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By C. E. Coleman, D. Hardie, A. E. Wraith

A photoguaplric method of measuring crack velocities has been applied to an examilzation of- the effect of hydrogen on the impact properties of zirconium. Results indicate that the crack in hydrided zirconit travels at about 26 m per sec whereas that in the uacuum -annealed is dependent on the speed of the hammer. RECENT work on the effect of hydrogen on zirconium reveals that when hydrided zirconium is tested in slow bending the crack producing failure can be unstable. The mode of fracture seems to involve the crack linking up broken hydrides by a ductile mechanism in the zirconium matrix.2" In order to compare the fracture of zirconium with that of other metals which show unstable crack propagation, notably steel, the rate of the crack spread must be known. As the methods previously used for measuring crack growth are either unsuitable for the present work5-'' or very costly," a simple technique has been devised in which the maximum crack velocity is derived from a series of crack position-time measurements. EXPERIMENTAL PROCEDURE The experimental arrangement is shown schematically in Fig. 1. The flash unit12 was triggered when the Charpy hammer touched the specimen and the 6-psec flash of the lamp delayed by a preselected time interval in the range 100psec to 10 msec. The camera was left on open shutter during the test. From direct measurement on a calibrated photographic print, Fig. 2, the position of the crack and the specimen was found at a known time after impact and, from a series of such tests using an appropriate range of flash-delay times, the crack velocity was estimated. Preliminary experiments were carried out on mild steel above and below its transition temperature. Vacuum-annealed zirconium, and zirconium hydrided to 100 ppm H were then tested at 20" and 150°C. For comparison, Zr-2.6 pct Nb alloy (in the 0 + transformed /3 condition), vacuum-annealed or hydrided to 100 ppm H, was tested at 20 C. The chemical analyses of these materials are given in Table I. For the high-temperature tests a fine chromel-alumel thermocouple was spot-welded onto each specimen close to the notch. The test piece was heated up to 200°C to allow enough time for preparing the apparatus while the specimen cooled to the testing tem- perature. It was assumed that the specimen cooled uniformly. The accuracy of the flash-delay time was better than i2 pct i 5 psec. The crack length was taken as its maximum distance traveled normal to the length axis of the specimen. Errors in these measurements arise as a result of the uncertainty in the location of the crack tip and the difficulty in defining the exact position of the crack starting point. The latter was due to the bonding and large amounts of deformation at the hammer contact point, especially in the vacuum-annealed specimens tested at 150°C. The maximum error in the measurements was however estimated to be about 5 pct. DISCUSSION OF RESULTS From the trial experiments using mild steel above its transition temperature it can be seen from the plot of crack length against time after impact, Fig. 3. that a reasonable estimate of the maximum crack velocity at the surface of the specimen may be made. Other features of note are the initiation time before the crack is first seen and the slowing down period

Jan 1, 1967

By L. W. Sink, B. H. Kear, S. M. Copley, M. F. Hornbecker

IT is well known that under appropriate conditions of chill casting, many metals and alloys develop a columnar grain structure having a high degree of preferred orientation.' In cubic materials, this principle has been employed to produce shaped castings with a unidirectional cube oriented columnar grain structure as well as shaped single crystals with a cube axis parallel to the growth ais.' "he purpose of this note is to describe how this same principle can be enlployed to produce wires, rods, or more complex crystal Shapes with a variety of conlpositions in cube or random orientations by a single casting operation. The procedure for directional solidification of in Fig. 2. Examination under crossed polarizers indicated that the striations were a second phase (presumably the B19 phase) which frequently forms initially at primary grain boundaries and then grows toward the interior as thin ribbons. X-ray studies on filings of this alloy reannealed at 1300°C for 15 min indicated a strong pattern of the fcc phase together with a substantial pattern of the B19 phase. The un-annealed filings, however, showed only the pattern of a cold-worked, fcc structure. In these two-phase alloys it appears, therefore, that the B19 phase is transformed into a disordered fcc structure by cold-working. The mechanical properties of these alloys would be of some interest since a fcc structure might be expected to possess greater ductility than the or-thorhombic B19 structure from which it forms. The author wishes to thank Mr. Harvey Yakowitz and Mr. Richard Manuszewski for obtaining the photomicrograph in Fig. 2. This research was partially supported by Research Grant DE-02455 from the National Institute of Dental Research. columnar grained ingots involves pouring a melt into a preheated mold having a water-cooled copper chill at its base? and controlling the temperature gradient in the mold so as to maintain columnar grain growth from end to end of the ingot.4 This is illustrated schematically in Fig. l(a). It should be noted that the longitudinal temperature gradient promoting unidirectional columnar grain growth is maintained by heat loss primarily through the solidifying ingot to the chill, so that both the temperature gradient and the growth rate diminish with increasing distance from the chill. As the distance from the chill increases? the columnar structure coarsens, and the perfection in preferred orientation tends to increase progressively. Using this same procedure of gradient solidification, Fig. l(b) shows a simple scheme for producing a batch of crystals having the same cube orientation rather than an assemblage of columnar grains. Wires and rods are produced by cementing ceramic tubes to the wall of the mold. The steep temperature gradient produced in the central chamber is controlled by the mold heater to produce favorable conditions for crystal growth. Clearly the success of the operation lies in the selection of individual growing columnar grains by some kind of orifice at the base of each channel in the mold. Using simple constrictions, experience with nickel-base alloys has shown that 4 -in.-diam holes at a distance of -1 in. from the chill yield crystals within 7 deg of (100); closer control of orientation is possible by placing the crystal selector farther away from the chill.

