Cast Brass Research Articles

The Art Market in Cameroon and the Central African Empire

The Art Market in Cameroon and the Central African Empire

Grain Refining and Hot Tearing in Brass Castings

Grain Refining and Hot Tearing in Brass Castings

An Investigation of Air-leakage between Contact Surfaces : 3rd Report, On Case in which Cast Iron and Brass were used as Specimen

In the last reports, assuming that the surface irregularities of specimens were isotropic and had a form of similar truncated cone whose deformations were elastic, plastic and elasto-plastic, the analytical solutions of equivalent gap for the fluid leakage between contact surfaces were verified with the experimental results using a lapped carbon steel. In this paper, the specimens, which are finished by lathing and grinding, are axamined. The results obtained can be summarized as follows : (1) In the case in which the phenomenon of leakage was a radial and sector flow, the experimental values of equivalent gap obtained by assuming the surface roughness as anisotropic were in agreement with the analytical values with deviation about 8 %. (2) The characteristic curves of parameters a and b for the carbon steel listed in the 2nd report can be applied for the materials tested in this experiment.

Water-soluble products from nitration of mineral oils as inhibitors of aqueous corrosion

The caustic-neutralized water-soluble compounds formed as byproducts in the nitration of mineral oils of relatively low molecular weight (transformer and industrial oils) are efficient inhibitors of the aqueous corrosion of cast iron, steel, and brass.

High Volume Pumping with Sucker Rods

Abstract Recent studies have shown that often large fluid volumes can be lifted by sucker rods with great effectiveness from shallow to medium-depth wells. Wherever feasible, significant redaction in cost of elevating a barrel of fluid may be realized by the operator. The advent of longer stroke units with improved geometry, larger speed reducers and bottom-hole pumps, as well as the new high-strength sucker rods, make high volume rod pumping a practical and economical achievement. Past applications of this type generally have been considered only for bottom-hole centrifugal pumps. This paper reviews some field studies and emphasizes the practicality of high volume production with sucker rods. Introduction A century ago the almost universal mechanism for artificially lifting fluid in an oil well was the standard rig-front. A wooden walking beam drove a string of hickory sucker rods, often called "well poles", as many as ten 15-in.- strokes/minute with the maximum tensile stress of the rods about 12,800 psi. The bottom-hole pump was cast iron or brass with the barrel approximately 1 1/4-in. in diameter, and the well depth ranged from 500 to 1,000 ft. The torque capacity of the band wheel and flat-belt speed reducer ran only a few thousand inch-pounds, and the unit's structural capacity was from 1,000 to 1,500 lb. Today, the structure of a modern pumping unit with its 240-in. maximum stroke reaches higher than the wooden drilling and servicing derricks of those early days. Its structural capacity exceeds 47,000 lb, with a torque rating greater than 2.5 million in. lb. The plunger diameter of some bottom-hole pumps (casing-type) runs as high as 5 3/4 -in. Perhaps the greatest improvement is in the sucker rod, which now has a tensile stress of some 140,000 psi. Today practice sucker rod pumping approaches 13,000 ft, and capacities of 5,000 and 6,000 B/D from shallow to medium depths are handled with ease. Volumes as high as 9,500 B/D are entirely practical with modern sucker rod pumping equipment. Comparing the modern sucker-rod system with its counterpart of 100 years ago produces some startling figures. The structural capacity of the modern unit has increased nearly fifty-fold, the torque capacity perhaps a thousand-fold, the area of the bottom-hole pump over 20 times; the stroke length nearly twenty-fold; and maximum rod tensile stress nearly 12 times. With the increased stroke length, even the maximum rate of polished rod travel per minute has increased five or six times. Since all of these are compounding increases, the sucker-rod pumping unit of today has the capacity for producing massive fluid volumes from relatively great depths.

On the Relationship between the Mechanical Properties and the Alloying Elements of High Strength Brass Castings

On the Relationship between the Mechanical Properties and the Alloying Elements of High Strength Brass Castings

黄銅鋳物の脱亞鉛について

The object of the work was to determine the effect of some added elements to 65/35 and 60/40 brass castings on their dezincification properties in NaCl solution.It was demonstrated that the quantitative measurement of dezincification could be performed by the method of colorimetric determination using the photometer, and that tin was most effective as an addition alloy element to protect the dezincification, though manganese and aluminum were slightly effective, while iron was assessed as an undesirable constituent.The 65/35 cast plain brass which was consisted of α-monophase was immunity for the dezincification phenomena showing the typical chemical corrosion.Micrographic examination of corroded surface has shown that the β-phase was locally attacked at the first stage of corrosion in α/β or β/γ alloy systems, then the dissolved copper was redeposited on the copper rich cathode which was formed on β phase.

