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By E. S. Machlin, W. R. Yankee

IN a previous study1 of the effect of heating com-mercial titanium in air on its subsequent friction coefficient against other metals, as well as itself, it was found that the friction coefficient markedly decreased from a value of about 0.7 to about 0.3. A tentative explanation was given that surfaces normally produced at room temperature are not contaminated sufficiently to prevent seizing or welding of the titanium to the softer mating metals. The latter tend to cleanse themselves during rubbing over the harder titanium. It was thought that the lack of a contaminant protective film on the titanium was due to the high solubility of titanium for oxygen and nitrogen and hence an inability to form a contaminant oxide or nitride. This explanation requires the ratio of the surface absorption rate to the diffusion rate to become much lower at room temperature than it is at high temperatures. In order to check the phenomenon further, commercial titanium specimens were nitrided or oxidized at 800°C for 20 hr in flows of prepurified N2 and 01, respectively, at about 1/2 in. H2O above atmospheric pressure. Friction runs were made in argon using a freshly cut copper hemisphere (cut in argon) on surfaces cut successively into the diffusion layers in the titanium (cut in argon) using the techniques described in a previous publication.' DPH values (100 gram load) were made as a function of depth into the diffusion layer using a Tukon tester. Also, micrographs were taken at separate cross sections to indicate the diffusion layers. The results obtained are presented in Figs. 1 and 2, which show the "static" friction coefficient vs hardness for the nitrided and oxidized specimens, respectively. A separate measurement of the friction coefficient of clean copper vs iodide titanium also was made. From results reported in the literature' giving the oxygen and nitrogen contents as functions of the hardness, cross plots were made showing the friction coefficients as functions of the amount of interstitial solute. These plots are given in Figs. 3 and 4. From micrographs of the diffusion layers and the phase diagrams, it was deduced that the data in Figs. l through 4 correspond to the single phase a region. The points observed on the compound regions have been excluded from the figures. It is apparent that nitrogen or oxygen in solution in the a titanium markedly affects the friction coefficient against a softer mating metal. Discussion of Results These results are extremely interesting from both a practical and theoretical viewpoint. The theoretical implications will be discussed first. According to Bowden, the friction coefficient should be given to a good approximation by the relation where a is the fraction of contact area that has welded, a is the shear strength of weaker component, and H is the hardness of softer component. Using this relation alone, it is difficult to understand the results because none of the terms should be affected by a variation in the oxygen or nitrogen content of the harder and stronger metal, titanium. Even if the ratio of S/H for titanium is used in Eq. 1, the ratio has been shown to be independent of oxy-gen or nitrogen content.' If a more rigorous equa-tion is used combining Eq. 1 and a result given pre-viously" for the case where welding is absent, then the relation obtained is µ = a S/H + (1-a) a W aß/H where a is constant and Waß is the work of adhesion between the two metals comprising the friction couple. This relation states that if a is less than 1/2 or so, variation in the work of adhesion Waß between copper and the titanium should affect the friction coefficient markedly. It is reasonable to expect that the work of adhesion will depend on the oxygen or nitrogen content of the titanium. Available data4 show that clean metals and oxides have much lower works of adhesion than the same metals against the

Jan 1, 1955

By A. Coskun, J. F. Elliott

The activity of aluminum in liquid Al-Fe alloys .has been measured by an improved version of the transportation method in which the metallic vapor has been collected by its solution in a metallic condenser. The results can be represented by the equation: log yAl = -3.0(1 - xAl2) (0.6 < XAl < 1.0) This equation applies at 1315°C. MORRIS and zellarsl adapted the transportation method for measuring the vapor pressure of a com- ponent of an alloy at high temperature. We have modified their technique further2 for use with metals that are strong oxide formers. In the present case the method has been applied to the Al- Fe system to obtain the activity of aluminum in the liquid region at 1315°C. Dried ultrahigh-purity hydrogen (Matheson) is the carrier gas. The operations, Fig. 1, of deoxidizing the gas, equilibrating the gas with the sample at 1315";, and then collecting the aluminum vapor are all accomplished within a single, continuous alumina tube to avoid contamination of the system by leaks. De-oxidation to a very low level of PO2 (<10-25 atm) is Obtained by passing the hydrogen through a tightly packed bed of aluminum powder. The temperature of this bed increases to approximately 550°C in the direction of the gas flow. The boat containing three pellets of the alloy is supported on the end of a

