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By Y. Nakada, U. F. Kocks, B. Chalmers

The stress-strain behavior of the gold single crystals in easy glide was found to be affected by the specimen dimension which is parallel to the projection of the Burgers vector of the primary-slip system. The larger this dimension is, the larger is the slope of easy glide. Previously severa1 investigators attributed the size effects to either the existence of surface films or the grip constraints. However, in this experiment both of these possible causes were not present. It is proposed that the length of slip path (defined as the crystal dimension parallel to the Burgers vector of the primary system) is the controlling factor in the size effect observed in gold. THERE are many possible effects of the specimen dimension on the work-hardening behavior of single crystals: grip effects which prevent end regions of the crystal from deformation or rotation; effects of a surface film, for example a coherent oxide; effects of a subsurface layer of accidental or intentional

Jan 1, 1964

By W. G. Pariseau, C. H. Schmuck, Fei Duan

The Homestake Mine is located in steeply dipping Precambrian metasediaents, an environment common to a number of world class ore bodies. Development of a pronounced plane of schistosity raises a question concerning the importance of anisotropy to the design of vertical crater retreat stopes. Little is known about the actual influence of elastic anisotropy in such -circumstances; even less is known about strength anisotropy. A cautious step- by-step approach was therefore taken towards a numerical assessment of the role of anisotropy in the analysis of stress and stability. The sequence of analyses begins with elementary test problems for computer program checks and proceeds to the analysis of a study stope area between the 6950 and 7100 Levels of the Homestake Mine. Anisotropy (orthotropy) is important at the Homestake Yine. No simple guidelines for evaluating in advance the need for plastic and strength anisotropy in design analysis appear to be forthcoming, ;o that some physical properties testing is necessary where the question is in doubt

Jan 1, 1984

By D. W. Smith

THE beta solid solution phases of the systems copper-zinc, copper-aluminum, copper-tin and silver-zinc are structurally analogous.1 R. F. Mehl and 0. T. Marzke2 have shown that the a phase upon segregating from the 0 phase in the system copper-zinc takes the form of needles lying parallel to a [111.] direction or some similar direction, such as [556], of the parent solid solution, and that the a phase upon segregating from the ß phase in the system copper-aluminum also takes the form of needles. By analogy they assume that in this case also the segregate needles lie parallel to the [111] or [556] direction in the ß lattice. The purpose of this investigation is to determine whether the structures resulting from segregation of the a phases from the respective 0 phases of the systems copper-tin and silver-zinc are analogous to those obtained by Mehl and Marzke in the systems copper-zinc and copper-aluminum.

Jan 1, 1932

By R. Schempp

DURING the past few years, general interest in the steel-producing and steel-consuming industries has been centered on the so-called "inherent characteristics" of steels. While often vaguely described, these char-acteristics are known to influence the response to heat-treatment and the hardening characteristics of the material. Although most of the recent papers and discussions have associated the "inherent characteristics" with the austenitic grain size and empha-sized the importance of it, comparatively little is known of the variables that may affect the size of the austenite grain. The work to be described in this paper was carried out during the course of a study on the inherent characteristics of tool steel containing one per cent cart on. The discrepancies encountered in the determination and classification of the austenitic grain size led to in investigation of some of the variants influencing the austenitic grain size as determined by standard methods.

Jan 1, 1937

By J. Taffanel

I am very much impressed by this manifestation of international brotherhood; the mining engineers on both sides of the ocean have similar subjects to deal with, meet with the same difficulties, expose themselves sometimes to similar dangers…

