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By J. A. Burkhardt

Field measurements and theoretical studies have been made of pressure surges—momentary variations in fluid pressure—produced by movement of pipe in mud-filled boreholes. Pressure measurements were recorded by five pressure gauges located at various positions in the borehole. An important positive pressure peak was found to occur as the casing moved with maximum velocity. Important negative peaks were found as the casing was lifted from the slips and as brakes were applied to stop pipe movement. A rigorously formulated theory has successfully predicted the sequence and magnitudes of these positive and negative surges and has established a basis for understanding how they occur. Both the measurements and theory indicate that the most important pressure surge is usually due to viscous drag of the flowing mud. The theory of viscous-drag pressure surges has been approximated by simplified graphs and calculation procedures to facilitate ready use in field operations. Comparison of measured results with those predicted by the simplified theory shows that the magnitude of this surge can be predicted accurately. INTRODUCTION It is widely recognized that raising or lowering pipe in a fluid-filled borehole produces momentary variations in fluid pressure, commonly called pressure surges. Both negative (or "swabbing") surges and positive (or "fracturing") surges may occur. In 1934, Cannon1 measured the negative surges and showed that they could be large enough to cause flow of formation fluids into the well-bore and, in extreme cases, lead to blowout conditions. Later, Coins2 measured the positive surges associated with lowering pipe. His results and subsequent field operations strikingly demonstrated that pressure surges could be an important factor in some cases of lost returns. In addition, although the evidence is less clear than in the case of blowouts and lost returns, other investigators 3, 4 feel that pressure surges probably play a part in many instances of minor gas cutting, salt-water flow and other hole trouble. The importance of pressure surges in drilling operations led naturally to attempts to explain the physical causes, nature and magnitude of the surges. Cardwell5 was the first to publish a theory which allowed the quantitative prediction of momentary pressure variations. He assumed that the drilling fluid was a 300-cp Newtonian fluid in turbulent flow. Most field muds have a considerably lower viscosity and are generally believed to be Bingham plastic in nature.6 However, card-well's results were useful because they were presented in a form convenient for field use and, in some cases, gave a reasonably accurate predicted value for the maximum pressure surge. Subsequently, Ormsby7 published a more comprehensive theory of pressure surges. He discussed both laminar and turbulent flow and considered the theory of mud-bypass devices for reducing pressure surges. As a consequence of his more rigorous approach, his results were more accurate but more complex and difficult to use. Further, both Ormsby and Cardwell considered only the pressure surge arising from viscous drag of the moving mud. Clark later published idealized graphs of surges and presented equations for predicting their magnitudes. In addition to pressure variations arising from viscous drag, he considered those caused by inertial effects. His theory was in this respect more complete than those of Cardwell and Ormsby, although he did not discuss pressures due to breaking of the gel. Furthermore, his equations, while not exceptionally complicated, were too complex for ready use at a drilling location. One difficulty common to all three theories is that none was tested rigorously by direct comparison with measured pressure surges. Their accuracy, therefore, could, not be demonstrated. Further, the two theories based on most realistic assumptions (Ormsby and Clark) required the solution of one or more rather complex algebraic equations. The research described in this paper was undertaken to supplement that described and to overcome some of the difficulties noted. It seemed obvious that a fully satisfactory study of pressure surges should encompass three main phases. 1. A valid theory useful in all field situations must be developed. This theory must be based upon realistic assumptions, must be formulated rigorously and should lead to clear concepts whereby the nature of pressure surges can be easily understood. 2. The theory, however complex and involved, ultimately must be presented in simplified form for convenient field use. This may involve extensive machine computations and the use of figures and empirical equations. 3. The accuracy of the simplified equations must be established by comparing measured pressure surges with those predicted by the theory. These must agree both in their characteristic nature and in magnitude. 'This means that careful measurements of surges occurring in actual field operations must be made.

