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The properties of a cast metal object are largely determined by how it solidifies and with the events that take place as the molten metal cools in the mold, cooling being critical in the process. Advances in understanding these events make it possible to control them. The way is opened to new forming methods including continuous casting, die casting of ferrous metals and the casting of composite materials.

A new process for the preparation and casting of metal-particulate non-metal composites is described. Particulate composites of ceramic oxides and carbides and an Al-5 pet Si-2 pct Fe matrix were successfully prepared. From 10 to 30 wt pct of A12O3, SiC, and up to 21 wt pct glass particles, ranging in size from 14 to 340 ώ were uniformly distributed in the liquid matrix of a 0.4 to 0.45 fraction solid slurry of the alloy. Initially, the non-wetted ceramic particles are mechanically entrapped, dispersed and prevented from settling, floating, or agglomerating by the fact that the alloy is already partially solid. With increasing mixing times, after addition, interaction between the ceramic particles and the liquid matrix promotes bonding. Efforts to mix the non-wetted particles into the liquid alloy above its liquidus temperature were unsuccessful. The composite can then be cast either when the metal alloy is partially solid or after reheating to above the liquidus temperature of the alloy. End-chilled plates and cylindrical slugs of the composites were sand cast from above the liquidus temperature of the alloy. The cylindrical slugs were again reheated and used as starting material for die casting. Some of the reheated composites possessed “thixotropy.” Distribution of the ceramic particles in the alloy matrix was uniform in all the castings except for some settling of the coarse, 340ώ in size, particles in the end-chilled cast plates.

SummaryOperating parameters of the cobalt-containing Ni-Speed electrolyte are described for producing low stress deposits suitable for electroforming applications. The mechanical properties of these deposits have been determined and their successful application in the zinc die casting industry is described.

A procedure for the direct polarographic determination of aluminium is described, with particular reference to zinc-base die-casting alloys. Interfering elements are removed by electrolysis of a solution of the alloy in a mercury-cathode cell. The solution is polarographed at a carefully controlled pH in a supporting electrolyte of magnesium chloride and sodium sulfate of appropriate concentration. The precision and accuracy of the method are shown to be satisfactory by the analysis of standard samples from three different laboratories.

This paper deals with the shrinkage of the casting in the molds with core. We analysed the casting process by time range to know the temperature of casting when it was ejected out from the core, because the shrinkage of casting is quite up to the temperature of casting.The temperatures were as follows:(1) Shringage varied according to the die temperature.(2) It varied according to the time interval in which the casting was laid in the die.(3) It varied according to the thickness of the wall of casting.(4) It varied according to the temperature of die cavity surface.From the above result, we could determine the shrinkage coefficent of the die to be designed. In the previous report the calculated shrinkage coefficent differed by 0-1.6×10-3 from the measured value.So that we must correct the previous formula and set up a new shrinkage formula as follows: ΔL=α(ts-20)-αf(tf-20)+σt/Et α: Expansion coefficent of casting. ts: Temperature of casting when it was ejected out. αf; tf: Expansion coefficent and temperature of die. σt, Et: Elastic limit and Young's modulus of casting at ts.From the present experiments we realized that this formula was more exact than the previous one.

In casting Aluminium alloys now used, most important and effective adding elements are Cu and Si as shown in SAE 306, 307, 303, 326, 329, 330, 331, and 332 type alloys and Fe is unavoidably contained. Then these casting alloys were regarded as Al-Fe-Si-Cu system alloy. In these alloys, Fe is most disliked becouse it decreases the mechanical properties and has the tendency of forming so-called "hard spots" in die casting. Al-Fe-Si constitutional diagram is well known as shown in Fig. 1. by H. W. L. Philips and P. C. Varley, but Al-Fe-Si-Cu diagram containing practical Cu content has not yet been studied in spite of its importance for common casting Aluminium alloys. It this report Al-Fe-Si-Cu diagram containing 4% of Cu which is most general content is studied using the samples slowly cooled from molten states in isolite mould which was conformed satisfactory for the purpose of determining the primary crystalization as compared with very slowly cooled specimen. Base alloys shown in Table 2 were made from 99.7% Al and mother alloys shown in Table 1 and then samples which contain 4% of Cu and constant Si content but have variation of 0.1% of Fe are made as shown in Table 3. Microstructres are shown in Photo. 100-169. From these results Fe limit. where Fe compound crystalizes as primary in Al-Fe-Si-Cu system containing 4% of Cu is determined as shown in Table 4. and Fig. 2. From this study, we understand that in the case of containing 4% of Cu, Fe limit of Al alloy containing 4-8% of Si is decreased about 0.5% as compared with non Cu and we must take care of decreasing of mechanical properties and formation of so-called "hard spots."

