Search Documents

By J. B. Caine

THE investigation outlined in this paper was carried on at the plant of the Sawbrook Steel Castings Co., Lockland, Ohio. EFFECT OF TEMPERATURE In the study of the effect of temperature, heats were made with the Sawbrook company's standard practice, using multiple slags, the only difference' being that the heats were tapped at two temperatures; one group between 2960° and 3040°F and the other group between 3200° and 3250°F. Slags were weighed throughout the heat at each slag change and after the heat was poured. Only the significant slag weights, those of the total slag and the finishing slag, have been reported.

Jan 1, 1947

By V. D. Tathavadkar

Chromite ore is of immense importance for the extraction of metallic chromium and chromium chemicals. The mineralogy and crystal structure of chromite phase are therefore important part of our investigation on the extraction chemistry of chromium species. In this investigation, we have studied the effect of the processing parameters, i.e., the temperature and the oxygen potential on the microstructure and composition of mineral phases formed in the Cr2O3 ?Al2O3 -FexOy -MgO system. In particular the importance of the spinodal decomposition reaction is emphasized in the extraction of chromium as sodium chromite and sodium chromate. Experiments were carried out in order to study the differences in the crystallography of different chromite minerals. Phase equilibria in natural chromite minerals were investigated by calcining chromite mineral in air, argon, and 5% hydrogen + argon atmospheres over a temperature range from 200 to 1200 °C. The effect of the oxygen partial pressure and temperature on the phase constituents of the calcined product has been discussed. The microstructural changes were examined using scanning electron microscope (SEM) and the changes in elemental composition in different phases were analysed by electron probe micro analyser (EPMA). The results obtained from EPMA studies were used to calculate lattice parameter of the spinel lattice, and these values were compared with the values obtained from X-Ray powder diffraction data. On the basis of the experimental data, the mechanism of the spinodal decomposition of complex spinel phases is described under the influence of oxygen partial pressure and temperature.

Jan 1, 2000

By Sebastian Fredes, Williams Calderon, Mauricio Toledo, Gonzalo Montes-Atenas

The influence of the temperature on leaching kinetics of copper-bearing minerals has been widely acknowledged: the leaching of copper oxide ores is generally described as exothermic reactions while copper sulfide ores are associated with endothermic reactions. Reports studying the influence of temperature on leaching kinetics at laboratory scale frequently involve the implementation of either fully flooded isothermal systems or jacketed column setups. Nevertheless, at industrial scale controlling or monitoring the temperature or temperature changes is almost impractical. In fact, leaching process is usually a large tonnage operation and changing the temperature of vast amounts of material would require an enormous amount of energy and highly specific heat transfer equipment. Preliminary computations on the amount of energy required to increase the temperature of a heap or dump in 1°C indicates that it would be impossible to find an energy source able to accomplish the task. In order to provide a solution to this matter it is suggested to create an energy managing protocol (EMP) that permits heat up or down the porous body locally taking advantage from the temperature gradients and from the reactivity of different regions within the material as a function of the leaching cycles. The aim of this study is to evaluate different heat transfer regimes in a 1 ton pilot column leach operation. It was found that best results of copper recovery are obtained when heating up the column in horizontal bands starting from the top of the column moving downwards as the leach cycle evolves. The system is expected to be suitable for industrial applications, but further development of the technique is required, particularly in the design of the heat transfer dispositive.

Jan 1, 2014

By I. U. Onyenanu, C. E. Ilochonwu, E. I. Nwonye, C. O. Nwajagu

This work shows how pure silica was derived directly from rice husks ash (RHA) in different temperatures for reduction to Silicon (Si). The processes to form Si materials are usually complex, costly and energy-intensive. The silica in the ash undergoes structural transformations depending on the conditions of combustion. A high purity silica was produced at 650oC after burning the rice husk (RH) for up to 7 hours. The purity of the silica was determined by dissolving the RHA with alkali solution to form sodium silicate solution of pH 11.0. This was added to hydrochloric acid of pH 1.5 which lowered the pH of the solution to 4.0 to form silica gels. The silica gels produced were washed and dried to powder and then characterized using XRD and EDX techniques. This study was done to reduce energy waste and environmental pollution in Nigeria as silica is used to develop many materials.