By Cuppam Dasarathy

The incidence of liquid inzmiscibility in binar)) indium alloys has been theoretically analyzed on the basis of the Hildebrand-Alott equation. Bedictions of miscibility or otherwise Imve in general been found to agree with those phase diagrams that are already publislzed in the literature. Out of a total of 27 systems, where either the complete phase diagrams are published or liquid immiscible behavior is reported, the Predictions agree with the experimental data in 25 systems, the exceptions being the Te-In and Ni-In systems. According to the equation, liquid immiscibility is also indicated in the binary alloys of indium with K, Rb, Cs, Na, Sr, Ba, Ti, Zr, V. Nb(Cb), Ta, W, U, Re, Ru, Rh, Os, and Ir. RECENT investigations by the author have shown that indium when alloyed with iron, chromium, and cobalt shows liquid immiscible behavior.1"3 The Fe-In phase diagram shows a wide range of compositions where the liquids are immiscible.4,5 No intermediate phases are present in this system. No precise information is available about the extent of liquid immiscibility in the Co-In system. However, it is certain that there is a range of compositions where the liquids are immiscible and that there are two or three intermediate phases,376 in the system. Liquid immiscibility is also strongly indicated in the Cr-In system and no evidence was obtained in the brief investigation to indicate the presence of intermediate Cr-In phases.2 The present paper deals with a theoretical analysis of binary alloys of indium with certain elements of the periodic table and indicates the systems where liquid immiscibility may be expected. The incidence of liquid immiscibility in binary systems has been theoretically examined by many workers and many excellent papers are available on the subject. In this paper, the alloy systems are examined on the basis of the more recent ideas proposed by Mott.7,8 It has been claimed8 that the Mott parameter predicts the incidence of miscibility or otherwise with reasonable accuracy and consistency. BACKGROUND TO MOTT&apos;S APPROACH Hildebrand applied his immiscibility rule for non-polar liquids to various alloy systems.9 The basis of this rule is that the equation for the excess free energy of formation of a liquid solution is rather similar to the theoretical expression for the energy of mixing of a regular solution. He postulated that when the heat of mixing is sufficiently high, separation into liquid phases will occur and the condition for complete CUPPAM DASARATHY is at the Research Centre, British Steel Corporation, (South Wales Group), Port Talbot, Glamorgan, Great Britain. Manuscript submitted March 12, 1969. IMD miscibility was shown as where VA and VB were the atomic volumes of the components A and B, and ?EV the energy of vaporization of the component. The term (?EVA/VA)1/2 was regarded as a measure of the binding energy of the component A and was called the L&apos;solubility parameter" 8A. On this basis immiscibility occurs when 1/2(VA+VB)(bA-bBf > 2RT [2] Apparently, however, there were several inconsistencies in that according to Eq. [2] several systems known to be miscible in the liquid state were predicted as immiscible. MOTT&apos;S ANALYSIS ~ott&apos;" regards that the reason for the inconsistencies arising out of Hildebrand&apos;s equation was largely due to the electrochemical attraction between the two elements, not being considered. Hence, Eqs. [I] and [2] were modified by taking into account the electro-negativities of the two elements XA and XB, and Mott arrived at an equation for immiscibility, i(VA + VB)(6A - aB)2 - 23,Q60n(XA - XBf > 2RT [3j which can be written as i **&£*&* >&apos;*°™- &apos;• HI T being the melting point of the more refractory component of the system. In Eq. [4], the numerator was called the Hildebrand term, the denominator, the electronegativity term, and their ratio, the Mott number. Mott observed that if the Mott number of a given binary system was greater than the maximum number of Pauling bonds which the two metals could form, then liquid immiscibility could be expected. The maximum number of bonds formed by a given metal was considered to be directly related to the number of bonding electrons available, i.e., to its maximum valency. Since the valencies of the elements considered vary from 1 to 6, Mott assumed that if the ratio of the Hildebrand term to the electronegativity term was >6, then immiscibility could be expected. On the contrary, if the ratio is <1, the metals should be miscible. Further, the alloying behavior is not only influenced by the valencies of the two elements but also by the relative atomic sizes that influence the types of packing and hence the coordination number. Mott considers that on average the maximum number of near neighbors of unlike atoms is 6. Thus, on both valency and size factor considerations, Mott concludes that the maximum number of bonds&apos; possible in any system was 6, this being the upper limit of the Mott number for miscibility. In considering the alloying behavior of systems with Mott numbers between 1 and 6, Mott plotted the num-

