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By J. E. Lamar, J. S. Machin

INSULATING materials include a wide variety of nonmetallic mineral products such as exfoliated vermiculite, expanded gypsum, 85 pct magnesia, diatomite, asbestos, perlite, cellular glass, pumice, silica aerogel, expanded aggregates and mineral wool. Except mineral wool, most of these products, or the materials from which they are manufactured, are described in other chapters of this book. PROPERTIES OF INSULATING MATERIALS The insulating properties of the materials considered in this chapter result in general from entrapping extremely small pockets of air in such a manner that heat is not transferred by convection. The minimum heat conductivities of such insulating materials are slightly greater therefore than the conductivity of still air. In addition, conductivity varies with the overall density of the material, the temperature range in which the measurements are made, and the form into which the material is fabricated. However, the numerical value of heat conductivity should not be the sole criterion of an insulating material; for a particular application it may be advantageous to use a material of somewhat higher conductivity in order to secure other desirable engineering properties. This is especially true with certain materials that are used because of their refractoriness. Comparative insulating values of some commonly used insulating materials are shown in Table 1. In comparing the values presented in this table it should be borne in mind that heat conductivity varies with the mean temperature, with the overall density, and with the amount of moisture present. With fibrous or granular materials it varies with fiber or grain size and with the amount and kind of binder, if any is used. Under some circumstances it may vary with the arrangement of

Jan 1, 1949

By J. Ruzicka

In creep testing, material is subjected to a constant load, preferably at a constant temperature, and its rate of deformation is measured. The method of loading can be of various types but in this paper only creep testing under tensile load will be considered. The ordinary tensile test is essentially a comparison test in conditions that frequently hear little or no relation to those under which the test material is to be used in service. The purpose of creep tests is to measure the strength of the test material at slow rates of deformation that more nearly approach the rates realized in service. One purpose of this paper is to illustrate that the creep test, in addition to its value as a service test, is superior to the ordinary tensile test as a sensitive tool for the comparison of certain metals in investigative testing. The other purpose is to describe equipment having distinctive features of design that make it especially suitable for such tests. Representative data obtained with this equipment on a group of rolled zinc-base materials are given. These data are compared with those from practical comparison tests of the creep type on weatherstrip fabricated from the same group of materials. The comparison illustrates the value of the fast creep test and of the equipment. The Equipment The creep equipment consists essentially of a tank containing a constant-temperature oil bath in which the creep of 14 specimens, loaded by means of levers, is measured by means of one movable extensometer. Figs. 1, 2 and 3 illustrate its general construction and appearance. Constant-temperalure Oil Balh.—A common constant-temperature bath requiring only one temperature-controlling equipment for a number of specimens was chosen as the best means of fulfilling the requirements of low cost and compactness. In addition, this allows the testing of a group of specimens under identical temperature conditions.

Jan 1, 1937

By P. V. Roundy

PUBLIC lands in Florida were first withdrawn from entry by President Taft on July 2, 1910, as a conservation measure because of their possible phosphate content. The reserve thus established was subsequently modified by further withdrawals and by restorations, so that on Jan. 1, 1934,' it contained 66,796 acres, of which only a small part had been defi-nitely classified. The reserved land was in scattered parcels, ranging from less than 40 acres to 320 or more, distributed in many counties. For administrative purposes and for final disposal of any of the numerous parcels, mineral classification of the land is legally necessary. In 1934 and 1935 the United States Geological Survey, under two successive grants from the Public Works Administration, prospected some 83 tracts of these lands in Polk County, comprising in all about 3300 acres, and six tracts comprising 240 acres in Citrus and Marion Counties. The tracts in Polk County were all in the so-called land-pebble field and the others in the hard-rock field. The Survey field party was under the direction of P. V. Roundy, from whose unpublished report the material in this paper is largely taken. The foreman of the prospecting crew was J. H. Wingate of Zephyrhills, Fla. The individual tracts were identified through the cooperation of the General Land Office, by transitman Hugh B. Crawford. This prospecting work fitted well the classification adopted for Public Works projects in general: it could not he done on any considerable scale under the Survey's usual appropriations; it gave employment to unem-ployed labor; and it may be expected ultimately to repay the Government in royalties more than the cost of the exploration.