Jan 1, 2015

By H. R. Manouchehri

Large variations in flotation characteristics of minerals have been observed in winter and summer in plant practices as a result of changes in pulp temperature. Variations in temperature may affect the quality for pulp and related process water through changes in dissociation of different chemical species within the pulp, as well as changing in gas and metal hydroxide solubility, reagent adsorption and its stability on mineral surfaces, water/pulp viscosity, etc. All of these affect the flotation characteristics of specific mineral to some degree or another. It has been observed in Cu-Pb-Zn and/or Pb-Zn sulfides flotation that sphalerite (ZnS) flotation is strongly affected by changes in pulp temperature. Plant practices have shown that at the both low, e.g., T <10-12°C, and high, e.g., T > 60°C, the recovery for copper activated sphalerite is dramatically dropped. Within this paper the effect of pulp temperature on flotation characteristics of sphalerite is brought into considerations and laboratory flotation tests were conducted in conjunction with surface and solution chemistry analysis to understand the effect of temperature on sphalerite recovery. The effect of temperature seems to be complex since the temperature affects both the physical (hydrodynamics) and chemical phenomena in the flotation cell. In fact all sub-processes in flotation, i.e., collision, attachment and detachment, are affected by changing in temperature. Experimental results indicating that at alkaline pH values, e.g., 8.5 to 10.5, the recovery for copper-activated sphalerite is dramatically reduced when temperature is below 10-12°C, which is in agreement with plant practice at Boliden?s Garpenberg plant in Sweden. However, results from other studies indicated that the zinc recovery is also considerably decreased at high pulp temperatures, i.e., 62°C and above.

Sep 1, 2012

By Hui-bin Wu, Rui Yuan, Yang Gu, Peng-cheng Zhang, Zheng-zhi Zhao

The corrosion behavior of three kinds of medium-Cr rolled steel pipeline steels in carbon dioxide collecting and transporting environment at different temperatures was studied. The results shew that the 5Cr sample was most affected by temperature. When the temperature rised from 30 °C to 90 °C, the corrosion rate increased from 0.12 mm/a to 1.87 mm/a, which was increased 15.6 times. The corrosion rate of 7Cr steel at 30 °C was similar to that of 5Cr steel. However, as the temperature increased, the corrosion rate rised slowly, increasing by 2.4 times at 90 °C. The corrosion rate of 9Cr steel was not obvious with temperature, and it was always below 0.06 mm/a. The thickness of the corrosion product film of the three samples gradually increased below 70 °C, and suddenly increased above 70 °C. This was related to the negative temperature coefficient of the solubility of FeCO3, and the thickening of the product film also affected the ion exchange of the cathodic reaction. An increase in the Cr content contributed to grain refinement and increased the proportion of the small-angle grain boundaries. More fine grains mean an increase in the total length of the grain boundaries, which could provide a diffusion channel for the free Cr element; on the other hand, the low-angle grain boundary structure was more orderly, with a lower free volume and lower interface energy. Under the combined effect of both, 9Cr steel and 7Cr steel had high volta potential and better corrosion

Oct 1, 2019

By Z. Zhang, Zongshu Zou, Nan Wang

"Thermodynamic calculation is applied to make an investigation on the equilibrium phase relations and liquids of CaO-SiO2-Al2O3-FeOx system for different temperatures. The calculated results with FactSage6.1 show that the effect of temperature on the the equilibrium phase relations and liquidus of CaO-SiO2-Al2O3-FeOx system and its sub-systems is appreciable. The liquid phase regions enlarge with increasing temperature from 1573K to 1873K, while the primary phase fields reduce distinctly.IntroductionThe main oxide components of vitrified bottom ash slag are CaO, Al2O3, SiO2, Fe2O3, MgO, and Na2O, accounting for more than 90% of the bottom ash by weight[1]. During slag processing, the knowledge of thermodynamic properties and liquidus temperature in the related slag systems is highly required [2, 3], which is not yet available. Through literature survey [4-6], it is clear that the systematic information on the concerned complex slag system is scarce. So far the engineers in the field have to make assumptions of the thermodynamic properties of the simplified oxide system, without taking into consideration the interactions of the different oxide components, which hinders the development of the slag valorization and utilization. In order to provide thermodynamic properties for the application of the vitrified bottom ash, the six-component oxide system (CaO-MgO-Al2O3-SiO2-FeOx-Na2O) is highly required. A preliminary phase diagram of the CaO-MgO-Al2O3-SiO2-FeOx-Na2O system can be obtained from extrapolation of the thermodynamic functions of constituent subsystems such as CaO-SiO2-FeOx-MgO, CaO-SiO2-FeOx-Al2O3, CaO-SiO2-Na2O-MgO and CaO-SiO2-Na2O-Al2O3. In this work, the equilibrium phase relation and liquidus of CaO-SiO2-FeOx-Al2O3 system, one subsystem of the concerned complex slag system, are calculated and the effect of temperature is also discussed."