Jan 1, 1969

By Murray Kaufman

Using en; 41 for a base alloy, 15 modifications were made in sheet form. The elements Al, Ti, C, Mo, Co, and Cb were varied. The effects on the phases formed and their temperature dependence, the aging characteristics, tensile and stress-rup- ture properties, and weld cracking were determined. The A1-Ti content and balance is the most important factor influencing the major sCrengthening phases [Ni,Ti and Ni,(Al, Ti)] and, consequently, mechanical properties. THE mechanical properties, fabricating and joining characteristics, dimensional stability, and so forth, of alloys containing secondary phases are largely determined by the phases present, their distribution, and their temperature dependence. The phases in the basic ternary and quaternary Ni-Cr-Al-Ti combina- tions have been investigated thoroughly.&apos;* The phase behavior of many commercial nickel-base alloys has been determined also. In some cases, for example U500, 5 the effect on mechanical properties has been found. However, little systematic work has been done to clarify the action of each of the important alloying elements in controlling the phases formed in complex commercial alloys and their behavior. The effect of molybdenum on the carbides formed in M252 was investigated by Beattie and verSnyder.6 Application of the results provided by that work

Jan 1, 1963

By A. J. Fenn

Long experience with underground mining inspired the unusual idea of using an underground crusher-conveyor system as a substitute for surface haulage at the Cananea open-pit copper mine in Sonora, Mexico. Now implemented and working well, the system has born out the expectations of its originator, Cia. Minera de Cananea S.A. de C.V., that it would effect substantial cuts in the high cost of haulage. The Cananea deposit is a large, low-grade orebody above the mined-out Colorada pipe which was once one of the largest high-grade underground deposits in the district. Present facilities at the pit consist of: (1) A large open-pit mine capable of moving 80,000 tons of material per day with a shovel-truck, underground crusher and belt conveyor haulage system. (2) A 25,000-tpd concentrator equipped for four stages of crushing, rod mill-ball mill grinding with cyclone classification, and flotation in conventional machines. (3) A dump leaching process producing 1 million lb of copper per month in a tin-can scrap precipitation plant. (4) A two-reverberatory, six-converter smelter which can make 140 tons of blister copper per day. (5) A well-integrated contingent of supporting departments running the gauntlet from housing to power generation.

Jan 3, 1969

By H. R. Hanley, D. F. Walsh, C. Y. Clayton

Lead-refining practice at the Bunker Hill differs to some extent from that of other United States refineries using the Parkes process, in that the Bunker Hill has reverted to a custom used years ago of making two kinds of skims, or crusts, in the desilverizing kettles. Also, this was the first refinery to adopt the liquation process for silver skims as developed in Australia. Both of these ideas were brought to the attention of the operator by H. S. J. Sommerset, in the summer of 1924, while he was visiting metallurgical plants in the United States, when he was general superintendent of the Broken Hill Associated Smelters Pty., Ltd., of Port Pirie, South Australia. Since Mr. Sommerset&apos;s visit, United States patents on the liquation process have been issued to George Kenneth Williams, of Port Pirie, South Australia. At the Bunker Hill, the lead bullion is conveyed from the blast furnaces to the refinery in brick-lined cast-steel pots, each having a capacity of 5 tons, by a 20-ton electric crane, to which is suspended a Fairbanks-Morse suspension-type scale on which the gross, tare and net weights are obtained. The bullion is poured from the small bullion pots into either one of two kettles of 105 tons capacity, and when a kettle is entirely filled the heavy dross is removed by skimming it into a 5-ton pot suspended by the crane. The crane operator becomes proficient in the manipulation and a kettle is skimmed in a very short time. After the kettle is skimmed clean the bullion is pumped to a kettle of the same size alongside, where the bullion is cooled until it has almost frozen. By using two kettles for the drossing operation, one to accumulate the bullion where the heavy dross is removed, and then pumping to a clean kettle comparatively free of hangings, etc., it is possible to reduce the copper content much lower than if only one kettle is used in the operation. The average yearly analysis of bullion is given in Table 1. During July, August, September, and October, when a considerable quantity of high-grade silver ore from the Yukon Territory is smelted,

