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By Charles A. Ashburner

DURING the early part of August, 1880, I was directed by Prof. J. P. Lesley, State Geologist, to assume charge of the geology and mapping. of the Second Geological Survey of the anthracite codfields. I visited the region uninaumbered by any instructions other than this,—that I should submit a plan for making the sur-

Jan 1, 1881

By A. W. Schlechten

The proposition is advanced that edutcation specifically for exlractive metallurgy is desirable not because the course content is cmique but rather as a means of indoctrinating the student with a backgrocmd that will give him an interest and pride in the profession. Factors that have caused the decline in enrollment in metallurgical engineering courses emphasizing extractive processes are being overcome. There is a need to distinguish between the sciences of metallurgy and the engineering applications to avoid confusion both in and out of the profession. AS a first step in preparing the 1967 EMD Lecture I searched the literature to determine what my predecessors had done hoping thereby to gain some clues for my own performance. The Transactions of the Metallurgical Society show that the first EMD Lec- turer in 1959 was Dr. W. J. Kroll, known chiefly today for his pioneering work on the production of titanium and zirconium, but equally respected by an earlier generation for his contributions to lead refining. He has been followed by a series of well-known and competent metallurgists all possessing specialized knowledge that has served as a basis for their lectures. The EMD Lectures have in general been a review of the development of a certain aspect of the extractive metallurgical industry or a preview of a particular area of science or technology that has applications in extractive metallurgy. The usual format is to describe developments of the past, summarize the present state of knowledge, and make predictions for the future. There has been great variation in the relative amount of time devoted to these three subdivisions, the past, the present, and the future. For example, Professor Gaudin, the 1961 EMD Lecturer, in speaking of Separation Engineering on the Moon, did not have too many examples of past practice and so had to emphasize the future. It is cheering to observe that all of these authorities were optimistic in their predictions. Despite the fact that four of the previous EMD Lecturers have been educators, Professors Gaudin, Pidgeon, Schuhmann, and Kellogg, none of them discussed the subject of education for extractive metallurgists. I might say parenthetically that lecturers in other divisions, such as B. M. Larsen, J. B. Austin, F. D. Richardson, John Chipman, and R. F. Mehl, have commented with concern on the present state of training for extractive metallurgy. What can you say that is new about extractive metallurgy education? Certainly nothing new can be said about the educational process itself. Professional educators do have new approaches to teaching and learn-

Jan 1, 1968

To the American Institute of Mining Engineers: The committee appointed at the February meeting upon Railway Resistances would respectfully report: That one person has been constantly employed in calculating the results of the data taken prior to March 1st, 1876. Also to complete the data taken upon the Lake Shore and Michigan Southern Railway, a diagram was taken upon a through freight train from Cleveland to Chicago, and one from Chicago to Cleveland. So that now we have diagrams from Buffalo to Chicago and return, which, when fully worked up, will give results of the utmost importance in determining the cost of transportation of freight. These data will be of much importance in determining the proper methods of equating grades and curves, which is so essential in the location of new lines. The calculations show that instead of our attempting to formulate results from data obtained on one road, it will be best for the in¬terests of transportation to enlarge the scope of our inquiries, and to extend the experiments so as to include all of the more probable causes which affect the cost of transportation. Were the details of railway equipment constructed alike, much work, which is now necessary, would be saved. It is not uncommon to find upon the same road 10 to 30 different patterns of something in construction to subserve the same purpose, which more or less modifies the friction of the cars. Take the majority of our trunk lines, with this diversity of construction, together with the varying conditions of track and manner of operating, and it will be at once seen that the labor and time to do the work and arrive at correct conclusions will occupy from two to three years. The results already attained in the short time in which they have been carried on, wholly by private enterprise, simply show what may be expected when the aid necessary is given to render them of the highest value to the great industries of the country. That the information may be general and of the greatest importance to our railway interests, the committee deem it advisable to secure, so * The following report, made at the June meeting of the Institute, is inserted in this place as appropriately supplementing the original communication of Mr. Dudley.

Jan 1, 1876

By AIME AIME

A REQUEST for information as to the details of activities of the Engineering Council was made by the Joint Conference Committee for the benefit of the new American Engineering Council. , This request was complied with, and the scheduled reply so succinctly sets forth the activities of the old Council as well as the scope of possible activities of ,the new Council, about whose efforts there has been much discussion, .that it' is given herewith in full, except the 'budget which is summarized.

