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By John P. Goheen

Considerable work has been done in developing a pyrometer to measure the temperature of molten brasses, bronzes, and aluminum in the crucible. On account of the high melting points and the amount of zinc and sulfurous fumes given off from molten brasses, the conditions are somewhat severe for a thermocouple of standard design; but satisfactory results are obtained with a portable pyrometer, 3 ft. (0.9 m.) of connecting lead wire, and a special 5-ft. nickel-nickel chromium thermocouple, composed of rods 1/4in. (6.35 mm.) in diameter. The lower 12 or 24 in., as desired, may be made detachable so that new tips may be connected at little trouble or expense. The portable instrument need not be of the extreme high-resistance type, as the movable parts of the galvanometer of a lower resistance instrument may be better constxucted to withstand the continuous handling such an instrument receives. Platinum-platinum rhodium thermocouples, protected with porcelain and graphite tubes, have been used, but the lag in registering the temperature is too great. It has been found that the range of temperature for various brasses is as follows: Red brasses...............2200-2250" F. (1205-1234" C.) Yellow brasses............2250-2400" F. (1234-1318' C.) Bronzes..................2300-2550" F. (1260-1400" C.) A recent test with a portable pyrometer having a range of 2600" F. with a bare 1/4 in. heavy exposed couple 5 it. long and a handle attached at the upper end showed that the temperatures of molten aluminum under varying conditions in an oil-fired crucible furnace and one of the Simplex type were as follows: CRUCIBLE, OIL-FIRED FURNACE SIMPLEX FURNACE Temperature of metal in furnace....... 1540" F. (837" C.) 1530" F. (834" C.) Temperature in ladle after skimming at furnace......................... 1480" F. (805" C.) 1440" F. (784" C.) Temperature in ladle after skimming at floor near mold................... 1440" F. (784" C.) 1430' F. (778" C.)

Jan 1, 1923

0PINION was general that this year's meeting of the Institute of Metals Division was one of the best in its history. In addition to its full and exceptionally fine program of professional papers, there were several other features of general interest-an in-spiring annual lecture by Dr. Cecil H. Desch which appears in abstract elsewhere in this issue, Mr. Sing-master's talk on the zinc industry at the annual dinner, and the presentation of the James Douglas Medal to one of the members of the Division, Dr. Zay Jeffries. Four technical sessions of the Division were held, dealing respectively with zinc, copper, aluminum, and general metallography, and in addition there was a joint session with the Non-ferrous Metallurgical Committee of the Institute. All of the papers presented were at-tended with much interest and followed by considerable discussion. The papers on plastic deformation of zinc by Messrs. Mathewson and Phillips, Romig, and Hoyt were of particular interest and awakened an extended discus-sion. They well illustrated the progress which is being -made today in the understanding of the mechanism of flow of metals, and the ingenuity of the authors in their crystallographic method of attack of this difficult problem was quite generally admired. A very old subject was treated in a modern way by Messrs. Corson and Bain in two papers on the harden-ing of copper and copper alloys. There has always existed a myth that the ancient Egyptians were masters of an art not possessed by ourselves; viz., that of hard-ening copper. This myth must have been quite defi-nitely dispelled in the minds of all those who listened to this admirable paper. Mr. Corson has applied the modern art of precipitation hardening to this old prob-lem with substantial success, employing small amounts of chromium, nickel, silicon, and cobalt for this purpose. The commercial application of these very important .developments of Mr. Corson is being actively investi-gated at the present time.