Polishing of Metal by the Barrelling Process

Practical methods for the barrel grinding and/or barrel burnishing of malleable cast iron, steel, brass, and nickel silver parts and of zinc-base die-caatings, and for deburring and cleaning, are d...

放電研磨の研究

The purpose of the research is to find out the working conditions in the grinding of Tungalloy G by Electric erosion. The direct current is used as electrolytic source, and a condenser is inserted parallel to both electrodes. The sample is connected to the positive side and a rotating wheel made of cast iron or cast brass to the negative side of the circuit; and kerosene or water is fed between them. The experimeuts are carried out by changing various conditions aff ecting the amount of metal grouned per unit time and the roughness of the surface finished.

The screening of transformers against electromagnetic "pick-up" effects

Measurements made upon the reduction of pick-up obtained by enclosing an intervalve transformer in boxes constructed from various materials are described. It is concluded that high permeability alloy 1/16 in. thick is of the greatest all-round value for screening transformers, particularly as regards the low frequencies. At medium audio-frequencies ¼ in. thick screens of other materials such as cast iron, aluminium or brass are also of value.

The Influence of Cutting Fluids on Tool Life in Turning Steel

Abstract Several reports, listed in this paper as a selected bibliography, already have been presented by the Subcommittee on Cutting Fluids. The first report deals, in general with the characteristics of cutting fluids (1); the second paper presents the results of an industrial questionnaire regarding the use of cutting fluids (2); and the balance of the reports (3, 4, 5) present experimental data dealing with the performance of cutting fluids when drilling and sawing various steels, cast iron, malleable cast iron, brass, and aluminum. The Committee now proposes a series of experiments by which further data may be obtained as to the use and properties of cutting fluids. It is hoped that eventually these data may be correlated to indicate the principles underlying the commercial use of cutting fluids. The object of this paper is to present the results of a series of tests in which various cutting fluids were used in turning steel. It is shown that the exponent, as well as the constant, in the formula VTn = C may change as the cutting fluids are changed, other conditions remaining constant.

高温度に於ける鋼並に鑄鐵の熱的傳導率測定と青熱脆性に就て

Some physical properties such as thermal conductivity, expansion, and drop-shock hardness are measured up to 700°C for some metals given below and their heat capacity, true specific heat were obtained from the results measured above. The metals tested are: (1) seven kinds of carbon steel of 0·04%C to 0·88%C (2) 3-grey and 4-white cast irons (3) a common brass of 70% copper and 30% zinc. Both the thermal and temperature conductivity were obtained in each measurement by heating sine periodically on one side of each specimen, quite different in heating manner of specimen from the previous way used for measuring the thermal conductivity. It has been further prove that both thermal and temperature conductivity of metal are measured more precisely by the periodic way than usual direct-heat-flow system hethertofore generally used. For the measuring of expansion, two micro-telescopes with 1/100mm reading scale in eye-piece were used, and for the hardness at high temperatures the Martell's system constructed in our laboratory spplied. From these measurements and their following results, a certain deviation or anormality covering a certain specified temperature for each metal, is found to exist commonly in all properties measured above. The temperature of such a maximum deviation has been proved to exist in 300°C-330 for steel, 350°C for both cast iron and brass. Further, it has been seen that the reduction of the sum of space among the grains of metal due to the expansion by heat is to be the direct cause of the Blue-Shortness of each metal, and all the other anormality is only as its secondary effect.

EFFECT OF VARIATIONS IN THE ALUMINA‐SILICA RATIO IN FUSED REFRACTORY MATERIALS UPON RESISTANCE TO METAL OXIDES*

ABSTRACTSolid pieces of electrically fused material, varying in composition from 630%, alumina 37%, silica to 100% alumina, of the ordinary abrasive grade were heated in contact with cast iron and brass which were allowed to oxidize and attack the refractory. The least attack was found in the case of the iron with 80% alumina 20% silica, and in the case of the brass with straight alumina, although the 80% alumina 20% silica was not greatly inferior.Bonds were developed for the materials thus selected and confirmatory tests were made on crucible fusions. Arc and powdered‐coal furnaces lined with the bonded materials have proved successful.