Jan 1, 1920

By James A. Barr

When phosphate mining operations first commenced in Tennessee the loss of both high- and low-grade material was large, because of the crude hand methods employed. Practically all rock smaller than 2 in. was thrown back into the pits and covered with the overburden of subsequent openings. With the advent of mechanical washers and other mining machinery, together with the abolishing of the contract system, the waste has been steadily diminished, until at present only the finest sand is being rejected; and even this is not lost, for in the majority of cases the water, slime, and sand from the washers are run into large settling ponds where practically all of the phosphate-bearing material is caught and stored for future use, or until it is profitable to ship lower grades. The latest equipment used to recover the fine and lower-grade phosphate sand includes Dorr thickeners, settling tanks, Dorr classifiers and settling ponds served by locomotive cranes with clam-shell buckets, making it possible to save material averaging as fine as 200 mesh. TO attempt saving finer material would necessitate a different type of drier, which might be patterned after the multiple-deck roasters. The present tailing runs from 15 to 25 per ccnt. of available phosphate, which, howrever, as mentioned before, does not represent a total loss to possible future operations. The demand of the consumer is the greatest factor in regulating the recovery at present. In the mining of blue rock, which does not require washing treatment, the main waste material is the capping of low-grade kidney formation, generally used for backfilling of the rooms. By reason of the introduction of improved methods in the early stages and the re-mining of territory skimmed over at the start, at the present time the net result of all operations is a comparatively small loss. One of the largest temporary losses in the industry occurs in the Florida pebble district where the recovery of phosphate runs about 25 per cent. The loss is classed as temporary because most of the tailing has been collected in ponds and piles, where it may be reclaimed in the future should developments or improved processes warrant. In cleaning the Florida pebble phosphate, aside from the elutriatisn

Jan 1, 1916

By Edward Keller

(New York meeting, February, 1912.) IN a paper, entitled A Uniform Method for the Assay of Copper Material for Gold and Silver,1 A. R. Ledoux invited the assayers of this country to contribute to a symposium, in which the results of their assays of given samples of copper-matte and metallic copper would be made comparable. This symposium 2 appeared about one year thereafter; and through it and its discussion, first became generally known the fact that the ,gold-yield by the all-fire method of assaying is usually higher than by the so-called combination (wet and dry) method, in which nitric acid is employed as a solvent for the copper. In the publication alluded to, the supposed cause of gold-losses in the latter method was declared to be the solvent action of copper nitrate, or of the reduction-products of the nitric acid, upon the gold. Up to a very recent date, gold has been held to be insoluble in pure nitric acid. (The solvent action of any chlorine present in the nitric acid must here properly be disregarded as belonging in the realm of carelessness. Among later allusions to this topic, W. R. Tan Liew 3 ascribes the solution of the gold in the combination-assay entirely to the action of nitrous acid at the high reaction-temperature of copper and nitric acid ; F. B. Flinn 4 a believes the low result in gold to be due exclusively to mechanical losses-finely-divided gold penetrating through the filter-paper-but presents no experimental data confirmative of this belief; and 0. Pufahl 5 attributes the solubility of the gold in some coppers to the presence of selenium-a view which appears to be shared by many as- 1 Trans., xxiv., 575 (1894). 2 Trans., xxv., 250 (1895). 3 Engineering and Mining Journal, vol. lxix., No. 16, p. 469 (Apr. 21, 1900). 4 Engineering and Mining Journal, vol. lxxxvii., No.11, p. 569 (Mar. 13, 1909). 5 Lunge, Chemische Technische Untersuchungs Methoden, vol. ii., p. 229 (1900).