Jan 1, 1970

By W. E. Showalter

This paper discusses some of the results of combstion-drive tests which were made in a test cell using a sand bed 10 in. in diameter x 10-ft long. The test method is illustrated and described. The relationship between the API gravity of the in situ oil and the amount of air required for combustion drive is discussed in detail. Other things constant, the air requirement for combustion drive increases as the APl gravity of the in situ oil decreases. If the test results apply to actual reservoirs, the lowest-priced oils may cost the most to recover by this method. Information is shown which indicates that the effect of pressure on the amount of hydrocarbon burned is not large. A method of predicting air requirements from the API gravity of the in situ oil is presented. INTRODUCTION Combustion drive is the term used to identify the process of interstitial or in situ burning as an oil recovery method. Part of the in situ oil is burned to generate the energy needed to produce the remainder of the oil. Combustion drive as an oil recovery mechanism remains an economic uncertainty in spite of all the work that has been done by the industry in both laboratory and field?-6 This paper will show some of the results of tests which were made in a test cell for the purpose of studying the nature of the combustion-drive process. It will present data which indicate that the API gravity of the in situ oil is a significant indicator of the amount of air required to drive a burning front through oil sand. Air requirement varies inversely as the API gravity of the in situ oil. EXPERIMENTAL The tests were performed in a cell which utilized a cylindrical sand section 10 in. in diameter x 10-ft long. The thin-walled metal pipe which held the sand was wound with twenty external electrical resistance heaters which, by means of an automatic controller, maintained adjacent sections of the wall of the pipe at temperatures equal to the temperatures of the contained sand. Each heater covered 6 linear in. of the pipe. By this means lateral heat loss from the sand section was minimized, thereby causing the sand section to simulate more closely a horizontal increment of a combustion-drive reservoir. Fig. 1 shows a schematic diagram of the test assembly. Thermocouples to measure the temperature in the sand were located every 6 in. along the length of the sand section. The pipe containing the sand was enclosed in a cell designed for an operating pressure of 500 psig. The inlet air pressure was controlled at the inlet, and the gas flow rate was controlled and measured at the outlet of the cell. The oil sand used for the tests was prepared by mixing first water and then oil with the noncon-solidated sand using a closed mixer similar to a cement mixer. Table 1 shows a screen analysis of the sand. Ninety percent of the sand was 100 mesh or finer. This sand was a mixture of 80 per cent No. 120 Nevada White Sand and 20 per cent Tennessee Hi-Fusion Moulding Sand No. 3. The Nevada sand was a clean silica sand. The Tennessee sand con-