Jan 1, 1937

Several of the current concepts of brittle fracture involve consideration of, the existence of defects or flaws. Griffith 1 observed that the tensile strength of brittle materials was several orders of magnitude less than might be expected from the calculated strength of the molecular bonds. He was able to show that the stress concentration at the tip of an elliptical crack is sufficient to raise the local stress level many fold. He therefore proposed that real materials do contain such stress risers in the form of minute cracks and that this accounts for the rather large difference between theoretical and actual strengths of brittle materials. The degree of stress magnification depends to a great extent upon the orientation of the crack with respect to the general stress system, and to the general geometry of the crack. It is but a small step to extend the theory to include flaws and defects of other sorts which, though they may be less tractable mathematically than cracks, may still function as stress risers in a real sense in real materials. Brace 2 proposed that the application of the Griffith theory to rock material could be tested in two ways: "(a) by finding the orientation of cracks from which macroscopic fractures have developed and (b) comparing failure strengths from tests at different conditions of loading." In 1963 the author and coworkers at the Bureau of Mines, Twin Cities Mining Research Center, working on a problem involving relationships between strength, sonic velocity, and microstructure "eveloped an experimental technique to examine several somewhat similar questions; namely. does the frequency of occurrence of actual or potential stress risers dictate the relative strength of the material as proposed by Weibull;4 can actual flaws or defects in the rock structure be identified and related to strength and perhaps other properties in accordance with Griffith's theory; and is the anisotropic strength and elastic behavior of certain rocks related to the preferred orientation of these actual or potential stress risers? The experimental approach developed to answer these questions appears equally applicable to the testing of Griffith's theory as proposed by Brace. Basically the approach consists of a series of point-load tensile tests followed by petrofabric examination of thin sections prepared from the specimens in order to identify and apply a quantitative measure to microstructural defects which may have contributed to the failure process. In the point-load test, tensile stresses are induced by a compressive load applied to the center of a disc-shaped specimen by means of two opposing hemispherical indentors. Failure generally occurs as a single fracture parallel to the axis of loading and bisecting the disc. Because of the geometrical symmetrical the induced tensile stresses are symmetrical about the loading axis

Jan 1, 1967

By Alexander L. Field

IN a previous paper,' the experimental methods used and some of the results obtained in an extensive investigation of steels containing zirconium were described. The present paper considers in greater detail one of the most interesting of these effects, namely, the elimination of " red shortness" and the occurrence in steel of a compound of zirconium and sulfur. A consideration of the actual percentages of zirconium, manganese, and sulfur in numerous steels in the light of behavior during rolling has led to new conclusions of the most practical import regarding the reciprocal relationships of these elements. The microscopic examination of high-sulfur steels containing zirconium has also been productive of interesting results. Before discussing the experimental data in question, it may be stated, briefly, that the rettetion between zirconium and sulfur in molten steel may be represented by the simple equation, Zr + 25 = ZrS², and that the zirconium sulfide thus formed occurs in the finished steel in the form of gray-colored inclusions, closely resembling manganese sulfide and, like the latter, exhibiting plasticity at rolling temperatures. Molten steel containing zirconium retains such a negligibly small amount of oxygen in solution that the foregoing reaction goes to completion. Hot-rolling Properties of High-sulfur Steels with and without Zirconium The chemical composition of twenty-eight steel ingots embracing eleven heats made in a basic-lined electric furnace is shown in Table 1. The practice followed in the manufacture of these high-sulfur steels was described in the previous paper. Table 1 also gives the behavior of the

