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By Robert Mehl

PART I. ORIENTATION RELATIONSHIPS IN OXIDE LAYERS Oriented overgrowths and intergrowths among both metallic and nonmetallic substances have been recognized and studied for well over a century. The work of Widmanstätten in 1808 on the geometrical struc-ture in meteorites, a structure known by his name, demonstrated that oriented intergrowths can occur in purely metallic systems. This fact led to much of the early microscopic study of alloys, contributing greatly to the advance of physical metallurgy. The problem has been attacked again in recent years in a comprehensive fashion, with the object of dis-covering what atomic movements may occur during phase changes in alloy systems. Much of this work has appeared in the A.I.M.E. TRANS-ACTIONS in a series of papers published by Mehl and coworkers beginning in 19311. Although many aspects of this general problem remain unsolved, it may be said that the orientation of a new phase forming by precipitation from solid solution or by transformation invariably bears, a unique relationship to the orientation of the phase from which it formed, and that similarity in atomic patterns on atomic planes in the two phases play an important part in determining the orientation relationship. Analogous orientation relationships exist in oriented intergrowths in nonmetallic systems-mineral or inorganic. In 1827 Haidinger2 dis-covered natural intergrowths of hematite and magnetite, and demon-strated that the rough form of the magnetite octahedrons was delineated by small crystals of hematite, of which the basal (00.1) planes lay parallel to the octahedral cleavage planes of the magnetite. The description of this orientation relationship was later completed by von Rath3, who showed that the edge (00-1):(10-1) in hematite lies normal to the [111]

Jan 1, 1937

By A. E. Dwight, A. F. Berndt

ThE published U-Ru equilibrium diagram indicates the existence of six intermetallic compounds in this system.' The structure of only two of the compounds, u2Ru2,3 and URU3,4 have been identified. This communication reports on the crystal structure and density of Uau3, which is formed by a peritectoid transformation at 1025° ± 5°C: U3Ru4 + U3Ru5 = U2Ru3. An alloy with the stoichiometric formula U2Ru3 was prepared by arc melting electrolytic uranium and ruthenium of 99.9 pct purity on a water-cooled copper hearth under an argon atmosphere. After homo-genization at 1000°C for 3 days, a metallographic examination revealed that the peritectoid transformation was complete and less than 5 pct of a second phase was present. A powdered sample, obtained by crushing the brittle compound, was annealed for 1 hr at 1000°C and air-cooled. Debye-Scherrer patterns were obtained with filtered CrKa, FeKa, CoKa, or CuKa radiation. The X-ray patterns of U2Ru3 weFe indexed as an fcc structure with a. = 12.895 0.00lA. The unit-cell constant and its standard deviation were calculated by a computer program described by Mueller, Heaton, and Miller.5 The density, measured by an immersion method, was 14.45 g cm-3. A calculated density of 14.48 g cm-3 was obtained on the assumption that twenty-four formula units (120 atoms) comprise a unit cell. The space group is either oh7 Fd3m, or the less symmetric, T4h, Fd3, since reflections indexed as hk0 with h + k + 4n are absent. All values of h2 + k2 + 12 permitted by both space groups are listed in Table I together with dc, do, and I. values. The calculated d spacings were obtained by the computer program of Mueller, Meyer, and simonsen.6 The observed d spacings above 0.77A were obtained from X-ray" patterns prepared with CuKa radiation, above 0.90A with CoKa radiaaion, above 0.98A with FeKa radiation, and above 1.16A with CrKa radiation. An attempt was made to identify the crystal structure of U2Ru3 by comparison with published data on other A2B3 compounds. A recent compilation7 of intermetallic compounds lists thirty-two structure types with the A2B3 stoichiometry. Only two of the structure types are fcc and they are Sb2O3(r), senarmontite, with 16 Sb2O3 per unit cell, and In2Te3 for which several structures have been proposed.8 However, the two cases cited do not have twenty-four formula units in the unit cell. We therefore, cannot identify UPRU3 with any of the other known A2B3 compounds. Ternary alloys were made in which 5 at. pct Os, Rh, or A1 were substituted for 5 pct of the Ru in U2Ru3. The osmium substitution increased the unit cell constant to 12.899 * .001A, which is to be expected since the atomic volume of osmium is slightly larger than