Jan 1, 2012

By Ahmad Ghahreman, Lin Li

"In this study, the Fe(II)/Fe(III) redox reaction kinetics on the surface of pyrite, have been investigated in a 0.5 mol L-1 sulfuric acid solution for a temperature range of 22 to 65°C. Based on mixed potential theory, chronoamperometry is introduced to study the Fe(II)/Fe(III) kinetics by subtracting the current density of pyrite oxidation in an iron-free acidic solution from that in an iron-containing solution at the same applied polarized potential. Tafel behavior was established by this method to analyze the kinetics of the Fe(II)/Fe(III) redox reactions. The results showed that exchange current densities increased slightly with temperature, however remained on the order of 10-5 A cm-2. The activation energy for Fe(II) oxidation and Fe(III) reduction on the pyrite surfaces was calculated to be 102.0 and 32.7 kJ mol-1, respectively. Anodic transfer coefficients also increased, from 0.24 to 0.39, with increasing temperature, which indicates a weakened n-type semiconductor property at higher temperatures. Electrochemical impedance spectroscopy measurements have indicated that at lower anodic over potentials the charge transfer is the rate determining step of pyrite oxidative dissolution in sulfuric acid solution. In the presence of Fe ions, the major contribution of the total current density comes from the Fe(II)/Fe(III) redox reaction. INTRODUCTION Pyrite, an abundant sulfides mineral in the nature, is commonly considered a valueless gangue mineral frequently associated with other valuable sulfide minerals such as chalcopyrite, or metals such as gold, or coal (Lin & Say, 1999). Pyrite oxidation has been the subject of extensive research in view of gold metallurgy, as oxidation of pyrite is the initial step to break down the pyrite lattice and expose the encapsulated fine gold particles (Gasparrini, 1983). Fe(III) ion and dissolved oxygen (DO) have generally been considered as the two most important oxidants with respect to pyrite oxidation, having been studied extensively in previous research (Zheng, Allen, & Bautista, 1986; King Jr & Lewis, 1980). The process of pyrite oxidation can be viewed as a series of reactions amongst pyrite, ferrous, ferric and oxygen in which pyrite is initially oxidized by the dissolved oxygen in water forming ferrous (Eq. 1), and then the ferrous also is oxidized by he dissolved oxygen to form ferric (Eq. 2). The ferric, produced by reaction 2, then could potentially oxidize pyrite (Eq. 3) and convert to ferrous."

Jan 1, 2017

By I. Nishkov, L. Alexandrova

The kinetics of froth flotation and the three-phase contact (TPC) parameters are studied at temperatures varying from 20°C to 40°C. The material floated consists of glass spheres and a quartz particles with various diameters. Dodecylamine hydrocloride (DDAHCI) is used as a collector. The equilibrium three-phase contact angle is measured with a microscope technique using the modified Mingins-Scheludko method. Using a Wilhelmy method, the temperature effect on the surface tension of the DDAHCI solution is determined. The formation of the thin film on a polished plate of vitreous silica and the expansion of TPC is monitored by means of a metallographic microscope and recorded on a attached camera at different temperatures. The experimental data show an intensification of the flotation kinetics at 30 and 40°C in the case of small particles. Such an intensification is not observed with the larger particles. The cause for intensification of the flotation kinetics is sought for in the dependence of the TPC rate of expansion and induction time on temperature.

Jan 1, 1995

By H. T. Byck

THE plastering properties of six representative California drilling muds were studied over a temperature range of 70° to 175° F. at several mud weights, using a high-pressure circulating filter press with full size consolidated cores. In all tests, with untreated as well as with chemically treated muds, the filtration rates at elevated temperature were higher than at low temperatures and in nearly every case this increased filtration rate was notably larger than could be attributed alone to the decreased viscosity of water-the flowing medium-at elevated temperatures. It is concluded that no existing method will permit even an approxi-mate determination of the filtration rate at high temperature from data at room temperature. It is necessary to measure filtration at the tem-perature actually anticipated in the well, or to make a sufficient number of tests at various lower temperatures so that a small extrapolation of these data to the anticipated well temperature may be applied. Such tests should be carried out on the mud as actually used in the well. The viscosity of each of the muds was determined over the same temperature range. While no relationship was observed between mud viscosity and plastering properties, it was found that chemical treatment of the muds for viscosity reduction shifted the temperature of minimum viscosity to appreciably higher values than for untreated muds.