Jul 1, 1912

By George B. Harrington

This paper is a brief description of the design and equipment of a new coal mine in southern Illinois, which has many features not common practice in shaft coal mining and which is laid out and equipped for such unusually large capacity that it promises soon to become one of the largest mining operations of its kind. Shaft sinking for the mine, New Orient, was commenced in May, 1921, by the Chicago, Wilmington & Franklin Coal Co. In October, 1924, the plant was practically completed and was producing over 6000 tons of coal per day. There is good prospect that within a few years, when the mine is fully developed and manned, the output will attain a daily rate of 12,000 tons. The coal seam at New Orient lies approximately horizontal, about 500 ft. below the surface, and may be said to run from 9 to 12 ft. in thickness. The tendency in Franklin County has been toward large mining units (5000 to 6000 tons per day) with great care being given to protection against fire and explosion hazards, and usually with quite elaborate surface plants permitting careful preparation of the coal into graded sizes comparable with those made in the anthracite region. The field is unionized, with uniform conditions of wages for various classes of work, hours, etc., and the Illinois mining laws are quite specific with regard to fireproofing and safety measures. These conditions make it difficult for any hut well-equipped and well-operated mines to meet the competition of the numerous fine properties of which this county can justly be proud. The coal company's property was already developed on the western side by the Orient mine—a much visited and written about operation (with which many of you are possibly familiar through the Department of Mines' film "The Story of Coal") which until recently held the 8-hr, production record with 8218 tons and usually ran quite consistently with production of slightly over 6000 tons per day. Experience at Orient wat naturally one of the greatest influences in determining the location and character of the New Orient.

Jan 1, 1925

By Charles White Merrill

Mankind's progress is measured in minerals. Man's emergence from prehistory is marked by passage through a Stone Age and a Bronze Age and into the present era, sometimes called the Iron Age or the Age of Metals. With the evolution of civilization and the development of a modem industrial economy, minerals become more and more important. Structures, roads, and machines are built largely of minerals; the energy to heat the structures and to drive the machines is mostly mineral; agricultural fertility is maintained by mineral fertilizers and water; and military strength is provided by fortresses, armaments, and munitions, largely of mineral origin. Thus in the material world, in the productivity of the economy, access to minerals has paramount importance. Every evidence indicates increasing dependence on minerals in the modem economy, particularly on the mineral fuels as energy sources to provide the power base for advancing industrialization. Both the total and the per capita consumption of almost every mineral is increasing in the industrialized nations. Moreover, nations with predominantly agrarian economies call themselves underdeveloped and universally strive to industrialize. Most mineral consumption trends in the more advanced economies have been greatly exceeding population growth-which itself has been advancing at an accelerating rate-and sometimes have surpassed the growth in real income. Some minerals have only recently been adopted or grown to importance in use. Titanium metal did not appear as a commercial product until 1948, and even coal seriously displaced wood as a source of heat less than two centuries ago. On the other hand, minerals have always played an important role in construction. The prehistoric megaliths that form the dolmens of Salisbury Plain are stone; the pyramids are andesite faced with limestone; and many other ancient structures are built of mineral materials. In modem times the whole course of architecture has been redirected by new building materials, mostly mineral. Most conspicuous is the sky-

Jan 1, 1964

By ROBERT R. ABUOTT

(Cleveland Meeting, October, 1912.) THE practice of carbonizing steel for the purpose of case-hardening has assumed great commercial importance within the past, 10 years. Formerly, case-hardened steel was held in more or less contempt, since it. was considered a cheap substitute for tool-steel. This is no longer the case. The development of the motor-car industry, and coincidentally that of modern alloy-steels, has resulted in overcoming many difficulties formerly experienced in case-hardening. This result has been accomplished by increased knowledge regarding the analysis of the steel which would respond most readily to case-hardening, and by more careful methods of treatment of the carbonized steel. The ordinary method of carbonizing consists in packing the steel with the carbonizing-material in cast-iron boxes and placing them in a furnace at a temperature of from 1,500° to 1,900° F. for a time sufficient to give the required depth of cc case." The steel is then either quenched directly from the box, or is allowed to cool without unpacking, and finally given a single hardening-heat., or, for special work, two or three heats. During the year 1911, more than 100,000 tons of carbonizing-material was sold in the United States, at an average price of probably $55 per ton. More than 85 per cent. of this material consisted of granulated bone. Within the past four years, many manufactured compounds have been placed on the market, consisting largely of some form of carbon or carbonaceous material, with or without the addition of chemicals. Steel will absorb carbon placed in contact with it at the temperature of the atmosphere. The reaction is exceedingly slow, but. increases rapidly with increasing temperature. Below * Metallurgical Engineer, The Peerless Motor Car Co.