Jan 1, 1924

NEW MEMBERS The following list comprises the names of those persons who became members during the period Dec. 10, 1918, to Jan. 10, 1919. ADAMS, W. W., Mine Supt., Cia. Minera Paloma y Cabrillas, Higueras,,Coah., Mexico. ANKENY, CLEMENT W., Golden Cycle Min. & Reduction Co., Colorado Springs, Colo. ARGUE, WILLIAM H Mech. Engr., Ohio Brass Co;, Mansfield, Ohio. ARTHUR, WALTER Chem. and Met., Garford Motor Truck Co., Lima, Ohio. BANGSER, WILLIAM, Supt., Treatment Dept., Bethlehem Steel CO., Bethlehem, Pa. BEACH, C: S Asst. Supt. and Engr., Kemmerer Coal Co., Frontier, Wyo. BEAVER, A. B., Chem. and Engr. of Tests, National Cash Register Co., Dayton, Ohio. BORRIES, WILLIAM J., Min. Engr., Gen'l Mgr., American Zinc & Slate Co., Picher, Okla. BOTSFORD, CLARENCE A., Acting Gen'1 Mgr., Mogollon Mines Co., Mogollon, N. M. BOTSFORD, GEORGE B., Asst. Supt., Sunrise Iron Mines, Colorado Fuel &. Iron Co., Sunrise,. Wyo. COLLINS, GEORGE N., Mine Shift Boss, New York & Honduras Rosario Min. Co., San Juancito, Honduras, Central America. COTS, HOMER, Resident Engr., Arkansas and Oklahoma Dist., Central Coal & Coke Co., Huntington, Ark. CRICHTON, WALTER CREIG, Min.. Engr., 20S Charleston National Bank, Charleston, W. Va.

Jan 2, 1919

By George Rupp

THE Sunrise iron mine of The Colorado Fuel and Iron Corporation is in Platte County, Wyoming, about 110 miles north of Cheyenne. It is served by the company-owned Colorado and Wyoming Railway, which connects with the Chicago, Burlington and Quincy and the Colorado and Southern railways at Guernsey, Wyoming, a distance of 6 miles from the mine. The original Sunrise claims were staked mainly by United States Army officers and soldiers stationed at old Fort Laramie, because of small showings of copper in the Carboniferous limestones that form a horizontal capping overlying the Huronian iron ore. A small copper smelter was operated for about three years at Fairbanks, now an aban-doned town on the North Platte River. As many of the copper shafts and test pits near the present Sunrise mine were deepened, they pene-trated the capping and encountered iron. ore or gray sericitic schist, and were abandoned. Evidence of an early interest in iron ore was found when the Chicago claim was stripped for mining. A narrow, winding crevice was dis-covered, which led downward 20 ft. through the capping to the underlying soft red hematite, in which a room 10 by 14 by 7 ft. had been excavated. Stone hammers and wedges and a few rusted pieces of iron were found on the floor, and the evidence is conclusive that the excavation was used up to rather recent times by Sioux Indian medicine men, to provide war paint.

Jan 1, 1939

By E. P. Polushkin

The object of this paper as to show that the structural composition of an alloy may be found by the planimetric measurement of the total area occupied by each of the constituents on a few representative photomicrographs of this alloy. When the area is determined the volume and the proportional weight of the constituent may be calculated. This method has been used for the determination of the structural composition of binary eutectics and other binary alloys with known constituents; also the composition of unknown constituents in binary alloys. The accuracy of the method is. high enough to justify its application to metallographic problems instead of the chemical analysis. THIS work has for its purpose the establishment of a new method for determining the structural composition of alloys. The area occupied by a constituent on a few representative photomicrographs of the alloy is measured, by a planimeter, especially designed for metallographic work, and the volume and proportional weight of the constituent calculated. Experiments have shown that 'the results are accurate enough to justify the application of the method to many problems in metallographic research instead of chemical analysis. The advantage of the method is the possibility, of determining the amount of the constituents with-out separating them from the alloy; their composition may also be determined if the ultimate chemical analysis of the alloy is known. DESCRIPTION OF PLANIMETER Suppose Fig. 1 represents a part of a photomicro-graph on which the total area of the black figures is FIG. 1?-PART OF PHOTOMICROGRAPH ON WHICH TOTAL AREA OF BLACK FIG- URES IS TO BE FOUND. to be found. By a system of parallel lines drawn short equal distances apart all figures may be divided into trapezoids. As the area of a trapezoid is equal to its median multiplied by its altitude, the relation between the total areas of the black and the white figures comprised within each strip is equal to the relation between the sums of medians for these figures respectively.

