Search Documents

By J. V. Emmons

It has long been known that the outside skin of tool steel frequently exhibits properties widely different from the interior of the mass.

Jan 1, 1915

By Clinton H. Crane

IN October, 1925, J. R. Finlay delivered an address entitled, "The Future Price of Lead." Lead was then selling at 8.85c. and Mr. Finlay and most of the rest of us were concerned about the shortage. Now, a little more than six years after, lead is selling for 3.55c., and nobody is worrying about the difficulty of getting plenty of it. For 1931 the U. S. G. S. reports United States produc¬tion as 390,000 tons of recoverable lead in ore. Our estimate is slightly higher than this; nearer 400,000 tons. This is the smallest production since 1911 and 1912, but in spite of this, stocks for the year-have increased nearly 50,000 tons. Our estimate for the production outside the United States is 1,120,000 tons, or more than double the production of either 1920 or 1921, and 30 per cent more than in 1913. Stocks abroad probably have not increased more than stocks in the United States. In other words, foreign consumption is double what it was in 1.920-21, whereas domestic consumption is substantially less. It looks as if Mr. Krueger, president of the Swedish match trust, was right when he said that "This country had better stop worrying about Europe and think a little bit more about its own affairs."

Jan 1, 1932

By Milton E. Wadsworth, John N. Ong, W. Martin Fassell

The temperature and oxygen concentration dependence on the reaction of sphalerite in oxygen at pressures from 6 to 640 mm Hg have been investigated in the temperature range 700° to 870°C. Sphalerite has been found to oxidize linearly over this entire temperature and pressure range. At higher rates, considerable self-heating was observed. The dependence of the oxidation rate on the oxygen concentration may be expressed by: Rate = k' where k' is the specific rate constant and 0 = K1[O2]/(1 + KI[O2]), where K1 is the equilibrium rate constant for the adsorption of oxygen on sphalerite. Values of the activation energy and the enthalpy of adsorption were found to be 60.3 and —59.6 kcal per mol, respectively. Data have been presented that indicate conditions under which either a sulphatizing or an oxidizing roast may be obtained. ROASTING processes have been employed in the metallurgy of a great number of basic metals in use today. Until recently, however, little attempt has been made to deduce the fundamental mechanism by which oxidation takes place. Structural changes upon oxidation have been investigated1 = and thorough work has been performed with regard to the reaction products and the thermodynamics of the oxidation reactions. The objective of this investigation was to determine the rate of oxidation of sphalerite and to apply the absolute reaction rate theory in the theoretilcal interpretation of the experimental results." "O Description of Apparatus The apparatus contains the following features: 1—a furnace with gas system, 2—an autographic weighing system, and 3—a temperature control system. Furnace With Gas System—The furnace was mounted by a yoke on each end and was free to travel up and down on steel guide rods, permitting the introduction and removal of samples from the apparatus with minimum difficulty. The furnace was heated by three sections of Kanthal wire wound externally on a zirconia tube and insulated with Fiber-frax. Pure gases or mixtures of gases were introduced into the lower end of the furnace through two flowmeters, a mixing chamber, and a gas-tight sparger, Fig. 1. The gaseous products of the reaction and the unused gases were prevented from escaping to the atmosphere by maintaining a small negative pressure on the system. This procedure permitted air from the outside to enter through the small an-nulus around the quartz suspension fiber and prevented the escape of the internal gases. Autographic Weighing System—The autographic weighing system consisted of an adapted gold balance, a photoelectric circuit, and a weight recorder, Fig. 2. The sample was suspended from one end of the balance beam by means of a platinum chain outside the furnace and a long thin quartz fiber on the inside of the furnace. On the other end of the balance beam, the necessary weights were added to counterbalance the sample. In addition, a calibrated chain was added to the balance which was linked directly to the weight recording unit. Control was effected by means of a photoelectric circuit." A parallel beam of light from a strong source was directed onto a small front-surfaced aluminum mirror mounted in the middle of the balance beam and then to a front-surfaced mirror mounted on the ceiling of the room. The beam was then reflected onto a front-surfaced right prism at a distance of 9 ft from the balance