Jan 1, 1969

By A. C. Boyle

PaGE I. Introduction.........68 II. Location of the District,....... • 70 .. III. Stratigraphy...........73 Description of the Rocks.......73 Triassic Eruptives (Andesite Flows and Tuffs) ....73 Triassic Sediments (Shales and Slates)..75 Areal Geology ............75 Structure...-.......76 Folds............. 76 Faults..........79 Shear ...........80 Intrusives..........81 Alaskite Dike.........81 Andesitic Intrusion.......82 IV. PetrogRaphy of thE Rock Types......83 Andesite Flows.........84 Tuff 8...........84 Andesite Tuff........84 Rhyolite Tuff.....-.......85 Alaskite-Porphyry.......89 Andesite Dike........91 V. Description of the Mines......92 VI. Metalliferous Deposits ........ 95 Character of the Ores...........97 Mineralogy of the Ores.......97 Metallic Minerals.......97 Microscopic Character of the Ores...98 Secondary Enrichment....... 103 Genesis of the Ores ...........104 VII. The Sulphate Deposits.......109 Gypsum ..... HO Anhydrite......... ,... 110 Barite............ 110 Origin. with special reference to Gypsum....111 VIII. Summary.............. 113 IX. BIblYogRaphY.............114

Jan 1, 1915

By Albert Sauveur

My first paper dealing with the theories of the hardening of steel by rapid cooling was published in the Transactions of this Institute in 1896— 30 years ago-under the title "The Microstructure of Steel and the Current Theories of Hardening," hence, also, the title of the present paper. It was extensively discussed and was, I believe, one of the starting points of many subsequent papers and discussions of the same subject, dis-cusssions which at times became almost violent and which led to the formation of different schools such as the "Carbonists" and the "Allo-tropists." Some of the older members of the Institute, who took part in the debate or who were interested observers, will, I am sure, have kept a vivid remembrance of it. The controversy gradually quieted down, apparently for lack of ammunition, without any side acknowledging defeat. Recently, however, interest in it ha been revived through the claims of some that these vexed questions had at last been solved. In an effort to ascertain if possible the prevailing view of those best qualified to express an opinion a questionnaire was submitted to the following gentlemen: J. 0. Arnold Sir Robert Hadfield Edgar C. Bain W. H. Hatfield Carl Benedicks Samuel L. Hoyt N. Belaiew Kotaro Honda H. M. Boylston Zay Jeffries Harry Brearley H. Le Chatelier G. K. Burgess H. H. Lester William Campbell Francis F. Lucas H. C. H. Carpenter John A. Mathews Pierre Chevenard A. McCance P. Dejean Albert Portevin C. A. Edwards Walter Rosenhain F. Giolliti Bradley Stoughton G. Grenet F. C. Thompson Leon Guillet

Jan 1, 1926

F. AT. FARMER*, New York (written discussion?)- The paper presents many phases of the welding art concerning which there are very divergent views. In many cases, the wide differences of opinion are based on the results of mechanical tests, but an examination of the mechanical test data discloses a wide variation in character of the tests made and in the details of procedure, so that it is frequently not only difficult to analyze and check the basis of the conclusions but impossible to correlate various groups of test results. It would seem, therefore, that the technique of testing welds is one of the phases of the welding art that should be studied and standardized in order that the results of mechanical tests made by different people may be strictly comparable and have the same significance to all. The vital difference between testing a specimen of steel that includes a welded joint and testing an ordinary specimen is the non-homogeneity of the weld specimen. The weld specimen has at its center a section composed of material that usually has physical, chemical, and metallurgical characteristics distinctly different from the adjoining metal. Furthermore, the section of added metal is more or less irregular and the ratio of added metal to original metal in the section is quite variable. Consequently the details of procedure and of recording data should be more minutely prescribed than in the testing of ordinary specimens. A conspicuous example f a mechanical test that requires standardization is the cold bending test, a standard test for mild steel. With the usual method, the specimen is bent around. a pin of prescribed diameter and, as all specifications usually require bending to 180° without fracture, the manner of applying the load is immaterial because the specimen is ultimately completely wrapped around the pin. But a specimen containing a welded joint at the center will usually not withstand bending to 180° because of the much lower ductility of the deposited metal in the weld. It is therefore obvious that the farther apart the points of support are the greater will be the angle attained before cracking occurs, simply because most of the bending will take place in the original metal. It is therefore highly desirable that there be prescribed a standard test that fixes exactly the distance between the supports, the curvature of the surface of supports, and the relation between this curvature, that of the loading surface, and the thickness of the specimen.