Jan 12, 1924

By Richard H. Jahns

Gem materials, comprising those minerals and closely allied natural substances used for personal adornment, for the fashioning of ornamental objects, or for other decorative purposes, have been valued in human commerce for thousands of years. Amber, jet, natural glasses, and at least 15 mineral species were sought and used by primitive man, and most of the materials in common use today were known well before the time of Christ. Their variety is remarkably great, and the traceable relationships among their respective sources, modes of occurrence, properties, and histories of production, preparation, and valuation are extremely complex. Their uses have been affected by numerous shifts in fashion, and from time to time by superstition, by decrees of church and state, by personal interpretations of religious significance, and by various presumptions concerning medicinal value and influence on human behavior (Ball, 1935, 1950; Kunz, 1913; Pogue, 1915; Whitlock, 1946). Thanks to their durability, portability, and relative scarcity, some gem stones have been employed as media of exchange, and the investment value of the more precious stones has long been recognized and exploited, especially in Asiatic and European countries. Demands for gem materials have stimulated trade among various peoples for centuries, and they also were responsible for much early geographic exploration. During more recent times they have prompted numerous geological studies and a considerable amount of research on the growth and properties of crystals. Apart from decorative uses, some naturally occurring gem materials also are employed directly in numerous fields of industry. Substances that are manufactured for gem or industrial uses are termed synthetic gem materials; most of these correspond in composition and crystal structure to certain minerals found in nature. Imitation materials are those whose use is based upon their resemblance to substances of different composition and greater intrinsic value. Gem stone is a designation commonly restricted to those materials suitable for personal adornment, and the complementary term ornamental stone is applied to the remaining materials not used industrially. This distinction is arbitrary and somewhat inconsistent, owing to numerous geographic differences and historical shifts in end uses. Further, there is a complete gradation between the category of ornamental stones and that of dimension stone. Substances that lose their identity in use are excluded from the gem category; thus a transparent crystal of beryl would not be classified as a gem stone if it were processed as a source of beryllium metal. The adjectives precious and semiprecious have been employed as a means for distinguishing different gem materials on the basis of recognized value. Diamond, emerald, ruby, and sapphire consistently have been regarded as precious stones, and in cut form they commonly are referred to as the noble gems. Opal, pearl, turquoise, and chrysoberyl also have been classed as precious at various times. In recent years, however, it has been increasingly recognized that no satisfactory distinction can be based upon assessed value or any group of specific properties, and now all gem stones normally are referred to as precious. Indeed, the tendency is to extend this term to include many of the so-called ornamental stones, and the designation semiprecious has been essentially discontinued. Unlike most mineral commodities of economic value, gem materials are little altered in processing for end uses. Some stones are used in essentially their natural form, and most are reshaped and polished without significant changes in their fundamental properties. Thus the preparation of gem and ornamental stones is intended chiefly to emphasize or enhance

Jan 1, 1983

By John L. Boardman, C. W. Goodale

The motives behind the organization of the Bureau of Safety were twofold. First, there was the policy of the company toward its employees, which was one of fairness and consideration for their welfare and which entails the prevention of injuries; second, in order to prevent injuries, a study of their causes was essential, and this study could be made only by a thorough systematic classification of accidents, which required a special department to form and carry out the plans. The Bureau of Safety was organized to begin operation Jan. 1, 1914, hut practically all of the first year was spent in collecting data, making plans, etc. This department is semi-independent of others and reports directly to the president and general manager. It consists of the president of the company and the managers of the following departments: Mines, Washoe Reduction Works, Great Falls Reduction Works, Coal department, lumber department, B. A. & P. railway; and the chairman of the Bureau of Safety. Working under this group is the General Safety Committee consisting of the manager of mines, as chairman, the general superintendent, two assistant general superintendents, and the heads of the following departments: mechanical, geological, purchasing, sampling works, and framing plant; and also the safety engineer. Operating under the General Safety Committee are the group safety committees, consisting of the Anaconda group of mines, Boston & Montana group of mines, zinc group of mines, Washoe reduction works at Anaconda, B. & M. reduction works at Great Falls, coal department, lumber department and the R. A. & P. railway. Each of these group safety committces was in charge of the superintendent or manager of the group represented and the committee consisted of the foremen of the mine's or works that the committee served, as well as the safety engineer. These foremen and superintendents had met regularly for the purpose