Jan 3, 1927

By Frederick Crabtree

WHEN Professor Stock asked for a paper on the above subject, it was too late to prepare by June 1, or near that time, one that would involve any appreciable amount of experimental work or original research; but the suggestion was made that a review of the literature bearing on the subject might be submitted in good time, and that later this could be supplemented by any experimental data obtained during the summer, if experiments were carried out. In accordance with this suggestion, there are submitted the following notes on references found in the literature of recent years bearing on sulfur in gas. It is to be, understood that, ill general, these notes express the opinions of the authors whose papers are abstracted, not necessarily the opinions of the abstractors. Very little published information was found bearing directly on producer-gas sulfur, so this has been supplemented, in certain phases of the subject, by references to illuminating gas. Methods of analysis and processes for the elimination of sulfur from the gas are, without much doubt, very closely related in these two products. As in illuminating gas, sulfur is found in producer gas mainly as hydrogen sulfide, mixed with a much smaller and variable quantity of carbon bisulfide.1 The presence of minute quantities of other organic-sulfur compounds has been intimated, but no definite statement is made concerning these. The amount of sulfur present in producer gas is variable and depends on several conditions. The primary factor is the quantity of sulfur in the fuel, but the form in which the sulfur exists, the temperature of the producer, the air-steam ratio, and the efficiency of the scrubbing process are all determining factors. When the coal used contains less than 0.5 per cent. of sulfur, the sulfur in the gas will not exceed the quantity found in the average illuminating gas.2 Sulfur in producer gas may safely

Jan 9, 1919

By John P. Goheen

Considerable work has been done in developing a pyrometer to measure the temperature of molten brasses, bronzes, and aluminum in the crucible. On account of the high melting points and the amount of zinc and sulfurous fumes given off from molten brasses, the conditions are somewhat severe for a thermocouple of standard design; but satisfactory results are obtained with a portable pyrometer, 3 ft. (0.9 m.) of connecting lead wire, and a special 5-ft. nickel-nickel chromium thermocouple, composed of rods 1/4in. (6.35 mm.) in diameter. The lower 12 or 24 in., as desired, may be made detachable so that new tips may be connected at little trouble or expense. The portable instrument need not be of the extreme high-resistance type, as the movable parts of the galvanometer of a lower resistance instrument may be better constxucted to withstand the continuous handling such an instrument receives. Platinum-platinum rhodium thermocouples, protected with porcelain and graphite tubes, have been used, but the lag in registering the temperature is too great. It has been found that the range of temperature for various brasses is as follows: Red brasses...............2200-2250" F. (1205-1234" C.) Yellow brasses............2250-2400" F. (1234-1318' C.) Bronzes..................2300-2550" F. (1260-1400" C.) A recent test with a portable pyrometer having a range of 2600" F. with a bare 1/4 in. heavy exposed couple 5 it. long and a handle attached at the upper end showed that the temperatures of molten aluminum under varying conditions in an oil-fired crucible furnace and one of the Simplex type were as follows: CRUCIBLE, OIL-FIRED FURNACE SIMPLEX FURNACE Temperature of metal in furnace....... 1540" F. (837" C.) 1530" F. (834" C.) Temperature in ladle after skimming at furnace......................... 1480" F. (805" C.) 1440" F. (784" C.) Temperature in ladle after skimming at floor near mold................... 1440" F. (784" C.) 1430' F. (778" C.)

Jan 1, 1923

By Paul D. Merica

One of the most useful, and at the same time least commonly used, methods of thermal analysis for the determination of transformations in metals and alloys consists in the recording of the time intervals required for successive increments of temperature change during heating or cooling, the temperature of the furnace containing the specimen being altered at a uniform rate. The curve obtained by plotting these time intervals as a function of the mean temperature of the specimen durnig the interval is called the inverse-rate curve. It is probably due to the fact that no simple and convenient method has apparently been available for the measurement of the successive time intervals that this method has not been so generally used as, for example, the differential method, for which several types of automatic or semi-automatic apparatus have been designed. Whenever this method has been used, the intervals have usually been measured with the use of a chronograph; its operation as practised at the Bureau of Standards1 is as follows: The temperature of the specimen is measured by a thermocouple and a dial potentiometer. The operator sets the potentiometer at successive values of the electromotive force differing by equal increments, usually 0.02 millivolt, and records the exact instant on the chronograph, by pressing a contact key, at which the galvanometer coil passes through its null position. Two-second intervals are also recorded on the chronograph record, and the number of seconds elapsing between successive signals is afterward counted from the record and plotted as a function of the electromotive force or of the temperature. This is an admirable method and by it most minute thermal arrests may be detected, but it requires a good chronograph, which is generally difficult to obtain, and the time of one operator during the recording and, subsequently, to read the intervals from the record; the latter operation often takes from one to two hours. There is here suggested a simple, convenient, and, it is believed, equally accurate method of recording the successive time intervals, by which the