Jan 1, 1970

By Niels Hansen

The substructure formed by drawing at room temperature in aluminum (99.5 and 99.998 pct purity) and in recrystallized aluminum aluminum-oxide products containing from 0.2 to 4.7 wt pct of aluminum -oxide was examined by transmission electron microscopy, and the flow stress of the drawn materials was measured by tensile testing at room temperature. A sub-grain structure was present after a reduction in area by drawing of 10 to 20 pct, and the subgrain size was observed to decrease with increasing deformation. The tensile data show that the increase in flow stress (0.2 pct offset) by drawing from 10 to 95 pct depends on the reduction in area, not on the composition of the materials. Dispersion strengthening and subgrain bowzdary strengtlzening contribute to the flow stress, and these strengthening processes have been found to be linearly additive. The flow stress (0) can be related to the subgrain size &) by the Petclz relation = uo + k . t, where go is dependent on the composition of the products and k is approximately the same far all materials. THE microstructure of dispersion-strengthened aluminum aluminum-oxide products consists of small oxide plates distributed in an aluminum matrix. The matrix structure depends on the manufacturing history, and in hot-worked as well as cold-worked products the matrix is divided by subgrain (or dislocation) boundaries. For hot-extruded products it has been shown1 that dispersion strengthening and subgrain boundary strengthening are linearly additive, and the flow stress (0.2 pct offset.) at room temperature has been related to the subgrain size (ts) by a Petch equation,2,3 s = so + k . ts-1/2, where s0, increases with increasing oxide content. For cold-worked products containing subgrains no systematic work has been reported, and it was the aim of the present study to examine the microstructure and the relationship between the flow stress and the subgrain size for such products. The behavior of&apos; aluminum aluminum-oxide products depends on the purity of the aluminum matrix, and aluminum of the matrix purity (99.5 pct) was included in the investigation. The literature contains few data about the behavior of this impure aluminum, and aluminum of a higher purity (99.998 pct) was therefore also examined. As regards the relationship between the flow stress and the subgrain size in cold-worked dispersion-strengthened products, no systematic work has been reported. For aged cold-worked structures containing fine precipitates (Fe-Mo carbide) a Petch relation has been found,4 and it has been shown that the k value NlELS HANSEN is Head, Metallurgy Department, Danish Atomic Energy Commission, Research Establishment Riso, Denmark. Manuscriot submitted January 9, 1969. IMD is approximately the same as in iron, whereas the s0 value is higher owing to the presence of the precipi-tates. Investigations of metals such as tungsten,&apos; ferrous metals,4,6 and molybdenum7 cold drawn or swaged at room temperature have shown that the flow stress can be related to the subgrain size by a Petch relation when ts is taken as the subgrain size perpendicular to the direction of deformation. For aluminum no work has been reported on the relationship between the flow stress and the subgrain size after deformation at room temperature, whereas for aluminum tensile strained at different temperatures in the range -183" to 375°C a Petch relation has been found by taking ts equal to the subgrain size.&apos; In the present study two aluminum materials (99.998 and 99.5 pct) and three aluminum aluminum-oxide products (containing 0.2, 1.0, and 4.7 wt pct oxide) were drawn at room temperature to reductions in area from about 10 to about 95 pct. The structures were studied by transmission electron microscopy, and the flow stress (0.2 pct offset) was measured at room temperature. EXPERIMENTAL Materials. The materials are given in Table I together with the chemical analysis. The three aluminum aluminum-oxide products were manufactured from aluminum powder that had been compacted and Table I. Chemical Analysis of Materials Al203 Fe SI Material wt pct wt pct wt pct 99.998 pct* - 0.0004 0.0012 Aluminum 99.5 pctt - 0.36 0.16 Aluminum AlMD13† 0.2 0.16 0.12 Aluminum- -Oxide AlMD105† 1.0 0.26 0.18 Products SAPISML960s† 4.7 0.22 0.19 *Other impurities: O.0004 pct max each of Cu and Zn (supplier&apos;s analysis). †Other impurities: 0.03 pct max Cu. 0.02 pct max each of Mn, Mg, Zn, Ti. Table 11. Mean Diameter of Aluminum-Oxide Particles in Extruded and in Cold--Drawn Aluminum Aluminum-Oxide Products Mean Diam. of A1203-Plates* Material State A AlMD105 Extruded 540 Cold Drawn 97 pct 510 SAP ISML 960 Extruded 770 Cold Drawn 95 pct 820 *The standard deviation of the mean is approx. 5 ±pct.

Jan 1, 1970

By Henderson, Robert

A GOOD idea of the magnitude of the underground operations at Climax can be gained from the following figures. A little more than 43,000,000 tons has been drawn from the mine and of this amount, 40,500,000 tons has been drawn in the past ten years and 12,000,000 tons was drawn in two of the war years. The maximum daily average output over a period of one month was slightly more than 20,000 tons but during this period, production on certain days was 24,000 tons, and 9000 tons was produced in a single eight-hour shift. This production came chiefly from 260 draw points although all of them were never in operation at one time. The haulage system for these draw points is made up of 7.5 miles of 36-in.-gauge track, and 131,000 ft. of subsidiary drifts and 44,000 ft. of raises have been driven to develop the necessary broken ore reserves for this high production. Power consumption is often considered an index of operating efficiency. In 1943, the year of maximum production, the mine power consumption was 19,223,000 kw.-hr. or 3 kw.-hr. per ton; in 1945 it was 3.5 kw.-hr. per ton. To handle this amount of power, there are four transformer stations and one switch station in the mine. Mr. Garrabrant, the chief electrician, describes the electrical installation in this issue.

Jan 1, 1946

By S. C. Hollister

An evaluation of the function of the engineer, so that means whereby education can best serve his needs can be adopted. THERE has been a steady increase in specialized branches of engineering during recent years. Some of these are simply specializations in the function of engineering, such as welding engineering, tool and die engineering, petroleum engineering, and refining engineering. Others are associated more closely with the basic sciences, as for example, geological engineering or engineering physics. Still others tend toward the border line of business, such as administrative engineering or general engineering.