Jan 5, 1919

By S.H. Ash, P.S. Miller

Extensive and diversified resources justify large populations and great industries. To carry on the business of commerce and meet the demands of large populations, the utilization of tunnels in some form for transportation purposes constitutes an important link in modern civilization. The driving of tunnels has been appropriated by the tunneling branch of the heavy-construction industry, and the progressive steps taken by modern tunnel builders were not even dreamed of 50 years ago. Great strides have been made toward more rapid progress in tunneling in the United States during the past I0 years. Tunneling consists of a definite cycle of operations developed from ideas that are crystallized and translated into action programs through various engineering phases that begin with the first preliminary survey and do not end until the job is completed. Once the line of the bore is established and a time set for the completion of the work, the face must advance according to estimates prepared before the work commences. This schedule must be followed in regular sequence from the moment the drills start against a new face of rock until they are ready again to drill the Succdeding face, constituting a round. Mining is largely tunneling carried on under conditions often more inherently hazardous than actual tunnel construction, but for various reasons" tunne1ing is more hazardous than mining in any branch of the mineral industry. On the other hand, obstacles are sometimes encountered in heavy-construction tunneling projects that when met in mining enterprises do not offer comparable tasks to avoid or overcome them. One is the existence of water under high pressures. In mining enterprises, various alternatives offer a solution in driving a tunnel, even to the extent of its discontinuance or the abandonment of the mine, but a "construction" tunnel usually must go forward because some important project depends largely if not entirely upon it. This paper describes an unusual method of driving a water-supply tunnel through rock carrying water under pressures and conditions that did not permit the use of ordinary tunneling methods. The Delaware Aqueduct The new Delaware aqueduct is a Manhattan project of some magnitude; when regular it will contain what probably will be, for some time to come, the longest tunnel in the world. Various features in its construction are currently described in the trade journals of the construction industry, and informative engineering details are given in the Delaware Water Supply News, published twice a month by the Board of Water Supply of the City of New York. Work was begun on this project on March 24, 1937. The tunnel will convey water from reservoirs at the headwaters of the Delaware River to the City of New York.

Jan 1, 1943

By P. S. Miller, S. H. Ash

Extensive and diversified resources justify large populations and great industries. To carry on the business of commerce and meet the demands of large populations, the utilization of tunnels in some form for transportation purposes constitutes an important link in modern civilization. The driving of tunnels has been appropriated by the tunneling branch of the heavy-construction industry, and the progressive steps taken by modern tunnel builders were not even dreamed of 50 years ago. Great strides have been made toward more rapid progress in tunneling in the United States during the past I0 years. Tunneling consists of a definite cycle of operations developed from ideas that are crystallized and translated into action programs through various engineering phases that begin with the first preliminary survey and do not end until the job is completed. Once the line of the bore is established and a time set for the completion of the work, the face must advance according to estimates prepared before the work commences. This schedule must be followed in regular sequence from the moment the drills start against a new face of rock until they are ready again to drill the Succdeding face, constituting a round. Mining is largely tunneling carried on under conditions often more inherently hazardous than actual tunnel construction, but for various reasons" tunne1ing is more hazardous than mining in any branch of the mineral industry. On the other hand, obstacles are sometimes encountered in heavy-construction tunneling projects that when met in mining enterprises do not offer comparable tasks to avoid or overcome them. One is the existence of water under high pressures. In mining enterprises, various alternatives offer a solution in driving a tunnel, even to the extent of its discontinuance or the abandonment of the mine, but a "construction" tunnel usually must go forward because some important project depends largely if not entirely upon it. This paper describes an unusual method of driving a water-supply tunnel through rock carrying water under pressures and conditions that did not permit the use of ordinary tunneling methods. The Delaware Aqueduct The new Delaware aqueduct is a Manhattan project of some magnitude; when regular it will contain what probably will be, for some time to come, the longest tunnel in the world. Various features in its construction are currently described in the trade journals of the construction industry, and informative engineering details are given in the Delaware Water Supply News, published twice a month by the Board of Water Supply of the City of New York. Work was begun on this project on March 24, 1937. The tunnel will convey water from reservoirs at the headwaters of the Delaware River to the City of New York.