Jan 1, 1921

By H. Biloni

A metallographic study of solute segregation produced during controlled solidification of Sn-Pb alloys has previously been reported.' It was found that the growth conditions which produced well-developed cellular substructures led to severe segregation, and even at solute concentrations of 0.2 wt pct Pb regions of a lead-rich phase were formed at the junctions of cell boundaries (nodes). Similar sample preparation and etching techniques have now been applied to several tin alloys at more dilute concentrations. The crystals were solidified uni-directionally under less-severe growth conditions so that the predominant interface structure was composed of two-dimensional cells.* Binary alloys with lead, using 9.999 pct Sn as a solvent, and ternary alloys with lead and bismuth or lead and antimony, using zone-refined tin as a solvent, were examined. The liquid was decanted from the growing crystals in all cases to reveal the interface structure and ensure that two-dimensional cells were being formed. However, since interference may arise from a liquid layer that clings to the interface during decanting,3 an examination of the segregation pattern was always made behind the interface. In all cases, the structure within the bulk of a crystal at greater than 1 cm behind the decanted interface was substantially the same as that nearer the interface. Representative photomicrographs of the dilute Sn-Pb alloy are shown in Figs. 1, 2, and 3. Most observations are similar to those of the previous investigation. For example, the solute concentration at the cell walls is higher than in the intercellular regions; where cell boundaries meet, the segregation is enhanced; the macromosaic or stria-tion substructure and grain boundaries show enhanced segregation; there is also a depletion of solute at cell walls near a striation boundary, as Spittle et a1.4 have observed at decanted interfaces. Not all these observations can be seen in the photos shown since attention has been focused on a special feature; as evident in the photomicrographs, cer-

Jan 1, 1965

By R. L. Frink

I FEAR that my treatment of this subject may not, in all instances, meet the approval of those who read my opinion as to the utility and efficiency of pyrometers in the making of glass, or bottle-glass. It may be superfluous for me to add that this opening statement is based on over 15 years' experience in an endeavor to successfully apply pyrometers, or heat-measuring instruments, to glass-melting furnaces, particularly the type known as tank-furnaces, and that such endeavors have proved more or less futile. It is my desire, therefore, to herein set forth the problems encountered, hoping thereby to stimulate further effort in the successful application of pyrometers. It is my desire, also, to invite criticism of the methods used and suggestions from those who may have a wider experience, or who may have better methods. Fin. 1.-GLASS TANK FURNACE. In general, I believe that the inefficient application of pyrometry to the melting of glass in tank furnaces is not due as much to the instruments as to the conditions under which they must be used and the character of the medium in which they must reside. Most of those present no doubt, are familiar, at least in a general way, with the methods and apparatus used in the melting and making of bottle-glass, or glass that is formed into containers of various shapes and designs. Most of this glass is made in what is known as a tank furnace, these furnaces vary widely in design and construction. In general, they consist of a rectangular tank-like form, built up of fireclay blocks, and range from 2 by 4 ft. (0.6 by 1.2 m.) to 24 by 140 ft. (7.3 by 42.6 m.) with a depth of glass from 2 to 5 ft.; or a capacity of from approximately. 2 to 700 tons. Fig. 1 shows the general

Jan 9, 1919

By H. C. Kenny

The annealing or softening temperature of cold-worked copper is appreciably increased by almost unbelievably small amounts of silver. As indicated by some data in this paper, the softening temperature of high-conductivity, tough-pitch copper may be increased from 200" to 350" C. by the addition of only 15 oz. per ton (0.052 per cent) of that element. Because it has this higher annealing temperature as compared with the silver-free metal, silver-bearing copper finds considerable use in industry. For example, when hard-rolled copper is used in operations that involve soldering or tinning, silver-bearing copper insures against loss of strength, whereas silver-free copper becomes "dead soft." Yet—though several investigators, beginning with Caesar and Gernerl in 1916, have shown that small amounts of silver do definitely raise the softening temperature of copper—data are lacking on the problem: What is the specific influence of different amounts of silver on this temperature? It was to help in filling this gap in the knowledge of what might be termed "alloy coppers" that the data given herein were obtained. The softening of cold-worked copper depends, of course, on a number of factors, of which the composition of the material is only one. Other highly important factors are the degree to which the material is cold-worked and the time it is held at the annealing temperature. The method of cold working and the grain size of the metal produced are also significant. All these variables were taken into account in the investigation reported here, and the influence of silver on the electrical conductivity and on the working was also considered. The coppers used in the softening tests were Lake coppers melted and cast by the Calumet and Hecla Consolidated Copper Co. The ires were fabricated by the Roebling Wire Co. and the sheets were rolled at the Battelle Memorial Institute. Partial analyses of some of the coppers are listed in Table 1, with their electrical conductivities.