Jan 1, 1950

By John H. Hollomon, C. Zener

It is commonly recognized that a given material may be described as ductile or brittle only with reference to the conditions of test. Thus under the usual test conditions quartz is brittle, but under high pressures it is ductile. Salts that are brittle at room temperature become ductile at elevated temperatures. Pitch, brittle with respect to rapid loads, flows at low rates of loading. Pearlitic steel, ductile under the usual conditions of test, may be embrittled under the proper conditions of combined stresses, temperature, and rate of loading. Earlier Investigations A clear analysis of the conditions necessary for plastic flow and for fracture was first given by LudwikI1 who introduced two types of stress, the "flow stress" and the "stress at fracture." These stresses may refer to tensile or to shear stresses, or, in fact, to any type of stress. Ludwik considered these two stresses to be independent of one another, functions of the conditions of test and of the prior history of the material. For the purpose of analysis. both a Flow stress and a stress at fracture can be envisaged as functions of strain over the entire range from zero to infinite strain. Thus, the material is brittle if the stress at fracturc is less than the flow stress and ductile if the reverse is true. According to Ludwik&apos;s analysis, the problem of determining the effects of combined stresses, of temperature and of strain rate upon the behavior of metals reduces to a problem of determining the effect of these variables upon the flow stress and upon the stress at fracture. In the present paper, methods are described for determining the effects of two of these variables, temperature and strain rate, and examples are given of the dependence of tlow stress and stress at fracture, upon these two variables. The effect of combined stresses will be discussed in a succeeding paper. The flow stress may be determined from a load-diameter curve. Load-diameter curves were obtained over a wide range of temperature and over the limited range of strain rates obtainable with the lever-type Riehle machine used. The curves were then converted to an extremely wide range of strain rate by making use of the equivalence of the effects of changes in strain rate and changes in temperature, previously proposed2 and demonstrated3 by the authors. According to this principle of equivalence, strain rate e and temperature T affect the flow stress only through a single parameter-p of the form: p = eeQ/RT 111 In this equation, R is the gas constant (2 cal. per gram mol per deg. C.), and Q is a heat of activation, which varies from material to material, and may depend upon the strain, but not upon the strain rate or the temperature. There is associated with every value of p a flow-stress curve. article of strain rate and of temperature that give the same p have the same flow-stress curve. Therefore, merely by changing the temperature of test, the effect of changing the strain rate may be obtained. Thus, under isothermal conditions, the material will behave the same at

Jan 1, 1944

By C. Zener, John H. Hollomon

It is commonly recognized that a given material may be described as ductile or brittle only with reference to the conditions of test. Thus under the usual test conditions quartz is brittle, but under high pressures it is ductile. Salts that are brittle at room temperature become ductile at elevated temperatures. Pitch, brittle with respect to rapid loads, flows at low rates of loading. Pearlitic steel, ductile under the usual conditions of test, may be embrittled under the proper conditions of combined stresses, temperature, and rate of loading. Earlier Investigations A clear analysis of the conditions necessary for plastic flow and for fracture was first given by LudwikI1 who introduced two types of stress, the "flow stress" and the "stress at fracture." These stresses may refer to tensile or to shear stresses, or, in fact, to any type of stress. Ludwik considered these two stresses to be independent of one another, functions of the conditions of test and of the prior history of the material. For the purpose of analysis. both a Flow stress and a stress at fracture can be envisaged as functions of strain over the entire range from zero to infinite strain. Thus, the material is brittle if the stress at fracturc is less than the flow stress and ductile if the reverse is true. According to Ludwik&apos;s analysis, the problem of determining the effects of combined stresses, of temperature and of strain rate upon the behavior of metals reduces to a problem of determining the effect of these variables upon the flow stress and upon the stress at fracture. In the present paper, methods are described for determining the effects of two of these variables, temperature and strain rate, and examples are given of the dependence of tlow stress and stress at fracture, upon these two variables. The effect of combined stresses will be discussed in a succeeding paper. The flow stress may be determined from a load-diameter curve. Load-diameter curves were obtained over a wide range of temperature and over the limited range of strain rates obtainable with the lever-type Riehle machine used. The curves were then converted to an extremely wide range of strain rate by making use of the equivalence of the effects of changes in strain rate and changes in temperature, previously proposed2 and demonstrated3 by the authors. According to this principle of equivalence, strain rate e and temperature T affect the flow stress only through a single parameter-p of the form: p = eeQ/RT 111 In this equation, R is the gas constant (2 cal. per gram mol per deg. C.), and Q is a heat of activation, which varies from material to material, and may depend upon the strain, but not upon the strain rate or the temperature. There is associated with every value of p a flow-stress curve. article of strain rate and of temperature that give the same p have the same flow-stress curve. Therefore, merely by changing the temperature of test, the effect of changing the strain rate may be obtained. Thus, under isothermal conditions, the material will behave the same at

Jan 1, 1944

By N. Brown

IT has been observed that a hexagonal-close-packed crystal will undergo the same macroscopic displacements as an isotropic material if the basal plane is perpendicular to the axis of twist.&apos; Other orientations may produce both bending and twisting, but this analysis will be confined to pure torsion of a right circular cylinder. The z axis, the axis of twist, and the specimen axis are coincident. The displacements are given by Uq = rz, Ur = Uz = 0 [1] where 4 is the angle of twist per unit length. This requires rotational slip, as discussed by Frank&apos; and Wilman, which may be observed readily. The relative rotation of adjoining slip planes is simply produced by a movement of a planar grid of screw dislocations."." The screw dislocations are of the same sign and they move radially inward. For hexagonal-close-packed metals, the grid is hexagonal and the screw dislocations lie in the < 2110 > directions. The displacement of a point is the resultant of two displacements produced by intersecting screws sweeping over the point. The dislocations must pass over the point (r, o) in such a manner that its resultant displacement corresponds to the observed macroscopic displacement. If 6&apos; is measured from the [1010] direction, then for 0 < ? < ~/3, only the [1210] and 121101 type screw dislocations are needed to produce the required displacement. If n1 screws of type [1210] and n2 of type [2110] pass over a point, then, in order that Ur = 0 n, sin ? - n2 sin (/3 — 6&apos;) = 0. [2] If the tangential displacement is to be independent of 0, then n1 cos ? + n2cos (/3 —?) = N [3] where N is independent of ? and thus depends only on r. Nb is the tangential displacement where b is the Burgers vector. Since U? is a linear function of r, then N must be a linear function of r. If a2 is the outer radius and a, is the inner radius to which the plastic deformation has extended, then N = Nm2 r-a1 [4] This function meets the conditions that at