By J. R. Long, E. T. Hayes, D. C. Root, R. S. Dean

THE U. S. Bureau of Mines has recently reported on the development of a process for preparing pure ductile titanium in substantial quantities' and on the physical properties that may be attained in the metal, when consolidated by powder metallurgy methods and fabricated by certain hot and cold-working procedures.2 The high physical properties (Table I), combined with excellent corrosion resistance and light weight, will lead no doubt to appropriate applications of the metal. In any application, methods of joining will be of considerable importance. The relatively high activity of the metal toward the common gases raises the question of weldability and conditions that might be required for successful welding. Since hydrogen, oxygen, and nitrogen embrittle the metal, it should be protected from these gases at elevated temperatures. This was demonstrated by a few preliminary trials of arc, gas, and resistance welding. In these trials only the resistance method proved to be immediately applicable. While atomic hydrogen welding of titanium may be successful in some instances, a considerable amount of development work will be required to prove its worth. In addition, it would be suited only to small assemblies that could be heated subsequently in a high vacuum to remove embrittling hydrogen. Heli-arc methods likewise would be limited to small assemblies, which could be completely protected by a helium atmosphere. It was quite apparent that titanium required more protection than was afforded by the normal flow of helium gas used for welding magnesium and aluminum. The hot metal is attacked by oxygen and nitrogen, and the rapid diffusion of the oxide into the metal prevents the formation of a protective coating and requires the helium atmosphere to be maintained until the weld has cooled nearly to room temperature. The preliminary work indicated that titanium could be successfully spot-welded without deterioration of the metal and that the microstructures of the welds were normal, exhibiting good bonding, and no oxidation. The high resistivity of titanium (53 microhms per cu. cm.) suggested that it would behave somewhat like stainless steel and allow considerable latitude in the several welding variables. The results reported here are intended to give a general picture of the effects of varying welding current, welding time, and tip pressure on single spot welds made on several different thicknesses of titanium sheet. The work was undertaken to demonstrate the feasibility of welding titanium rather than as an exhaustive study of spot welding. There are, therefore, a number of factors that will require further investigation to establish the specific controls required for actual applications.

Jan 1, 1946

By P. Eadington

I feel sure that the apparent anomolies between his findings and ours arise as a result of the different experimental methods used. The modem oxygen electrode method he used is sensitive to nano moles of oxygen uptake whereas the method we used was only sensitive to micro moles at best. Furthermore, our experimental method did not permit measurements to be made in the first ten to fifteen minutes of reaction, the very time he is observing. Direct comparison of his data to ours is made difficult because of not knowing the specific area of the samples he used. However, we found that precipitation of PbS using sodium sulphide gave rise to samples of area approximately 30 m2 g - 1. Noticing the rapid decline in oxidation rate over ten minutes, as reported in Table 1, one can conclude that we could not measure the rate after ten minutes using our method. Taking the above area I estimate that at these rates only a small fraction of surface would be oxidised in a period of hours. I can only conclude that at some point a change in oxidation mechanisms occurs giving rise to a much faster rate such as we observed. Finally, I would like to comment on the apparent inertness of the homogeneously precipitated lead sulphide sample 11. This method of preparation we found to give specific areas of 20 to 30 times less than other methods and this would account for the very low oxidation rate.

Jan 1, 1982

By Van Manning

IN SUBSTANCE, the international aspects of the petroleum industry, as these relate to the United States, are as follows: The domestic production is not keeping pace with the domestic demands; our best engineering talent warns us of the imminence of a decreased production by our oil wells, although more oil is needed; and the only practical source whence this increasing demand can be supplied for some time to come will be the foreign fields. Other nations have given thought to the future and, in recent years, have shown a tendency to adopt strong nationalistic policies regarding their petroleum resources, policies that hinder or prevent the exploitation of these resources by other nationals. In consequence, we find that, facing a probable shortage of the domestic supply, our nationals are excluded from foreign fields; and this in spite of the fact that foreign nationals have been permitted to enter into and exploit, our own oil resources on an equality with American citizens and without hindrance or restrictions. This country: has supplied the larger part of the petroleum consumed by the world and yet, with a failing supply imminent, it finds that those countries that have been drawing upon our resources to supply their needs are showing a tendency to exclude us from their resources. In this way we shall be transferred from a position of dominence to one of dependence; and only by sufferance of those countries that are now seeking financial or political control of petroleum supplies, shall we be able to obtain the oil we will need.

Jan 2, 1920

By Howard N. Eavenson

WHEN the A.I.M.E. was formed 75 years ago the bituminous coal industry was in its swaddling clothes, although it had been operating for more than a century and coal was being mined in every state now producing it, and its output had long passed that of anthracite. In 18/1, the value of bituminous coal was about seventy per cent of the value of all metals produced and more than one fifth of the value of all products of mines, both metallic and nonmetallic.[1a] While many of the operating mines then shipped by rail, most of the development was along waterways, although the canal era of transportation was nearly at its end. Coal mining is a heavy industry and one of the best measures of its progress is its output throughout the period. Fig. 1 shows this graphically from 1800 to 1945. From 1870 to 1910, the production-which is very nearly the consumption-almost doubled every decade, a most amazing growth. In 1918, in World War I, a peak was reached and a decline began, which ended in 1932. A gradual recovery then started, interrupted in 1938 but culminating in the record output of 1944, when, owing to World War II, a tonnage of 619,576,000 was produced. It is evident that the forces leading to the continuous increase ending in 1918 have spent themselves and that only unusual conditions will require so large a production again. The postwar conditions of World War II will probably