Jan 1, 1939

By Zhucheng Huang, Ronghai ZHONG, Tao Jiang, Jun ZOU

The method of reduction roasting and magnetic separation of low-grade, micro- fine disseminated refractory iron ore following granulation with coal produced unexpected success. Pellets of iron ore with diameter between 3 and 8mm were granulated with coal, bentonite and water. The raw pellets and reduction products were analyzed by scanning electron microscopy and x-ray diffraction. Results show uniformly distributed coal powders inside the pellets improved the kinetics of the reduction process and accelerated the reduction rate. Reduction time was higher at temperatures below 890℃, which resulted in the formation of substantial amounts of fayalite. When temperature was increased, micro- fine hematite was then quickly reduced to iron metal and the amount of fayalite decreased sharply. When pellets were reduced at 950℃ for 25min, reduction products with 56.73% metallization rate were obtained. After grinding and magnetic separation, a concentrate with 72.18% Fetot was obtained.

Jan 1, 2015

By B M. Washington, R R. Lovel, G J. Sparrow, M J. Fisher-White

"Work in CSIRO with several Australian ores has shown that?by heating a high-phosphorus goethitic iron ore and then leaching with caustic or acid, the phosphorus levels in the ore can be lowered to a commercially acceptable value of around 0.08 weight per cent phosphorus (P). With increasing heating temperatures up to 1300¦C, the extent of phosphorus removal increased. This is considered to be associated with mineralogical changes in the iron oxide phases in the ore during the heating.Little phosphorus was removed from four high-phosphorus goethitic iron ores containing 0.12 - 0.16 weight per cent P in leaches with boiling water. However, leaches with sulfuric acid removed ten to 20 weight per cent of the phosphorus and leaching with sodium hydroxide removed even more phosphorus to produce leach products containing between 0.08 and 0.12 weight per cent P from three of the ores.After heating at 300¦C, leaches at a low pulp density of 0.5 weight per cent solids with 1 - 5 M NaOH and 0.1 - 1 M H2SO4 gave leach products with 0.06 - 0.09 weight per cent P. The lixiviant concentration required and extent of phosphorus removal depended on the ore. At a higher pulp density of 25 weight per cent solids, leach residues with between 0.07 - 0.14 weight per cent P were obtained.More phosphorus was removed from ores heated at 900¦C. Leaches at both the low and high pulp densities, with 1 - 5 M NaOH and 0.1 - 1 M H2SO4, gave leach products with 0.05 - 0.09 weight per cent P. However, the lowest phosphorus levels were obtained after heating the ores at 1200 or 1300¦C and leaching with 1 M NaOH or 0.1 M H2SO4. Leach residues with 0.02 - 0.06 weight per cent P were obtained, even from leaches at the higher pulp density of 25 weight per cent solids. Leaching tests on heated samples under heap leaching conditions at ambient temperatures have shown that phosphorus levels can be reduced to similar levels to that achieved in an agitation leach within ten days.CITATION:Fisher-White, M J, Lovel, R R, Sparrow, G J and Washington, B M, 2013. Effect of temperature on removal of phosphorus from Australian Goethitic iron ores, in Proceedings Iron Ore 2013, pp 373-380 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

By Strathmore R. B. Cooke, Iwao Iwasaki, Hyung Sup Choi

The effect of temperature as a parameter in ore flotation has not been systematically studied, although for some ores it has been known for many years that selectivity and grade of concentrates can be improved by conditioning or flotation at moderately or substantially elevated temperatures. In 1934 Coghill and Clemmer&apos; stated that "elevated temperature seems to make hard water more tolerable" in soap flotation, and a cursory examination of the literature indicates that some earlier investigators were aware of beneficial results obtained by floating above room or mill-water temperatures. Tartaron,&apos; Mitchell et al.,3 and particularly Hamilton et al." have shown that high pulp temperatures give high recovery and selectivity in soap flotation of fluorite from a variety of gangue minerals. As a result of the work of these and of other investigators, high-temperature flotation has been successfully applied to industrial flotation of fluorite. Falconer" stated: "The use of high temperature conditioning (above 35°C and preferably above 60°C) in connection with the soap flotation of nonsulphide ores, as covered in B. Kalinowski&apos;s French Patent No. 847,- 215, Dec. 7, 1938, is claimed to provide more intense activation, better separation of values from gangue, and reduction in quantity of reagents." The various investigations quoted above clearly demonstrate the improvements to be realized by increasing the temperature at which fluorite is floated, and it is surprising that little or no information has been published on systematic investigation of the same method as applied to other ores.