Jan 1, 1957

By G. F. Bolling

Single crystals of each metal were deformed at 77°K and heated at constant rates, variously in the range 0.125" to 4o°Kper min from 77" to -390oK, while being monitored in an X-ray diffractometer. Changes in diffraction-peak heights and line breadths were used to ascertain the temperature ranges of recrystalliza-tion. The results were subjected to the analysis of nicholas' in order to obtain the rate-controlling activation energies,Q. In this analysis no recourse to a separate and distinct nucleation stage is required and the results of studying recrystallization proved consistent with the hypothesis of a constant number of nuclei or equivalent hypotheses. The values Pb = 5.5 ± 0.5 keal per mole Zn ~ 7.5 Sn - 5 Bi - 9. 5 correspond for lead, zinc, and tin to activation energies obtained elsewhere for grain boundary migration, and for bismuth and lead to previous studies of re-crystallization by Barrett.6 This correlation allows the conclusions that interference from recovery was minimal and that the observed recrystallization rates in these pure metals are effectively governed by grain boundary migration. Good agreement was not found between the results of this kind of study in zone-refined aluminum and previous work; and supplementary isothermral experiments involving hardness tests and metallography did not resolve the discrepancy. Nevertheless, at least a range,Q = 11.5 ± 2 keal per mole, can be assigned to the activation energy for boundary migration in aluminum. An experimental study of one aspect of the recrystallization process is presented here for four metals of different crystal structure. The metals chosen for study were all zone-refined to reduce impurity effects, but the attendant high purity presented a difficulty. For any reasonably high driving force a "re-crystallization temperature", TR, is in the range of 0.25 T,, where T, is the absolute melting point, and study was therefore restricted to lower temperatures. An X-ray technique under constant heating-rate conditions adequate above 90°K was devised for the study; in consequence, a newer type of analysis following Nicholas1 had to be used to obtain quantitative information about activation energies. The standard methods of studying recrystallization have involved the comparable analyses of Johnson and Mehl2 and Avrami3 which are reviewed by Burke and Turnbull.* The general analysis4 which is applied only to isothermal studies using any of various investigative techniques states:

Jan 1, 1968

By A. E. Bellis

ROBERT J. ANDERSON, Cleveland, Ohio (communication to the Secretary *).-The paper by Messrs. Bellis and Hardy was interesting to me and has led me to make a few remarks concerning some of the points brought out. The question of employing correct hardening temperatures is one that is sadly neglected, particularly in many large plants that forge and treat their machine tools for private use. As is most aptly remarked in this paper, "The custom of using one, high-speed temperature for all tools is very poor practice;" still, such practice is more common than otherwise. An instance came to my attention some time ago, in connection with some work with the standardization of high-speed steels for machine tools, where there were no less than six different brands of alloy steels being used for machine tools such as lathe, shaper, planer, boring mill and cutters of like nature. All of these different steels received identical heat and forging treatment-or at least that was the aim of the tool hardener. That the results were highly unsatisfactory goes without saying. That the hardening department of many plants is conducted on a rule-of-thumb fashion is the reason for a great deal of the trouble and disappointment which seems to be the lot of many tool-steel users. Exceedingly crude execution is the rule rather than the exception, and it is no small wonder that the results are as good as they sometimes happen to be. It would seem that at the present price of alloy steels the subject should receive a closer scrutiny by purchasers than it does. One not familiar with the workings of souse plants that disdain to lend an ear to scientific heat treatment would scarcely give credence to some of the methods employed, not only in the treatment of the steel but also in its selection and purchase. Heating for hardening should be conducted under close pyrometric control only after the correct hardening temperature has been determined.