Jan 1, 1943

Dues: Arrears........................................... $ 4.878.18 Current........................................... 96.174.46 New Members..................................... 6.281.50 Dues for future periods received in advance........... 1.745.28 $109.079.42 Initiation Fees.................................................. 7,879.00 Magazine Receipts: Advertising Gross Receipts.......................... $39,247.77 Magazine Sales.................................... 3,820.04 43.067.81 Sale of Transactions Volumes 75 and 76............; .... $ 2,525.93 Sale of Transactions and Special Editions............... 7,586.00 Sale of Year Book.................................... 141.60 Sale of Authors' Reprints............................. 2,032.97 Sale of Pamphlets.................................... 1,346.29 Sale of Bindings...................................... 4,551.90 18,184.69 Interest Received: On Bank Balance and Temporary Investments......... $ 2,780.75 On Life Membership Fund.......................... 2,106.43 On James Douglas Library Fund..................... 5,399.45 On General Reserve Fund........................... 1,995.33 12.381.96 Miscellaneous Receipts........................................... 131.16 Total Receipts................................................ $190,624.04

Jan 1, 1929

By E. H. Rose

IN the realm of ore dressing the most pregnant feat of all time was announced in 1945: the winning of the mineral raw materials which made the harnessing of atomic energy possible. Lost in the stupendous implications of the end result, in the two billion dollar hugeness of the project, and in the famous names attached thereto, the fact that crude uranium ores had to be concentrated received relatively little notice in the press. Only the final link in the concentrating chain was publicized-ether extraction of uranyl nitrate, developed by Hoffman and carried on by the Mallinckrodt Chemical Works, or methods developed by the Ames group under Spedding. Some of the earlier links represented less glamorous but equally difficult and exacting research. One may only speak a word of admiration for those who worked hard, accomplished much, and said nothing. The universal lament for most of the year was "man shortage." A group of Canadian engineers expressed it as "being so short of labor that no labor was available to develop laborsaving devices." . Despite this, an outstanding amount of mineral-dressing progress was made in 1945. Necessity allowed no alternative. The insatiable demand of war for minerals forced the exploitation of lower and lower grade ores, and of others not before considered of commercial character or use, requiring the mineral dresser to fight for and win new bridgeheads on the home front.

Jan 1, 1946

By S. W. Ihle, L. J. Warren

A sample of garnet from the scheelite ore body on King Island, Tasmania, Australia, was upgraded and ground to produce an ultrafine portion suitable for micro-electrophoresis. X-ray and chemical analysis identified the garnet as andradite with some admixed grossular. At neutral pH the garnet particles were negatively charged, their zeta potential becoming rapidly more negative with increasing pH. An iso-electric point was found at pH 3.5. The effects on the zeta-potential of various electrolytes, hydrolyzable metal ions, and flotation collectors were also studied.