Jan 1, 1915

By J. M. Oblak, R. F. Hehemann, R. H. Goodenow

STUDIES of surface relief and growth kinetics have lead to the concept that widmanstatten ferrite along with upper and lower bainite constitute a continuous series of decomposition products.1-4 Current models4 propose that these products form as plates with a coherent or semicoherent leading edge which propagates at a rate controlled by diffusion of carbon into the surrounding austenite. There are, however, important crystallographic and morphological differences between these products—particularly between upper and lower bainite. For example, upper bainite appears to exhibit a (11lIy orientation habit, whereas lower bainite develops with a more irrational habit near {2251y.5-7 Many of the morphological features of these decomposition products are not yet well-documented. Recent studiess have demonstrated that low-carbon martensites form as sheets of closely spaced needles on {lllly planes while higher-carbon martensites form as plates with {225}? or other orientation habits. The similarity in the crystallography of these two modifications of martensite with upper and lower bainite is striking. Therefore, a study of the morphology of bainite in a series of hypoeutec-toid alloy steels has been initiated to explore these relationships further. The question of immediate interest is whether upper and lower bainite form as plates or needles. A two-surface (approximately perpendicular) metallographic method was employed to study the morphology of bainite in a variety of low and medium alloy steels. Compositions of these steels have been reported elewhere. The behavior of 4340 and 4370 was typical and will be described here. Austenitizing treatments involved 20 min at 2350°F for 4340 and at 2000°F for 4370. Isothermal transformation was conducted in molten-salt baths. Upper bainite was produced at 925°F in the 4340 steel and lower bainite at 575°F in 4370 with transformation times adjusted to produce 10 to 15 pct of the decomposition product. Many of the morphological features of upper bainite have been catalogued in the recent literature.'' The two principal variants observed in the present investigation are illustrated in Fig. l(a). One form appears as long, thin plates or needles and the other as small, frequently irregularly shaped particles. Both variants may occur as isolated forms but more frequently appear in groups as demonstrated in Fig. l(a). Two-surface analysis reveals that these two variants constitute different sections through a single morphological form. To demonstrate this, a number of sections perpendicular to the plane of Fig. l(a) were prepared at various positions along the length of the elongated particles. A section taken at position 1 in Fig. l(a) is presented in Fig. l(b). Here, the dark line represents the edge of the sample and the left-hand portion of this photomicrograph is that from the surface perpendicular to the original plane of polish. Since it was necessary to repolish the original surface after each sectioning, the shape of the bainite particles on this surface, right hand side of Fig. l(b), changes with each sectioning. The disappearance of plate A, Fig. l(a), in Fig. l(b) emphasizes the small cross section of these structures. The group of particles in the lower left-hand

Jan 1, 1964

By E. Stamboliadis

Dithiophosphates are reaction products of phosphorous pentasulfide with various organic compounds such as phenols, alcohols, mercaptans, dioalcohols, amines, and nitrides. The products with alcohols are commercially known as "aerofloats" and these are investigated in this presentation. It appears that the formation of insoluble metal dithio phosphates is responsible for their collecting properties with minerals." In this aspect they are very similar to xanthates.3 The solubility of metal dithiophosphates depends on the number of carbon atoms in the organic chain of the corresponding alcohol. An empirical mathematical model is presented here. It allows one to predict the number of carbon atoms necessary to ensure that a certain metal dithiophosphate will form at a selected pH value of the water solution. The Nature of Dithiophosphates Dithiophosphoric acid is the product of the reaction of phosphorus pentasulfide with an alcohol, as shown in the following equation: [P2S3 + 4 ROH - 2 (RO)2 PS2H + H2S (1)] where R stands for a hydrocarbon chain. The acid so produced can be neutralized by a base to produce the corresponding salt as shown in the following: [(RO), PS2H + NH- (RO)2 PS, NH,. (2)] In this aspect dithiophosphates are similar to xanthates, the only difference being the substitution of the tetravalent carbon atom in the xanthate polar group by a pentavalent phosphorus atom in the dithiophosphate group. This difference implies at least two characteristics: (1) that there are two hydrocarbon chains associated with the polar group so that an increase in the number of carbons of the single chain is expected to have a pronounced effect on the flotation properties, and (2) that the bond between the sulfur and the central atom is stronger than in the xanthate group. This probably leads to a decrease in both the polarizability of the electronic cloud of the sulfur and the interaction with cations.3 However, what is lost in the dithiophosphates by having a weak polar group can be gained by an increase in the number of carbons as will be seen later. Taking into account the size of the atoms involved in a dithiophosphate molecule, as listed in Table 1, It is possible to draw an approximate diagram of its structure as shown in [Fig. 1]. It is assumed here that the length of the single hydrocarbon chain is equal to that of the corresponding alcohol. Preparation and Purification Acid dithiophosphates can be prepared, as previously mentioned, in accordance with Eq. 1. The rate of this reaction is too slow at room temperature and can be improved by increasing the temperature to about 60° or 80°C7 or by evacuating the system. In our investigation evacuation was performed by a water aspiration pump. The dithiophosphoric acid so produced is liquid and dissolves in the alcohol. At the end of the reaction the product is filtered from the remaining P2S3; and dissolved in petroleum ether. By blowing anhydrous ammonia gas into the ether phase the ammonium salt forms as a white precipitate and can be sepa-

