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By Frederick N. Rhines

BECAUSE of the nature of the environments in which metals are handled, it is natural that gases should be suspected of intruding into metallurgical operations, there to produce effects both beneficial and detrimental. The problem of tracing and controlling such effects is often made difficult by the complexity of the conditions surrounding 'their occurrence, even though the fundamental mechanisms involved may be simple and of familiar type. Many gas-metal reactions are known to be implemented by processes of diffusion. These form a homogeneous group of phenomena which become more readily understandable when viewed together, in that the knowledge gained from one serves to interpret the next. It is the purpose of the present paper to present, by means of examples drawn from practice, a brief survey, of the ways in which gas-metal diffusion serves and obstructs the purposes of the metal-fabricating industries. The selection of the cases described was made by consulting more than thirty-six practicing experts whose combined experience provided an extensive coverage of the field and who were in a position to supply examples of occurrences of present day interest. The response was generous and it is regrettable that space permits the description of only a limited number of typical examples with but brief mention of parallel cases. THE NATURE OF GAS-METAL DIFFUSION The term "gas-metal diffusion," although commonly used, is ambiguous in so far as it implies that a definite group of substances may be identified as gases and may be expected to behave in a manner distinct from other substances in association with metals. "Gases" such as oxygen and hydrogen when diffusing through a liquid or solid metal are properly components of the liquid or solid solution; they behave as alloying elements and are not to be distinguished in their diffusion characteristics from other elements, except that each has an individual rate of diffusion. On the other hand, a number of metals in certain temperature ranges are volatile to the extent that they may appear in the form of vapor in metallurgical operations. For the sake of greater definiteness, therefore, it will be convenient to- regard as "gas-metal diffusion" any process in which the result depends upon one or more of the diffusing elements appearing, at some stage, in the gaseous state, or as a compound gas. No element, gaseous or otherwise, can diffuse through a liquid or solid metal unless it is at least slightly soluble in that metal. The elements of low atomic number

Jan 1, 1944

By Norbert R. Morgenstern

INTRODUCTION An understanding of the role of water in controlling the stability of rock masses is central for a rational approach to the subject. The presence of water can hinder mining opera- tions in two ways: 1. excessive discharge 2. excessive pressure It should be noted that if the rock mass is very tight, excessive pressures can exist without large discharges. Alternatively, if abundant water is available and the rock mass is open, then substantial discharges can occur under quite small pressures. The problems associated with excessive discharge are usually well understood by the mining engineer. Vehicle mobility is inhibited, some areas are flooded and hence become inaccessible; at best, a costly nuisance exists. The methods of solving these problems are also well-known to mining engineers. They generally involve tapping the source of the excessive discharge and channeling it away in such a manner that any hindrance to the mining operation is minimized. The effects of water pressure on the stability of rock masses are less obvious and the following will be devoted solely to this aspect of the problem. The manner in which water pressures enter into the consideration of stability is made clear by an understanding of the concept of effective stress. THE CONCEPT OF EFFECTIVE STRESS The simplest mechanical model for the problem of rock slope stability consists of a rough, rigid block sliding down an inclined plane under the influence of gravity. This is illustrated in [Fig. 1]. The down-slope component of the weight of the block tends to produce movement which is resisted by the shearing force generated by friction along the base of the block. The shear stress per unit area inducing movement is

Jan 1, 1971

By Henry M. Howe

THE natural effect of large size should be to increase segrega¬tion. I have previously pointed' to the excessive segregation in many large ingots as tending to confirm this, but I have shown that in case of ingots less than 16 in. square this expected effect of ingot-size is liable to masked by that of other variables. Under these conditions we should expect that if large ingot-size really does tend to increase segregation, this effect would be shown by taking the average of large numbers of cases, so that the effects of these other variables might off-set and cancel each other.