Jan 1, 1934

By I. R. Kramer

A study was made of the effect of surface-active agents an copper, gold, and zinc single crystals as well as polycrystalline aluminum. The study on coppw showed that the maximum effect of the surface -active agent occurred at the same concentration of the solution as that at which the rate of solution of the copper soap was the greatest. Surface -active agents did not affect the creep behavior of gold or freshly polished zinc specimens. The creel-, rate of zinc specimens in a solution containing a surface-active agent zoas always lower than that of freshly polished specimens. In previous papers1'2 it was reported that the surface played an important role in the plastic deformation of metals. By removing the surface layers of a crystal of aluminum by electrolytic polishing dur- ing tensile deformation, it was found that the slopes of Stages I, 11, and In were decreased and the extent of Stages I and I1 were increased when the rate of metal removal was increased. The results of the investigation of surface-active agents showed that changes in the slopes and extents of Stages I and II occurred when single crystals of aluminum were deformed in tension in a bath containing solutions of paraffin oil and stearic acid. The amount of change was a function of the concentration of stearic acid and the maximum effect occurred at a concentration of 0.002 mole per liter. These results were interpreted2 in terms of the rate of solution of metal soaps which form as a result of the chemical reaction between the surface-active agent and the metal. According to this interpretation, the "weakening" effect is controlled by the rate of solution of the soaps which depends upon the concentration of surface-active agents. At low concentrations, the number of metal soap molecules formed is low; at high concentrations, the rate of solubility is low, because of the high degree of saturation.

Jan 1, 1963

By Sir Robert Hadfield

(New York Meeting, February, 1913.) THE Hadfield method of producing sound steel ingots has been the subject of a paper 1 read before the Iron and Steel Institute, so that it will be unnecessary to describe it fully here. The object of the method is to make possible the production of steel ingots in which the pipe is almost entirely obliterated, and it is applicable particularly to the production of sound ingots, from which good rails could be rolled. The method in brief consists in casting the ingots on cars, usually with the small end down. Each ingot mold is provided with a sand top, rammed up in the well-known manner. After the mold is filled to the desired height with steel, a layer of slag about 0.5 in. thick is placed upon it and the balance of the mold is then filled with charcoal. Then, through suitable piping, an air blast is directed in numerous jets upon the charcoal, which is burned thereby, the combustion supplying additional beat to the top of the ingot, which helps to keep the top fluid and to retard its solidification, while the lower parts are rapidly losing heat by its transfer to the mold. By-one plan the ingots are cast in molds placed upon bogies, movable trucks, or platforms, in the position A, Fig. 1. The ingots are cast vertically on bogies, say four or more ingots on each bogie, as may be found most convenient, and the upper surface of the steel is maintained in a molted condition during the transit of the ingots from the casting pit to the stripper. This is effected by a series of air pipes, for example, three in number, with jets or holes on the under surface of such pipes, placed preferably horizontally, arranged in such a manner as to cause jets of air to impinge on the upper surface of the ingots. These holes or jets are made throughout the entire length of the overhead pipes, the length of such pipes being