Jan 1, 1930

By Alfred Beasley

LEAD-REFINING practice at the. Bunker Hill differs to some extent from that of other United States refineries using the Parkes process, in that the Bunker Hill-has reverted to a custom used years ago of making two kinds of skims, or crusts, in the desilverizing kettles. Also, this was the first refinery to adopt the liquation process for silver skims as developed in Australia. Both of these ideas were brought to the attention of the operator by H. S. J. Sommerset, in the summer of 1924, while he was visiting metallurgical plants in the United States, when he was general superintendent of the Broken Hill Associated Smelters Pty., Ltd., of Port Pirie, South Australia. Since Mr. Sommerset&apos;s visit, United States patents on the liquation process have been issued to George Kenneth Williams, of Port Pirie, South Australia. At the Bunker Hill, the lead bullion is conveyed from the blast furnaces to the refinery in brick-lined cast-steel pots, each having a capacity of 5 tons, by a 20-ton electric crane, to which is suspended a Fairbanks-Morse suspension-type scale on which the gross, tare and net weights are obtained. The bullion is poured from the small bullion pots into either one of two kettles of 105 tons capacity, and when a kettle is entirely filled the heavy dross is removed by skimming it into a 5-ton pot suspended by the crane. The crane operator becomes proficient in the manipulation and a kettle is skimmed in a very short time. After the kettle is skimmed clean the bullion is pumped to a kettle of the same size alongside, where the bullion is cooled until it has almost frozen. By using two kettles for the drossing operation, one to accumulate the bullion where the heavy dross is removed, and then pumping to a clean kettle comparatively free of hangings, etc., it is possible to reduce the copper content much lower than if only one kettle is used in the operation. The average yearly analysis of bullion is given in Table 1.

Jan 1, 1930

By W. C. Ellis, E. S. Greiner

Metallic titanium has been prepared in small quantities since the beginning of the century. Hunter1 reported in 1910 that he obtained a malleable product of 99.9 pct purity by the reduction of the tetrachloride by sodium in a closed container. Later Van Arke12 and Fast prepared small quantities of malleable titanium by thermal decomposition of titanium iodide. Another method for producing malleable titanium from tetrachloride was reported by Kr0ll4 who used magnesium as the reducing agent. More recently Dean, Long, Wartman, and Anderson5 working at the U.S. Bureau of Mines have reported the preparation of the metal on a pilot plant scale by the reduction of titanium tetrachloride by magnesium in an atmosphere of helium. Their product, which is malleable, was used in the present investigation. Early in 1948 after the work of this paper was completed Campbell, Jaffee, Blocher, Gurland, and Gonser6 described the strength and working characteristics of pure titanium which was prepared by the iodide method on a scale producing 300 to 600 g per run, in the form of 0.3- to 0.4-in. diam rods. Their product is characterized by low hardness and large capacity for cold work which they attribute to a high degree of purity with respect to oxygen, nitrogen, and carbon. Titanium has a melting point of about 1725 C," it may be classed as a light metal since the specific gravity is 4.5 g per cc-I. The crystal structure is close-packed hexagonal from room temperature to 885°C. Above this temperature the structure is reported7 as body-centered cubic. The change in crystal structure has been associated with discontinuities in specific heat,8 electric resistanceg and theimoelec-tric force10 at temperatures near 890°C. It is reportedll that annealed titanium has a tensile strength of 78,700 psi which can be increased by cold-work to 123,000 psi. In the present investigation, the lattice constants at room temperature, the thermal expansivity between 30 and 800°C, as well as the electrical resistivity and thermoelectric force against platinum between — zoo and I000 C have been determined. Materials For the measurements, two series of specimens were prepared from titanium furnished by the U. S. Bureau of Mines. The first was made from an annealed sintered compact, 0.38 in. thick. Sections of the compact were cold-swaged with intermediate anneals in vacuum to the sizes used. Sizes over 0.25-in. diam were annealed at I000°C and smaller sizes at 800°C. Specimens originating from the sintered compact are designated in this paper as A. The second series of specimens was made from a rod of titanium, 0.19 in. in diam, which was cold-swaged with the necessary intermediate anneals to the required sizes. This series of specimens is designated B. The impurities in the specimens of titanium, determined by chemical analysis, are given in Table 1. Oxygen and nitrogen which Were not determined by analysis, are probably present although in small quantities in view of the ductility of the material.