Jan 1, 1947

By Edward Keller

About a dozen years ago the art of bessemerizing copper- * matte, brought to these shores from France, was first established at the smelter, in Butte, Montana, of the Parrot Silver and Copper Company, which had bought the process from Mr. Manhks, the inventor. Through the efforts of Mr. J. E. Gaylord, general manager, and Mr. A. J. Schumacher, snperintendent,, assisted by an able staff, the new method rapidly underwent, at the Parrot establishment, an evolution towards higher perfedion, and within a few years its success and its advantages were so marked that all the great works in the west followed in the footsteps of this pioneer. The converter-process has now practically superseded the reverberatory-process in this country. The latter will undoubtedly, in a not very distant future, be relegated to metallurgical history. The writer has availed himself of what was perhaps the last chance to make comparisons of the two methods, working practically on the same material on an extensive scale, the reverberatory process being that of the Baltimore Copper Smelting and Rolling Company,* while the converter-process is that of the Anaconda Copper Company—both using the matte from the latter company's works in Anaconda, Montana. For the greater portion of the material considered in this paper, the writer is indebted to the two companies. In order to understand the difference of behavior of the several elements, and the difference of the copper produced in the two processes, it is best to study and follow those elements

Jan 1, 1899

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, discusssions which at times became almost violent and which led to the formation of different schools such as the "Carbonists" and the "Allotropists." 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 has 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 2, 1926

By Frank S. Shuri

INTRODUCTION The Calumet Pumping Station, located on the south side of the Greater Chicago area, is part of the Tunnel and Reservoir Plan to accomodate the city's wastewater. The Station consists of two parallel rock caverns, each 18 m high, 20 m wide, and 62 m long, located in Silurian dolomite approximately 91 m below the ground surface. The caverns are oriented N-S with a 24-m-wide pillar between them. Prior to construction, rock mechanics studies were conducted in an L-shaped test adit at the location of the west cavern. The purpo3e of the rock mechanic studies was to characterize the site, particularly the in situ stress field and deformation characteristics of the rock. This information, together with other physical properties of the rock and geologic data, was used to evaluate the stability of the preliminary cavern design, with particular emphasis on cavern orientation, rock reinforcement, and pillar stability. GEOLOGY OF THE SITE Stratigraphy The Chicago area is located on the Kankakee Arch, a broad, gently sloping arch of Paleozoic sediments. Rocks in the project area consist of Silurian dolomites unconformably overlain by Pleistocene glacial deposits. The formations of interest to this study are: - Racine Formation, inter-reef facies. This dolomite is gray- brown, silty, and compact. It contains occasional prominent bedding surfaces. The Racine Formation in the project area varies from 73 to 74 m in thickness.

Jan 1, 1984

By William G. Gates

INTRODUCTION The Heath Steele mine is located in the Bathurst-Newcastle area of northern New Brunswick. It is jointly owned by American Metal Climax, Inc. and the International Nickel Company of Canada who hold a 75% and 25% interest, respectively. The ore deposits of lead, zinc and copper sulphide occur in very fine grained pyrite and/or pyrrhotite masses. A consistent spatial relationship with a quartz feldspar porphyry is characteristic of these deposits and the many other similar sulphide deposits in the district. The two principal mineral assemblages of pyrite-sphalerite-galena, and pyrrhotite-chalcopyrite-pyrite, occupy characteristic positions relative to the enclosing rocks. This feature and the nature of the sulphide mineralization are described and the variations in metal content are noted .with special emphasis on the lead-zinc ore zones. The mine product ion rate is 3,000 tons per day of a mixed lead- zinc and copper ore which is extracted from the B-1 zone. The complex nature of the ores presents many metallurgical problems. Optimum metal recoveries are achieved when milll feed grades are relatively consistent and proportions of the contained metals are with in acceptable limits. Ore outlines and stoping blocks are delimited by close spaced diamond drilling. From this information it is possible to forecast the grade of any portion of a stoping block. Production from the various stopes may then be scheduled so as to achieve an acceptable mill feed grade.