Jan 1, 1923

By John L. Boardman, C. W. Goodale

The motives behind the organization of the Bureau of Safety were twofold. First, there was the policy of the company toward its employees, which was one of fairness and consideration for their welfare and which entails the prevention of injuries; second, in order to prevent injuries, a study of their causes was essential, and this study could be made only by a thorough systematic classification of accidents, which required a special department to form and carry out the plans. The Bureau of Safety was organized to begin operation Jan. 1, 1914, hut practically all of the first year was spent in collecting data, making plans, etc. This department is semi-independent of others and reports directly to the president and general manager. It consists of the president of the company and the managers of the following departments: Mines, Washoe Reduction Works, Great Falls Reduction Works, Coal department, lumber department, B. A. & P. railway; and the chairman of the Bureau of Safety. Working under this group is the General Safety Committee consisting of the manager of mines, as chairman, the general superintendent, two assistant general superintendents, and the heads of the following departments: mechanical, geological, purchasing, sampling works, and framing plant; and also the safety engineer. Operating under the General Safety Committee are the group safety committees, consisting of the Anaconda group of mines, Boston & Montana group of mines, zinc group of mines, Washoe reduction works at Anaconda, B. & M. reduction works at Great Falls, coal department, lumber department and the R. A. & P. railway. Each of these group safety committces was in charge of the superintendent or manager of the group represented and the committee consisted of the foremen of the mine's or works that the committee served, as well as the safety engineer. These foremen and superintendents had met regularly for the purpose

Jan 1, 1923

By M. C. Leverett

The behavior of mixtures of immiscible liquids in porous solids is of rapidly increasing interest to those engaged in the production of petroleum. The operation of artificial water-floods and the control of natural ones immediately raise questions concerning the fundamental nature of such processes. Moreover, it is now recognized that often water occurs dispersed throughout the rock from which the oil issues into the well,' and thus tends to move toward the well simultaneously with the oil. The work reported here is a laboratory investigation of the simultaneous, steady-state flow of oil and water through the same column of uncon-solidated sand. It is thus directly related to the situation in which water occurs in oil-producing sands; it may have less direct implications for the displacement of oil from sands by water. However, it is to be clearly understood that the experiments to be described were performed primarily to obtain information of a more or less fundamental nature, and are not an attempt to reproduce, on laboratory scale, any part of an oil field. The dynamic behavior of a system in which oil and water are flowing simultaneously through sand is best described in terms of its "effective permeability" to either phase. For incompressible fluids flowing through a system of uniform cross section, the effective permeabilities to the two phases, in darcys, may be defined by the equations: Ko = PA6A [la] and Ku = Q [lb] In order to put the results obtained on a comparable basis for different sands, the effective permeabilities will be stated as fractions of the normal permeability of the sand; i.e., fractions of its permeability to a homogeneous fluid. Algebraically, these fractions are: KO' = Ko/K, and KWr = K,/X [2a] and [Zb]

Jan 1, 1939

By M. C. Leverett

The behavior of mixtures of immiscible liquids in porous solids is of rapidly increasing interest to those engaged in the production of petroleum. The operation of artificial water-floods and the control of natural ones immediately raise questions concerning the fundamental nature of such processes. Moreover, it is now recognized that often water occurs dispersed throughout the rock from which the oil issues into the well,' and thus tends to move toward the well simultaneously with the oil. The work reported here is a laboratory investigation of the simultaneous, steady-state flow of oil and water through the same column of uncon-solidated sand. It is thus directly related to the situation in which water occurs in oil-producing sands; it may have less direct implications for the displacement of oil from sands by water. However, it is to be clearly understood that the experiments to be described were performed primarily to obtain information of a more or less fundamental nature, and are not an attempt to reproduce, on laboratory scale, any part of an oil field. The dynamic behavior of a system in which oil and water are flowing simultaneously through sand is best described in terms of its "effective permeability" to either phase. For incompressible fluids flowing through a system of uniform cross section, the effective permeabilities to the two phases, in darcys, may be defined by the equations: Ko = PA6A [la] and Ku = Q [lb] In order to put the results obtained on a comparable basis for different sands, the effective permeabilities will be stated as fractions of the normal permeability of the sand; i.e., fractions of its permeability to a homogeneous fluid. Algebraically, these fractions are: KO' = Ko/K, and KWr = K,/X [2a] and [Zb]