Jan 3, 1917

By Charles M. Rolker

The main tin-producing regions of the world are known to be England, Australia and the Dutch East Indian possessions, chiefly Banca and Billiton. During recent years, the tin of the Malay Peninsula, exported from Penang and Singapore, has been coming prominently to the front. France, Austria, Hungary, Germany, Spain, South America, Russia and China still present insignificant figures. The conspicuous part which the Dutch possessions in the Indian Archipelago have taken in supplying the world with tin, is well known. Tin was discovered in Banca as early as 1710, and has been produced there ever since; but the supply has been most important since Banca came fully into the possession of Holland, in 1821. In Billiton and the adjoining island of Singkep, the existence of tin was known prior to 1822.* The Lingganese knew of its existence in the valley of Embalong, from creeks and streams in the neighborhood of Tima and Simper hills, on Billiton and also on Singkep island, but the prevailing superstition that tin-mining brought misfortune, influenced them to let this industry lie idle. The attempts of the Dutch government to test this question were lukewarm, perhaps by reason of the fear of reducing, through new discoveries, the price of Banca tin, and the island was abandoned in 1826, leaving only a military post. In 1850, Dr. Crookewit, a chemist and naturalist, was sent out to verify the rumors that tin existed in Billiton. His report was unfavorable; but in 1851 Mr. C. De Groot, a mining engineer, found tin readily, and the active work on Billiton dates from that time. Less than 600 tons were produced during the first ten years, and 3000 tons in the next decade. Billiton tin-mining is done by

Jan 1, 1892

By Samuel B. Christy

The present paper is a continuation of a study of the reductionworks of New Almaden, the first part of which was published under the title " Quicksilver-Reduction at New Almaden," in the Transactions of this Society, vol. xiii., p. 547.* Frequent reference will be made to some of the data there given. The following is an outline of the contents of this paper: I. Condensing appliances used at New Almaden: a. Brick condensers, b. Iron condensers—flues and " water-backs," c. Glass and wood condensers, d. Friction-coudensers—filters and revolving screens, e. Flues, towers, and chimneys. II. Analysis of condensing-systems. III. Temperature of condeusers. IV. Product of condensers. V. Treatment of soot. VI. Losses of treatment: a. Nature of losses, b. Composition, weight, and volume of dry gases, c. Volume of wet gases, d. Specific weight of quicksilver vapor, e. Vapor-loss at various temperatures. VII. Comparison with New Almaden practice. VIII. Comparison with results at Idria, Austria. IX. Comparison with results at Almaden, Spain. X. Future improvements in quicksilver-condensation. I. Condensing Appliances. The complete condensation of mercurial fumes in a large way presents numerous practical difficulties, familiar to all who have had to retort amalgams. In condensing the quicksilver-fumes discharged

Jan 1, 1886

By R. W. Shoenberger, J. E. McNulty, B. R. Kuchta, William Spackman, A. A. Terchick, M. E. Hopkins, Norman Schapiro, R. J. Gray, A. F. Duzy, M. P. Corriveau

INTRODUCTION * The United States is fortunate in having abundant reserves of metallurgical-grade coals. Although these coals are better in quality and more accessible than most metallurgical-grade coals found throughout the rest of the world, the best grades of these coals are being depleted. Consequently, more efficient exploration tools and techniques, such as advanced methods of core drilling and logging, correlation by petrography, paleontology, palynology, † physical stratigraphy, and geophysical methods are being used to help assess the extent and quality of the remaining coal reserves. Exploration and assessment of new and existing coal properties become of utmost importance in determining ( 1 ) the economic justification for mining the coal, (2) the optimum design of the preparation plant, and (3) the most effective use of the coal. Recent progress has been made in relating mineral matter, especially pyrite, in coal to geologic conditions and paleogeographic trends. l * Editor's note: Because of the numerous and varied contributions of the associate authors of this chapter, the text does not differentiate between sections prepared by each individual as has been done in other chapters. † Palynology is the science concerned with plant microfossils, especially spores. pollen. and other fossils of microscopic size.