The growing demand of die-casting in industry and for household articles is very great, and hence the author studied die-cast aluminium alloys and compared the mechanical properties with the gravity cast specimens of the same alloys. For the as-cast state, die-casting has superior qualities to gravity casting, and no beneficial eftect is noticed by heat treatments, but annealing, if neccessary, should be made at 100-200°.

Among the finishing of zinc base alloys used for die casting, the electroplating has been applied for general uses. Owing to the intercrystalline corrosion and surface corrosion of zinc alloy die castings, the metal coating must have the thickness sufficient to prevent their corrosion. Therefore, we investigated on the direct nickel plating and copper plating, and we could find that it was necessary to have the thick and compact copper coating, in order to prevent the corrosion and make the mass production.

Reproducibility of ion intensities, relative senisitivities of various elements by a spark source mass spectrograph were invesigated, and iron and steel were analyzed. Reproducibilities in repeated measurements with constant source parameters were5-35% in coefficients of variation, and in separate measurements6-70%. It seemed that inhomogeneity of emulsion and samples did not attribute to the fluctuation. Relative sensitivities(platinum was unity)of various elements in low alloy steel, nickel base temperature alloy, copper alloy, aluminum alloy, zinc base die casting alloy and stainless steel were 0.17-24.6. They were not related with sample materials, but with heat of sublimation of each element, however, some problems in reproducibility and measuring condition remain to be resolved. More accurate determination was performed by calibrating with relative sensitivities in analysis of standard samples stainless steel. Commercial pure iron was analyzed, and comparison with results in wet chemical methods was tried. The limit of detection was0.005 Reproducibility of ion intensities, relative senisitivities of various elements by a spark source mass spectrograph were invesigated, and iron and steel were analyzed.Reproducibilities in repeated meas urements with constant source parameters were5-35%in coefficients of variation, and in separate measurements6-70%. It seemed that inhomogeneity of emulsion and samples did not attribute to the fluctuation.Relative sensitivities(platinum was unity)of various elements in low alloy steel, nickel base temperature alloy, copper alloy, aluminum alloy, zinc base die casting alloy and stainless steel were0.17-24.6.They were not related with sample materials, but with heat of sublimation of each element, however, some problems in reproducibility and measuring condition remain to be resolved. More accurate determination was performed by calibrating with relative sensitivities in analysis of standard samples stainless steel. Commercial pure iron was analyzed, and comparison with results in wet chemical methods was tried. The limit of detection was0.005-1ppm.

There are two sorts of hard spot which appears in the products of die-casting, one is of metallic and the other of non-metallic nature. The former is chiefly of primary crystals of various intermetallic compounds containing iron and manganese, as shown in Table. 1 and Photo. 1, a-h.The latter or hard spot of non-metallic nature has also been detected in some products of diecasting (Photo. 4-Photo. 8), as the causes of which the reaction products between the material of crucible or fire-clays and the molten alloy as well as the slag itself contained in the crude silicon have been pointed out.Some remedies according as the causes of hard spot have been suggested.