Jan 1, 1949

By John E. Dowis

Ore distribution being what it is, many of today&apos;s mining companies are forced to develop foreign reserves to satisfy the demands of their customers. This necessity complicates the economic picture for a company, because management must look well be- yond grade and tonnage to determine the feasibility of developing a foreign orebody. Above all, the taxes on such a development must be assessed. The difference that taxes can make in mining profits will be illustrated here for three countries-Canada, Mexico and the United States. For purposes of comparison, identical orebodies will be assumed to occur in all three countries. Only the taxes on these properties will vary. Grade, tonnage, gross income, production costs and production rates will all be the same. The discussion will be limited to federal taxes, because state and provincial taxes are usually negligible by comparison. Assumptions relative to the orebody and the nature of the company undertaking the operation are as follows: (1) Copper is the only value to be recovered. (2) Sixty million tons of ore have been delineated. (3) Underground mining is required, and the production rate will be 3 million tpy. (4) The life of the property is 20 yr. (5) Operations in Mexico or Canada will be handled by a subsidiary of a U.S. parent company. (6) The subsidiary will offer stock.

Jan 1, 1970

By Kent W. Pilz

Wet dust suppression can be achieved by 1) confinement of the dust within the dust producing area with a curtain of moisture, 2) wetting of the dust by direct contact between the particles and droplets of moisture or 3) the formation of agglomerates too heavy to remain airborne, or too heavy to become airborne, by combining small dust particles with each other and with the droplets of liquid. From the standpoint of economy, availability and safety, water is the ideal fluid; however, it is not as effective for dust suppression as when small percentages of specially formulated dust control compounds are blended with it. Performance of dust control com pounds is related to surface active agents and surface activity. In all liquids there is an attractive force between molecules which varies inversely as the sixth power of the distance between molecules. Thus, in the liquid phase where molecules are crowded together, the intermolecular forces are powerful; whereas in the liquid-vapor phase where the molecules are relatively far apart, these forces diminish rapidly. In the body of a fluid there is an uneven distribution of forces resulting in an inward pull called surface tension. The force which keeps two surfaces apart or causes them to coalesce is termed interfacial tension. Fluids of high surface tension exhibit poor wetting, spreading and penetrating qualities. Water has the unusually high surface tension of 72.75 dynes per cm at 20°C.

Jan 7, 1972

By T. C. King

AT the new Graham-Central Mill of Eagle-Picher, near Galena, Ill., material is simultaneously dewatered and introduced into the ball-mill scoop boxes by the use of variable-speed, 24-in. spiral classifiers. This arrangement has proved satisfactory in that the moisture content of the wet feed is reduced, thus allowing maintenance of density within the mills, and a constant feed at any desired rate to the mills is provided. In this mill the primary feed is wet crushed to minus 1/2 in. and preconcentrated by jigs to produce a bulk lead-zinc-iron concentrate and a waste tailing. The jig concentrate is then dewatered by a conventional dewatering classifier and stored in bins ahead of the ball mills. Even though this material is well dewatered, the discharge at the bin bottom is sloppy because of the gradual drainage of the water from the surface of the particles. Conventional belt feeders with vertical cutoff gates are unsatisfactory because of the flushing characteristic of the wet sand. The new installation employs 24 in. x 10 ft, 9-in. Simplex double-pitch spiral classifiers for feeders from the bin bottoms to the ball mill scoop boxes (fig. 1). These units are arranged with straight tanks and are driven by 5 hp motors through a U. S. Vari-Drive to provide a 4 to 1 speed ratio. Each bin discharges through a chute into the rising side of the spiral. The flushing characteristic of the material from the bottom of the bin is utilized to maintain a steady feed. A small amount of water tapped into the bottom of the bin insures uniform feed to the classifier. Excess clear water drains over the weirs. Feed rate to the mills is controlled by the variable-speed drives. The feed delivered by the spiral at a given speed setting is relatively dry, uniform, and steady, and as such is easily controlled by the operator. The classifiers are set on a pitch of 5 in. per ft and have a sand-raking capacity of from 8 to 32 tons per hr. It is believed that the solution of this problem offers possibilities for the storage of deslimed rod-mill sands and other similar products of the industry.