Jan 1, 1979

By C. R. Ramachandra, C. C. Patel

Flotation of chalcopyrite from a low grade ore was studied by using different xanthates and dixanthogens as collectors and by conditioning the flotation pulp with oxidizing gaseous systems. The improvement in the recovery of chalcopyrite with the oxidizing systems was mainly due to the auto-activation of chalcopyrite, leading to the enhanced adsorption of xanthates and dixanthogens even when the latter were formed by oxidation of the xanthates. With air or oxygen as oxidizing system, the amount of ethyl xanthate required at pH 8.5 was much less than normally employed in the industry, the recovery being 97-99% of chalcopyrite with a concentrate of 24% copper. With isopropyl and isoamyl xanthates, the recovery was improved but the grade was lowered. By conditioning the pulp with air-CO2 or oxygen-CO2 mixture, the recovery was lowered with ethyl xanthate only, mainly due to the depressant action of bicarbonate formed. Flotation with dixanthogens gave cleaner concentrates of chalcopyrite. because iron pyrite did not float with these collectors. Of the dixanthogens tried, diisopropyl dixanthogen gave the highest recovery, 99% chalcopyrite with a concentrate containing 28.5 to 30% copper, when the pulp at pH 8.5 was condi-tioned with air. Isopropyl dixanthogen was found to be the best collector of all the xanthates and dixanthogens studied. It was found that the adsorbed ethyl, isopropyl and isoamyl xanthates at chalcopyrite surface, activated by cupric sulfate, and at iron pyrite surface were oxidized to the corresponding dixanthogens to different degrees in presence of air, oxygen, air-carbon dioxide mixture and oxygen-carbon dioxide mixture.' The dixanthogen formed at chalcopyrite surface was, however, firmly adsorbed while that at iron pyrite surface was easily desorbed. Since dixanthogens formed have greater hydrophobicity than the corresponding xanthates, as revealed by contact angles,1,2 the former were expected to improve the flotation results. It was, therefore, thought desirable to find out the effect of air, oxygen, air-carbon dioxide mixture and oxygen-carbon dioxide mixture on the selective flotation of chalcopyrite when individual xanthates were used as collectors. The effect of direct use of dixanthogens as collectors on the selective flotation of chalcopyrite was also investigated. For these studies, low grade chalcopyrite ore, received from the Indian Copper Corp., Ltd. (I.C.C.), Ghatsila, Bihar, was employed. At the milling plant of the I.C.C., chalcopyrite is floated at a pH of 8.5, employing ethyl xanthate as collector. EXPERIMENTAL Materials Employed: XANTHATES - Ethyl, isopropyl and isoamyl xanthates of potassium were prepared in a pure state by the methods described earlier.4 A 0.03% aqueous solution of a xanthate was freshly prepared in air-free distilled water for flotation studies. DIXANTHOGENS - Diethyl, diisopropyl and diisoamyl dixanthogens were prepared by the oxidation of xanthates by iodine and purified by extraction with petroleum ether. A 0.03% alcoholic solution of dixanthogen was used as a collector. FROTHER - A 0.2% solution of pine oil in ethyl alcohol was employed. SODIUM CARBONATE - A 0.4 N solution was used. ORE - The composition of the -100 +200-mesh size (Tyler standard) powdered ore, as determined by standard methods of analysis, was: copper 1.57%, iron 10.29%, sulfur 3.15% and acid insolubles 66.10%. Iron present as chalcopyrite (CuFeS2) was 1.38%, while that present as iron pyrite (FeS,) was 1.37%. Both chalcopyrite and iron pyrite were found to be liberated from the gangue minerals and from each other, as observed under a microscope. Flotation of Chalcopyrite with Xanthates in Presence of Different Gaseous Systems: Fifteen grams of -100 + 200-mesh size ore were shaken well with 100 ml of distilled water. The pH of the pulp was adjusted to 8.5 by the addition of sodium carbonate solution. Then 0.1 ml of xanthate solution (0.005 lb xanthate per ton of the ore) was mixed with the pulp, and the latter together with washings transferred to a

Jan 1, 1963

By J. A. Church

I. Early Furnaces,......423 11. Experiments with the HIgh-Shaft FURnace,..... 426 III. ExperMents wIth the Wide FURnace,..429 IV. ExperEentS with Extreme BOSH,... 43.2 V. Survival of the 56 by 180 IN. Furnace,.434 VI. Recent ExpeEiments,.....436 VII. SUMMary,........438 I. Early Furnaces. Copper blast-furnace construction in America has long recognized a general standard in the rectangular water-jacketed shaft with separate forehearth. The details, however, and especially those relating to shaft dimensions, have had to meet a great variety of conditions, and show no uniformity whatever. Selecting a few of the present day Western plants, we find furnace lengths varying from 12.5 to 87 ft., widths at tuyere level from 42 to 84 in., and heights above tuyeres from 5 ft. 4 in. to 22 ft. 4 in.; and comparing present designs with those of the past, we meet contrasts no less striking. Unlike its transverse section, the length of a furnace has come to depend rather on the size of unit desired than on the requirements of smelting; and if the question of length be ignored, several of the various existing designs can be grouped together on the basis of a common transverse section. This section, having a width at tuyere level of 56 in. and a height above tuyeres of 18 ft., was developed at Great Falls, and the story of its development contains some interesting features. Ground was broken for the Great Falls works in the spring of 1891. About a year later, the concentrator was able to begin operation, followed within the next few months by the Brueckner, reverberatory, and converter departments, and in April, 1893, by the first blast fur-

