produce the observed isothermal reaction curve has been analyzed in a paper published in I939.3 Two types of process were described: (I) that in which nucleation occurs at the grain boundaries of the parent phase, with the nodules growing toward the centers of the grains, initially as hemispheres and then after impingement as roughly radial-columnar structures; and (2) that in which nucleation occurs generally, with the nodules growing to full spheres until impingement with other growing nodules restricts growth. Both cases are met in the formation of pearlite from austenite (Fig. I);2,4 the former, occurring near the knee of the S-curve, has been named "grain-boundary transformation," and the latter, occurring at temperatures near Ael, has been named "group-nodule transformation." In developing our knowledge of the factors that determine the rate of formation of pearlite from austenite, it is important1,2 to obtain data on the rate of nucleation and the rate of growth of pearlite. Such data, when obtained near the knee of the S-curve, will furnish information of use in understanding the factors that affect hardenabil-ity; when obtained at higher temperatures, such data will be useful in understanding the behavior of steels that during heat-treatment react to pearlite.2 It is the purpose of this paper to present data on the rate of nucleation and the rate of growth of pearlite in dependence upon composition, grain size, temperature, and the degree of homogeneity of the parent austenite. The studies are restricted chiefly to plain carbon commercial steels." Previous Data on Rate of nucleation and rate of Growth Data on the rate of nucleation and the rate of growth of pearlite have been published by Scheil and Lange-Weise,5 by Mirkin and Blanter,6,7 by Meh1,l and by Dorn, De Garmo and Flanigan.2, It is difficult to interpret the data, for in most cases too little information is given on austenitizing temperatures and times, the state of homogeneity of the austenite (presence or absence of carbide, etc.), austenite grain size, and mode of formation of pearlite at the temperatures given. Except for the approximations of Mehl and the work of Dorn, austenite grain size was disregarded, though it is well known

Jan 1, 1942

By Ursula E. Wolff

The precipitation of carbides from an alloy containing 33 pct Ni, 21 pct Cr, balance iron, was investigated electron microscopically by means of extraction replicas and thinned metal foils. Annealing temperatures ranged from 565°to 870°C and up to several thousand hours. M23C6 precipitated in pain boundaries, incoherent and coherent twin boundaries in that sequence. The orientation relationship between carbides and austenite matrix was determined and correlated with the morphology of the carbides and with the type of boundary in which precipitation occurred. In large-angle grain boundaries, as well as in coherent twin boundaries, the carbides had the same orientation as one of the adjacent pains. These carbides formed sheets of individual flakes with shapes related to the orientation of the boundary. In incoherent twin boundaries carbides precipitated in ribbons composed of pavallel rods. An unidentified subcarbide was found to precede precipitation of M23C6 in these boundaries. The M 23 C6 rods had a kind of fiber texture with (110) parallel to the long dimension of the rods and ribbon, and with orientations of both of the adjacent twin-related austenite crystals Predominant in the texture of the carbide. A hard sphere crystal model has been used to discuss orientation and morphology of the carbides in terms of free volume and vacancies available in the boundaries. A number of papers have dealt with the morphology of chromium carbide (M23 C6) precipitated in austenitic stainless steels.1"7 In all these investigations, the carbides were examined in the electron microscope by means of extraction replicas. With this technique, the carbides retain the spatial distribution they had in the bulk sample. However, since the matrix is dissolved in the process, the particles can turn in an unpredictable way; and the orientation relationship between matrix and carbides cannot be established. In this paper the results of studies on extraction replicas and on thinned metal foils are reported. These studies were undertaken to determine the matrix-to-car bide orientation relationship, and to correlate the orientation of the carbides with their morphology. PROCEDURE The material used was an austenitic alloy with 33 pct Ni, 21 pct Cr, balance iron, containing approximately 0.05 pct C. Coupons of 1.25-mm sheet were first solution-annealed at 1050°C for 15 min and air-cooled. Then, to precipitate the carbides, samples were isothermally annealed in the range from 565" to 870°C for times up to several thousand hours. All further specimen-preparation procedures were carried out after the final anneal. Carbon extraction replicas from polished and etched surfaces were made with 10 pct bromine in methyl alcohol.&apos; Thin foils were prepared from punched-out 3-mm-diam disksg which fit into the electron-microscope holder. The disks were prethinned by grinding to approximately 0.5 mm thickness, and then electro-polished in a polytetrafluoroethylene holder1&apos; with a solution containing 5 pct perchloric acid in acetic acid to which 10 g per 1 Cro3 and 5 g per 1 nickel chloride were added (etchant modified from that of Briers et al."). This solution dissolves neither the carbides nor the austenite around the carbides preferentially. By using extraction replicas, electron micrographs and selected-area electron-diffraction patterns were taken from the same carbide arrays. By using thin foils, electron micrographs were made from a grain boundary area containing carbides. Electron-diffraction patterns were then taken from the same area and from each of the adjacent grains separately. In this manner, the orientation of each grain could be determined without interference by the carbide pattern. A peculiarity of extraction replicas should be pointed out. After the matrix is etched away, the carbide arrays float freely in the etching and washing solutions, and are held in place only at the anchoring points in the carbon replica. When the replica is picked up with a screen the carbide arrays tend to flip to one side. Thus, while the surface features are preserved, the original arrangement of the carbides may severely and unpredictably be disturbed whenever the specimen contains large amounts of interconnected carbides. Nevertheless, it is possible to correlate the different morphologies of the carbides with the type of boundary in which they have precipitated. RESULTS 1) Extraction Replicas. Fig. 1 shows that the grain boundaries usually are curved, multicornered surfaces of random orientation. The coherent twin boundaries (which are (111) planes) cut a grain into parallel slices. Incoherent twin boundaries occur at the ends and on the steps of twins and are often narrow, parallel-sided strips which are much longer than they are wide. Different morphologies can clearly be distinguished for the M23Ce carbides precipitated in each of these types of boundaries, and agree well with those observed by kinzel.2 The kinetics of this precipitation has been investigated." The first carbides precipitate in junctions of three grain boundaries and fan out from there into the adjoining boundary surfaces, Fig. 2(a). These carbides are oriented randomly, Fig. 2(b), and become coarser and thicker as annealing time increases. The large-angle grain boundaries are next to fill