Dec 1, 1912

By RALPH HAYES SWEETSER

ONE per cent. of ash in a ton of coal has been so little considered that in many circles it has been positively ignored. Even P. T. Barnum had never heard of it, or he would have had one on exhibition alongside the Cardiff Giant and the White Elephant. One per cent. of ash is closely related by both those freaks of Barnum in that it is "stone" and, in its aggregate, it is the greatest "White Elephant" that the American public now supports. Some of you may have paid Mr. Barnum for a look at the "petrified man" (named the Cardiff Giant by the gullible wise men of the early seventies); but it is certain that everyone of you is now paying for the support of the great White Elephant that is being constantly carried by our railroads all over the country-at the public's expense. " One per cent. of ash in a ton of coal" requires 120,000 open-top railroad cars each year to transport this use- less stone giant from its native bed in the coal seams of the bituminous regions to the coal bins of the consuming public.

Jan 1, 1924

By John A. Ames

Webster's dictionary nearly equates portland cement with its current primary definition of cement. While such equation may be a triumph of common usage, the confusion between the terms cement and concrete unfortunately is very widespread. Full definition of cement properly would extend to many substances, but for purposes of this chapter cement is restricted to "varieties" of portland cement including "portland-pozzolan" cement. Among the usually recited historical notes concerning cement is that it was developed by the Romans. Their use of cement in the great structures of Rome, and even in the far corners of their Empire, such as Hadrian's Wall in the north of England, testifies to the antiquity of a major cement industry. From English sources we know of John Smeaton's carefully proportioned hydraulic cement mixed in 1756 and of Joseph Aspdin's patented cement to which, in 1824, he gave the name portland cement. (He claimed that his cement mortar looked like the famous dimension limestone quarried from the Isle of Portland on England's south coast.) The year 1971 marked the centennial of portland cement manufacture in the United States. A fair historical account of the many real contributors to the cement industry between 1756 and 1972 unfortunately would be too extensive for this chapter. Development of rotary kiln practice and burning at higher temperatures clearly was the major move into today's technology. As part of the 4th edition of Industrial Minerals and Rocks, this chapter on utilization focuses on inferred interests of the anticipated readers. The main period for which statistics are cited generally is that since the 3rd edition (1960) of this same volume. Cement manufacture is the processing of selected and prepared mineral raw materials to produce the synthetic mineral mixture (clinker) that can be ground to a powder having the specified chemical composition and physical properties of cement. Cement making incorporates a number of distinct steps, but it is characterized by the key pyroprocessing (or "burning") step, which brings about the necessary changes in the raw materials. This pyro processing is a chemical process. Conversion of large volumes of mineral raw materials into specification-controlled cement at relatively low cost is the objective. Statistics on the cement industry are of uneven quality. The U.S. Bureau of Mines (USBM) is the principal collector of available data. These statistics can be only as good as the quality of information supplied by the reporting companies. The data perhaps most often questioned relate to productive capacity of the industry. The questions submitted by USBM are valid, nevertheless, and the information gained from them, as good as is available, is what is generally used. The Portland Cement Association also is a source of much quality information. The year 1972 witnessed a test of the adaptability of cement industry statistics. This was the year of conversion from barrels and sacks of cement as the units of measure to tons and hundredweights. The barrels and sacks related to volumetric measures in that a sack was judged to be 1 cu ft (weighing a "standard" 94 lb). A barrel was 4 sacks. Volumes of concrete are stated in cubic yards, and the number of cubic feet of cement in a cubic yard of concrete was a sensible approach to the mensuration involved. However, cements do not weigh the same amount from plant to plant or from type to type, and the buyer was more interested in getting an assured weight for his money than in "buying air." Thus, a sack, in accepted practice, became 94 lb instead of 1 cu ft, and a "barrel" became 376 lb, regard- less of whether it would fit into 4 cu ft of space. With the de facto dealing in weight rather than in volumes, the awkward numbers made little