Jan 1, 1977

By T. W. Healy, P. Somasundaran, D. W. Fuerstenau

The flotation behavior of quartz in the presence of alkyl ammonium acetates as a function of alkyl chain length has been interpreted in terms of hemi-micelle formation at the solid-liquid interface. The van der Waals cohesive free energy that is responsible for hemi-micelle formation has been found from these results to be 1.0 kT per CH2 group. This is in excellent agreement with literature values obtained from research on the properties of micelles in bulk systems. Collectors of the type CH3(CH2)n-2CH2-P, where P is a polar group and n is the number of carbon atoms in the straight alkyl chain, will induce flotation of an appropriate mineral at lower concentrations as n increases. This reduction in collector concentration with increasing n has been reported for such systems as xanthates on sulfides1,2 and amines on quartz.' The effect of chain length of alkyl surfactants on such solution properties as conductivity,' surface tension,' and solubility6 and such interfacial properties of solids as contact angle7 and electrokinetic potential8 have received considerable attention, but only limited quantitative descriptions of the effects have been given. The electrokinetic studies of alkyl amine salts on quartz indicated that the solution concentration of collector at which the marked change in electrokinetic potential of quartz occurs decreases systematically as the length of the alkyl chain increases. The aim of the present work was to obtain a quantitative description in terms of current theories of flotation of the effect of the hydrocarbon chain of alkyl ammonium acetates on the flotation behavior of quartz. BASIC PRINCIPLES The marked changes in electrokinetic potentials of quartz in dodecylammonium acetate (DAA) solutions were postulated to result from the association of adsorbed collector ions into two-dimensional aggregates, called hemi-micelles.9 Subsequently, the rapid increase in flotation rate of quartz was shown to coincide with hemi-micelle formation." We would like to discuss briefly the concept of hemi-micelles in terms of recent interpretations of micelles in bulk solution. Micelle hypothesis: In dilute solutions, alkyl ammonium and related salts behave as ordinary strong electrolytes, but at a certain concentration there is a marked change in physical properties of the solutions, e.g., in equivalent conductance, transport number, freezing point lowering and viscosity. To account for these phenomena, McBainl1 introduced the concept of micelles, which are aggregates of long-chain ions. It is believed that the ionic heads of the constituent ions of the micelle are in contact with water, whereas the nonpolar groups turn away from it and are in contact with each other. Work must be done to bring these charged polar groups together, but energy is gained (i.e., so called van der Waals cohesive energy) when hydrocarbon chains are expelled from the water and allowed to associate. For a given polar group, the tendency to form micelles will therefore strongly depend on the hydrocarbon chain length. Theoretical treatments of micelle formation by Shinoda12 and Phillips13 and others lead to the following expression for the concentration at which micelles form (the critical micelle concentration or cmc) in aqueous solutions of long- chain electrolytes

Jan 1, 1964

LAWFORD H. FRY, Burnham, Pa. (written discussion*).-As a sup-plement to the information given by Mr. Bash, a diagram is submitted showing the results of a somewhat similar experiment carried out at the ordnance plant of the Standard Steel Works Co. In this case the ingot to be heated was a nickel-steel octagon ingot, weighing 14,700 lb. (6667 kg.). This ingot was to be forged into two 255-mm. howitzer jackets. A hole was bored half way of the length of the ingot, extending into the longitudinal axis, and a base-metal thermocouple inserted in this hole.

Jan 11, 1919

The Mining and Metallurgical Club of the University of Toronto held a very successful meeting at the Engineers' Club on Jan. 29, 1917. Interesting papers on the Arizona Mining Districts and on the Creighton Mine at Sudbury were read. Several members of the freshman class who have changed from other branches of engineering to mining have been taken into the Club, so that we are now booming. We are also making an attempt to have more of our members apply for junior membership in the Institute, and hope to report favorably along these lines in the near future. C. A. RICHARDSON, Secretary.

Jan 3, 1917

Three. meetings for the presentation and discussion of papers were held in 1914, as follows: The 107th Meeting, including the Annual Business Meeting, in New York, Feb. 16 to 19; the 108th Meeting, Aug. 10 to 14, in Salt Lake City, and the 109th Meeting, Oct. 8 to 10, in Pittsburgh, Pa., under the auspices of Iron and Steel Committee, Committee on Coal and Coke, Committee on Petroleum and Gas, Committee on Non-Metallic Minerals. Local Sections ' Three new local sections were established during the year, namely; / Pennsylvania Anthracite Section, Chicago Section, and Utah Section.

Jan 1, 1917

Attention is called to the changes in officers of the Committee, whereby Albert Sauveur becomes Vice-Chairman, and Herbert M. Boylston, Secretary. Three new members of the Committee have been added, as follows : J. Esrey Johnson, Jr., William Kelly, William R. Walker. The death of Dr. F. WV. C. Schniewind is a severe personal blow to the members of the Committee, as well as a loss on the technical side that will be hard to fill. During the absence of Mr. Kirchhoff in Europe the activities of the Committee will be under the charge of Professor Sauveur.