Jan 10, 1909

By Wolfgang Pietsch

Prior publications have shown that the structure and characteristics of direct reduced iron produced by direct reduction from iron ores or iron ore pellets depend on many parameters which include process variables, such as, reduction temperature, reduction gas composition, and type or origin of the raw material. Most of the published literature deals with direct reduced iron produced in the laboratory at theoretically interesting but commercially uneconomical or technically impossible conditions. Much of the work was carried out in pure carbon monoxide in pure hydrogen, or in such mixtures of carbon monoxide and hydrogen which are of no commercial interest. Other results were obtained at temperatures which are too high and would cause sticking in large scale plants. For this reason, work was initiated by Midrex Corporation to investigate the influence of raw materials and reduction temperature on structure and characteristics of direct reduced iron. The composition of the reducing gas used to prepare the samples for this study produces results corresponding to those obtained with a typical commercial gas. The temperatures at which reduction was carried out are in a technically feasible range. This paper reports on the results.

Jan 1, 1979

By Bernard Amadei, Richard E. Goodman

A medium is anisotropic if its properties vary with direction. This is the general characteristic of many rocks, for example, schists, slates, gneisses, phyllites and other metamorphic rocks. Bedded and regularly jointed rocks also display anisotropic behavior. This paper is concerned with the influence of rock anisotropy on in-situ stress measurements. It is limited to stress measurements by overcoring techniques for which strains and displacements are recorded either on the walls of a pilot hole at the end of one or several boreholes or within instrumented solid or hollow inclusions perfectly bonded to the surface of the pilot hole. The rock is described as homogeneous, continuous, anisotropic and linearly elastic. The following questions are answered with special emphasis on rocks that can be classed as transversely isotropic or orthotropic: the number of independent measurements obtainable in a single borehole; the number of boreholes required to determine the in-situ stress field; the influence of rock anisotropy on these numbers; the influence of the anisotropy type and the error involved by neglecting rock anisotropy.

Jan 1, 1982

By ALEX. S. THOMAS

HOWEVER good a furnace may be in regard to design, etc., or however excellent in the quality of the gas used, a suitable heat for the successful working of the metal cannot be obtained unless the melt be coated with a proper quantity of slag. This coating may be excessive or it may be deficient in quantity. The right degree of heat is the essential condition of successful working, for the quality of the steel made is never very good when the metal is allowed to simmer in the furnace for an excessive period, and this heat cannot be obtained if the metal is not protected by a proper covering of slag. This is not only to prevent the metal being over-oxidized and wasted, but also to prevent the metal being chilled when exposed with only a thin covering of slag. The slag may be obtained in either of two ways : 1, naturally, by the presence of sufficient silicon in the iron used, to unite with iron oxide to form a staple slag ; or, 2, by the addition of slag or free silica. In the first case the slag is formed naturally by the action of the oxygen in the flame - i.e., the oxidizing atmosphere of the furnace-on the silicon in the metal when melting. The charge then melts, as it is termed, "thick," and protects the banks from being cut. If too much silicon be present, however, and an excessive quantity of slag be formed, it will be found to be rather infusible, and unless care be taken to add the oxides quickly and follow the furnace up-thus rendering the slag more fusible by the extra iron oxide-the furnace bottom is liable to be pulled up. In such cases the author has frequently been able to warn

Nov 1, 1906

By H. M. St. John

MAINTAINING a satisfactory structure in brass and bronze castings has always been a foundry problem of great practical importance. While metallurgists and scientific investigators have not entirely ignored this matter, it has received less of their attention than has been given to iron, steel and the wrought copper and aluminum alloys. Investigation in this field has probably been discouraged to some extent by the complicated nature of the alloys involved. Hundreds of alloys are in more or less common use, most of them containing copper, zinc, lead and tin in-widely varying proportions. They also contain appreciable percentages of iron and antimony as impurities, and often phosphorus, which has been added as a deoxidizer and fluidifier. Small amounts of sulfur are usually present. It is not uncommon to find nickel, sometimes in rather substantial quantities. Traces of other metals are frequently present. So complicated and variable a mixture obviously offers difficulties in. any investigation of the various factors that influence the structure and other properties of the casting.