Jan 1, 1967

(Members are, urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period April 10 to May 10; I. N. Knapp, Ardmore, Pa. E. P. Mathewson, Anaconda, Mont. Herbert B. Cox, New York, N. Y. H. B. Barling, New York, N. Y. A. McLintock, Brooklyn, N. Y. M. M. Thompson, Morsemere, N. J. Heinrich Ries, Ithaca, N. Y. Howland Bancroft, Denver, Colo. R. M. Catlin, Franklin Furnace, N. J. John H. Adams, Birmingham, Ala. Percy E. Barbour, Candor, N. C. Henry D. Boddington, London, England. A. D. R. Galloway, Qruro, Bolivia. William J. Cox, Denver, Colo. M. K. Rodgers, Westgate, Cal. W. J. Morrison, Toronto, Canada. W. J. Richards has been elected President of the Reading. Coal & Iron Co., succeeding the late George F. Baer.

Jan 6, 1914

Truman H. Aldrich &apos;78 Andrew S. McCreath &apos;75 W. S. Ayres &apos;73 Walter McDermott &apos;74 A. A. Blair &apos;75 Philip N. Moore &apos;74 Walter M. Brodie &apos;72 Henry S. Munroe &apos;72 H. M. Chance &apos;74 James Wilson Neill &apos;79 Frederick G. Corning &apos;77 I. P. Pardee &apos;73 Henry S. Drinker Founder Edward C. Potter &apos;79 Ernest F. Eurich &apos;74 Alexandre Pourcel &apos;77 W. E. C. Eustis &apos;76 William H. Radford &apos;76 A. Heckscher &apos;79 Robert H. Richards &apos;75 Henry D. Hibbard &apos;79 Albert F. Schneider &apos;74 Julian Kennedy &apos;79 Porter W. Shimer &apos;79 William St. George Kent &apos;72 John Stevenson, Jr &apos;76 Frank Lyman &apos;77 Arthur Thacher &apos;76 John Markle &apos;79 Edward H. Williams &apos;76 Samuel Mather &apos;79 Thomas D. Wood &apos;79

Jan 1, 1929

By Chung Yu Wang

DURING the time I was in charge, of this mine, from 1914 to 1915, I had occasion to read the interesting papers by T. T. Read and C. M. Weld about these deposits, to find how far their observations corroborated mine. To quote from the paper on "The Mineral Production and Resources of China" by T. T. Read:&apos; "The iron ores at Tayeh lie along the contact between a marble and an intrusive body of a dark gray syenitic rock. * * * * At one place it is slightly magnetic, apparently having been partly reduced to the magnetic oxide by the action of reducing solutions, which have deposited small amounts of copper and iron sulphides along the foot wall." To quote from the paper on "The Tayeh Iron Ore Deposits"2 by C. M. Weld: "I find the orebodies described as occurring along an approximately E-W contact between horn-blende-granite and limestone. * * * * The granite is a granitoid rock consisting essentially of quartz, potash-feldspar and hornblende." These quotations show the differences of opinion entertained by two observers. My own study of these interesting deposits has been intermittent amid the manifold duties devolving upon a superintendent. General Description of the Deposits The deposits are situated to the west of the Yangtse River, being con¬nected with the river by a standard-gage railroad of 56 li (16.16 miles, 26 km.) in length, as shown in Fig. 1. The general topography of the region is of mature age, showing broad valleys with sluggishly meandering streams. These deposits are worked as two mines, named the Tieh Shan Mining Department and the Teh Tao Wan Mining Department; the former consisting of three orebodies more or less connected, named Tieh Man Kan, Sha Mau Tze and Lung Tung, and the latter consisting of Chang Pei Shan, Sze Tze Shan, Ta Shih Men, Yeh Chih Ping and Tsin Shan, also more or less connected, as shown in Fig. 2.

Jan 3, 1917