Jan 1, 1976

The Hurghada field is still the major producing field in Egypt. There was almost no activity in the Abu Durba field during 1936 and no new evidence is available. The following table summarizes the information on the Hurghada field for the year 1936. Hurghada Field Age of field to end of 1936, years.................... 23 Producing area for gas and oil, acres................. 1,050 Barbels Total oil production to end of 1936.................. 29,046,572 Total oil production during 1935.................... 1,212,182 Total oil production during 1936.................... 1,218,708 Daily average during November, 1936............... 3,249 MillionB CU. Ft. Total gas production (Aug. 1925 to end of 1936)...... 3,966 Total gas production during 1935................... 278 Total gas production during 1936................... 280 Maximum daily in 1936............................ 0.9 Number of producing wells completed to end of 1936... 94 Number of producing wells completed during 1936. ... 3 Number of wells abandoned during 1936............. 3 Producing wells at end of 1936...................... 768 Average depth of bottom of producing wells, ft....... 1,720 Average depth of top of producing horizon, ft......... 1,598 Character of oil, approx. average during 1936: Gravity at 60' F., 0.900; base mixed. Character of gas, approx. average during 1936: gallons gasoline per 1,000 CU. ft., 6.2. Producing rock (main): Nubian sands, Cretaceous; character, sand rock and sandy shales. 1 The figures given by the author were in tons. A conversion factor of 6.98. based on 0.900 sp. gr., was used to obtain the number of barrels.—Ed. 2 All pumping.

Jan 1, 1937

By W. C. Hagel, H. J. Beattie

Seven austenitic alloys of varions base compositions and minor-alloy additions were solution-treated, aged systematically between 1200oand 1800oF, and examined by X-ray and electron metallography. Intragranular preczpitations of µ, Laves, s, ?', Ni3Ti, and x phases were observed as a function of composition and aging time and temperatwre. Phase solubility limits were detevtnitzed within 100Fo intervals. These inter metallic compounds fall into two distinct general classes, and whichever class predomznates depends on base composition. It has become increasingly evident that multicom-ponent austenitic alloys are well characterized by their precipitation processes. Since certain groups of elements act as one, the relationships among these processes are reasonably simple; complete identification of such processes is usually attainable by a systematic aging study with a combination of techniques centered on microscopy and diffraction. Several nickel- and cobalt-base alloys illustrating cellular precipitation and its interaction with general precipitation were reported previously.1 The group of alloys covered in the present paper demonstrates precipitation-hardening reactions involving two distinct classes of intermetallic compounds where the predominating class appears to depend on base composition. This dependency ties in with a crystal-chemistry regularity first observed some twenty years ago by Laves and Wallbaum but never amplified to our knowledge. Results of electron-microscope and X-ray diffraction studies on systematically aged hot-rolled alloys known commercially as S-816, S-590, Rene-41, Incoloy-901, M-308, and M-647 are reported here. Some of these alloys have previously undergone minor-phase analyses by other investiators. Alloy S-816 was investigated by Rosenbaum, Lane and Grant,3 and Weeton and Signorelli.4 Rosenbaum found only CbC in hot-rolled bars. Lane and Grant found CbC and a small amount of M6C in the cast structure and stated that both carbides form during aging, most of the precipitation being CbC. Weeton and Signorelli found CbC, M23C6 and a weak indication of a phase after a slow step-down cooling cycle from 2250°F. Rosenbaum also investigated hot-rolled samples of S-590 and identified CbC and M6C. Preliminary information on Rene-41, gained partly from the present work, was reported by Morris.5 Long-time precipitation phenomena in Incoloy-901 at 1350°Fwere investigated by Clark and Iwanski.B heir raw data re- semble those of our present heat with 0.1 pct B, while their interpretation of these data resembles our interpretation of data from another heat with only 0.001 pct B; they made no statement as to boron content. No previous minor-phase studies of alloys M-308 or M-647 have been reported. EXPERIMENTAL METHODS Table I gives alloy compositions in both weight and atomic percent. Specimens were solution-treated from 1700º to 2200ºF, aged at logarithmic-time intervals up to 1000 hours between 1200 and 1800 F, and examined in accordance with procedures previously described in detail. ' ' Phase extractions were carried out in electrolytic cells containing 800 ml of either 7 pct HC1 in denatured ethanol or 20 pct H3PO4 in water. After electrolysis for 48 hr at 0.1 to 0.2 amp per sq inch, residues were separated by filtration or centrifuging. X-ray powder patterns of residues were recorded on a diffractometer for accuracy and on film for sensitivity. Lattice parameters were calculated by least-squares analyses of indexed sin 8 values, and relative abundances were estimated from intensities of strongest lines of each phase. These phase abundances denote relative amounts with respect to each other rather than to the alloy. Mechanically polished specimens were etched in a freshly mixed solution of 92 pct HC1, 5 pct H2SO4, and 3 pct HNO3. Parlodion replicas for the electron microscope were chromium-shadowed in high vacuum at a glancing angle of 20deg. All electron micrographs are reproduced here with the shadowing source above. The correspondence betweenelectronmicrostructures and phases identified by X-rays was established by a high redundancy of correlation between relative amounts at different stages of aging and examination above and below critical transformation or solubility temperatures. EXPERIMENTAL RESULTS S-816 and S-590—The phases found in S-816 and S-590 after various aging and solutioning treatments are listed in Table 11. These data and the observed