In 1970 only two manufacturers existed in the United States, namely the American Machine and Foundry (AMF) Versatran and the Unimation, Inc. Unimate. These robots, still in the forefront today, were just emerging and gaining acceptance in 1970, with approximately 200 industrial robots at work in the U.S., and an amassed 600,000 hours on the job, a negligible amount considering that the total U.S.blue collar work force puts in 200 million hours each day. However more than seventeen types of robots are now available in the U.S. at least twelve of which are manufactured in this country. They range from minirobots with payloads of only a few ounces and reaches of less than a foot to the larger universal robots which can handle payloads of up to 150 lbs., reach 3 ½ ft., and move at speeds up to 3 ft./sec. Recent additions to the U.S. arsenal are the Burch Control robot with a payload capacity of 6000 lbs. Industrial robots are easily reprogrammable, operatorless handling devices that can perform simple, repetitive jobs that require few alternative actions and minimum communications with the work environment. They are well suited to handling parts that are red hot or feezing cold, and they can function in corrosive, noxious or extremely dusty atmospheres that would be injurious to human beings. Passage in the United States of the Occupational Safety and Health Act of 1970 has provided strong impetus for the use of industrial robots. As discussed in a recent article in Assembly Engineering Magazine (Ref.1), the Act currently states that a human being cannot place his hands within punch press dies to load or remove parts, and it is imminent that OSHA standards will be extended to cover other fabricating and assembly machines, such as staking presses, spot welding machines, riveting machines, holding and clamping equipment, electron component Inserting equipment, and automatic screwdriving machines. In many cases the cost and time to retool an existing operation to conform to the standards will be prohibitive compared to the cost and time required to purchase and program an industrial robot to perform the potentially dangerous operations.

Describes aging changes in Zn-25 pct Mn-15 pct Cu-0.1 pct Al experimental die casting alloy in temperature range 60–185°C. The exponential increase of aging rate with temperature is used in predicting lower temperature behavior, and the analogy between aging and diffusion behavior is noted. Q values derived from aging rate curves show some agreement, ranging from 18,400 to 21,200 cal per g atom for the various property changes studied.

The behavior of die lubricant during casting in a diecasting process has not been fully investigated. Small amounts of HCl solution of radioactive H/sub 3/PO/sub 4/ were added to the die lubricant mechanically, and the radiographs of the surface and the inner part of the casting were taken after solidification. Comparatively large amounts of radioactive lubricant were applied. Zinc alloy ZAC No. 1 was cast in the dies. The results obtained were as follows: (1) The lubricant travelled with the flow front of the molten metal through the die cavity and accumulated at the place where the movement of molten metal came to end or remarkable turbulent motion occurred. (2) A large amount of lubricant was entrapped in the casting and distributed comparatively uniformly. (3) The chilled layer of casting occluded hardly any particles of the lubricant. (4) The entrapping of lubri cant increased with the rise of casting temperature and with the increase of gate area. (auth)

For the manufacture of intricately-shaped parts, it is advisable to cast thermoplastic suspensions fired at 1450° of industrial alumina ground down to particles finer than 2 microns.

An analysis of the effect of certain physical properties on the solidification behaviour of a die casting shows that typical die-casting porosity could be explained through a bulk modulus hypothesis. Subsurface porosity could be reduced by modifying the composition of the alloy and central defects can be controlled through increased packing pressure and choice of alloy composition.

This report an account of an investigation into the fundamental features of the internal standard method of spectrographic analysis, with special reference to the determination of lead in high purity zinc using the direct current art, which requires the closest control. It corner from the lead anodes used in. tire electrolysis and since their condition, with respect to the transfer of lend from anode to cathode, changes continually throughout the cycle from one cleaning period to the next, the grade of line from any particular row of tanks in the tankhouse must be determined daily, if the cathode sheets are to be sent to the correct molting furnace. For zinc of die casting quality, the British Standards Specification No. 1003 allows only 0·003% each of lead, cadmium and iron. The latter two impurities are easily kept less than 0·001% in the electrolytic line process, but lead requires control. Obviously to keep the tonnage of this grade of mental as high as possible, the lead is run as close to the limit as is safe. The margin of safety depends upon the accuracy of the available methods of analysis.

In order to improve quality of the die-cast, it is important to control heat (temperature) together with the design of dies, character of die-casting machine, etc., and we studied the effects of shot number and water cooling on variation of distribution of die-temperature.A method of qualitative improvement for uniform temperature of cavity might be found and an equation for efficiency of water cooling might be proposed by the measurement of die temperature.