Jan 1, 1956

By John Mathews

IT is a great honor to be asked by. the Board of Directors of this Institute to deliver the Henry Marion Howe lecture. The invitation carries with it a great responsibility, which I accept with considerable hesitation and with a feeling of unworthiness to perform the duties expected of me in this hour devoted to the memory of the life, character, and work of the late Professor Howe. Many of you recall the scholarly address delivered here a year ago by Prof. Albert Sauveur, and the beautiful tribute he paid-to his friend and colleague of many years in the great work of changing the art of iron making into the science of iron. My association with Professor Howe, was of brief duration-only one year-and the relation was that of pupil to teacher. My feeling toward him in later years was always that of a humble disciple at the feet of a master. He attained his third academic degree in the year that I was born. I recall the pride I felt when, after entering the, steel industry, I received from him, from time to time, letters asking for information or, perchance, asking my opinion, and he was always most punctilious in acknowledging the source of such bits of information in his writings. It was also my good fortune to sit at the feet of another great teacher-Sir William Roberts-Austen, at the Royal School of Mines. I mention him because his name was used by Osmond in coining the word "austenite," which is the subject of this address, and Osmond&apos;s suggestion was heartily approved by Howe. These three international metallurgists were the best of friends and delighted to honor the achievements of one another. There are other reasons for mentioning Roberts-Austen at this time. It was an introduction from Howe that opened to me the door of his -laboratory as well as of his heart. It was while at Roberts-Austen&apos;s laboratory that I .worked side by side with William Campbell

Jan 4, 1925

By John A. Mathews

It is a great honor to be asked by the Board of Directors of this Institute to deliver the Henry Marion Howe lecture. The invitation carries with it a great responsibility, which I accept with considerable hesitation and with a feeling of unworthiness to perform the duties expected of me in this hour devoted to the memory of the life, character, and work of the late Professor Howe. Many of you recall the scholarly address delivered here a year ago by Prof. Albert Sauveur, and the beautiful tribute he paid to his friend and colleague of many years in the great work of changing the art of iron making into the science of iron. My association with Professor Howe was of brief duration—only one year—and the relation was that of pupil to teacher. My feeling toward him in later years was always that of a humble disciple at the feet of a master. He attained his third academic degree in the year that I was born. I recall the pride I felt when, after entering the steel industry, I received from him, from time to time, letters asking for information or, perchance, asking my opinion, and he was always most punctilious in acknowledging the source of such bits of information in his writings. It was also my good fortune to sit at the feet of another great teacher— Sir William Roberts-Austen, at the Royal School of Mines. I mention him because his name was used by Osmond in coining the word "aus-tenite," which is the subject of this address, and Osmond&apos;s suggestion was heartily approved by Howe. These three international metallurgists were the best of friends and delighted to honor the achievements of one another. There are other reasons for mentioning Roberts-Austen at this time. It was an introduction from Howe that opened to me the door of his laboratory as well as of his heart. It was while at Roberts-Austen&apos;s laboratory that I worked side by side with William Campbell

Jan 1, 1925

E. Hill, South Norwalk, Conn. (communication to the Secretary*) :—The phenomenon described by Dr. Ledoux, involving an apparently abnormal high temperature in the air-cylinders of compressors, has not been, so far as I know, discussed in technical literature. The common formula for the adiabatic compression of dry air does not account for heat suficient to flash ordinarily decent cylinder-oils, nor do the text-books include in their theoretical statements any quantitative consideration of the effect of leaks in the ideal machines which they contemplate. This lack I have endeavored to supply by preparing, in the form of a circular, for the use of the customers and correspondents of the Norwalk Iron-Works, a brief mathematical

Jan 1, 1904

By Henry Mulryan

DIATOMS are microscopic aquatic plants of the order Bacillariaceae. They are unicellular plants with skeletons made up of amorphous opaline silica. The skeletons show highly ornate, complicated geometrical designs. Diatoms live in water virtually everywhere. They are found in clean sea water, brackish water, and fresh-water lakes and ponds. When conditions are right, diatoms propagate by subdivision in huge numbers. Alkalinity, temperature, and the presence of high concentrations of silica in the water largely control diatom life. When the diatoms die the skeletons drop to the bottom of their habitat to form oozes of vary-ing thicknesses. DIATOMITES Diatomite, or diatomaceous earth, is composed essentially of the siliceous remains of the diatoms, although other organic skeletons are also present, especially in sea-water deposits where radiolaria, sponges and silico-flagellates are common. Impurities are generally carbonaceous material, fine-grained silt, volcanic ash and dust, and occasional coarse grains of sand. Diatomites are marine, brackish, or fresh-water, depending upon types of diatoms and their method of deposition.