Jan 4, 1913

By W. M. Hirthe, E. H. Greener, D. R. McCann

It has been proposed1'2 that, at low temperatures, point defects are a strengthening factor in inter-metallic compounds whereas, at high temperatures, the deformation is diffusion-controlled and, therefore, an increase in the concentration of point defects tends to soften or increase the plasticity of a compound. More recent investigations, including those of Bloem and Kroger' on PbS, Kramers and smith4 on TiO, and Nadeau5 on LiF, have extended this concept to ionic crystals. Rutile (TiO2) is a tetragonal transition metal oxide which has a defect structure over at least the compositional range. The defect in near-stoichiometric rutile is either an oxygen ion vacancys or a titanium ion interstitial.' This investigation does not contribute to resolving the defect question but either defect would satisfy the results obtained. Six specimens having the same orientation, see Fig., 1, utilized in an independent investigation1' were cut with a diamond saw from a single-crystal boule purchased from the Linde Co. Three specimens were annealed in air at 1200°C for 4 hr and slowly cooled to room temperature in a period of 12 hr. The remaining specimens were reduced in a vacuum of l0 mm Hg at 1200°C for 4 hr and cooled at the same rate in vacuum. The reduced specimens were weighed before and after reduction and, assuming the weight loss to be oxygen, the corresponding oxygen-to-metal ratio is 1.998. All specimens were chemically polished and etched utilizing the techniques described by Hirthe, Adsit, and Brittain." The specimens were embedded in acrylic resin and mounted on a leveling vise in a Kentron micro-hardness tester. A 200-g load was applied to a Knoop indenter with a descent time of 18 sec and a dwell time of 20 sec. Eight indentations were made on a near (171) surface, approximately 3 deg from the (lii) plane, for each orientation of the major axis of the indenter relative to the crystal structure. The dependence of microhardness on orienta-

Jan 1, 1963

By T. F. Bower, M. C. Flemings

The classical explanation for formation of the fine equiaxed "chill zone " in ingot solidification is that local supercooling near the chill wall causes copious nucleation in this region. This work indicates, however, that convection is an essential element in formation of the chill zone. In the absence of convection, no chill zone forms even though rate of. heat extraction is extremely vapid. Alloy studied was Al-l.5 pct Cu alloy solidified against a copper chill wall. When solidification was initiated at the chill wall in absence of. cor-vection, surface grain size was large (>I cm diam). When it was initiated in the presence of convection, it was fine (<0.05 cm diam). It is concluded that some form of "crystal multiplication" plays an important role in formation of the chill zone. INGOT macrostructures are generally classed as containing one or more of the three zones: "chill zone", "columnar zone", and central "equiaxed zone". These three zones are sketched in Fig. 1; their origin has been discussed in some detail.&apos;-&apos; The classical explanation for formation of the chill zone is that supercooling occurs in the region of liquid metal adjacent the mold wall, and copious nu-cleation then takes place in this region forming numerous small crystals. The columnar region then results by growth of favorably oriented grains (den-drites) which crowd out their less favorably oriented neighbors."5 The mechanism of the columnar-equiaxed transition has been the subject of considerable interest. The generally accepted mechanism, until recently, was that constitutional supercooling developed in front of the growing columnar grains with eventual nucleation of new, equiaxed, grains ahead of the growing solid front.&apos; Recently, it became evident this explanation was not completely satisfactory and it is now evident that "crystal multiplication" plays an important role. This crystal multiplication occurs by separation of dendrite arms from growing dendrites,8?"&apos; and has been shown to be strongly influenced by convection.6, 10-13 Reduced convection results, for a given alloy, in longer columnar zone, larger columnar grains, and larger equiaxed grains.7, 12

Jan 1, 1968

By M. J. Pool, J. R. Guadagno

THE relative partial molar heats of solution in liquid tin have been determined for phosphorous, arsenic, and antimony at 750°K. This work was carried out as part of an over-all program to determine the heats of formation of the III-V semiconducting compounds. A differential twin-type liquid tin solution calorimeter was used in the investigation. All three elements are endothermic upon solution in tin. The relative partial molar heats of solution go through a minimum value at arsenic. No concentration dependence of the heat of solution was found in the dilute (0 to 2 at. pct solute) solution range investigated. The measured heat effects and the calculated relative partial molar heats of solution at infinite dilution are listed in Table I along with the relative heat contents of the solutes calculated from the data of kelley.1 All of the values are referred to 750°K even though the calorimeter temperature fluctuated by *1°K during the course of the experiments. In this range of temperature change no variations were found which were outside the experimental error. This would be expected since the partial molar heat of solution is in general a very insensitive function of temperature. The limits of error given in Table I represent the standard deviation from the mean. The reported error estimates only apply to the estimated precision of the data and not the accuracy. Systematic errors could be present which would affect the absolute values given. This is especially true in the case of phosphorous and arsenic where vaporization could occur. If this were true, the experimental values reported here would be too high and the true partial molar heat of solution would be less than that given in Table I. Moreover, the heat-content data could be in error and this would also affect the calculated values. The relative partial molar heat of solution of phosphorous at infinite dilution in liquid tin is given in Table I. This value is based on eight drops at