Jan 1, 1930

By Charles W. Schwartz, Subash Kolluru

INTRODUCTION Creep of rock in situ, like most rock mass behavior, will be largely governed by the behavior of the natural discontinuities -- bedding planes, faults, and joints, in particular, Several past studies have investigated various aspects of the time-dependent deformation of rock discontinuities; examples include Amadei and Curran (1980), Engelder and Scholz (1976), Johnson (1975), Kaiser and Morgenstern (1979), Solberg et al. (1978), and Wawersik (1974). These studies have provided much insight into the general phenomenon, but they have also produced some inconsistent conclusions and left many unanswered questions. This paper will attempt to shed some light on one of these questions: What is the influence of stress level on the creep of unfilled rock joints? The discussion will follow a two-part approach to the problem: (1) laboratory creep experiments on small scale jointed specimens, (2) a simple theoretical mechanism to explain, at least in qualitative terms, some of the results from the experimental program. EXPERIMENTAL PROGRAM Uniaxial creep tests were conducted on intact and jointed samples of a specially formulated gypsum plaster "synthetic rock." Synthetic rock materials have several advantages over natural rock for long-term creep testing: (a) higher creep rates, (b) lower strength and therefore lower loading requirements, (c) simpler specimen preparation, and (d) more controlled and consistent properties. Gypsum based plasters have been used previously in studies of short-term strength and deformability of jointed samples (Patton, 1966; Einstein and Hirschfeld, 1973). Furthermore, Williams and Elizzi (1977) demonstrated that natural gypsum, at least, creeps in a manner similar to that of most other creep-susceptible natural rocks.

Jan 1, 1982

By J. K. Jeyapalan, A. P. S. Selvadurai

Plate loading tests which use surficial loading of a rock mass are employed quite extensively for the determination of in situ deformability characteristics of rock masses. The cable jacking method is essentially a surficial plate load test in which the test load is provided by reaction against a cable anchored at some depth below the rock surface. The results of the test are usually evaluated within the framework of the classical theory of elasticity to generate estimates for the bulk deformability properties of the rock mass. In the conventional evaluation of this test it is assumed that the test plate is rigid and that the embedded anchor load has no influence on the test plate settlement. The purpose of this paper is to examine the possible influences of the plate flexibility and the anchor load location on the effective settlement of the test plate. The variational estimates presented in the paper are valid for moderately flexible test plates which are characterized by a relative rigidity parameter Numerical results are developed in the form of correction factors that should be applied to the cable jacking results to arrive at the deformability characteristics of the tested rock mass.

Jan 1, 1982

By H. M. Howe

THIS paper presents an experimental verification of some of the predictions made by one of us' concerning 'the influence of certain conditions of casting upon the size and position of the pipe', and the position of the segregate, in steel ingots. The predictions which we have been able to verify are the following A. That the pipe is shortened and the segregate raised 1. By slow casting; 2. By casting with the large end up instead of down; 3. By retarding the cooling of the top, e.g., by means of a sinking-head. B. That the pipe is shortened by slow cooling. C. That the pipe and segregate lie in the last freezing-part. Our procedure was to cast ingots of wax (commercially pure stearic acid) containing a little bright green copper oleate (usually 1.5 per cent.) under varying conditions; to saw each ingot open along a longitudinal plane passing through its axis ; and to examine the longitudinal section thus laid bare. In order to make the segregate or enriched part more distinct in color from the impoverished part, a very little red cerasine was added. An experiment which will be described later showed that the cerasine itself does not segregate markedly, if at all. Hence we may assume that the strong contrasts between the green and red shown in so many of our ingots are due, not to segregation of cerasine, but to that of the green oleate, in the wax which in itself is uniformly reddened with cerasine.