Jan 5, 1960

By G. O. Oniyide, H. Yilmaz.

"This paper presents the result of the research done on the effect of temperature on the dilatancy of rocks from the Bushveld Igneous Complex (BIC), where the South African Platinum mines are located. The BIC has higher virgin rock temperature (VRT) than the gold mines of the ‘Witwatersrand Basin Complex’. If the platinum mines advance to ultra-deep levels as the gold mines, since the Merensky Reef has been reported to extend beyond 5km, then the virgin rock temperature at 5 km below surface would be approximately 140oC. Hence, there is a need for the investigation of rock behaviour at high temperatures. Five different rock types (norite, leuconorite, mottled anorthosite, pyroxenite and chromitite) were tested in a 2600 kN servo-controlled multi-purpose triaxial testing machine. The tests were done at a constant strain rate of 5 x 10-1 S-1 and a confining pressure of 10 MPa within temperature range of 20 °C (ambient temperature) to 140 °C. The results show a general strength reduction and increasing dilation angles with increasing temperatures. The results also demonstrate that dilation angle is close to the internal friction angle at lower temperatures; however, they are greater at higher temperatures.INTRODUCTIONMany challenges are faced with increasing depth of mining in underground mines. The most obvious are heat, in-situ stresses and those associated with logistics. Issues related to underground heat have mainly focused on the side effect of heat on workers' health, increasing production costs as a result of higher cost of ventilation. The effect of increasing temperature with increasing depth on the behavior of rock has not been given much consideration. Generally, gold mines in South Africa are deeper than the platinum mines but the latter have higher temperature gradient, which makes the platinum mines to be warmer at similar mining depths. Although the study of the effect temperature on the behaviour of rock can be beneficial to both gold and platinum mines, the focus of the research is limited to the platinum mines because of their higher temperature gradient. Donoghue (2004) stated that the virgin rock temperatures (VRT) and air temperatures increase with depth, due to the geothermal gradient and auto-compression, that is, compression of air by its own weight."

Jan 1, 2015

By O. Ofor

Finely-ground hematitic ore, too high in silica (quartz) to be commercially viable, was treated by emulsion flotation. A three-component emulsion mixture was used at temperatures ranging from ambient (22° C) to 30° C, 40° C, 49 °C, 59° C and 68° C. The optimal emulsion dosage and composition at ambient temperature were used to determine that dosage for higher-temperature flotation tests. The crushed ore (100%, -8 mesh) was repeatedly washed with tap water, and the filtrate&apos;s ionic content was analyzed. The separation efficiency values (a measure of the selective separation and concentration of hematite from gangue minerals) demonstrated temperature dependence, with marked increases at temperatures above ambient. The optimal separation efficiency occurred within the range from 30° C to 60° C. The improved separation efficiencies at temperatures exceeding ambient are explained by quartz depression. This depression is attributed to: • the precipitation of quartz-activating cations, principally calcium and magnesium, at increasing temperature; and • temperature&apos;s effect on the collector&apos;s solubility and attachment to the aqueous hematite surface.

Jan 1, 1993

By B. I. Routh

A STUDY of the effects of temperature on the gel strength of drilling muds is a natural outgrowth of the present era of deep drilling. The control of the gel solids&apos; is now considered important because it affects the wall-building qualities; the suspension of weighting material; the removal and release of sand, cuttings, and gas; and the control of cav-ing formations. With regard to the effect of temperature on gel strengths Herrick2 states: "Temperature variation within ordinary limits does not have much effect on yield points." Lewis, Squires and Thompson3 investi-gated one clay and found no marked change with temperature in either yield point or mobility. Reed4 found that potassium bentonite showed a great increase of gelation with increase in temperature and qualitatively there occurred a marked increase in viscosity upon heating. The apparatus used in these experiments consisted of a Stormer viscosimeter, Marsh funnel viscosimeter, rectangular and cylindrical shearometers, Mudwate hydrometer, and other minor laboratory equip-ment. The various methods of measuring viscosity and gel strength have been extensively described by Evans and Reid.5

Jan 1, 1938

By P. Somasundaran

Electrochemical properties of silicate minerals govern their behavior in processes such as flocculation and enhanced oil recovery that can occur at elevated temperatures. Knowledge of these properties as a function of temperature can be helpful in developing an under- standing of the role of these interfacial properties at non-ambient temperatures. Zeta potential of Sodium Kaolinite and quartz has been determined as a function of pH and temperature in this work. Both systems exhibited markedly different behavior at higher temperatures and also exhibited significant hysteresis. Results are examined in terms of possible dissolution of the minerals and surface reactions at different temperatures.