Jan 1, 1975

By A. G. Metcalfe

Observations at temperature are used to investigate the phase changes in alloys containing more than 50 pct Co and above 1000°C. The nonsuppressible transformations in cobalt above 1120°C and in the intermetallic compound Co2Cr3 are studied. The liquidus and solidus surfaces are determined. Insufficient data is obtained to complete the constitution diagram. A REVIEW of some of the earlier work on cobalt' and on the binary systems with chromium2-4 and with molybdenum,5 showed that one likely source of differences might be attributed to the presence of phases at high temperatures which could not be retained by quenching. Consequently, the decision was made that only methods of examination at temperature should be used in this work. The correctness of this decision was confirmed during the course of the work by the investigation of the martensitic nature of the transformation in cobalt- and by the decomposition of the high temperature form of the phase Co2Cr3 on quenching.' The use of high temperature methods, including dilatometry and thermal etching led to the postula-tion of the existence of a high temperature form of cobalt with a probable hexagonal close-packed structure, transforming from cubic cobalt over a range of temperature from 1119° to 1145°C.8 One of the important pieces of evidence for this transformation was that it was observed in alloys with chromium and molybdenum which were nonmagnetic at this temperature so that confusion with magnetostriction effects was impossible. These results were not reported in this earlier paper, so that the data given here supply further evidence for the existence of a second allotropic transformation in cobalt. High temperature observations are necessarily much slower in producing results than the examination of quenched specimens at room temperature by conventional means such as X-ray diffraction or microexamination. The investigation has only covered a limited part of the field, as a result, extending from the liquidus down to about 1050°C and from the cobalt corner up to 50 pct alloying elements. The differences between the various reported diagrams for the constitution of the Co-Mo and Co-Cr systems have already been mentioned. The best available diagram in the first system is due to Sykes and Graff' which is shown in Fig. 1. Fig. 2 shows the latest Co-Cr diagram due to Elsea, Westerman, and Manning.' A comparison reveals that these are incompatible because of the disagreement with regard to the number of allotropes of cobalt. Elsea, Westerman and Manning took their liquidus and solidus curves from Wever and Haschimoto.2 The temperature horizontal in the two-phase field beneath the eutectic was placed 35" to 39°C higher than in earlier work2,4 with a new interpretation of the nature of this transformation. This interpretation also required a peritectic horizontal at about 1470°C, which has been confirmed here for an alloy with 53 pct Cr. No investigation had been made of the ternary system until after this work had been terminated, when a section at 1200°C was published." In this work a ternary compound was found by the X-ray diffraction examination of quenched alloys. This compound contained less than 50 pct Co, and was thus outside the field investigated here. However, some reactions were found dilatometrically which could not be fitted on the diagram and are now believed

Jan 1, 1954

By Carl Zapffe

THE object of the Bradley process is to free manganese oxide from its associated gangue and separate the contained iron oxide by dissolving the manganese and precipitating it from the solution. 'The fundamental features of the process are : making. both 1 a manganese ore and an iron ore; effecting a separation of manganese .and. iron by means of selective roasting; leaching- the manganese from the roasted ore by using ' ammonium sulfate; precipitating the manganese by using the ammonia gas generated during leaching; fixing the precipitate by oxidizing with air; breaking down and reforming the ammonium sulfate, so that daily very little additional ammonium sulfate beyond that originally charged into the system is required; washing the manganese precipitate and the iron-silica residue and evaporating the liquor to conserve the dissolved salts in the moistures of these two products and 'to reduce the sulfur content,; drying the precipitates; magnetic wet-concentration of the iron-silica residue; sinteriny the manganese-and .the' iron-concentrates.

Jan 1, 1929

By L. G. Sprague

The fact that this latest and most modern of the Universal Atlas Cement Company's plants at Northampton, Pa., is the fifth to be built on these same properties, and their development has been coincidental with the development of the portland cement industry in the United States, makes it appropriate to sketch briefly the history of the successive steps. In 1889 the original Atlas Portland Cement Co. started its first plant at Coplay, Pa., which is just across the Lehigh River from the present operation. Here the first successful rotary kiln was operated. These kilns were 6 ft. in diameter and 60 ft. long; they used oil for fuel until 1895, when the company developed the first burner for pulverized coal. Shortly thereafter the Atlas company acquired property on the Northampton side of the river and built its plants Nos. 2, 3 and 4 within the following 10 years. During the same period the production of portland cement in the country was increasing rapidly; owing largely to the development of the rotary kiln and improved grinding machinery, which lowered the cost and improved the quality of cement. The general tendency has been to increase the length of the kiln and grind both raw material and finished product Liner. In 1930 the Atlas Portland Cement Co. and the Universal Portland Cement Co. united to form the Universal Atlas Cement Co., and the same policy of improving the product has been continued. Because of the large amount of research carried on by manufacturers and consumers, including government agencies, there is a demand for cement of different chemical and physical characteristics for different kinds of structures. Hence many engineers in recent years have been asking for cements of certain definite chemical analyses, which they think are best for their particular jobs. This has compelled the manufacturer to make several different types of cement by variations of chemical composition. These are generally made by adding silica, iron and lime to the standard mixture, which necessarily increases the cost of the product. Therefore the Universal Atlas Cement Co., in planning the modernization of its Northampton plant, gave this particular phase of the problem considerable study. Research and experimentation have developed the practicability of making a wide variety of differently proportioned raw materials for cement by a process of subtraction rather than by addition. With such process, it is possible to discard the undesirable aluminates and silicates from the ample supply of impure limestone available from the company's property rather than by adding high-grade limestone obtained from distant sources. This procedure requires mineral separation by centrifugal sedimentation and froth flotation. Since the chemical and mineral constituents of Lehigh Valley "cement rock," together with the methods of separating them, have been thoroughly described in published