Jan 1, 1914

By J. J. Crowe, G. K. Burgess

PAGE, Theories of Allotropy of Iron........... 667 Previous Determinations of A2 and A3 in Iron........ 668 Critical Ranges as Determined by Expansion........ 669 Critical Ranges by Thermoelectric Observations........ Critical Ranges in Terms of Crystalline Structure....... 670 Critical Ranges as Detected by Mechanical Methods...... 670 Critical Ranges as Given by Electrical Resistance....... 670 Critical Ranges as Determined Magnetically........ 671 Critical Ranges as Determined Calorimetrically....... 673 Critical Ranges from Heating and Cooling Curves....... 673 Summary of Previous Determinations of A3 and A2 in Pure Iron.... 675 The Present Investigation............ 678 The Experimental Method........... 678 Arrangement of the Apparatus.......... 679 The Measurements of Temperaturc.......... 679 The Measurement of Time........... 679 The Thermocouples............ 681 Temperature Scale and Calibration of Thermocouples...... 681 Mounting of Thermocouples........... 682 The Differential Measurements.......... 682 The Furnace and Accessories........... 682 The Vacuum Pump............ 683 The Energy Supply............683 The Rheostat.............. 683 The Materials Investigated............ 685 Sources of Iron............. 685 Preparation and Description of Samples......... 685 Chemical Analyses............. 687 The Experimental Data............. 688 The Preliminary Observations.......... 688 The Definite Series............691 Description of the Plotted Curves........... 694 The Effect of Plotting at Different Intervals........ 694 The Curves of the Definite Series.......... 695 . The Curves of the Preliminary Series......... The Existence of Other Critical Ranges......... 696 The Microscopical Examination........... 697 Summary and Conclusions............ 698 Bibliography............... 701 Plates................ 704

Jan 1, 1914

By Galen G. Waddell

Several years of rock-burst research conducted by the U.S. Bureau of Mines in cooperation with the mining companies of the Coeur d'Alene mining district, Idaho, in addition to progress made by others throughout the world, have led to a good understanding of the rock-burst problem. This paper describes conditions which have caused specific bursts, present capabilities of detecting stress buildup and bursts, control methods, and a suggested approach to analyzing any individual mine-burst problem. A rock burst is the sudden, violent release of stored strain energy in rock by some mechanism of rock failure, generally accompanied by expulsion of rock with consequent damage to the mine. A burst may be audible for only a few hundred feet, or on the surface it may sound like a sonic boom miles away. A Dictionary of Mining, Mineral, and Related Terms, U.S. Bureau of Mines (USBM)* 1968yand defines a burst as Bureau "That phenomenon which occurs when a volume of rock is strained beyond the elastic limit and the accompanying failure is of such a nature that accumulated energy

Jan 1, 1971

Philip Argall, Denver Col. (communication to the Secretary): Dr. Raymond claims (Trans., xxiii., 560)) that my statement (p. 557) regarding the crystallization of iron "is beyond question incorrect." He says: "It is not even settled that vibration will crystallize iron under any conditions." While admitting that authorities differ on the possibility of cold crystallization of iron, I believe it is a settled and undisputed fact that vibration in the presence of heat will crystallize iron. Bloxam and Huntington say :* " Vibration assists 'in converting fibrous metal (iron) back into a crystalline state when heated, a lower temperature sufficing than in the absence of vibration." Mr. A. F. Hill, summing up a very exhaustive review upon the crystallization of iron and steel, pronounces against crystallization, but only at temperatures below 900' F. Mr. Howe, discussing ,the breakage of a 20-foot porter-bar with a crystalline fracture, suggests that it was attributable to heat, jointly with the jar. We see, then, that vibration of heated iron bars will induce crystallization and consequent change of structure. Referring to my statement, I wish to point out, that I was discussing the vibration of stamps arid should have said, "vibration under all such conditions," etc. That is, vibration attended with sharp blows, such as a stamp-stem is subjected to, will crystallize iron; yet I believe that intense vibration under any condition will