The object of this study was to know the effects of various die casting conditions such as injection pressure, locking force, injection speed, sleeve temperature, chill period, molten metal temperature, automatically controlled mold temperature, and injection speed ratio on the mechanical properties of ADC12 alloy products (ASTM E8 test bar). The die casting machine used in our laboratory was of DC 250 type, which can record the measuring results of the above casting conditions and also can control the mold temperature. The results obtained were as follows:1. Injection pressure and locking force gave almost no effects on the mechanical properties of ASTM test bar.2. Mechanical properties decayed at extremely high or low injection speed, but they were improved with the increase of injection speed, because the pressure increased immediately after filling molten metal into the cavity, whereby beneficial effects were given on the strength of the products.3. Higher casting temperature (680°C) was recommended for better mechanical properties from the viewpoints of fluidity and castability of molten metal.4. Mechanical properties decayed with the elevation of mold temperature.5. They were the best at the injection speed ratio of 1 to 1.6. Mechanical properties of ASTM test bar, were independent of the chill period of 5-10 seconds.

There are many problems to solve in connection with the manufacture of diecast rotors that require the co-ordinated efforts of the design and manufacturing engineers. Forcing molten aluminum under high pressures into the rotor slots causes excessive stray load losses unless the laminations are insulated properly and strain relieved, and the slots insulated from the cast aluminum conductors. Heating processes may be necessary after machining the surface. It is also necessary to select the best and most economical die casting methods, equipment, and furnaces. The moulds properly gated, holding pressure, pressure on the die-casting metal, and temperature are all important to the production of homogeneous die cast rotors free from impurities. With proper control, die-cast rotors can be manufactured to relatively close limits of rotor resistance and with the stray load losses reduced to a satisfactory value resulting in satisfactory performance, and generally at a lower cost than copper cage rotors. This paper explains the cause of the stray load losses, processing to reduce them, and suitable test methods. There are curves showing the effect of excessive stray load losses upon performance, results of various processes, and illustrations of die-casting methods and diagrams of equipment for testing die-cast rotors.

In the previous paper on the shrinkage formula of die casting and gravity casting, we explained the nature of shrinkage, and said that it must differ in the case of the casting with cores from that of the casting without cores.In this paper we tried to ascertain whether the shrinkage formula was corret or not and whether the nature of shrinkage deduced from the formula was in accord with the results of the experiment.This experiment showed that the shrinkage coefficient of castings is nearly the same as the one inferred from the shrinkage formula.But in some castings slight differences were visible. The cause of these differences is not yet found.The nature of shrinkage coefficient which we came to know was:(1) On the casting with cores.(A) Shrinkage coefficient varied according to the temperature of each die and casting.In the early process of casting when the temperature of die and casting was low, shrinkage coefficient was small, and later as the temperature rose coefficient also became large, and in the last stage it became nearly constant.(B) Shrinkage coefficent was influenced by the shots number per hour.(C) Casting temperature did not give direct influence upon the shrinkage coefficient, but generally shrinkage coefficent became larger with raising the casting temperature.(D) Shrinkage coefficient differed according to the surface condition of the dies, that is, it was small in the earliest period but after about 10 thousand shots it became larger, because the die cavity surface was covered with oil and an oxidation film.(E) Shrinkage coefficient varied in every part of the same casting because the temperature of a die or a casting differed according to each part of the die or casting.And the products could not have exactly the same figure of the die.(2) On the casting without cores.Shrinkage coefficient became linearly small in proportion to the rise of die temperature and was not influenced by the casting temperature.

Pressure die casting in zinc alloy is a method of production eminently suited for components required in very large numbers. Particularly when they are to be plated, strict attention must be given to the design of the die and to conditions of casting if die castings of a suitably high standard are to be produced. Freedom from sub-superficial porosity and a flawless surface are required—the smooth matte “hardware” finish. It is desirable that the plater be consulted at an early stage in the designing of a die casting if his interests are to be safeguarded, otherwise unnecessary difficulties may be created for him. Preparation for plating should imply a minimum of emery bobbing, light pressure in polishing and only a brief electrolytic cleaning in mildly alkaline solution. On significant surfaces a primary deposit of copper not less than 0–0003” in thickness is necessary. The copper deposits most satisfactory for bright nickel plating are not necessarily those of highest lustre.