Jan 1, 1951

By T. C. King

AT the new Graham-Central Mill of Eagle-Picher, near Galena, Ill., material is simultaneously dewatered and introduced into the ball-mill scoop boxes by the use of variable-speed, 24-in. spiral classifiers. This arrangement has proved satisfactory in that the moisture content of the wet feed is reduced, thus allowing maintenance of density within the mills, and a constant feed at any desired rate to the mills is provided. In this mill the primary feed is wet crushed to minus 1/2 in. and preconcentrated by jigs to produce a bulk lead-zinc-iron concentrate and a waste tailing. The jig concentrate is then dewatered by a conventional dewatering classifier and stored in bins ahead of the ball mills. Even though this material is well dewatered, the discharge at the bin bottom is sloppy because of the gradual drainage of the water from the surface of the particles. Conventional belt feeders with vertical cutoff gates are unsatisfactory because of the flushing characteristic of the wet sand. The new installation employs 24 in. x 10 ft, 9-in. Simplex double-pitch spiral classifiers for feeders from the bin bottoms to the ball mill scoop boxes (fig. 1). These units are arranged with straight tanks and are driven by 5 hp motors through a U. S. Vari-Drive to provide a 4 to 1 speed ratio. Each bin discharges through a chute into the rising side of the spiral. The flushing characteristic of the material from the bottom of the bin is utilized to maintain a steady feed. A small amount of water tapped into the bottom of the bin insures uniform feed to the classifier. Excess clear water drains over the weirs. Feed rate to the mills is controlled by the variable-speed drives. The feed delivered by the spiral at a given speed setting is relatively dry, uniform, and steady, and as such is easily controlled by the operator. The classifiers are set on a pitch of 5 in. per ft and have a sand-raking capacity of from 8 to 32 tons per hr. It is believed that the solution of this problem offers possibilities for the storage of deslimed rod-mill sands and other similar products of the industry.

Jan 1, 1951

By Howard H. Fields

Any mining engineer with a desire to operate independently, with some financial backing, and with no fear of heavy responsibility and long hours, should be able to make a comfortable living in Mexico. Barring a few inconveniences such as a lack of satisfactory liability or accident insurance, the difficulty of obtaining repair parts or vehicles, and the length of time required to receive returns from shipments, the operation of small mine is not at all difficult. It is, in fact, a little easier to find a good prospect in Mexico than in the U.S.

Jan 1, 1950

By R. V. Norris

THE wage rates and working conditions in the anthracite. region of Pennsylvania have been governed for nearly 20 years by the award of the Anthracite Coal Strike Commission, appointed Oct. 16, 1902, by President Roosevelt. The report of this com-mission, made in March, 1903, was accepted and, with eight modifications made at various dates, has had .almost the force of law, and has kept this great indus-trial region free from strikes for almost a generation. In 1920, President Wilson appointed an Anthracite Coal Commission, and its report, accepted Aug. 30, 1920, governed wage conditions to April 1, 1922. Actually, the agreements have been for terms of two to four years, and lately, in 1916 and 1920, the employ-ees have continued at work pending the negotiation of new agreements which were made retroactive, and which have all been modifications of the original 1903 award. With the expiration, April 1, 1922, of the 1920 award approaching, Mr. Lewis, president, of the United Mine Workers of America, addressed a letter, on Feb. 20, to the operators, suggesting a meeting on March 15; this date was accepted by the latter, with the notation that the time was short. At the meeting, the Mine Workers presented 19 demands, and advised that if a satisfactory agreement was not reached by April 1.a suspension of mining would occur, contrary to the practice since 1916 of continuing work with a retro-active adjustment.