Jan 1, 1895

By Charles W. Dickson

Jan 1, 1904

By O. W. Ellis

The question of the influence of gases upon the properties of copper has received the attention of a number of investigators, among whom Sieverts,' Iwase,2 Lobley and Jepson3 stand preeminent. Solubility of Gases in Copper Sieverts and Iwasé concerned themselves with the solubility of a variety of gases in the metal in the solid and liquid states. They determined the absorption coefficients of these gases and in all cases found a sharp change in solubility at the melting point of the metal. In this respect they disagree with Lobley and Jepson, who have based their opinions upon the appearance of small ingots of the metal which had been fused in an atmosphere of one or other of three gases and had then been rapidly cooled, while surrounded by gas, to the freezing point (rate—possibly 30" to 60" C. per sec.). The ingots that had been fused and cooled under nitrogen and carbon monoxide were free from blowholes and it was assumed that these gases were not absorbed in amounts much in excess of those which would dissolve in the solid metal; the ingots similarly treated under hydrogen were full of blowholes and it was assumed in this case that gas was ejected on solidification of the copper. The effect of varying the rate of freezing upon the character of the test ingots was not examined by these investigators; otherwise, it is felt, their views might have been subject to modification. Sieverts' most important contribution is that the solubility of a gas in any metal is proportional to the square root of its pressure or concentration. Knowing then the absorption coefficients of the various gases in copper, it should be possible to determine the analysis of the

Jan 1, 1929

By O. W. Ellis

The question of the influence of gases upon the properties of copper has received the attention of a number of investigators, among whom Sieverts,' Iwase,2 Lobley and Jepson3 stand preeminent. Solubility of Gases in Copper Sieverts and Iwasé concerned themselves with the solubility of a variety of gases in the metal in the solid and liquid states. They determined the absorption coefficients of these gases and in all cases found a sharp change in solubility at the melting point of the metal. In this respect they disagree with Lobley and Jepson, who have based their opinions upon the appearance of small ingots of the metal which had been fused in an atmosphere of one or other of three gases and had then been rapidly cooled, while surrounded by gas, to the freezing point (rate—possibly 30" to 60" C. per sec.). The ingots that had been fused and cooled under nitrogen and carbon monoxide were free from blowholes and it was assumed that these gases were not absorbed in amounts much in excess of those which would dissolve in the solid metal; the ingots similarly treated under hydrogen were full of blowholes and it was assumed in this case that gas was ejected on solidification of the copper. The effect of varying the rate of freezing upon the character of the test ingots was not examined by these investigators; otherwise, it is felt, their views might have been subject to modification. Sieverts' most important contribution is that the solubility of a gas in any metal is proportional to the square root of its pressure or concentration. Knowing then the absorption coefficients of the various gases in copper, it should be possible to determine the analysis of the

Jan 1, 1929

By L. W. McKeehan, W. C. Elmore

THE magnetic powder method, long used for roughly mapping magnetic fields, has recently been refined 1,2 for investigating the microscopic variations in the surface magnetization of ferromagnetic crystals. Bitter' first discovered regular powder patterns connected with the crystal structure of such specimens. Several other investigators3 have used Bitter's original technique, with slight modifications, to study the variation of the patterns with variations in the magnetizing field applied parallel to the surface, and their dependence upon the state of strain, of polish and of crystal cut. All of the explanations of these patterns on metallic ferromagnetics have been couched in general terms. In a preliminary report we have described an improvement in the powder technique which led us to the discovery of a new effect throwing considerable light on the magnetic secondary structure of alpha iron4 and of nickel' single crystals. We now report additional evidence confirming the existence and stability of a magnetic block secondary structure. SPECIMENS The following list describes the specimens used in the present investigation. DESIGNATION DESCRIPTION A1 Silicon ferrite furnished to us by Dr. W. E. Ruder, of the General Electric Co., for which he gave the following typical analysis: C, 0.05; P, 0.038; 5, 0.026; Mn, 0.15; Si, 3.24. Disk, 0.60 cm. diameter, about 0.05 cm. thick.