329. Benin Brass Castings and Handicrafts in the Cameroons.

329. Benin Brass Castings and Handicrafts in the Cameroons.

An experimental study of the flow of water in pipes of rectangular section

During the course of study, by the authors, of the flow of fluids in the small clearances which exist between the moving and fixed parts of certain machines, an accurate knowledge was desired of the range over which the equations of viscous flow could be applied. An exhaustive search revealed an absence of any record of experimental work which could be of direct assistance. An investigation was accordingly undertaken with the object of obtaining the desired information, and as the preliminary results were of an interesting and unexpected nature, the experiments were extended to cover the whole range of velocities and dimensions permitted by the apparatus. They have shown briefly that the lower critical velocity (as ordinarily understood) for flow between flat plates occurs at a value of the Reynolds number about one-half that found for pipes of circular cross section, if the linear dimension in that number is the distance between the plates and the diameter respectively. For velocities well below this limit there is evidence, however, of a distinct deviation from true viscous flow if initial disturbing factors are present, and the influence of such disturbing factors does not disappear entirely until a second well-defined limit is reached, which has a value of about one-tenth of the lower critical number. It would appear that below this limit eddies do not exist at any point in the pipe, and the flow is truly viscous. The suggestion is accordingly made that there may be three distinct types of flow: ( a ) one in which eddies cannot exist, corresponding to truly viscous flow; ( b ) one in which eddies may exist, due to an initial disturbance, but cannot be sustained in the pipe, the initial eddies therefore ultimately disappearing; and ( c ) one in which eddies once generated will be maintained without decrement throughout the pipe, corresponding to truly turbulent flow. The use of a channel of rectangular cross section for a study of the fundamental laws of the flow of fluids possesses advantages, in point of simplicity, which were recognised at once by Reynolds in his classical research into the cause of instability of flow. In the form in which this channel is used by the present writers, an additional and important advantage is obtained over the circular pipe by the fact that the controlling dimension may be varied over a wide range whilst retaining the same surfaces as boundaries. It is, in essentials, an adjustable pipe. The upper plate A (fig. 1) and the lower plate B are brass castings suitably drilled to provide inlet and outlet passages and pressure measuring points. The surfaces forming the pipe are hand scraped to a surface plate, and are separated at the ends by brass foil shims of suitable thickness, thus providing a passage between the inlet and outlet ports. The sides of this passage are closed by the plates C and D, very thin rubber insertion providing a watertight joint. All parts are sufficiently robust to reduce distortion under pressure to an amount found to be negligible.

IX. On the ultra-violet spark-spectra of some of the elements

In the following paper an account is given of an investigation on the extreme ultra-violet spectra of a number of the elements. In the preliminary part of the work the spectrograph described by Prof. Mclennan* was employed, together with a Rowland grating of 100 cm. focal length, having 6273 lines per cm. and an area 5·4 cm. wide and 7·8 cm. high. The source employed was a water-cooled arc chamber in which the electrodes were tipped with the metals whose spectra were required. This apparatus proved to be unsuitable, for the reason that the spectrograph, as constituted, did not allow the source to be brought nearer the slit than about 1 foot. This resulted in very feeble illumination and consequently long exposures were required, which lasted in some cases for 10 hours. Such exposures were found to be necessary, not only because the source was too far removed, but also because the angular aperture through the slit included only a band across the centre of the grating about 2·5 cm. wide. Some of the modifications which were made in the spectrograph greatly improved its efficiency. A short description of these follows. Fig. 1 shows a horizontal plan and fig. 2 a vertical elevation of the spectrograph and spark chamber, as at present constituted. The body of the spectrograph A, B, was designed for a grating of 1-metre focal length and is about 130 cm. long over all. The enlarged portion A, which encloses the grating G and its mounting, is 22 cm. in diameter and 30 cm. long. The smaller portion B has a diameter of 15 cm. As shown in fig. 2 the opening above the grating is closed by a brass cap which fits into a tapered ground joint. The opening gives ready access to the grating for adjustment, and when the cap is placed in position, with the bearing surface slightly smeared with “Airtite” and the groove shown in the figure filled with the same, a perfect seal is obtained. The ead of the spectrograph nearest the grating is closed by a plate-glass window R, 2 cm. in thickness, set into a cast brass ring, the joint being made air-tight by a hard wax. This window enables one to see that the source, slit and grating are properly aligned.

Switchgear standardization

General principles underlying standardization.Standard test pressure for switch and controlling gear.Conductivity of current-carrying alloys : specifications of cast brass and gunmetal.Knife switches : millivolt drop at contacts.Suggested standards for back connection studs and nuts.Oil switches and circuit-breakers : urgent necessity of standard oil-switch rules in view of the position in foreign countries; breaking capacity; connection between breaking capacity and quantity of oil.Resistance and reactance type of oil circuit-breakers.Length of break of oil switches.Single and multiple tanks on oil switches.Amount of oil required for oil switches.Speed of operation of oil circuit-breakers.Air-break circuit-breakers : millivolt drop at brush contacts.Cut-outs: National Electric Code enclosed cut-outs; short-circuit tests on cut-outs; time element of cut-outs; determination of normal fusing current.Resistance wire: suggested British copper-nickel standards.Motor starting-gear; liquid starters.Copper strip connections of switchboards: suggested standard sections; temperature rise; millivolt drop of bolted contacts.Switchboards: cellular principle; suggestions put forward by Swiss Electrotechnical Society.Lightning protective gear : horn gaps; choking coils; lightning arresters.