Jan 1, 1948

By L. G. Sprague

The fact that this latest and most modern of the Universal Atlas Cement Company's plants at Northampton, Pa., is the fifth to be built on these same properties, and their development has been coincidental with the development of the portland cement industry in the United States, makes it appropriate to sketch briefly the history of the successive steps. In 1889 the original Atlas Portland Cement Co. started its first plant at Coplay, Pa., which is just across the Lehigh River from the present operation. Here the first successful rotary kiln was operated. These kilns were 6 ft. in diameter and 60 ft. long; they used oil for fuel until 1895, when the company developed the first burner for pulverized coal. Shortly thereafter the Atlas company acquired property on the Northampton side of the river and built its plants Nos. 2, 3 and 4 within the following 10 years. During the same period the production of portland cement in the country was increasing rapidly; owing largely to the development of the rotary kiln and improved grinding machinery, which lowered the cost and improved the quality of cement. The general tendency has been to increase the length of the kiln and grind both raw material and finished product Liner. In 1930 the Atlas Portland Cement Co. and the Universal Portland Cement Co. united to form the Universal Atlas Cement Co., and the same policy of improving the product has been continued. Because of the large amount of research carried on by manufacturers and consumers, including government agencies, there is a demand for cement of different chemical and physical characteristics for different kinds of structures. Hence many engineers in recent years have been asking for cements of certain definite chemical analyses, which they think are best for their particular jobs. This has compelled the manufacturer to make several different types of cement by variations of chemical composition. These are generally made by adding silica, iron and lime to the standard mixture, which necessarily increases the cost of the product. Therefore the Universal Atlas Cement Co., in planning the modernization of its Northampton plant, gave this particular phase of the problem considerable study. Research and experimentation have developed the practicability of making a wide variety of differently proportioned raw materials for cement by a process of subtraction rather than by addition. With such process, it is possible to discard the undesirable aluminates and silicates from the ample supply of impure limestone available from the company's property rather than by adding high-grade limestone obtained from distant sources. This procedure requires mineral separation by centrifugal sedimentation and froth flotation. Since the chemical and mineral constituents of Lehigh Valley "cement rock," together with the methods of separating them, have been thoroughly described in published