Jan 1, 1939

By Charles Morgan

An increased demand for brown iron ore in the Birmingham district during the past 18 months has caused renewed activity both in prospecting and mining these ores. In recent years the production in Alabama has ranged from 41,559 tons in 1932 to 639,351 tons in 1928. During the last 9 years about 83 per cent of the total brown ore produced in the United States has come from Alabama (Tables 1 and 2). Prospecting Two methods of prospecting are used in this district: (1) test pits, (2) churn-drilling. Usually there is certain quite definite information on an area to be prospected; some of the indications are float ore such as small gravel or small and large boulders known as "dornicks" scattered over the surface, and ore exposed by erosion in gulleys and ravines, which have cut or eroded through the overburden. Often these natural erosions furnish an indication of the thickness of the ore and to some extent of the area of the ore body. Deposits of brown ore are very irregular both in thickness and extent. Deposits are often lens-shaped or long narrow leads, some of which may be parallel and separated from one another by sand, clay or gravel. The bottom—the footwall—is also very irregular. This footwall is usually lime clay—disintegrated limestone, locally called "white horse," which usually is found at a depth of 6 in. to 20 ft. overlying the limestone. At some places sand and gravel is found under the ore instead of clay. No ore is found under the lime clay, although often the ore has sunk or slumped and is found in the upper portion of this clay, as at some of the Sloss workings at Russellville. The origin of these ores has been discussed by Major E. C. Eckel and Dr. E. F. Burchard in U. S. Geological Survey Bulletin 400, and recently the latter has done further work on ores in the Russellville district, of which reports undoubtedly will be published.

Jan 1, 1940

By Charles Morgan

An increased demand for brown iron ore in the Birmingham district during the past 18 months has caused renewed activity both in prospecting and mining these ores. In recent years the production in Alabama has ranged from 41,559 tons in 1932 to 639,351 tons in 1928. During the last 9 years about 83 per cent of the total brown ore produced in the United States has come from Alabama (Tables 1 and 2). Prospecting Two methods of prospecting are used in this district: (1) test pits, (2) churn-drilling. Usually there is certain quite definite information on an area to be prospected; some of the indications are float ore such as small gravel or small and large boulders known as "dornicks" scattered over the surface, and ore exposed by erosion in gulleys and ravines, which have cut or eroded through the overburden. Often these natural erosions furnish an indication of the thickness of the ore and to some extent of the area of the ore body. Deposits of brown ore are very irregular both in thickness and extent. Deposits are often lens-shaped or long narrow leads, some of which may be parallel and separated from one another by sand, clay or gravel. The bottom—the footwall—is also very irregular. This footwall is usually lime clay—disintegrated limestone, locally called "white horse," which usually is found at a depth of 6 in. to 20 ft. overlying the limestone. At some places sand and gravel is found under the ore instead of clay. No ore is found under the lime clay, although often the ore has sunk or slumped and is found in the upper portion of this clay, as at some of the Sloss workings at Russellville. The origin of these ores has been discussed by Major E. C. Eckel and Dr. E. F. Burchard in U. S. Geological Survey Bulletin 400, and recently the latter has done further work on ores in the Russellville district, of which reports undoubtedly will be published.

Jan 1, 1940

A week-long educational program and two-day symposium on applying the fluidizing reactor to the minerals industry drew more than 100 engineers to the University of Arizona at Tucson several weeks ago. The educational program, intended for engineers who will work closely with the reactor, attracted registrants from all sections of the U. S. and Canada. Meeting at the College of Mines on February 23 for a full week of intensive classwork, the engineers ploughed in with enthusiasm. Eight hours daily of lectures and laboratory work were followed by a generous helping of homework supplied by Professor Sigmund L. Smith, who directed the course. The study program was completed on Friday and the following Monday marked the start of a symposium of technical papers covering a wide variety of operations and new ideas.

Jan 4, 1959

CONTENTS PAGE World-V. R. Garfias 3 Russia-R. C. Beckstrom 6 Rumania-I. I. Gardescu 11 Germany-W. Kauenhowen 14 France, Italy and Poland-W. P. Haynes 20 Persia-Sir John Cadman 23 Iraq-E. B. Swanson 27 Burma and India-L. D. Stamp 30 Venezuela-H. Sherman 37 Trinidad-H. W. Reid 44 Colombia-O. C. Wheeler 47 Peru-O. B. Hopkins 50 Mexico-V. R. Garfias and R. V. Whetsel 51 Canada-L. C. Snider 55

Jan 1, 1933

A regular feature of the December issue is to be abstracts of graduate theses in the mineral industry field presented during that year. The following abstracts were submitted for this first article in the series.