Jan 1, 1965

By R. W. Heins, N. Street

Recently Hiller1 reported results on the impairment of the strength of quartz glass rods through wetting, indicating that there was general agreement with the prediction of the Griffith formula in that for the liquids used the rods were weakest in water i.e. the liquid which probably had the greatest free energy of immersion. The Griffith equation predicts that the tensile stress necessary to propagate a crack of length c is where ? is the interfacial free energy, E Young&apos;s modulus. Since for a solid immersed in a liquid of surface tension ?L and contact angle 8 at the solid-liquid-gas contact, ?s - ?SL = ?L cos ? where ?s is the surface free energy of the solid. Hence comparison between ?L cos 0 and strength impairment should be possible. In a study of the usefulness of the Kuznetsov pendulum2 as a means of studying rock drillability we have determined the effects of various liquids on the pendulum hardness of Bavarian limestone. The pendulum used had diamond points (Burgess Vibro-graver), a period of 1.14 sec and a total on sample weight of 1191 g. The decline of the pendulum oscillations was recorded by a light beam on light sensitive paper carried on a kymograph. Rehbinder&apos;s expression relating hardness to amplitude attenuation as a function of time can be written In A = - (1/H) t + In Ao where A, A, = amplitude at time t and initial amplitude respectively, H = hardness parameter, and t = time. The line of best fit to the experimental points was determined using the IBM 7090 electronic computer, the computer also gave A, by extrapolation to zero time. The results for the various liquids tested are given in Table I and Fig. 1. The limestone surfaces were highly polished before testing and each reported hardness value represents the average of at least ten separate determinations of the pendulum decline curve. On each newly prepared surface the water value was again determined (also

Jan 1, 1964

Lewis, B. LINDEMUTH, ?New York, N. Y.-I would like to confirm Dr. Howe&apos;s supposition that a process could be worked out for steel along similar lines. About 1 ½ years ago, F. D. Carney and myself were working on the elimination of columnar crystals which are particularly evident in nickel steel. We discussed rotation and varying speeds of rotation, but figured that with just rotation the steel would eventually catch-up to the motion of the mold and that the desired effect could not be obtained in that way, so we decided to alternate the direction of rotation. We rigged up in ordinary commercial turntable and on the same mounting attached a blast, furnace and mud gun, which is a simple steam cylinder, and mounted an 18-in. ingot mold on the turntable. The turntable had a stroke of about 10° to 12°, with stops at the ends. The steam cylinder would bang the table against the stops so that the stopping was so violent that it would tend to keep the metal in motion when the mold stopped and thus wash away any crystals that would form. We made quite a few interesting experiments; the results of which were that the columnar crystallization was entirely eliminated. At the same time we cast ingots in a similar mold, allowing the molds to remain stationary; these showed columnar crystals of from 2 to 4 in. in depth. The grain structure of the balance of the ingots, which were rotated, was very much finer than the grain structure of the ingots that were cast and allowed to cool slowly. The experiments were made on a 0.35 per cent. carbon nickel steel, which is probably more susceptible to columnar crystallization than any other. I think that the rolling properties and the forging properties of some alloy steels could be very much improved by a similar method, or some commercial method of casting ingots to eliminate this columnar crystallization.