Jan 4, 1913

An ore search for commercial titanium-bearing ore deposits is in progress by the Crane Co., manufacturers of valves, because they expect this metal to be important in valve manufacturing in the future. The company will eventually be mining and making titanium sponge. At present they are buying titanium tetrachloride from the Stauffer Chemical Co, at Niagara Falls and making titanium by reaction with magnesium. Production from the Babbitt concentrator of Reserve Mining Co. is scheduled to begin in late 1951 or early 1952. The capacity is to be 300,000 tons of pellets per year made from magnetic taconite concentrates.

Jan 7, 1951

* Phosphate from the Maiden Rock deposits in the Missouri River Basin, Mont., are to be developed by the Victor Chemical Works of Chicago. A $5 million plant for processing the rock into elemental phosphorus is to be constructed in the vicinity of Butte. The plant will receive power from the Bonneville Power Administration. * Tests are being made to determine whether iron pellets from taconite concentrates will boost blast furnace and open hearth output at the Campbell Works of the Youngstown Sheet & Tube Co. About 35,000 tons of iron pellets have been shipped from Minnesota for this purpose.

Jan 2, 1951

Full details of the program for the New York meeting .were given in the January Bulletin and the announcement mailed to members. The following brief synopsis is offered simply as a reminder of the principal events of this meeting which Chairman Browne says is going to be "different." Time.-Monday, Feb. 14, to Thursday, Feb. 17, 1916, inclusive. Place.-Engineering-Societies' Building, 29 West 39th St., New York. Events.-Monday, Tuesday and Wednesday (Morning and Afternoon) Technical Sessions. Tuesday, 10 a. m.: Annual Business Meeting, Luncheon served in the-Engineering Societies Building between sessions each day.

Jan 2, 1916

By G. A. Josey, T. P. Floridis

INFORMATION on the effect of alloying elements on the solubility of sulfur in solid iron alloys is limited to the effects of carbon,' manganese,' and Silicon.Refs. 3 to 5 provide information on the combined effects of silicon and manganese also. In the investigation reported in this communication, the effect of chromium, copper, nickel, and vanadium on the solubility of sulfur in solid iron was determined at 1000". The specimens for this investigation were prepared by melting electrolytic iron and reagent-grade alloying additions in an induction furnace under an argon atmosphere. The melts were allowed to solidify in

Jan 1, 1969

By H. W. Mead, C. E. Birchenall

SELF-DIFFUSION of cobalt has been investigated by Ruder and Birchenall,1, 2 Nix and Jaumot,3 and Gruzin.4 The results for a given tem- perature differ by a factor of about six in the extreme cases with no really close agreement between any two sets of data. The first two groups of investigators employed the decrease of surface activity method. Since Ruder and Birchenall have shown that the values obtained from this method are sensitive to the surface preparation, it seemed desirable to perform a few check experiments by a method not open to this objection.

Jan 1, 1956

"IRON for iron" may soon be the primary concept of Mexico's mining industry. If reports that President Adolfo Ruiz Cortines intends to extend federal control over mining are true, Mexico will export iron ore to the U. S. only in return for machinery. Actual exporter will be the Federal Government, with negotiations through the Bank of Mexico. Shipments of iron ore, under this kind of arrangement, can be tightly controlled, assuring that machinery and heavy equipment instead of dollars are the means of payment. Expansion of this policy in the next few years can be expected according to reports.

Jan 6, 1953

By H. C. Fiedler

It was recently shown with 3.3 pct Si-Fe containing 0.026 pct S and 0.06 pct Mn that the extent of secondary recrystallization to a cube-on-edge texture is determined by the cooling rate from the solution temperature of the manganese sulfide inclusions.1 With a rapid cooling rate, many small inclusions rather than a few large ones are formed, which leads to increased restraint to normal grain growth and more complete secondary recrystalliza-tion. Strip samples 12 mils thick, rolled from 1-in.-thick slabs that were cooled at 130°C per min

Jan 1, 1964

By R. R. Odman, O. N. Lofgren

At the planning stage for this plant it was scheduled that the plant operate at a low energy consumption. After start up in 1973 it was established that outcome was even better than the forecast. In view of the 1977 ore market it was decided to operate the plant at half capacity. This initiated efforts to reoptimize the process in order to hold back expected increase in energy consumption. The result from this work proves that a detailed study and tuning of the process can not only avoid expected increase, but also reduce specific energy consumption.

Jan 1, 1983