Jan 6, 1922

By Nicholas J. Grant, Italo S. Servi

SPECIAL polishing and etching techniques were developed during an investigation of the high temperature mechanical properties of high purity aluminum (99.995 pct Al).* Electrolytic polishing was done successfully in the following electrolyte: 5 ml perchloric acid (72 pct), and 95 ml glacial acetic acid. No special precautions need be taken during the preparation of the electrolyte since no appreciable heat of mixing is evolved. Although the electrolyte is not an explosive, it is recommended that Jacquet&apos;s safety rules&apos; be followed during the polishing operation. A voltage of 25 to 60 v gives a good polish in about 2 min at room temperature after preparation on 3/0 metallographic paper. Most of the grain boundaries are visible under the microscope after polishing. Since the current is controlled essentially by the resistance of the bath, it is necessary to keep the anode-to-cathode distance as constant as possible. Accordingly, polishing of irregularly shaped pieces will be difficult. A cooling bath and a stirring system are advisable in order to keep the temperature of the bath uniform and constant. Coarse-grained samples can be macroetched in a few seconds by lowering the voltage below 10 v. This is done after electrolytic polishing, without removing the sample from the bath, Fig. 1. The specimen can be repolished in less than 1 min by raising the voltage above 25 v. The "galvanic etching" technique, which has been described elsewhere,&apos; was found to be helpful not only for macroetching, but also for microetching coarse-grained specimens. In fact, the different orientations of adjacent grains provide good contrast at the grain boundaries, when the sample is observed under polarized light. If the specimen is only partially etched, Fig. 2a, the grain boundaries can be located without completely destroying the appearance of the surface of the specimen. The unetched surface appears black under polarized light. Excellent color contrast is obtained by using a "sensitive tint" plate in the optical system of the microscope. In this case, the unetched surface has a magenta color, while the etched part of the sample assumes different colors varying from green to brown, according to the orientation of the grains. Etch pits were produced on high purity aluminum by using the technique suggested by Lacombe and Beaujard." Good results also were obtained by substituting 70 pct nitric acid for the fuming nitric acid recommended. This gave an etching reagent of the following composition: 70 ml nitric acid (70 pct), 50 ml hydrochloric acid (37.5 pct), and 3 ml hydrofluoric acid (48 pct). An example of the results is shown in Fig- 2b. The outline of the etch pits is revealed sharply if the specimen is observed under polarized light, as shown in Fig. 2c. These metallographic techniques are not suitable for the examination of commercially pure (2s) aluminum. References &apos;P. A. Jacquet: Metal Finishing (Nov. 1949) 47, p. 62. 21. S. Servi: Metal Progress (1950) 58, p. 732. 3 P. Lacombe and L. Beaujard: Journal Inst. of Metals (1947) 74, p. 1._________________________

Jan 1, 1952

By C. P. Kempter, H. L. Brown

Recently Chang determined heat content values of tantalum monocarbide and tungsten monocarbide from 325" to985°Kand 326" to 912"K, respectively, and, using other published data, made certain solid-state calculations for these two compounds. Chang expressed his Cp values in units of cal per "g-atom alloy" OK. We consider this poor usage since l) tantalum monocarbide and tungsten monocarbide are not alloys, and 2) an atom of an alloy does not exist. However, one may convert his values to units of cal per mole OK by merely doubling them. For TaC he calculated a Nernst-Lindemann parameter of 9.07 x lo-&apos; "g-atom per cal". We have refined the calculation of this parameter and have arrived at a much lower value. Rather than approximating the true coefficient of volume expansion, a,, as three times the true coefficient of linear expansion, a, we calculated u, from the TaCo.99, lattice expansion data of Fries and Wahman.38 At 25°C a, = 14.3 x 10s per OC. The molar volume was calculated to be 13.32 cu cm per mole at 25°C. From the lattice compression data of Champion and Drickamer~&apos; for "TaC,.,," we determined the room-temperature compressibility to be 3.5 x 10-l3 sq cm per dyne by plotting l/Vo (aV/ap) vs applied pressure. (Since the lowest pressure at which Champion and Drickamer reported a relative volume was 20 kbars, one may calculate an approximate compressibility only. Chang calculated a compressibility of 3.175 x 10-l3 sq cm per dyne from the same data.) We also used twice Chang&apos;s value of Cp = 4.38 cal per "g-atom alloy" OK for the molar heat capacity at 25°C. From these four values we calculated a Nernst-Lindemann parameter of 5.8 x 10-l4 mole per erg or 2.4 x lo- &apos; mole per cal, and a Cdil value of 2.3 x 10&apos; ergs per mole OK. In the case of tungsten monocarbide no isothermal compressibility has been reported; however, one may calculate an approximate Nernst-Lindemann parameter by using the adiabatic compressibility reported by Brown, Armstrong, and Kempter." Using the WC lattice expansion data of Mauer and Bolz~l we calculated a, to be 12., x l0-&apos; per OC. The molar volume was calculated to be 12.5 cu cm per mole. We used twice Chang&apos;s value of Cp = 4.18 cal per "g-atom alloy" OK for the molar heat capacity at 25°C. From these four values we calculated an approximate Nernst-Lindemann parameter of 2 x lo-&apos; mole per cal, which is much