Jan 5, 1919

By John S. Rinehart, Norman Ahlquist

The model which Birkimer has developed to explain the increase in fracture strength of brittle, rock-like materials with increasing rate of loading may have some applicability. It should be noted that since his analysis presupposes elastic behavior he could equally well express his result as an increase of stress to fracture with increasing strain rate, a fact which is well known. Certainly his experimental results do not contradict his strain rate to the one third power law. On the other hand, we do feel that the data are insufficient and inadequate to establish the relation- ship definitely. &apos;In metals, the whole fracture picture is greatly complicated by concomitant plastic flow and, in rocks, by the presence of macroscopic flaws and inhomogeneties. Both lead to uncertainties as to the state of stress during the fracture process. He quotes in support of his theory Rinehartfs results on rock in which the latter found that under impulsive loading by explosives, rocks appear to be many times stronger than under static loading. We suspect that the observed increase has little specific relevance to the theory which Birkimer puts forward. Rinehart&apos;s measurements were made by spalling rocks using a sawtooth shaped stress wave of known intensity and duration. The rise time of such a pulse is essentially zero, certainly less than 0.1 microseconds, so that it is not possible to apply Birkimerfs theory quantitatively. We favor attributing the increase in fracture strength to two factors. First, the action takes place very quickly in an exceedingly thin region so that statistically the probability is small of encountering one or more of the large flaws that contribute so significantly to the reduction of strength of most rocks under tension. It is also conceivable that the compressive wave that has just passed by the region of fracture has strengthened the rock by collapsing some of the larger flaws. Second, the state of stress obtaining at the time of fracture is not all that existing when the

Jan 1, 1971

By A. H. Daane, W. J. Wunderlin, B. J. Beaudry

In an earlier study at this laboratory,&apos; the authors investigated the solid solubility of holmium in copper, silver, and gold, and also the melting point of the first eutectic on the noble-metal-rich side in these systems. In a more recent study of the solubility of rare-earth metals in gold at this laboratory. Rider, Gschneidner, and McMasters2 noted that the reported eutectic temperature in the Ho-Au system was lower than the corresponding eutectics in systems of dysprosium and erbium with gold. A redetermination of the eutectic temperature in the Ho-Au system with the same alloy used in the original study showed the eutectic temperature to be 810°C instead of 778°C as originally reported. (The eutectic temperatures in the Ho-Ag and Ho-Cu systems were also redetermined and were found to be 795" and 864°C compared to 787° and 868°C, respectively, which were reported originally.) Since this large change in eutectic temperature made the solubility data appear questionable, new alloys were prepared, heat-treated, and examined metallographically. The procedure of sample preparation and heat treatment used in the original work&apos; was followed except longer heat treatments were used ranging from 7 days at 600°C to 6 hr at 900°C. The results obtained are shown in Fig. 1. There is good agreement between the two studies in the maximum solubility of holmium in gold. Since the slope of the solvus is less pronounced in the present study, the extrapolation to 550°C shows a solubility of 1.6 wt pct Ho in gold compared with 1.0 wt pct in the original work. Since additional data were obtained and longer heat treatments were used in the present study, the larger value is believed to be more accurate. The authors wish to express their appreciation to P. Rider and K. A. Gschneidner. Jr., for bringing this discrepancy to their attention, and also to D. Thompson for assisting in the present study.

Jan 1, 1965

By J. Gordon Parr, L. P. Srivastava

DUWEZ1 has shown that pure titanium and pure zirconium transform martensitically during rapid cooling at temperatures about 30° and 15°C re spectively below their To temperatures. Holden et al.2 determined M, temperatures of Ti-Cu alloys by a metallographic technique applied to isothermally treated samples. Their results, superposed on the McQuillan3 version of the partial Ti-Cu diagram are shown in Fig. 1. Sources of metals were: Titanium: Iodide bar; Foote Mineral Co. Ltd. Zirconium: Iodide bar; Foote Mineral Co. LM. Copper: Spectrographic Standard; Johnson Matthey and Co. Ltd. Alloys were prepared by levitation melting under argon to the following nominal compositions:* 0.5, Quenching, at rates to about 8000°C per sec, was performed by cooling in a stream of helium (99.999 pct pure) a 3/64 in. cube of material previously heated by a tungsten coil in a system operating at. 10-5 mm Hg. Cooling rates below 200°C per sec w were obtained by controlling the current to the heater coil. The specimen was supported on a 32 gage Pt, Pt-Rh thermocouple attached through a DC amplifier to an Edin magnetic oscillograph (Model 8082) with a maximum chart speed of 250 mm per sec. Transformation temperatures were read off the oscillograph charts at the location of the beginning of the thermal arrest. The same specimen was quenched several times, and all runs were repeated on new samples. Regular calibrations of the oscillograph against a potentiometer were made between quenching experiments. The criterion of martensite formation was the effect of surface rumpling. Previously polished samples that showed a rumpled surface after transformation are assumed to have undergone martens itic transformation: transformations of a diffusion type produce no surface disturbance, Figs. 2 and 3. Electrochemical measurements were made in a cell described elsewhere4 whose electrodes were the martensitic and the diffusion-transformed materials in the following electrolytes:

Jan 1, 1962

COLUMBIA SECTION STANLY A. EASTON, Chairman, FREDERIC KEFFER, Vice-Chairman, L. K. ARMSTRONG, Secretary-Treasurer, P. 0. Drawer 2154, Spokane, Wash. D. C. LIVINGSTON FRANK A. Ross The first meeting of the Columbia Section was held on March 24, as a part of the 1916 Northwest Mining Convention which was held under the -auspices of the Spokane Mining Men&apos;s Club assisted by the Spokane Chamber of Commerce, the technical program being in charge of the Spokane Engineering and Technical Association assisted by the local sections of the A. I. E. E., A. S. C. E., and A. I. M. E. The program of the successive sessions was carefully arranged with view to its application to mining, and in addition to the technical program there were exhibits of ores, minerals, devices, etc., of interest to the delegates, who numbered over 500. A portion of the program was also arranged with special reference to the requirements of the prospector and miner. A reception, a banquet, a complimentary luncheon, a regular daily call&apos; of the Stock Exchange, a visit to the High Schools and to one of the substations of the Washington Water Power Company and to the Union Iron Works kept the visitors entertained, the ladies being looked after by a special committee of ladies who held open house during the entire week. Several important resolutions were passed by the Convention and one by the Columbia Section, A. 1. M. E. With Stanly A. Easton, chairman, presiding, the Columbia Section, American Institute of Mining Engineers, occupied the time between 2.00 and 5.30 p.m., March 24th, the Moorish room of the Spokane hotel being filled with members and their guests. "The Apex Law and the Mineral Surveyor" was a paper presented by F. W. Callaway and generally dis-cussed because of its local application in the Coeur d&apos;Alenes, the conclusions being reached after expensive litigation between two of the large mining operators in that district.

Jan 6, 1916

By Robert B. Fulton

Commercially, celestite (SrSO,) is the only significant strontium mineral. Among other strontium-bearing minerals, only strontianite (SrCO,) occurs commonly; however, it is not an item of commerce. The principal production of celestite is in England, Mexico, and Spain. New production is now coming on stream in Canada. Consumption is mainly in the United States. Lesser quantities are consumed in Japan and Europe. Main uses are for the manufacture of strontium carbonate and nitrate. The carbonate is used in glass for TV tube face plates and in ferrites for magnets. The nitrate is used in pyrotechnics to which it imparts a characteristic brilliant red color, mainly in safety flares. Minor amounts of strontium compounds are used in electrolytic zinc manufacturing and very small quantities in greases, ceramics, soaps, alloys, and pharmaceuticals. Specifications and Prices Typical celestite specifications for the carbonate and nitrate markets are as follows: [ ] Celestite currently shipped from Mexico for carbonate manufacture tends to be slightly better than these industry specifications, assaying about 92-93% SrSO, with less than 1% BaSO, but it is generally below the 95% minimum required for nitrate production. Contract prices for celestite are approximately $32-34 per st at U.S. Port of Entry in 50 to 60-ton carload lots for Mexican material. Spot prices are generally reported as low as $20 per st but are for minor volumes. A recent sale of surplus from the U.S. stockpiles, announced by the General Service Administration (GSA), was 4005 st sold to Du Pont for $140- 455 or $35.07 per st. British celestite, ground, washed, and graded, 95% SrSO, bulk, ex- works, 240 mesh, is quoted at £ 28.75 per mt in British trade journals, and a recent figure quoted for crushed lump material was $36.00 per st f.0.b. vessel Bristol Channel port (1973). Specifications of manufactured carbonate made from celestite and sold in two grades, one to the glass industry, the other to the electronic industry for ferrites, are given in [Table 1]

Jan 1, 1975