Jul 1, 1907

By Richard Conkling

A SHALE layer, buried beneath two or three thousand feet of strata, in some instances, will upon folding become thicker in the synclines and thinner on top of the anticlines. This can be accounted for, in part, by the stretching on the crests of the fold and the compressing in the troughs; but this will by no, means account for all of it, as is shown in the example herein set forth. It is my firm belief that the rest of the thickness is due to flow. What causes the movement, however, does not concern us here, so long as there is movement, for this article purposes to show its effect upon the producing area of different sands. It is the author's hope, in this way, to drop a hint or two that may be valuable to the oil geologist, in making estimates of future productions and values of oil properties. An example will be given from property in the famous Cushing Pool in northeastern Oklahoma, where the author has had occasion to make a detailed study before recommending some property to his company, and has then been able to watch the results of this work. The author never mapped the surface structure in this pool, as this had been done by Frank Buttram when he was with the Oklahoma Geological Survey. We are using, therefore, a section of his map in this article for our surface contours. The main east clip comes farther east than this section shows.

Jan 10, 1916

By R. A. Conkling

DORSET HAGER, Tulsa, Okla. Recently we have, been doing a little work along the same lines Mr. Conkling has outlined iii his paper. I am not prepared to say that Mr. Conkling is not correct but our results do not agree with his. I think it is a question of difference in correlation and interpretation of the well records. Our cross-section of the Cushing pool does not agree with that of Mr. Conkling and we find instead of the beds thickening in the syncline, there is a tendency to thicken on top of the anticline. We took the north dome of the Cushing field, and are now trying to get all the records. It will probably be another month before we have all the data complete but our results at present do o not agree with those of Mr. Conkling at all.

Jan 4, 1917

RICHARD A. CONKLING (communication to the Secretary*).-Mr. Hager says that his results on the correlation of well logs in the north Cushing field are the opposite to those of the author. Can he, then, explain why the structural dip of the formations increases with depth, as Dr. Ohern, in his criticism, sets forth that it does, and as all who have worked in these fields will admit, if the shales thicken on the crest of the anticline, as he says they do? We are willing to agree with Dr. Ohern that there is some evidence of a slight unconformity below the Bartlesville sand and think that we can prove, from a specimen in our office, that .this unconformity comes at the base of the Bartlesville sand in the south Cushing pool. On the Ingalls dome, in the southeast corner of Township 19 North, Range 4 East, however, we get results the same as those given by the author on Cushing. The Ballard well in the center of the Northeast Quarter of Section 33 is just 10 ft. higher, structurally, according to tile, surface contour, than the Ringold well -in the center of the Southwest Quarter of Section 34. The dip in the Bartlesville sand, between these wells, is 40 ft. and the dip on the top of the Mississippi lime is 75 ft. This also might be accounted for, partly by the unconformity, but the author used the interval between the top of the Oswego lime, which is about 420 ft. above the Bartlesville sand, and the oil horizon found in the lime in the Ballard well-just mentioned above-to find the depth at which the same oil should be found in a well in Section 5, Township 22 North, Range 3 East, 25 miles North. Using this interval below the Oswego in the former well, we predicted within 2 ft. where they would find the oil in the latter well. Of course, we know that it was accidental that we missed it only by 2 ft., but if there were much of an unconformity in this interval it would be more of an accident if we came within 100 ft. of the depth. Since it can be proven from most of the structures in this section that the clip continues to increase downward, below the Bartlesville at least, to the Mississippi lime, it does not seem necessary to the author to try to prove otherwise that the depth at which the shales will tend to thicken on top of a fold, has not been reached above the

Jan 6, 1917

By Richard A. Conkling

D. W. OHERN, Oklahoma, Okla. (communication to the Secretary*). -The author states: "A shale layer buried beneath 2,000 or 3,000 ft. of strata, in some instances, will upon folding become thicker in the synclines and thinner on top of the anticlines." In any series of folded strata there is a level of no strain. Provided the strata do not slip on each other, there would be above this level a thickening of strata in the synclines and a thinning on the anticlines, as the author states, while the converse would obtain below this level. In order that the author's