Jan 1, 1939

By William P. Mason

FoR reasons unnecessary to enter into here, I was called upon to contradict the statement that " closed metallic vessels, partly filled with water and heated, do not become shattered by violent explosion, but simply rupture by over-pressure;" and the following experimental results were obtained in support of my position : A piece of drawn brass tubing (telescope-tubing) 1 1/2 inches in diameter and 15 inches long was closed at both ends by screwing on heavy caps of bronze. Before closing the second end the vessel was half filled with river water, the cap was then screwed on, and the closed vessel was supported upon two iron anvils, and heated in the interval between the supports by a large Bunsen lamp. The resulting explosion (which was doe to over-pressure only and not to any more occult cause) was exceedingly violent. No small damage was done to the room in which the experiment was undertaken; and the noise was like that of a cannon. Those of the pieces which could be recovered are shown in Fig. 1. Upon examining the wreck, it was noticed that one of the heavy bronze end-caps had preserved its circular section and still contained that portion of the barrel of the tube which had been screwed into it, while the other end-cap contained no portion of the tube, and was moreover sprung into a shape more or less elliptical, as if from excessive lateral strain. It was also observed that the large pieces of the shattered boiler predominated towards the end which had been closed by the un-sprung end-cap. The reasonable explanation, in view of the facts, was, that over-pressure had caused the boiler to yield through the screw-threads at A B, Fig. 2, and the righthand end-cap had blown off, thus leaving the boiler half filled with water, greatly super-heated for the new (atmospheric) pressure to which it was suddenly reduced; that this water had consequently sprung instantly into steam with dynamite effect, shattering the tube and springing the remaining end-cap. The large pieces would be expected at the open end of the boiler, as at that point the "tamping "would have been that of the atmosphere only. This explanation assumes a rupture to have been caused by gradually increased pres-

Jan 1, 1893

R. F. WOOD,* Sandusky, Ohio.-I made a few tests of gun-metal specimens, after I noticed the results on quenching -reported by the Bureau of Standards. The data of one such test are given herewith. The bars were heat treated and quenched before they were machined, and in all cases they were brought up to 700° or 800°. They became extremely brittle,, showed almost no elongation, except such as was caused by the failure of the pieces to fit together after they were pulled, and the tensile stength was reduced from around 35,000 to about 13,000 lb. per sq. in. In addition, the weakening effect of the quenching seemed to be almost as marked when the bar was allowed to slowly air-cool from red to black, and then quenched, as it was by quenching directly from the red heat. Test Bars.-Rough size, 9/16 in. diam. over test section, grips 13/16 in. diam. Cast two in a flask, one on each side of a block 8 by 4 by 1 in. and fin-gated thereto from the grips but not from the test section. Poured with flask in inclined position, with gate to lower end of block and riser from upper end of each test bar. Bars were machined to ½ in. over the test section, after heat treatment. Casting the Bars.-Charge of 1500 lb. consisting of 400 lb. of new metals and 1100 lb. of G turnings and scrap was melted in open-flame oil furnaces and then poured into a 1-ton ladle. From the ladle 150 lb. was poured into a preheated No. 50 crucible, land from this the flasks of test bars were poured. The six flasks are indicated below by the numbers 1 to 6 and the bars in each flask by the letters a and b, thus 4a and 4h, for instance, were the two bars in flask No. 4.

Jan 12, 1919

By E. A. Anderson, P. W. Ramsey, E. J. Boyle

Only a few zinc-rich alloys are in commercial use today, and these depend largely upon solid solution effects for their desirable properties. Typical examples are rolled alloys containing about 1 Per cent of copper, with Or without additions of elements such as magnesium, and die-casting alloys containing about 4 Per cent of aluminum with small amounts of magnesium and sometimes copper." A number of elements are capable of forming alloys with zinc, Which do not enter into solid solution except in limited degree. The Present Paper considers One such system, zinc-titanium, in which alloys having potentially useful properties in the rolled form were found. Zinc-titanium System The zinc-rich portion of the zinc-titanium diagram, as determined by standard methods in this laboratory,3 is shown in Fig. I. The portion of the diagram of significance in the present work extends from 0 to about 0.5 per cent titanium. Gebhardt4 places the eutectic at 0.45 per cent, but the evidence in favor 01 the composition given in Fig. I is considerable. The solid solubility of titanium in zinc is very low indeed and possibly places these alloys in a somewhat different category from the commercial alloys previously mentioned. Alloy Preparation All of the alloys used in this work were prepared with titanium metal of 98.9 per cent purity. In most cases high-purity zinc (99.99 per cent) was used but sufficient work was done later to show that zinc of about high-grade composition would yield approximately equal results. Best practice in alloy manufacture seemed to be to prepare a zinc-titanium hardener by adding about 4 per cent of titanium metal to molten zinc and holding under a boric acid cover, with frequent stirrings, at 750°C, until the titanium had dissolved. The desired titanium content could readily be obtained in the final alloy by adding the calculated amount 01 this hardener. The alloys proved to be quite stable in composition, unless overheated, and, with reasonable temperature control, required no cover or flux to prevent loss of titanium content by oxidatioll, Hot-rollig Tests Three alloys containing, by analysis, 0.05, 0.12, and 0.23 per cent titanium were selected for preliminary study. Slab cross sections a a marked grain refinement* (Fig. 2) in the two alloys of highest titanium content. Cast unalloyed zinc has a columnar grain structure similar to that shown for the alloy of lowest titanium content but without the scatter of small equiaxed grains at the center.