The mechanical properties of die-castings, the effects of casting conditions upon these, and the relation between the microstructure and the strength of the products have been studied. The results are summarized as follows.1. The mechanical properties of the die-cast tensile specimens were sensitively affected by the casting temperature, but not by the die-temperature.2. The injection pressure affects upon the mechanical properties. A sufficiently high pressure is needed for improving the strength.3. The proof stress at 0.2 percent offset of the silumin die-cast tensile specimens lies almost within the range between 12 and 14kg/mm2, and was nearly constant regardress of the tensile strength when its strength was above 17kg/mm2.4. The average elongation in 50mm of the above-mentioned specimens was 2.8% for the nominal tensile strength (24.5kg/mm2 of ASTM), which was lower than the nominal value.5. The relation between the microstructure and the mechanical properties of the die-cast automobile parts were examined, but the difference of strength which depended on the micro-structures could not exactly be decided.6. The roughness of surface of the die-casting and the die cavity was tested. It is considered from these tests that the roughness of surface of the davity is propertional to numbers of shot.

A procedure has been developed for the determination of tin in high-purity zinc and zinc die-casting alloys present in amounts from 0.001 to 0.2%. The samples are dissolved in sulphuric acid, oxidized with hydrogen peroxide, precipitated with cupferron, redissolved and reduced, and finally the tin is determined polarographically. By this method, the tin can be determined with an accuracy of ± 2.0% when present in amounts less than 0.005%. A method is now available for the routine polarographic determination of trace amounts of copper, lead, cadmium, and tin in high-purity zinc and zinc die-casting alloys with a high degree of accuracy and precision.

Summary A titrimetric determination of magnesium in die casting alloys is described; it is unaffected by impurities commonly present in such alloys. The visual titration with EDTA is carried out after removal of phosphoric acid with an anion-exchange resin. The aluminium present in the alloy is determined gravimetrically by a special precipitation method.

An electrical resistance method was adapted to test both aluminum and zinc die cast materials in tap water, detergent solutions, and detergent solutions plus bleach. Since the rate of attack of these materials in aqueous media is sometimes low, with consequent small resistance changes, low resistance circuitry is necessary. Plotted data show comparative corrosion resistance of zinc and aluminum materials and establishes the technique satisfactory for the intended use. Conclusions reached are: (1.) In all three test media the aluminum-silicon alloy No. 13 and the aluminum-silicon-magnesium alloy No. A360 are superior to the aluminum-copper-silicon alloy (A380) and the zinc die-cast material (D3), (2.) In solutions of detergent (not chlorinated) a reasonable amount of inhibition is conferred by the silicates which are present, (3.) No. 13 (aluminum-silicon) alloy appears to offer the maximum resistance to corrosion and No. 360 (aluminum-silicon-magnesium) alloy the next best. (4.) The method offers a satisfactory laboratory means of comparing corrosion resistance of metals. 2.3.5

Pistons were made by low-pressure die casting process. Aluminium alloys used for this process were JIS AC8A, AC8B and AC3A. The main defects occurred were gate solidification, misrun, internal defect, surface defect, and various kinds of shrinkage cavity, etc. The causes of defects were investigated except for the gate solidification and misrun. The result was that these defects were closely relevant to the die mold temperature and pouring speed.

Surface treatments were conducted on aluminum alloy ADC 12 by chemical tin plating, electroless nickel plating, molybdenum disulfide coating on zinc phosphating, and hard anodizing. Then, frictional and wear resistances of the above treated surfaces were studied.The results obtained were summarized as follows.(1) These treated surfaces showed particularly lower coefficients of statical friction by preventing adhesion of metallic substances.However, the combinations of the platings of the same kind, such as tin plating with electroless nickel plating, showed higher coefficients of statical friction.(2) Molybdenum disulfide coating had the most remarkable effects on lubrication and tin plating was the second.(3) It was found by wear test that these treated surfaces showed higher wear resistances than those of no treatment.(4) Molybdenum disulfide coating showed the highest wear resistance.(5) Electroless nickel plating and hard anodizing showed the next highest wear resistance. However, these surfaces considerably weared out the other contacting metal when they were combined with other metals. In particular, hard anodizing had remarkable effects.Therefore, it was found that anodizing is not a proper surface treatment if the treated surface is used in combination with a soft metal such as an aluminum alloy.(6) Tin plating was not very effective in surface treatment for rotors, because it gave thin film showing low wear resistance.On the other hand, tin plating was very effective for stators, because of higher wear resistance. The combination of tin plated surface on the stator and molybdenum sulfide coating on the rotor showed higher wear resistance than any other combinations.