Jan 3, 1917

By G. F. Comstock

A serious disagreement as to the effect of titanium on the hardenability of steel exists in published references to this subject. Kramer, Hafner and Toleman reported' that acid-soluble titanium decreased creased the hardenability, with multiplying factors less than unity according to [ ] Grossmann's system for calculating hardenability from the composition. Crafts and Lamont, on the other hand, showed2 how titanium increased the hardenability, with multiplying factors up to nearly 1.7 for about o.' per cent titanium, though reducing the hardenability with higher titanium. Their data, however, were obtained almost exclusively from steels containing more than 2.4 per cent manganese, and thus should be considered as applying mainly to manganese steels. Likewise, the results of Kramer, Hafner and, Toleman regarding titanium are subject to the limitation that although they eliminated the effect of the insoluble titanium compounds from their calculations, they did not make a similar correction for the carbon that was combined with titanium and therefore occurred in a similarly ineffective form. It is suggested by the literature referred to that titanium may have different effects on hardenability, depending on the mode of its occurrence in the steel. The different effects on strength, ductility, etc., have already been discussed by the author.3 In the present discussion some comparisons, on the basis of hardenability as revealed by the Jominy end-quench test, are given between three titanium and two non titanium steels heat-treated in the same ways, and between other titanium steels heat-treated in several different ways. COMPARISON OF PLAIN-CARBON, VANADIUM AND TITANIUM STEELS The five steels used for these experiments were commercially melted and rolled products received in the form of 1.5-in. rounds from three different mills. Their analyses are given in Table I. Steels 2, 3, and 4 are from the same basic electric heat, containing 0.009 per cent of phosphorus and the same amount of sulphur. They were made by, adding aluminum and low-carbon ferrotitanium to different ingots. No. I is a plain-carbon coarse-grained S.A.E. 1040 steel made by the basic open-hearth -process. No. 5

Jan 1, 1945

Discussion of the paper of Robert R. Abbott, presented at the New York Meeting, October, 1913, and printed in Bulletin No. 82, October, 1913, pp. 2389 to 2400. ALBERT SAUVEUR, Cambridge, Mass.:-Mr. Abbott has certainly made a strenuous effort to ascertain the influence of the various elements on the absorption of carbon by steel-a subject of great importance to those dealing with the case hardening of that metal. Because of the extensive and careful character of Mr. Abbott's experiments, one is all the more disappointed that his results, as he himself recognizes, are not more satisfactory; for, indeed they leave us just about where we were,-still entertaining uncertain views in regard to the carbon-absorbing power of various alloy steels. It might be asked whether Mr. Abbott's method of estimating the amount of carbon absorbed-namely, by weighing the specimens before and after the carburizing treatment-was the best one to select. Are not serious sources of error. inherent to such procedure because of the difficulty of satisfactorily removing the earburizing material attached to the specimen ? The method of least squares has certainly failed to solve the problem satisfactorily. By manipulating Mr. Abbott's results in a different manner I have obtained the following expression: P = 100 - 50 C - 7 Ni + 20 Cr, in which P represents the carbon-absorbing power; C, the percentage of carbon; Ni, that of nickel; and Cr, that of chromium. It is assumed that the carbon-absorbing power of pure iron, or what might be called its carburizability, is represented by 100. Applying the formula, for instance, to a steel containing 0.15 per cent. C, 3 per cent. nickel, and 0.50 per cent. chromium, its carbon-absorbing power would be 100-50X0.15-7X3+20X0.50=81.50; that is, 81.50 per cent. of the carbon-absorbing power of pure iron.

Jan 12, 1913

By Robert Abbott

THE influence of various elements in retarding or accelerating the absorption of carbon during the process of carburization is fairly well known. In general those elements which forth carbides accelerate the absorption, while those which do not retard it. It has sometimes been wrongly stated that those elements which raise the temperature of the critical range increase the absorption, while those which lower this temperature decrease it. Silicon is a notable exception to this rule, for its influence is to raise the critical range but to lower the absorption of carbon. Some elements which do not form carbides have no apparent influence upon the absorption rate. Carbon itself retards the absorption rate. With a view to obtaining more exact data upon the subject the following experiments were undertaken : 208 steels of different chemical composition were selected to represent most of the types of modern constructional steels. Specimens 3 in. in diameter and in. in length were weighed to milligrams. They were then packed in the special carburizing box shown in Fig. 1, and kept in .the furnace for 10 hours at a temperature of 900° C. A duplicate experiment was conducted at 1,000° C. At equal' intervals of time the box was rotated in the furnace so that. two complete revolutions were made in the 10 hours. This precaution was taken to neutralize as much as possible any effect of unequal heating. At the end of the 10 hours the box was allowed to cool in the furnace with the doors open. The specimens were then weighed again and the increased weight (carbon) determined. In. the following table are given the analyses of the various steels, together with the. increased weight of .carbon expressed in milligrams.