Jan 1, 1970

By A. T. Miesch

The purpose of this paper is to explore relations between the distribution and composition of uranium deposits on the Colorado Plateau and mineralogic, chemical, and lithologic aspects of their host rocks. The paper also appraises the host-rock sandstones as possible sources of elements in the uranium deposits. Other possible sources of elements are not discussed. Uranium deposits on the Colorado Plateau consist largely of sandstone and small amounts of mud-stone impregnated with uranium and vanadium miner- als and a suite of minor accessory minerals containing copper, lead, zinc, silver, iron, cobalt, nickel, yttrium, molybdenum, selenium, and arsenic, in addition to other elements locally. The deposits consist of clusters of closely spaced ore bodies which commonly aggregate several thousand tons, but range in size from less than one ton to several million tons. With only rare exception, the deposits show no close relation to fractures. The ore bodies are generally tabular in layers nearly parallel to the bedding in the host rocks, or they cross bedding at large angles to form roll structures. Absence of fracture control necessitates that the ore and associated elements were transported to the deposits by way of interstitial pore spaces in the sandstones. This points to the general process of lateral secretion as a possible mechanism of ore formation, and suggests the host-rock sandstones as a possible source of the metals. Roll structures in the ore

Jan 1, 1962

It is claimed that the first mining of copper by Americans in Arizona was done at Ajo, near the Mexican border, in 1854,* a year after this region had been added to the United States, under the terms of the Gadsden purchase. A group of adventurers, organized at Los Angeles under the name of the Arizona Mining & Trading Company, came, to the district. This party of prospectors consisted of 20 men, led by Major B. Allen, J. D. Wilson, and William Blanding. † They went first to Yuma, where the party divided, some of them going southward into Mexico while the remainder took the trail to Tinaja Alta, where they heard of the copper deposits of Ajo, which is 85 miles southeast from Yuma.‡ They found attractive outcrops of copper ore, and set to work energetically, but their operations suffered many interruptions, because that part of the country was still controlled by the Mexicans, who were uncertain about the exact position of the new international boundary. The Mexicans tried to expel them, but they held their ground. The first shipment of ore, consisting of native copper and cuprite, came from what is now the western end of of the New Cornelia workings; it was hauled in ox-carts to San Diego, 400 miles across the desert. § Later shipments were hauled to Yuma and floated on barges down the Colorado river to the Gulf of California, whence the ore was loaded on

Jan 1, 1932

By J. V. N. Dorr

THE Elko Prince mine is in the Gold Circle district, Nevada, about ½ miles(2. 4km.) from the town of Midas, 55 miles (88.5 km.) west of Battle Mountain and 50 miles (8.5 km.) northeast of Golconda. The district is described by Emmons in U. S. Geological Survey Bulletin 408, 1910. Little was said of the Elko Prince, however, as only a small amount of work had then been completed. The geological structure of the region is simple. The oldest exposed formation, covering most of the area, is rhyolite, which has a light-colored devitrified groundmass enclosing phenocrysts of feldspar, quartz, and magnetite. It has been somewhat weathered and partially stained with oxide of iron. There are several outcrops of andesite which cut the rhyolite. The ore deposits occur as fissure veins, replacement veins, and sheeted zones. The Elko Prince vein is of the first type. The rhyolite near the veins is silicified, stained with oxide of iron, and, at some localities, replaced by ore, or is so permeated by metals as to be classed as ore. The vein filling consists chiefly of quartz, and the values consist entirely of gold and silver. Part of the gold exists as the native metal and part is associated with pyrite. Silver occurs free and its argentite in handed streaks through the vein. These veins trend in a northwesterly direction, with dips varying from 65° to vertical.