Jan 1, 1986

By C. H. Jr. Herty

IRON oxide .(Fe0) plays an extremely important part in the manufacture of steel. In the open-hearth furnace and the Bessemer converter it is the chemically predominant compound and controls to a large extent both the operation of the furnaces and the composition and quality of their products. Almost all of the refining action is carried out through the medium of FeO, which oxidizes carbon, manganese, silicon, and phosphorus. At the end of any open-hearth or Bessemer heat the steel contains dissolved iron oxide, which must be wholly or partly eliminated. The type of deoxidation product depends on the amount of dissolved iron oxide and on the deoxidizer used. After the heat has been deoxidized and while it is being teemed, iron oxide diffuses from the ladle slag into the metal, causing losses of deoxidizer and increase in iron oxide content of the steel. It is generally believed that non-metallic inclusions are responsible for a great many failures of steel in service and for decreased yield of steel during rolling. The basis of most non-metallic inclusions is dissolved iron oxide. This investigation was undertaken in order to determine the amount of iron oxide that will dissolve in iron under various conditions. Steel-making slags are complex and it has been thought best to determine solubility under simple slags as a first step. The study is being continued under slags whose compositions approach those of operating. slags.

Jan 1, 1928

By John Chipman

IT has been long known that the gas evolved during the boil in the open-hearth furnace is mainly carbon monoxide associated with smaller quantities of other gases. A number of attempts have been made to determine the precise effects of carbon and oxygen content of the bath, and of other factors, such as temperature, upon the evolution of carbon monoxide. In his investigation of the carbon-iron oxide product in liquid steel, Herty1 showed that the value of this product at equilibrium could be approximated by plotting the value of the product observed in open-hearth reactions against rate of carbon elimination, and extrapolating to zero rate. The results of this study showed a slight but definite effect of temperature upon the carbon-iron oxide reaction. Experimental studies of the evolution of gases from rimming-steel ingots have not yet attained the degree of precision necessary for an exact understanding of the effects of pouring temperature, carbon content, and iron oxide in the metal upon the composition of these gases. Klinger2 showed that the gas consists mainly of carbon monoxide, and that con-siderable variation in its composition occurs during the solidification of the ingot. In order that these variations may be understood in their proper relationship to the progress of solidification of the ingot and the segrega-tion that accompanies solidification, it is essential to have a knowledge of the condition of equilibrium in the several chemical reactions by which the gases are being formed. It is also necessary to understand the effects of temperature upon the equilibria, and further, to know the manner in which the temperature of the liquid metal within the ingot changes as the skin of the ingot is being built up. The reactions in which we will be chiefly interested are those involving in the one case the oxides of carbon, and in the other case steam and hydrogen, with iron oxide and carbon in the liquid metal. The reactions as they occur in unalloyed liquid iron, and their respective equilibrium constants are written as follows:

Jan 1, 1937

By Bert Sandell

MUCH has been said and written about the various uses of die-castings, their applications in the various industries and their advantages and disadvantages. Examination of this literature, however, fails to disclose any data concerning the effect of temperature upon any of the physical properties of die-casting alloys. The uses and applications of die castings are so numerous, and of such a varied nature, that far too lengthy a manuscript would be required to list all of them. Brief mention of some specific cases will suffice to illustrate the temperature ranges in which certain die castings function. Automobile hardware, such as hub caps, door handles, radiator caps, etc., can be used as one example. Castings of this type are constantly exposed to varying climatic conditions, temperatures ranging from below zero to upwards of 100° F. Refrigerator parts, such as ice-cube trays, etc., form another example. Approaching the other temperature extreme, we encounter conditions such as are found in kitchens in which oven-heat indicator parts, cooking utensils, waffle grids, etc., embody use of die castings, where temperatures as high as 500° F. are often met with. Because of this variation in service temperatures, it was felt necessary to ascertain the effect of these temperatures upon the physical properties of die-casting alloys. The Charpy impact test was chosen first because of its simplicity, and because of the fact that brittleness is more likely to be objectionable in die castings than hardness or other physical properties.

Jan 1, 1932