Jan 1, 1935

By Frederic Becket

IN a recent article,1 which described the softening effect of columbium in plain high-chromium steels, the authors stated that their investi-gations had shown columbium to be also a particularly valuable inhibitor of intergranular corrosion in steels of the 18 per cent chromium, 8 per cent nickel type. It is the purpose of the present paper to record some of the results obtained through the introduction of columbium to the austenitic chromium-nickel steels. The damaging effects of this type of corrosion have become so widely known as to restrict considerably the applications of the steels under consideration, and therefore there is little question of the importance of the goal to be attained. Numerous contributions concerning the susceptibility of the aus-tenitic chromium-nickel steels to intergranular corrosion have appeared during the past few years, and among others who have dealt construc-tively with the subject are such well-known authors as Strauss and Houdremont of Germany, Hatfield of England, and Bain in the United States. Different theories have been propounded as to the cause of intergranular corrosion, and various remedial measures have been proposed, the majority of which involve the use of addition agents. Titanium is the addition agent at present most generally employed, as suggested by Houdremont and modified as described by Bain, Aborn and Rutherford.2 Little has been published on the effects of holding these steels for long periods at the relatively lower temperatures in the presence of

Jan 1, 1934

By W. E. Remmers

The defect in wire known as "cuppiness" has appeared and disappeared from time to time but the exact cause of its appearance or disappearance has not heretofore been known definitely. This defect is not limited to one particular metal or alloy but seems to be found at various times in all of the materials that are drawn into wire. Fig. 1 represents cuppy wire made from an aluminum alloy and Fig. 2 illustrates copper wire that became cuppy in drawing without intermediate annealing. Differences of opinion are current among the manufacturers of wire and in the literature (see bibliography at end of paper), some believing that the source of the trouble lies in segregation in the wire rod, oxides, sulfides, slag, etc.; others that the trouble is created by an unevenness of stress distribution across the section of the wire, usually thought of as being a function of die shape. All of the published work is of a qualitative rather than a quantitative nature. With this in mind, it was deemed advisable to make a study of the shape of the wire-drawing dies, as well as the oxygen content of the copper to be drawn. Experimental After several methods were tried, it was found that by studying the contour of the butt-end of the rod after drawing a measure of the "working" across the section of the wire could be made. The butt-end of the annealed rod was not sheared but was sawed off. The end was then smoothed with a fine file so that the plane of filing was perpendicular to the drawing axis. It is to be noted that this method is not an absolute measure of the distribution of cold working but is a very good indicative means of studying comparative values. The method of examining a tension break in wire was found to be the most sensitive in detecting cuppiness. Other methods, such as microscopic examination of longitudinal sections, X-ray radiographic studies, etching away of outer layers with nitric acid, and fracture by bending, can all be used to identify cuppy wire but the tension break will give the fracture characteristic of cuppiness before any of the other methods can

Jan 1, 1930

By Lawrence Adler

In-situ rock has well-recognized rupture and yielding responses. Attention is called to an intermediate response, granulation, which consists of an evenly distributed, small-scale crumbling accompanied by swelling. Granulation results in a negative slope for the inelastic portion of the stress-strain curve as successive interlocks are destroyed, and the load-carrying capacity of the material is reduced. Volumetric swelling with softening also takes place. The prerequisites for such a response are moderate confinement and a uniformly distributed defect pattern. Since rock masses, as well as rock as an intact material, have such patterns in their jointing and texture, respectively, granulation is characteristic of them. The presence of granulation can be demonstrated for a very wide scale, ranging from laboratory testing to regional geologic phenomena. The response of an engineered structure is considered in detail. Granulation appears to be dependent upon internal moments, the formation of which can be controlled by engineering design. The practical implications of such control can be significant in optimizing underground instability and in improving excavation techniques. Rock is usually considered to behave inelastically under high load, by fracturing as a brittle material, or by yielding as a ductile material, ignoring time dependency. These responses, which are characteristic of metallic behavior, appear idealized in Fig. 1, where linear-elasticity approximates the initial behavior. However, another major deformation mechanism peculiar to rock has long been recognized in geology, the granulation of an interlocked material. Granulation consists of a uniformly distributed fracturing and crumbling of the material, accompanied by swelling and softening. Predictably, the associated inelastic portion of the load-deformation curve has a negative slope,

Jan 1, 1971