Jan 1, 1969

With a mine output as high as 5000 tpd and mill capacity of 7000 tpd, the uranium mining and milling complex owned and operated by Kerr-McGee Nuclear Corp. in the Ambrosia Lake area is the largest in the U.S. and is likely to remain so for some time. Next year, Kerr- McGee expects to have in production another mine in Section 19 of the Ambrosia area-and will begin ore production in 1976 at its new $15-million mine at Church Rock, located northeast of Gallup, N. M., where the company has already completed the shaft work and is in the early stages of project development. Ore from Church Rock will be transported to the company&apos;s facilities at Ambrosia Lake for processing. Kerr-McGee&apos;s existing eight mines in Ambrosia Lake go to depths of about 800 to 1500 ft to tap the various horizons of uranium-bearing sands in the Westwater Canyon of the Morrison formation.

Jan 8, 1974

The resin-in-pulp (RIP) ion exchange process was originally conceived by the Atomic Energy Commission in the early 1950&apos;s. However it was developed to commercial success by the Anaconda Co. at its 3000-tpd ore processing mill in Grants, N. M. Essentially, the Anaconda mill&apos;s crushing, grinding and acid leaching operations are the same as at the nearby Kerr-McGee mill, except that Anaconda uses manganese dioxide instead of sodium chlorate as oxidant during acid leaching. The real differences between the two mills become evident when considering how Anaconda treats its leached materials.

Jan 8, 1974

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&apos; that acid-soluble titanium decreased creased the hardenability, with multiplying factors less than unity according to [ ] Grossmann&apos;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.&apos; 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

By W. S. Potter

THE proportions of manganese and carbon in manganese steel are familiar to all, because manganese-steel castings have been well known for a decade or more in this country. The same alloy has now become a commercial product in the wrought state, and, as not only rails and bars are rolled daily but a great variety of forged and otherwise fabricated shapes are appearing, it may be interesting to mark the progress and, perhaps, to look a little closely into the nature of this important material of engineering.

Jan 4, 1914

By William Metcalf

IT is the object of this paper to oppose unnecessary changes, and the introduction of new and confusing terms. From the earliest times of which we have any record on the subject, iron has been divided into general classes. Whether iron was first known in the form of wrought iron or of steel, is a matter of no importance; but at the time when cast iron first became a prominent article of commerce, wrought iron and steel were old products¬steel, at that time, being generally made from wrought iron by the process of cementation. As steel was then properly defined as iron containing more carbon than wrought iron, so cast iron was appropriately defined as iron containing more carbon than steel. Until the year 1776, when Huntsman first began the manufacture of a new kind of iron by melting wrought iron and steel in crucibles, the above definitions were all that could be desired. At first, probably, owing to imperfect appliances, only a highly carburized iron was melted in crucibles, and this led to its being called cast steel. If our ancestors had found a name for this material not involving the use of the word steel, we would have been saved the trouble of the present discussion. As the arts developed, new uses were found for steel, and the products of the crucible were varied, until at the present day it is quite common to find steel containing no more carbon than average wrought iron, and other steel containing nearly or quite as much carbon as some cast iron. All of these various products of the crucible have retained, or received, the name cast steel, usually abbreviated to the simple word steel, without causing any confusion among producers or consumers in regard to terms or their meaning. In 1855, twenty-one years ago, the Bessemer process was introduced ; this was followed in a few years by the Siemens-Martin process, and the products of both were at once, and have ever since been, called steel, from the fact that they were identical in chemical and physical properties with crucible cast steel. At the present time, then, we have three subdivisions of cast steel, viz.: Crucible cast steel, Bessemer cast steel, and Siemens-Martin,

Jan 1, 1877