Jan 8, 1918

By A. R. Kaufman, P. Gordon

THE large-scale manufacture and use of uranium in conjunction with the atomic energy development during the war led to a need for knowing the equilibrium diagrams of uranium with various other metals. The alloys of uranium with aluminum and with iron were among the first that were studied for this purpose. Much of the work was done in the manner of a survey since it was necessary to determine the important features of the phase diagrams rather than to obtain completely detailed results. For this reason no attempt was made to locate exactly such features as liquidus lines, solid solubility limits and compound and eutectic compositions. It is believed, however, that there are no great inaccuracies in the diagrams reported here and that no important points were overlooked. Earlier work on alloys of uranium with aluminum and iron is almost nonexistent and in each case is considered to have been of little value by M. Hansen. It is interesting to note, however, that the compound UAl3 was first reported in 1902 by L. Guillet. Experimental Procedure Materials: The uranium used for making most of the aluminum alloys was obtained from material prepared by Metal Hydrides, Inc., and melted in vacuum at M.I.T. Because of the lack of an adequate supply of metal, it was necessary to use material from several different batches and hence it is impossible to state an exact analysis. However, a few results indicated about 0.01 to 0.03 pct iron and probably about 0.03 to 0.05 pct carbon. Toward the end of the work a small amount of metal was obtained from Brown University and from Iowa State College and this was used in determining the transformations in pure metal and in some dilute alloys. All of the aluminum used in this investigation came from a supply of high purity metal (greater than 99.9 pct aluminum) which was obtained through the courtesy of Dr. Mehl of the Carnegie Institute of Technology. The uranium used for making the alloys with iron was produced by the bomb reduction process which has been described by J. Chipman.² This metal, after vacuum melting, contained about 99.9 pct uranium by weight with carbon and iron as the chief impurities. Electrolytic iron containing about 0.012 pct carbon, 0.020 pct nickel and 0.009 pct copper was used in making the melts. Melting Equipment: The melting of the alloys went through a stage of development which culminated in the use of beryllia or beryllia-lined crucibles and in the use of high frequency heating in either vacuum or in an atmosphere of argon. It was found that uranium at a few hundred degrees above its melting point would pick up aluminum and to a lesser extent silicon from an alundum thimble while aluminum above 1000°C would extract silicon from the impure alundum. No reaction of either metal with beryllia was noted at temperatures as high as 1800°C. The distillation of aluminum from the aluminum-rich alloys was quite troublesome at temperatures above about 1300°C and was only partially avoided by the use of argon instead of vacuum. Melting in resistance furnaces,

Jan 1, 1951

By Frank Firmstone

When in charge of the Glen don Iron Works, the importance of good methods of filling was forcibly brought to my attention, and it occurred to me that the first step toward the discovery of the best plans was the accumulation of exact information as to the distribution actually effected by various chargers; also, that something could be done in this direction by careful measurements in the furnace, to be afterwards recorded for comparison on drawings. The figures shown herewith have been prepared from such measurements, and nearly all of them refer to Glendon, where the fuel used was anthracite and the ore-mixture about threequarters of New Jersey magnetic ores and one-quarter of brown-ores from the vicinity of the works. Every occasion furnished by the blowing-in of furnaces was utilized, but the data accumulated rather slowly in this way; and, opportunity oEering to make special trials at no great expense, the figures from 2 to 7 were thus obtained. The trials were made by dumping a hopperful (6 barrows) of material at once into the furnace, and, when all the fuel of a round (12 barrows) had been put in, the profile of the upper surface was obtained by stretching a steel tape across the top on a diameter and at a known height. By measuring down from this with a graduated rod, the profile was easily obtained with sufficient accuracy, especial pains being taken to get correctly the crests of the ridges and the bottoms of the hollows, as many intermediate points being included as seemed necessary. This was repeated on another diameter when there was occasion. The same course was followed for the limestone and ore.

Jan 1, 1899

By C. M. Sellars, F. Maak

Electvomotie -force measurements hazle been made on ten Au-Ni alloys at temperatures 7754 825O, 900O, and 935°C using galvanic cells with solid electrolyte. Partial and ivtegral thermodynamic functions are derived from the determined activities. which show la9,ge positive deviations jvom Raoult's law. The enthalpies of mixing- are in close accord with calorinletric data and are of comparable accuracy. The results are used to determine the miscibility gap and the spinoidal curL1e, and are qlalitaticely interpreted in terms of the large size difference and electvonic interactions between gold and nickel. Tabulated nalues of the actielities and partial and inteqal free energies, entropies , and enthalpies of mixing are given in the appendix. The Au-Ni binary alloys are of particular interest thermodynamically as despite the large size difference between gold and nickel atoms they have a simple phase diagram.' This shows complete solid solubility above a miscibility gap with a maximum at about 71 at. pct Ni and 810°C. Activity measurements (over a range of temperature) have been made previously on this system using an electrolytic-cell method with a liquid chloride eletrolyte. The accuracy of this data has, however, been queried3'4 as it leads to values for the enthalpy of mixing which are too high when compared with calorimetric measurements.46 Also, the entropy of mixing is too high when compared with the values derived from specific-heat measrements. It was therefore considered worthwhile redetermining the activity data using a galvanic cell with a solid electrolyte (0.85 ZrO, 0.15 CaO). This method is based on a technique introduced by Kiukkola and aner'' and has been used to determine the thermodynamic data for Cu-Ni alloys.' THE ELECTROLYTIC CELL The cell used to determine the activity of nickel in Au-Ni alloys was: The cell reaction, which is discussed for a similar cell by Rapp and Maak, gives a direct measurement of the activity of nickel in the alloys as where aNi(alloy) is the activity of nickel in the alloy, 3 is Faraday's constant, E is the measured electromotive force, R is the gas constant, and T is absolute temperature. For the valid application of this type of cell the arrangement must be ther modynamic ally stable, which means that: 1) The free energies of formation of the oxides fulfill the relation 2) The vapor pressures or dissociation pressures of each component must be so small that during the time of the experiment the amount of any material transported by the gas is negligible. 3) Side reactions which change the alloy composition must be negligible. These reactions are possible both with the surrounding gas atmosphere and with neighboring solid material. The first two conditions are fulfilled by the above cell.' The third condition is approached by care in the experimental technique. The factors which control the attainment of equilibrium in this type of cell have been considered by Rapp and aak, who conclude that metallic diffusion in the alloy is the rate-control ling step. A lower temperature limit for the practical application of this cell is therefore set by the condition that equilibrium must be attained in reasonable times. EXPERIMENTAL MATERIALS AND TECHNIQUE The starting materials were mint gold (99.99 pct Au) and Mond nickel (99.9 pct Ni). Alloys, nominally 5 at. pct Ni and then each 10 at. pct across the system, were produced by vacuum-levitation melting compacts of mixed drillings of the pure metals. The nickel used for the reference tablets in the cells was melted in a similar manner. The alloy ingots, cast in boron nitride molds, were cold-forged and