Jan 1, 1962

By Charles Fulton

This paper describes experiments carried on at the Case School of Applied Science, together with their results. Their success led to the design of the larger furnace herein described, but which has not been built. A PREVIOUS article' by the authors contained a general description of the new roasting furnace herein described but it did not go into detail as to the metallurgical behavior or the results obtained. Believing that such information would be of great value, they have elaborated on the subject and have given many unpublished details. The furnace described applies the principle of roasting finely divided zinc-sulfide ores, now produced in large quantity by the flotation process, in gaseous suspension; that is, the ore particles are carried, in suspension, in a current of air and gaseous products of the roast. The relatively great fineness of flotation concentrate presents difficulties and problems of roasting in furnaces of the ordinary type; the fine ore is forwarded through the furnace in the form of a shallow bed and its very fineness leads to dense impervious bedding which prevents oxygen from reaching the interior of the bed, thus unduly lengthening the time of roasting and preventing the elimination of the last of the sulfur. The fineness of the concentrate, normally, should lead to a rapid and complete roast, for the speed of roasting is a function of the surface exposed to oxygen, which surface is greatest, per unit of weight, in very fine material. The difficulty in bed roasting is to get the oxygen to the particle. If the fine ore, during the roasting, could be freely suspended in oxidizing gases, full advantage could be taken of the great surface conferred by its fineness. This fundamental idea, of course, is not new, for the Stedtefelt furnace, familiar to the older metallurgists, is an example of it; but the manner in which this is accomplished may be new.

Jan 10, 1924

By Charles F. Park

Mining in the Pacific Coastal Region has passed through three stages of development. First came the gold rush days, a period when gold and silver were the objects of intensive search. Second was the development of the high-grade base-metal deposits and of the smaller and more refractory precious metal deposits. And third was the modern period that covers the discovery and development of the rarer metals, of large low-grade deposits, and of the industrial and nonmetallic minerals. Brief discussions of the salient geologic features of the region and of a few of the better known mineral deposits are given. The regional geology is favorable for continued exploration and discovery of new deposits and districts.

Jan 1, 1968

Discussion of the paper of BOYD DUDLEY, JR., presented at the New York meeting, February, 1915, and printed in Bulletin No. 96, December, 1914, pp. 2767 to 2782. H. 0. HOFMAN, Boston, Mass.-At the close of the paper Mr. Dudley said that his experiments in the laboratory had shown that it was possible to separate nickel from copper by means of a chloridizing roasting, but that in order to demonstrate a process of this kind, work upon a large scale would have to be carried out. I think it was in 1913, that experiments of this kind were carried out at the works of the Pennsylvania Salt Manufacturing Co., Philadelphia, in a Wedge furnace, and at Sault Ste. Marie in a Sjöstedt furnace. They showed a satisfactory separation of nickel and copper. The ore was first subjected to an oxidizing roast, then mixed with pyrite and salt, and given a chloridizing roast. A. H. Carpenter published in the Engineering and Mining Journal, vol. xcvii, p. 1085 (1914) the details of this work. The conclusion arrived at is, that if you subject sulphide ore to an oxidizing roast, finishing at the temperature at which all nickel sulphate is dissociated, i.e., 764° C., then mix it with pyrite and salt, and subject the mixture to a chloridizing roast between 600° and 700° C., you can chloridize a high percentage of the copper without chloridizing any of the nickel, and obtain thereby a satisfactory means of separating the two.