Jan 10, 1913

By Jerome Strauss, Carl L. Shapiro

THIS is a critical examination of the theory that the amount of carbon necessary to form the iron-carbon (carbide) eutectoid is lowered by the addition of any carbide-forming element. Although this theory has been built up over a long period of years,, it appears, in the light of recent published investigations upon the ternary constitutional diagrams of iron with carbon and other alloying elements, to be no longer tenable. A survey of these new results, summarized below, shows that (as is known) some metals lower the carbon content of the iron-carbon (carbide) eutectoid, whereas others raise it, but (as not heretofore clearly set forth) some first move the eutectoid in one direction and then, at higher concentrations, shift it in the opposite direction. Moreover, these differences in behavior exist even among the common alloying metals classed as carbide formers. PART I INFLUENCE OF BODY-CENTERED CUBIC ELEMENTS The effects of the various body-centered cubic metals (chromium, tungsten, molybdenum, vanadium, columbium and tantalum) are reviewed individually. Iron-carbon-chromium System.-In the monograph on Alloys of Iron and Chromium, Kinzel and Crafts' concluded that the carbon content of the eutectoid is lowered by increasing the chromium content. The quantitative influence of chromium on the eutectoid point of iron-carbon alloys was shown by Monypenny2 (Fig. I) and no data have been forthcoming to refute his findings. Iron-carbon-tungsten System.-Gregg,3 in the monograph on Alloys of Iron and Tungsten, accepted the data showing that tungsten decreases the amount of carbon required to form the eutectoid. The influence of tungsten on the eutectoid percentage of carbon as determined by Oberhoffer and Daeves4 is shown in Fig. a; these results have received general approval. Iron-carbon-molybdenum System.-In the monograph on Alloys of Iron and Molybdenum, Gregg5 reviewed the work of Guillet,6 Swinden,7 and Reed,8 all showing that molybdenum lowered the carbon content of the eutectoid, whereas Takei9 contradicted this conclusion. Svetchnikoff and Alferova,10 a little later, showed that large additions of molybdenum shift the eutectoid to the right. These last-named investigators found that molybdenum, up to 1.2 per cent, shifts the pearlite point and the point of maximum solubility of cementite in the gamma phase only slightly in the direction of lower carbon content; on the other hand, increasing amounts of molyb-

Jan 1, 1943

By J. E. Johnson

At the Cleveland meeting of the Institute in October, 1912, I had the honor to present a paper outlining the conditions surrounding the charcoal iron industry…

Jan 1, 1915

By J. E. JR. Johnson

AT the Cleveland meeting of the Institute in October, 1912, I had the honor to present a paper outlining the conditions surrounding the charcoal iron industry, and giving some of the results of an investigation started about three years ago for the purpose of determining the reason for the poor reputation of the Lake Superior charcoal irons as compared with the Southern and Eastern irons. In that paper I explained the effect of high carbon on quality, and tried to make clear that that paper was a preliminary one, as we felt convinced that we should eventually discover other factors affecting quality. The progress of the investigation has brought out facts that seem to us of the utmost importance practically and theoretically, and the purpose of the present paper is to present these facts with the proofs which seem to us to establish them. The closing year of the nineteenth century saw the publication of the first definite and connected statement of the relationship between the cast irons and the steels.' The metallurgical world was ready to accept the fundamental unity of these two series, acceptance being greatly hastened by Professor Howe's classic paper, The Constitution of Cast Iron, presented at the Richmond meeting of the Institute, February, 1901.

Jan 1, 1914