Jan 1, 1967

By J. H. Swisher

The rate of internal sulfidation of austenitic Fe-Ti alloys in H2S-H2 gas mixtures is controlled primarily by sulfur diffusion, with counterdiffusion of titanium playing a minor role. At temperatures below 1100°C, enhanced diffusion along grain boundaries becomes important. The rate of internal sulfidation at 1300°C is approximately equal to the rate computed from the sulfur diffusion coefficient. The diffusion coefficient of titanium in y iron has been determined from electron microprobe traces in the base alloy near the subscale interface. The solubility of sulfur in Fe-Ti alloys has been measured in the temperature range from 1150° to 1300°C. The equilibrium sulfur content is found to increase with titanium content, due to the large effect of titanium on the activity coefficient of sulfur. The Ti-S interaction becomes stronger as the temperature decreases. TITANIUM as an alloying element in stainless steels is an effective scavenger for interstitial impurities, carbon in particular. Titanium is known to form stable sulfides; however extensive thermodynamic data on the Ti-S system are not available. Schindlerova and Buzek1 have shown that the Ti-S interaction in liquid iron is moderately strong. There have been no previous studies of the Ti-S interaction in solid iron. Internal sulfidation of Fe-Mn alloys was the subject of a recent investigation by Herrnstein.2 He found the rate of internal sulfidation to be an order of magnitude greater than predicted from available solubility and diffusivity data. A satisfactory explanation for the discrepancy could not be given. In the present study, the solubility of sulfur in austenitic Fe-Ti alloys was measured using a standard gas equilibration technique. Fe-Ti alloy specimens were also internally sulfidized. The rate of internal sulfidation was measured as a function of temperature and alloy composition. Supplementary electron micro-probe measurements were made to provide additional information on the nature of the internal sulfidation process. EXPERIMENTAL The starting materials were alloys containing 0.12, 0.24, 0.38, and 0.54 wt pct Ti. The alloys were made in an induction furnace by adding titanium to electrolytic iron that previously had been vacuum-carbon-deoxidized. The major impurity in the alloys as determined by chemical analysis was carbon. The carbon content of the alloys averaged about 100 ppm; metallic impurities were presented in concentrations of 50 ppm or less. Specimens were made in the form of flat plates, 0.03 by 2 by 4 cm for the equilibrium measurements and 0.5 by 1.5 by 3 cm for the rate measurements. The experiments were performed in a vertical resistance furnace wound with molybdenum wire and containing a recrystallized alumina reaction tube. In the gas train, flow rates of the reacting gases were measured using capillary flow meters. The source of H2S was a mixture of approximately 2 pct H2S in H2, which was obtained in cylinders from the Matheson Co. A chemical analysis was provided with each cylinder. The H2-H2S mixture was diluted with additional hydrogen to obtain the desired ratio of H2S to H2, and the resulting mixture was diluted with 30 pct Ar to minimize thermal segregation of H2S in the furnace. Argon was purified by passage over copper chips at 350°C and subsequently over anhydrone. Hydrogen was purified by passage over platinized asbestos at 450°C and then over anhydrone. The H2-H2S mixture was purified by passage over platinized asbestos and then over Pas. The samples used in the solubility measurements were analyzed for sulfur by combustion and iodometric titration. The subscale thickness in the internally sulfidized samples was measured on a polished cross section, using a microscope with a micrometer stage. Electron microprobe traces for titanium in solution were made on several samples that had been internally sulfidized. A Cambridge microanalyzer was used, and the known titanium content at the center of the specimen was used as a calibration standard. The procedure for the microprobe measurements will be described further when the results are presented. RESULTS AND DISCUSSION Equilibrium Data. Fig. 1 shows the sulfur concentration as a function of gas composition for three alloys equilibrated at 1300°C. The dashed line is based on data published by Turkdogan, Ignatowicz, and pearson3 for pure iron. The breaks in the curves are the saturation points for the alloys. The fact that the initial slope decreases with increasing titanium content indicates that titanium interacts strongly with sulfur in solution. To obtain information on the composition of the precipitating sulfide phase, the measurements described in Fig. 1 were extended to higher sulfur partial pressures. These results are shown in Fig. 2. (The initial portions of the curves are reproduced from Fig. 1.) The highest PH2s /pH2 ratio used is believed to be below the ratio required for the formation of a liquid sulfide phase. Time series experiments were used to study the approach to equilibrium in the samples. It was found that equilibrium with the gas phase was reached in less than 4 hr at 1300°C.