Jan 1, 1948

By A. W. McReynolds

One characteristic of plastic deformation which distinguishes it from elastic strain is the essential inhomo-geneity of plastic strains. Elastic strain varies continuously through a material, and average relative displacements of initially adjacent atoms are only small fractions of their initial spacing, (strains of the order of 0.01 or less). On the other hand, plastic flow corresponds to the appearance of discontinuities in strain of the lattice, such as dislocations or slip bands, where local strain, on an atomic scale, is several orders of magnitude higher. These discontinuities are visible on a microscopic scale as the familiar slip lines (Fig 1). In spite of this obvious microscopic inhomogeneity, however, macroscopic measurements almost invariably show a smooth curve of stress vs. strain (Fig 2b) even if measurements of linear strains be made to an accuracy of one part in 107. This macroscopic homogeneity of strain indicates that the discontinuities in strain on slip planes occur in increments too small or too slow to be recorded individually, and further that they occur sufficiently independent of one another so that the small increments add at random to a smooth stress-strain curve. The present paper describes observations of plastic strain in aluminum of commercial purity and in high purity Al-Cu alloys, where there exists a strong coupling between slip in various regions of the specimen such that once initiated it spreads rapidly through a large volume. The total effect is that of relatively large, rapid, and regularly spaced steps of strain followed by periods of only elastic strain. Fig 2a illustrates the type of "stair-step" stress-strain curve which results. The properties of this cooperative slip phenomenon will be described further in the section on results: in par- ticular it will be shown that each step corresponds to the propagation of a wave of plastic deformation through the specimen. Some interpretations of the mechanism by which it occurs will be made in the following section. Although the type of plastic wave phenomena to be described has not previously been reported, there are numerous cases of related effects in the plastic yielding of metals: YIELD POINT PHENOMENA The most familiar of such effects is the "yield point" observed in low carbon steels, brass, duralurninum, and the like. It consists in the sudden termination of the elastic portion of the stress-strain curve by a large plastic strain. Since the usual tensile machine is such that yielding of the specimen relieves the load, the resulting curve is as shown in Fig 3. As the strain continues, deformation occurs at a lower stress for some time, then follows a rising curve, but with no further sudden yielding. This effect has been observed in brass by Sachs and Shojil and later by many others. Edwards, Phillips and Jones2 made extensive studies of the effect in steel, and of the role of various alloying elements. Although there seems to be fairly clear evidence that the yield point is caused by a hardening of the material by precipitation of impurities, no satisfactory explanation for the sudden yielding has been given. Winlock and Leiter3 have shown that the strain. level of the upper yield point depends strongly on the rate of loading, the yield point increasing by almost a fac- tor of two as the strain rate goes from 0.002 in. per in. per min. to 4.4 in. per in. per min. This effect would seem to imply an incubation period before yielding is initiated at a certain stress. On the other hand, by going to very slow loading rates, Edwards, Phillips and Jones2 showed that the yield point does not become lower and eventually disappear as might be expected, but, on the contrary, begins to rise at loading rates below about 25 Ib per in. per min. becoming much higher than at rapid loading rates. STRAIN AGING If, instead of continuing straining of a specimen after occurrence of a yield point, the load is removed and the specimen aged, resumption of the test results in occurrence of another yield point as shown by the dotted curve of Fig 3. The new yield stress is generally higher than the previous maximum applied stress. This hardening of the material by straining and subsequent aging is undoubtedly related to quench age-hardening resulting from the aging of a specimen quenched from high temperature. Since neither effect is observed in pure metals, it is generally accepted that quench-aging in all cases is the result of hardening by precipitation of a supersaturated alloying element, and that strain-aging is probably a similar precipitation, accelerated by disruptions of the lattice by previous strain. Pfeil4 has shown that strain-aging does not occur in iron from which all of the carbon has been removed, but that only a very small carbon content, around 0.003 pct, is necessary to cause strain-aging. In accord with this observation is recent work by Dijkstra5 in this laboratory showing that the solubility limit of carbon in iron is extremely low, less than 0.001 pct at 400°C. Edwards, Phillips and Jones2 have shown that the strain-aging effect is also removed by the addition of small quantities of elements such as Mo, Mn, Ti, and the like, which readily form carbides. Their results demonstrate the

Jan 1, 1950

By P. D. Bush, E. H. Gates, M. D. Vijayaraghavan, L. F. Engle

The process developed over the last few years by Republic Steel Corporation in conjunction with Colorado School of Mines Research Institute has been used as a basis for the conceptual engineering of full size plants. The paper will cover the equipment design criteria, equipment design itself, and the integration of the complex unit operations. There are unique features of agitation and use of gas media through- out. The paper will provide an illustrative example of the process requirements for a variety of raw material feeds. It will discuss the materials of construction approach required.