Jan 1, 1944

By P. W. Ramsey, E. J. Boyle, E. A. Anderson

Only a few zinc-rich alloys are in commercial use today, and these depend largely upon solid solution effects for their desirable properties. Typical examples are rolled alloys containing about 1 Per cent of copper, with Or without additions of elements such as magnesium, and die-casting alloys containing about 4 Per cent of aluminum with small amounts of magnesium and sometimes copper." A number of elements are capable of forming alloys with zinc, Which do not enter into solid solution except in limited degree. The Present Paper considers One such system, zinc-titanium, in which alloys having potentially useful properties in the rolled form were found. Zinc-titanium System The zinc-rich portion of the zinc-titanium diagram, as determined by standard methods in this laboratory,3 is shown in Fig. I. The portion of the diagram of significance in the present work extends from 0 to about 0.5 per cent titanium. Gebhardt4 places the eutectic at 0.45 per cent, but the evidence in favor 01 the composition given in Fig. I is considerable. The solid solubility of titanium in zinc is very low indeed and possibly places these alloys in a somewhat different category from the commercial alloys previously mentioned. Alloy Preparation All of the alloys used in this work were prepared with titanium metal of 98.9 per cent purity. In most cases high-purity zinc (99.99 per cent) was used but sufficient work was done later to show that zinc of about high-grade composition would yield approximately equal results. Best practice in alloy manufacture seemed to be to prepare a zinc-titanium hardener by adding about 4 per cent of titanium metal to molten zinc and holding under a boric acid cover, with frequent stirrings, at 750°C, until the titanium had dissolved. The desired titanium content could readily be obtained in the final alloy by adding the calculated amount 01 this hardener. The alloys proved to be quite stable in composition, unless overheated, and, with reasonable temperature control, required no cover or flux to prevent loss of titanium content by oxidatioll, Hot-rollig Tests Three alloys containing, by analysis, 0.05, 0.12, and 0.23 per cent titanium were selected for preliminary study. Slab cross sections a a marked grain refinement* (Fig. 2) in the two alloys of highest titanium content. Cast unalloyed zinc has a columnar grain structure similar to that shown for the alloy of lowest titanium content but without the scatter of small equiaxed grains at the center.

Jan 1, 1944

By Henry W. Edwards

Concrete is not a new, nor even a modern substance. Important structures built by the old Romans before the commencement of the Christian Era are to-day sound and solid— for example, the dome of the Pantheon in Rome, 142 ft. in diameter. I do not propose, therefore, to discuss the durability of the material, as in the mining and metallurgical business, structures, as a rule, are not calculated to endure for two thousand years. I do wish to urge, however, that much of the stone masonry around mines and smelters would have given better results if concrete had been used in place of stone. Concrete looks better; is stronger, cheaper, more durable, more quickly built, and above all requires no skilled labor, except that of the carpenter, who, like the poor, is always with us. Well proportioned concrete, that is to say, having well proportioned ingredients, may be safely relied upon to withstand a compressive or crushing strength of 50 tons per square foot. In most American cities, however, the building laws limit it to the absurdly low figure of 16 tons. This restriction is probably due to the political influence of the building-trades unions, which object strongly to its too free use, undoubtedly owing to its not requiring the services of skilled workmen. I hope to show that quite important construction work may be&apos; undertaken without the aid of the gentleman with the trowel. In some of the isolated districts of the West and Southwest this is no mean advantage. The weight of good concrete, dry, is from 130 to 160 lb. per cubic foot. Ingredients of Concrete. Concrete is composed of four ingredients; viz., 1. Crushed Stone; 2. Sand; 3. Cement; and 4. Water.