Jan 1, 1975

By Michael B. Bever, Carl F. Floe

he possibility that carbon may be soluble in copper to a limited extent has bten recognized for over a century. The quantitative investigation of this problem, however, requires more sensitive techniques than have formerly been available. Three recent developments have made possible more accurate determinations: the vacuum-fusion method of analysis, the production of copper of high purity and the availability of high-purity refractories, particularly graphite. In addition to its obvious theoretical interest, the problem of carbon solubility in copper is of practical importance. In the production of copper and of high-copper alloys, carbonaceous covers are freauerltlv used. If even minute amounts of carbon are dissolved, insoluble carbon oxide gases will be formed when such metals are poured under oxidizing conditions. A mechanism of this kind could well be one of the principal causes of gas porosity in casting copper-base products. Review of Literature In 1823 Vivian1 raised the question as to whether copper by overpoling becomes "combined with a minute portion of carbon." Karsten2 asserted, in 1832, that carbon reduces the high-temperature strength of pure copper, so that when the carbon content has reached 0.2 per cent the metal will be brittle at a dark red heat. According to Karsten, carbon contents of 0.05 per cent make it difficult to hot-work copper. He also reported that the specific gravity of copper is 8.8969 and that it increases to 8.9258 if the copper is cemented with carbon and then melted. He emphasized the difficulty of determining analytically the small amounts of carbon present in copper. The metal was removed by wet methods and the residue considered as carbon. At Percy's request, Dick,3 in 1856, carried out various working tests on copper that had been ill prolonged contact with carbon, and found that the working properties of the metal had not been affected. He also attempted to determine the presence of carbon analytically. In one experiment the copper was dissolved and the residue was fused with litharge, and in another essentially a combustion analysis was made on a copper sample. In a final experiment, a sample was dissolved and the residue subsequently subjected to a combustion analysis. Indications of as much as 0.005 per cent carbon were found, but Dick considered his work inconclusive largely because of the possible interference of sulphur. Percy4 concluded, from Dick's experiments and from some experimental work of his own, that the solubility of carbon in copper had not been established with

Jan 1, 1946

By Carl F. Floe, Michael B. Bever

he possibility that carbon may be soluble in copper to a limited extent has bten recognized for over a century. The quantitative investigation of this problem, however, requires more sensitive techniques than have formerly been available. Three recent developments have made possible more accurate determinations: the vacuum-fusion method of analysis, the production of copper of high purity and the availability of high-purity refractories, particularly graphite. In addition to its obvious theoretical interest, the problem of carbon solubility in copper is of practical importance. In the production of copper and of high-copper alloys, carbonaceous covers are freauerltlv used. If even minute amounts of carbon are dissolved, insoluble carbon oxide gases will be formed when such metals are poured under oxidizing conditions. A mechanism of this kind could well be one of the principal causes of gas porosity in casting copper-base products. Review of Literature In 1823 Vivian1 raised the question as to whether copper by overpoling becomes "combined with a minute portion of carbon." Karsten2 asserted, in 1832, that carbon reduces the high-temperature strength of pure copper, so that when the carbon content has reached 0.2 per cent the metal will be brittle at a dark red heat. According to Karsten, carbon contents of 0.05 per cent make it difficult to hot-work copper. He also reported that the specific gravity of copper is 8.8969 and that it increases to 8.9258 if the copper is cemented with carbon and then melted. He emphasized the difficulty of determining analytically the small amounts of carbon present in copper. The metal was removed by wet methods and the residue considered as carbon. At Percy's request, Dick,3 in 1856, carried out various working tests on copper that had been ill prolonged contact with carbon, and found that the working properties of the metal had not been affected. He also attempted to determine the presence of carbon analytically. In one experiment the copper was dissolved and the residue was fused with litharge, and in another essentially a combustion analysis was made on a copper sample. In a final experiment, a sample was dissolved and the residue subsequently subjected to a combustion analysis. Indications of as much as 0.005 per cent carbon were found, but Dick considered his work inconclusive largely because of the possible interference of sulphur. Percy4 concluded, from Dick's experiments and from some experimental work of his own, that the solubility of carbon in copper had not been established with

Jan 1, 1946