Jan 5, 1915

By George A. Miller

ALTHOUGH the Andean mountain belt, which contains almost all the metal deposits of the other South American nations, does not enter Brazil, this country is rich in mineral resources, for in area it accounts for half the continent and geologically it contains almost all of the Brazilian Shield. This great mass of ancient rocks has been relatively stable for a long time and forms a great area of plateaus and highlands interrupted only by the syncline which carries the Amazon River across it to the sea. Lowland Brazil - the great flood plains of the Amazon. Tocantins, Paraguay, and Parana Rivers-is of no interest to the miner, and in fact supports but a small proportion of the country's population. The highland area is divided into unequal parts by the Amazon River; the north half is underlain by the north lobe of the Brazilian Shield which extends into Venezuela as far as the Orinoco, and into the Guianas, and is known as the Guiana Highlands. Mineralization appears to have been weak in the Brazilian portion of these hills. In fact most of the ore deposits are to be found in the States of Minas Gerais and Bahia, although the neighboring states of Sao Paulo, Pernambuco, and Piauhy can also boast of some deposits. Goias and Matto Grosso are as yet incompletely prospected but are considered to contain reserves for the future.

Jan 1, 1945

By T. S. Lovering

The Moffat tunnel passes through the continental divide about 50 miles west of Denver, Colo., on the Denver & Salt Lake R. R.: It is 16 ft. wide, 24 ft. high, and 32,383 ft. long, a distance of a little more than 6 miles. The advantages accruing from its construction may be briefly summarized as follows: The tunnel eliminates 27 miles of grade averaging more than 3.5 per cent. and actually running well over 4 per cent. in many places, and changes the steepest grade from 4.5 to 2 per cent. It reduced the peak of the railroad from 11,660 to 9249 ft. which enables one engine to pull four times as much freight as it could before the tunnel was built. If the Denver & Salt Lake R. R. completes its line, this road will shorten the distance between Denver and Salt Lake City by 200 miles and will have no steeper grades than the lines now connecting the two cities. The proposal to drive the tunnel through the divide dates back about 25 years and D. H. Moffat, who was the leading spirit in the organization of the Denver & Salt Lake R. R. spent much of his time and energy in efforts to raise money for the tunnel that bears his name. He was unsuccessful and died before the work was started. In 1920 an effort was made to obtain state legislation favoring a bond issue to finance three important railroad tunnels in Colorado but the measure was defeated, largely through the efforts of the citizens of the region near Pueblo. A few years later devastating floods caused the Pueblo voters to seek relief from the state and at this time they withdrew their objection to the tunnel bond issue. As a result, a $6,720,000 bond was issued to finance the Moffat tunnel. Construction bids were so high that the work was finally allotted on a scheme analogous to a cost-plus basis. The contract was awarded to Hitchcock and Tinckler, who are paid a fee of $140,000 for driving the tunnel. All bills are paid by the Moffat Tunnel Commission. The contract was let Sept. 19, 1923, and Hitchcock and Tinckler agreed to complete the work by July 19, 1927. In the event of finishing before this date they were to be given a bonus of $1000 a day and

Jan 1, 1928

By Cyril Smith

SOMEWHAT over ten years ago the author described studies1,2 on the constitution of the copper-silicon system. The copper-rich portion of this diagram is shown in Fig. 1. The experimental points freely dotted about the diagram seemed to justify an otherwise unconvincing diagram and for several years the curious reverse bend in the alpha-phase bound-ary was accepted as substantially correct, even by later investigators3,4 of the system who introduced changes in the high-silicon phases. The binary diagram has been used as a base for several ternary systems" without any suggested changes. Voce10 suspected the existence of another phase from his study of the cast alloys in the copper-manganese¬silicon system, but evidently hesitated to extrapolate this to the binary diagram, particularly in view of the too ingenious explanation that was advanced" to account for the pools of constituent clearly visible in castings; namely, that they were secondary alpha of twinned orientation deposited from beta. Von Schwarz,12 in 1932, called attention to the fact that this micro-constituent in copper-silicon alloy castings was anisotropic under polar-ized light and asserted that a new phase, not cubic, should be placed in the diagram adjacent to alpha. Sautner,13 on the basis of investigations with the polarizing microscope and with X-rays, introduced this phase into the diagram at about 6 per cent Si. The relevant part of his dia-gram is shown in Fig. 2. Sautner called the new phase beta, renaming the old beta phase zeta. To avoid confusion, in redrawing Fig. 2 the phases have been renamed in accordance with the terminology adopted in the present paper, in which the new phase is called kappa and the other phases retain the designation given them by Arrhenius and Westgren.4