Jan 1, 1905

By G. Sachs, E. J. Ripling, J. J. Lynch

It is general practice to evaluate the strength properties of a particular metal from its stress-strain (s1 — el) curve obtained by means of a conventional tension test. Such a stress-strain curve, Fig I, illustrates two important properties of a metal, its ability to strain harden, and its ability to withstand a certain limiting stress, the "fracture stress," (s), and a certain limiting strain, the "ductility" (es), before it fails by separation. These two fracturing characteristics are the coordinates of the point of fracture in Fig I. In the case of a metal which necks in a tension test, both the fracture stress and the ductility (measured in a tension test) are dependent upon (I) the shape of the neck and (2) average values of the stresses and strains over the cross-section at the moment of fracture. However, for the pur. pose of this investigation, these average quantities, rather than the actual values, may be considered for reasons of simplicity. It appears that the conclusiom also hold true if the analysis were carried out for actual values of fracture stress and ductility at the locos of failure. In this paper, the effects of straining (at room temperature) by various methods on the above metal characteristics, which were determined by subsequent tension tests will be discussed. According to Our present knowledge, any such prestrainitlg results in a stress-strain curve (in subsequent testing by tension), Fig 2, the general shape, or flow characteristics, of which can be derived from the original stress-strain curve of the unstrained metal minus a certain portion exhausted by the initial straining. This phenomenon is called strain hardening, and may be measured by the magnitude of the cut-off, or the "effective strain,&apos;&apos; from which the new curve must start in order to coincide in its plastic branch with the original stress-strain curve.

Jan 1, 1949

By E. J. Westerman

Prealloyed powders of nickel-base superalloys were sintered to almost theoretical density in short sinterilzg times. It was ascertained that the rapid densification was caused by a small amount of liquid phase at the grain boundaries, which apparently ovriginated by incipient melting at temperatures considerably below those at which macroscopic melting of the compacts occurred. An increase in the quantity of liquid phase present during sintering-, caused by an increase in the sintering temperature, increased the densification rate, but resulted in a decrease in the room temperature tensile propevties. NICKEL-base superalloys, which presently comprise an important group of high temperature alloys, are difficult to fabricate by the forging, casting, and machining operations presently used. As it was felt that fabrication by powder metallurgical techniques might offer advantages in the production of super-alloy parts, a basic investigation of the most important process in the sequence of powder metallurgical operations, the sintering process, was undertaken on Rene 41, Udirnet 500, and Nimonic 90 and 100 powders. These alloys age harden by the precipitation of the ? Ni, rA1,Ti) phase. Nickel-base superalloys of the Nimonic type have been fabricated by powder metallurgical methods, and their mechanical properties reported in detail.&apos; Other alloys for high temperature service which have been fabricated by powder metallurgical methods include a Co-base alloy of the Vitallium type;2,3 alloys with a Co-Ni-Fe-Cr base;4 stainless steels;5&apos;6 Cr-W-Co alloys;" and a Co-base alloy, X-40.8 METAL POWDERS The superalloy powders investigated were: a) a prealloyed at.omized Rene 41 powder; b) a prealloyed atomized Udirnet 500 powder; c) a prealloyed atom-

Jan 1, 1962

By B. Blumenthal

THE present investigation was planned as a survey of the lead-rich portion of the ternary lead-antimony-silver system by thermal analysis. Since, however, a rigorous application of the conventional thermal analytical method is time consuming, an attempt was made to speed up the investigation by reducing the time required for a single thermal analysis. This was done by increasing the rate of cooling to 12° to 18°C. per minute. Since such a rate does not permit even an approach to equilibrium conditions, the melt was stirred vigorously by a stirrer operating at the high rate of 665 r.p.m. This proved to be effective in obtaining cooling curves with distinct points of arrest and of excellent reproducibility, which satisfactorily compare with those obtained at a rate of 1° to 2°C. per min. with or without slow stirring (Fig. 1). By this method the lead-rich end of the lead-antimony system and a series of ternary alloys in sections parallel to the lead-antimony side of the ternary system were investigated and it was observed that the two branches of the&apos; liquidus curve of the .binary alloys did not intersect at the eutectic temperature. An equivalent effect was observed in the ternary system. The eutectic temperature of the binary lead-antimony system was found to be 252.0°C., which confirms the recent investigation by Pellini and Rhines,1 who determined the eutectic temperature to be 251.5°C. The observation that the curves of primary crystallization of the lead-antimony system do not intersect at the eutectic temperature was previously made by Dean.2 Dean explains the phenomenon by assuming the existence of a compound Sb4Pb. He felt that super-cooling was not the cause of the phenomena because he was unable to influence them by inoculation. The X-ray investigation by Solomon and Morris-Jones,3. the metallographic investigations by Stead,4 Charpy,5 Gontermann,6 and Dean, Zickrick and Nix,7 and the numerous investigations of physical properties, definitely disprove the occurrence of any compound. The work of Dean was not confirmed by Broniewski and Sliwoski,8 whose experiments did not show any irregularity and who report a eutectic composition of 13 per cent antimony and a eutectic temperature of 250° to 252°C. at a rate of cooling of about 6°C. per min. Abel, Redlich and Adler9 then report a eutectic composition of 12.1 per cent upon reviewing the previous, publications and adding a few of their own cooling curves. In 1934 Quadrat and Jiriste10 found from careful analyses of the bottom portion of slowly cooled hypereutectic melts that the eutectic contains only 11,4 to 11.5 per cent antimony. (Previous analyses by Stead4 in 1881 gave 13 per cent:) Weaver," however, reported in 1935 that cooling curves indi-

Jan 1, 1943