Jan 1, 1969

By C. W. Davis, R. S. Dean

The purification of iron ores by means of hand magnets dates back more than 100 years. The first record in the United States Patent Office of a machine for the magnetic separation of ores shows that on Feb. 20, 1849, U.S. Patent 6121 was issued to Ransom Cook for improvement in electromagnetic ore separators. The patent covered the use of a revolving cylinder, or drum, with poles of electromagnets in its periphery for the purpose of separating magnetic oxide of iron from substances with which it might be associated, by causing the electrornagnets when revolving as component parts of the cylinder to be successively charged to take up the ore and discharged to part with it. Since this patent was issued the science and technique of magnetism have advanced more than most other fields of endeavor. The development of electrical machinery has required and obtained better and better magnetic materials, and the science of applied magnetism is as completely and satisfactorily developed as any branch of physics. Nevertheless, the patent of Ransom Cook, issued in 1849, comes close to covering everything that is now being applied in magnetic separation. The cynic may conclude that this proves the uselessness of modern science and may point in confirmation to flotation, which has grown in a few years, practically without benefit of science, to be the most versatile and useful of concentration methods. On more careful study, however, it appears that an accurate determination of the magnetic properties of minerals and their amenability to control by mechanical and heat treatments has not heretofore been made. The first essential, therefore, in the design of improved magnetic separators has been missing. In spite of this hiatus in scientific data inventors have been busy, and patents are on file covering mineral separations by means of nearly all known magneto-mechanical effects. Because of a lack of knowledge of mineral properties, most of these inventions never worked well enough to find commercial use. The Metallurgical Division

Jan 1, 1935

By E. C. Rudolphy, M. E. Potter, J. R. Mitchell

The effects of 0.006 to 0.20 pet Sn ml the hot workability and the annealed mechanical properties were investigated for Types 302, 410, and 430 stainless steel. The hot workability of these steels was not significantly affected by their tin content within the range studied, although some effects on mechanical properties were noted. Apart from the effect of tin, optimum hot-working temperatures and V-notch Charpy impact transition temperatures for these grades were determined. HIGH tin residuals in some heats of stainless steel have been blamed for the poor hot workability, particularly during secondary mill rolling. However, very little quantitative information has been available. Previous work1"6 with carbon steels indicates that tin increases tensile strength and hardness but de- creases tensile and impact ductility. Halley,7 in reviewing the sources and effects of residual elements in carbon and alloy steels, concluded that much of the surface checking (hot shortness) encountered in rolling was caused by copper, and that tin, arsenic, and antimony combined with copper to form low-melting constituents which further increase the steel's sensitivity to hot shortness. These elements had little effect in the absence of copper. A more recent paper by Langenberg and Johnson8 concluded that tin reduces hot workability but that researchers disagree concerning the amounts which will cause trouble. They state that laboratory investigations with small ingots seem to indicate a higher tolerable level of tin than do statistical studies of mill data, and also that statistical analysis of mill data indicate that small amounts of residual tin are detrimental to the surface quality of stainless sheet. The accumulative increase in the general level of tin and other tramp elements in steelmaking materials will present greater problems to steelmakers in the future. The purpose of the present study was to obtain quantitative information on the specific effects of tin on the hot workability and mechanical properties of such common stainless steels as Types 302, 410, and 430.

Jan 1, 1962