Jan 1, 1939

By A. E. Nehrenberg

THE mechanism by which austenite forms in steels has received a great deal of attention in the literature in past years.'-'* Our present knowledge concerning this mechanism has been recently summarized quite concisely by Bain and Vilella,1 while a few years ago the literature was carefully reviewed by Roberts and Mehl.² The consensus is that any ferrite-carbide interface is a potential site for the nucleation of austenite during heating above the Acl temperature, and that the new austenite generally grows freely to produce approximately equiaxed grains, whether the carbides are initially present in the lamellar or the spheroidal form. In the case of eutectoid steels, growth of the new grains of austenite continues until contact is established with other grains. Then growth stops and an initial austenite grain size is established which does not change until the heating is continued to some high temperature at which grain coarsening begins. In the case of pearlitic steels which are not of eutectoid composition, the proeutectoid ferrite or carbide may interfere with the growth of the austenite if the temperature is not above that designated the A63 or the Acm, respectively. Although a large amount of work has been done to establish the mechanism of austenite formation in steels, it became clear to the present author while he was studying the transformation characteristics of a new 0.25 C Mn-Si-Ni-Mo hypoeutectoid steel" that the manner in which austenite grows in steels depends upon some factor, or factors, not previously considered. This was indicated by the fact that when this steel in the spheroidized condition was heated above the Ae1 temperature the new austenite which was formed did not envelop the carbides and grow in an equiaxed manner as described by Bain³ or spheroidized steels. Instead, in this steel, the austenite was observed to grow much more readily in certain directions than in others with the result that at temperatures within the Ac1-Ac³ ransformation range the austenite grains were acicular in shape. The excess ferrite was also found to be acicular with the distribution of these phases being such that a lamellar pattern was developed. This unusual directional growth of austenite in this new steel initially in the spheroidized condition is illustrated by fig. 1. A search of the literature revealed that this type of growth was not necessarily peculiar to this steel for similar microstructures had been observed by other investigators.4-8 However, the full significance of these microstructures does not appear to have been appreciated, and no work has been done to determine the conditions responsible for this directional growth of austenite or to arrive at an understanding of it. It was for this purpose that the work described in the present paper was carried out. Material: During the course of this investigation a total of 15 steels was studied. They consisted of hypoeutectoid, eutectoid and hypereutectoid carbon steels, and hypoeutectoid and hypereutectoid alloy steels, all of which were obtained in the annealed condition from commercial warehouse stock. As received, the carbon and alloy hypereutectoid steels had microstructures which consisted of spheroidal carbides in ferrite, whereas the eutectoid steel and the hypoeutectoid steels were pearlitic. The grades of steel represented were 1050, 1080, 10110, 3310, 4140, 4340, 4615, 6145, 8620, 9260, 9442,

Jan 1, 1951

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) The following members registered at Institute headquarters during the month of April: J. C. Ralston, Spokane, Wash. E. P. Ross, Johnson City, Tenn. C. H. James, London, Eng. F. L. Garrison, Philadelphia, Pa. E. H. Benjamin, Oakland, Cal. A. Radcliffe, Copiapo, Chile. W. H. Shockley, Palo Alto, Cal. S. S. Wyer, Columbus, Ohio. A. C. Mauney, Salisbury, N. C. W. B. Kunhardt, Reading, Pa. A. W. Newberry, Los Angeles, Cal. W. E. Saunders, Philadelphia, Pa.

Jan 5, 1913