Jan 1, 1973

By A. J. Griest, P. D. Frost, J. R. Doig

During the past 5 years, research directed toward the development of titanium alloys having improved strength-ductility relationships and heat treatability has been carried out at Battelle for the U. S. Air Force.1"3 In the course of this work, a method of heat treating ß-stabilized titanium alloys was developed which produced a wide range of useful properties.4 The heat treatment consisted of two steps: a) solution treating at temperatures in the a-ß phase region, and b) overaging at a lower temperature in the range 800°to 1100°F. Corollary to the alloy development work, research was conducted on the mechanism of the heat-treatment reaction. The investigations of Frost and co-workers on isothermal transformation in Ti-Cr5 and Ti-Mn8 alloys disclosed the existence of the transition phase, w, during the course of the decomposition of metastable ß phase. Subsequent work at Battelle7,8 'and at Case Institute by Brotzen and co-workerss further clarified the nature of the decomposition process. Beta decomposition was found to proceed by the following series of reactions: 1 2 3 4 a + Ti, My (in eutectoid systems). ßo, ßr, and ßU refer to ß phase of original, enriched, and ultimate alloy contents, respectively. Omega is a transition phase having a complex structure. 10-13 Step 4, of course, occurs only in ß-eutectoid systems. This paper presents data correlating transformation behavior with mechanical properties for the following alloys: Ti-8Mn, Ti-8Mn-2A1, Ti-4Mn-4A1, Ti-6Al-4V, and Ti-4Fe. The isothermal decomposition of ß in titanium-manganese alloys of similar composition has been investigated by Frost and coworkers8 and the effect of various annealing treatments on alloys in this system has been studied by Holden, Ogden, and Jaffee.14 The compositions Ti-8Mn-2Al, Ti-4Mn-4A1, and Ti-6A1-4V, were studied in the present work in an effort to define more clearly the effect of aluminum on the response to solution and aging treatments. Ogden, Holden, and Jaffee15 have invesitgated the effect of aluminum on the response of a similar alloy (Ti-8.8Mn-2.46A1) to annealing treatments, and Luini and Lee16 have made an exploratory investigation of the heat-treatability of the Ti-4Mn-4Al alloy. The Ti-4Fe alloy was studied as an example of a moderate1y active eutectoid system. Holden, Ogden, and Jaffee 17 have studied Ti-Fe alloys and have presented some hardness data for aging at 400°C for alloys of Ti-2.56, 5.01, and 7.35 iron after quenching from the a-ß field (750°C). EXPERIMENTAL PROCEDURES The experimental procedures generally used in the precipitation-hardening study are outlined in the following sections. Departures from these techniques are noted in the discussions of the individual alloys. Table I presents the nominal and actual compositions of the alloys studied, together with the swaging and rolling temperatures. In all cases, these temperatures were in the a-ß field and the microstructures consisted of an equiaxed a-ß mixture. Melting and Fabrication—Except for the commer-

Jan 1, 1960

By F. B. Plummer

GEOLOGICAL engineering as applied to oil fields, or production geology as some prefer to designate the profession, is designed to fill in the border line between pure geology and pure petroleum engineering. Therefore the production geologist may, and frequently does, reach out to grasp much in both professions. Where once the oil geologist was content to pick samples out of a mud ditch and try to identify oil formations from the color or appearance of flakes of rock bailed out of a well, now he has to deal with graphic electrical logs obtained by intricate and highly technical electrical apparatus and to make exact determinations to the fraction of an inch of the depth and thickness of an oil sand 2 miles below the surface.

Jan 1, 1944

By L. C. Uren

Some of US have been impressed with the need for a better understanding of the future place of the engineer in the petroleum industry. In academic work we are continually asked to advise students as to the opportunities in different directions, to guide them in their selection of professions, and it would be extremely helpful to those in academic lines of work to have the opinion of engineers from the industry relative to the need for petroleum engineers. IS the industry going to require a continually growing number of engineers in the future years, or have we perhaps reached equilibrium in that regard ? In anticipation of this meeting, I undertook to canvass opinion among a number of engineers of my acquaintance and I have been rather astonished to learn that the expenditure on engineering salaries in the producing branch of the oil industry is extremely low. I have figures from eight or 10 of the larger oil companies and it seems to be a fair statement on the basis of these figures to say that the average American oil company is devoting less than 2 per cent. of its gross expenditures in oil production to the payment of engineering salaries. A few examples will be of interest. I shall not mention names of individual companies, but one large Mid-Continent company is spending slightly less than 1 per cent. of its gross expenditure—that is, less than 1 per cent. of the total expenditure in the producing department—on engineering salaries and about as much on engineering research, which might properly be regarded as a phase of its engineering work. Another Mid-Continent company is spending about 11/4 per cent. on engineering salaries. A large California company is spending about l1/2 per cent. The largest figure that has come to my attention is that of an important Rocky Mountain and Mid-Continent company that is spending a little more than 6 per cent., but that is apparently an extreme case. The petroleum producing industry is a highly technical business in these days. It is spending in excess of $500,000,000 annually in new

Jan 1, 1929